Timing belt directions are below. I read in forums that the pulley and tensioner are the failure points. They leak the internal lubrication and can seize. So change these along with your belts.
It is possible change the timing belt without taking off damper but it is quite a fishing trip to clear several tight spots. Some notes on this in the links below. The above video also shows the blockage points after the damper is removed. Take a closer look.
Here is a diagram showing the location of that plastic piece held by the 2 10mm bolts as well as some nice notes about doing this job properly.
Some of my misc notes and where the tight spots are
Here are some pictures I posted on checking my timing marks. Maybe a good visual reference before you start.
The front timing belt cover (not the upper one covering the cam gears but the front one that covers most of the belt and the pulleys) has a couple of plastic tabs down the midde and bottom that fits into a plastic frame on the front of the engine. I have no idea how to line these up and get it in properly and they break off easily. A couple of mine broke but it didn't really change the fit as this covered has a bolt to hold it in anyway. I did search and remove the broken tabs so it doesn't somehow rattle around and cut my new belt :)
Lining Up Timing Marks
Volvo's cam timing mark positions are on the plastic cover just above the cam gears. But the gap between the marks on the gear and the marks on the cover is over an inch long and depending on which angle you look at, there isn't really a "dead on" alignment. Furthermore, the crank shaft marker is buried down pretty and barely have a sliver of opening to see it clearly.
I had no problems getting my timing marks right. But from what I have read, others seems to get 1 or 2 tooth off on their repair. You want to do the "Check" section of the above replacement direction carefully. There are a couple of issues you likely will face.
1. There are 3 timing markers, 2 on the upper cam cover and one on the crank itself. My timing discussion thread above contains the pictures to these. The markers on the upper cam cover timing cover is far enough (about an inch or so) from the marker on the cam itself that it doesn't provide a visual "dead on". Mine at least seems ever so slightly off depending on which angle you look at. I think the best correct angle is perpendicular to the timing cover (which is slightly off horizontal to the ground) You can just rotate the crank every so slightly back and forth after you get the belt on and you can see how all three timing marks line up. I make sure the crank mark is dead on and then look at the cam marks. I then imagine what if I was 1 tooth off in either direction on the cam and visualize how far off would the cam marks be against the timing belt cover. This tells me if I have the best tooth chosen since the cam timing marks are hard to see dead on. I've read some people have cam lockers that prevents movement while belt is off that makes it fool proof (I guess you stilll don't want to move the crank tho).
Here is another thread with a good diagram of the timing mark on the crankshaft gear.
2. It also seems hard to fit the belt between the two cams without moving one of the cam a little. Perhaps the old belt is a little stretched. It is okay to move the cams slightly... Just make sure you get all 3 timing marks are set properly.
Other methods to line up timing marks are to use a cam locker or the following link with a nifty usage of a ruler.
Here is an inventive method by counting the teeth between the cams
Here is another inventive method by marking the old belt and transfer the marks to the new belt. Basically a way to count teeth. See post #7 and #8
Setting the Tensioner
The tensioner needs to be set while the timing belt doesn't have any slack in the natural engine rotation direction. Remove the slack by rotating the crank shaft clock wise. If you rotate it counter clock wise (for example, checking the top timing marks), you need to make you to rotate it clock wise even just slightly to remove the slack in the rotatioal direction.
Once the tensioner is setup properly (indicator in the middle of the goal post at typical cold temperature of 25C). The indicator will stay centered when rotating the crank in the clock wise direction. If you rotate the crank in the counter clockwise direction, the indicator with shift clockwise because belt would have slack in it and the tensioner moves to take up this slack.
Reinstalling the Plastic Timing Cover
There are tabs on this cover that clips into the plastic housing behind the timing belt on the engine. I think the bottom tabs are pretty easy to break so be careful. Go from the opening in the wheel liner to clip it on properly while someone help you from the top.
Variable Valve HUB
The 01-02s have variable valves (VVT) on the exhaust cam while the 03+ (turbos) have VVT on both intake and exhaust cam. I've never had to deal with the VVT as my cam gears didn't move during my timing belt job. The following link suggest you need to turn 1/4 turn CW and then CCW after linking up the timing marks to relax an internal VVT HUB spring
Note the serpentine belt tensioner roller would be good to replace at the same time. I had one that went out maybe 20k miles after the timing belt job. See here (link)
There was some intermittent rubbing squeaking sounds on the passenger side of the engine. Took off the serpentine belt and the tensioner roller had a bit of play in it.
You can replace just the roller instead of the whole tensioner unit. It is cheaper and faster. To remove the roller, just turn the bolt (same bolt you use to turn clockwise to release the tension) counter clockwise, remove it and replace the roller.
Mine had a bunch of cracks in it at 87k miles.
This belt isn't too bad to take off. Losening the tensioner is the hardest part and not much space to work with. IPD sells an extra long handle tool they claim makes this job easier. I found a box wrench with a built in ratchet allowed me to achieve maximum leverage.
Only the 2001 models of this car was plagued by the ETM problem. Your mileage to failure may vary. I'm on my third one at 90k miles (more on this in a minute) Usually get "Performance Reduced" message. Basically, the ETM include 2 resistance film based throttle position sensor (TPS) that wears out.
Early failures can be infrequent and may not occur in 2 consecutive drive cycles (each drive cycle is one engine start/shutdown sequence). 2 consecutive drive cycle detecting the same failure is required to store a code in the engine computer and turn on (and stay on) the Check Engine Light. Part + Labor is free with Volvo's 10 year 200k mile extended warranty on this part (a big thanks to Don Wilson) but that is expired as of now :(
Volvo also introduced new ETM software update in 2005 that may can allow the ETM to function longer. It won't always fix it. I venture to guess that since ETM has 2 TPSt and compares them to determine position, the new software is probably tolerates more differences and/or can smartly decide to bias the reading towards the good TPS. My 01 XC is on the original ETM at 72k miles with the new software while my T5 is on its third ETM (with new software) at 110k miles. However, the first ETM was probably unnecessarily replaced because Volvo hadn't developed the new software yet. The second ETM was replaced at the beginning of the extended warranty. Volvo probably have since then learned... try new ETM software first before replacing ETM as a cost saving measure. This is what they did to my XC70 when the ETM problem showed up.
If you want to read more about how the ETM fails, more info here
How To Determine ETM Failure
One of the most common ETM failure symptoms is feeling the engine hesitate at certain speeds. Unfortunately, a number of things can cause this symptom as well. The best way to diagnose the ETM failure is to run an ETM test from Volvo's diagnostic tool called VIDA DiCE. This test will cause the ETM butterfly to open and close 3-4 times and measure the difference between the 2 rotational sensors on the ETM. Volvo recommends maximum difference of 13 degrees. I recently did this test on 3 different ETMs and its amazing the difference between a good one and a bad one. You can read about it in the link below (starting from post 54 of the thread)
Volvo's extended 10 year warranty has expired on these 2001 cars. If you are sure you have an ETM failure, there is a aftermarket solution with contactless sensors to eliminate the problem forever.
I recently cleaned my V70XC's ETM at 116k miles. It has never been cleaned and had a nice black ring around the butterfly. The result is more smooth idling and power delivery and 2+ mpg increase! I was amazed. Probably want to do this cleaning every 50k miles or so.
Here are some directions and writeupshere for more info.
When you replace the spark plugs, you are likely to find the plastic wire looms crumple into bunch of little pieces when you move them around. I just took mine off and replace it with cheap 3/8 inch wire looms from your local auto or electronics store and tape it up with electrical tape. It has held up fine after 50k miles so Volvo's original looms must be much weaker against the heat.
Here is what a retaped loom looks like
Mass Air Flow sensor is located in the air intake tube just after the air filter. It measures amount of air flowing through the tube by heating a wire and measure how much it is cooled by the air flowing past it.
The heated wire on the sensor gets dirty and I had engine shut off and sputtering problems on my 2001 V70 T5 when the car was warmed up at 115k miles. Most of the time I got no codes and finally got 3 ECM codes (ECM 1300 - MAF, ECM 982A - control module, ECM 904D - accelerator pedal sensor) a couple of times when the car was sputtering.
I suspected MAF so I swapped the MAF from the other Volvo we own and it worked like a charm.
There is a way to clean these MAF, you just buy MAF cleaner ($6) at the auto parts store or use any electrical contact cleaner. Insert the spray tube (don't worry about the strong spray, its okay) and aim at the heated metal in the MAF to spray it a few times. Mine had blackened and took a few sprays to get it back to bare metal.
Volvo's MAF removal directions aren't very clear so I took a few pictures.
Here are the pictures along with notes in the captions
Cleaning didn't quite work for for me as the car still had rough idling and sputtering problems. I finally replaced the MAF with a new one and WOW, it idles and runs super smooth now.
A failing MAF seems to also produce some rough transmission shifts. These all went away when my new MAF was installed.
Aftermarket Parts Warning
I got an aftermarket new MAF from ebay for like $60. There is no marking of manufacturer and it introduced different sputtering problems. Be sure you get Bosch or Volvo MAF. Bosch is the MAF maker for Volvo.
Note there are several different versions of MAF for this car depending on year, engine type turbo, none turbo, and R. So make sure you get the right one. (01 turbo is Bosch 0280218108 and 02+ turbo (none R) is Bosch 0280218088, none turbo have different part number) Here is ipd's site on which ones to buy.
The PCV system on this car seem to get clogged up around 100k miles for some cars. Usually, cars using synthetic will be cleaner while cars using non-synthetic will have greater clogs. Here are the statistics I've had personal experience with
Why is PCV necessary? How does it work?
Here is a little diagram of how the PCV system works in all cars. Basically, some gases will leak by the rings on the pistons and enter the crank chamber. This vapor pressure must be vented to not blow out the seals. Emissions regulation prevents us from dumping this vapor pressure into the atmosphere so it is fed back to the intake and back into the the combustion chamber. This is why there is negative pressure in the engine's chamber where the oil flows. Engine's own air suction power is the force that creates this negative pressure in the oil chambers.
Now this is for non-turbo cars. Turbos are more complicated because intake manifold (IM) is not a constant source of vacuum. When turbos boost, IM is pressurized so crankcase pressure need an alternative path to escape. There is an alternative circuit that routes the pressure before the turbo to be fed back in the engine. This is also why you will see oily airways on the entire air intake system after turbo. Its because the oily crankcase vapor if fed into intake just before the turbo.
One more important note on theory of operations. IM vacuum when not under boost is a great source of vacuum. Throttle butterfly is mostly closed while the pistons are constantly providing suction. However, when under boost, the alternative vent before turbo is not really a vacuum source. Even with the turbo sucking in air, the outside air channel (through the air filter) isn't blocked so there is no restriction that creates a high vacuum source. Therefore, IM is vacuum source while pre-turbo is "venting" path. Here is a full explanation
How do I test the PCV system?
First, I should mention the only definitive test involves a manometer (super air pressure gauge) to measure the airflow rate. But even then, I think no one has done a complete plot of the PCV system's flow rate over its serviceable lifecycle over a large number of cars. Think of it like the arteries in your heart, how do you know which one is clogged without sticking a camera in there?
Best to just assume you have to do the PCV to keep it healthy every 100k miles or so.
This said, there are a couple of simple checks to know if your PCV system is venting properly? Here is a summary
There are 2 different circuits to vent the blowby pressure in this car. I believe this is probably common to turbo cars from what I've seen (VW 1.8T, Audi 2.0T engines)
Intake manifold provides the vacuum source during idle. An easy test is to put a latex rubber glove over the oil filler hole with the engine idling. If the rubber glove gets a little air sucked out of it, there is vacuum and a healthy unclogged idle circuit. If the rubber glove blows up, then there is no vacuum and you have a clogged idle circuit.
Intake manifold on turbo charged cars switches from vacuum to pressure under boost so can not be used as the exclusive source for vacuum like normally aspirated cars. Instead, the pressure has to be vented to air path between air filter and turbo (just in front of turbo)
I found the best way to do a boost circuit test is to take out the dipstick, stick a tube in it that seals tight against the dipstick tube wall (5mm ID works well). Routed it into the cabin (hood can latch for safety but not fully closed as it will crimp the hose) with a latex glove rubberbanded at the end. Then go for a drive. The glove will inflate because boost circuit is a vent rather than vacuum source. However, one should not get very high pressure. A normal pressure gauge will not even register 0.5PSI. If there is any visible pressure on the pressure gauge, boost circuit is surely clogged. All of this is explained the "Test" section in the following link.
The following link shows a home made device and tested while torquing the brakes (applying both brake + acceleration to create load and therefore boost).
Personally, I like the hose in dipstick tube test outlined above. You can get a better sense beyond just a test for a short few seconds.
Other signs of a plugged PCV is the dip stick being forced out of its hole and oil leaks that aren't the common ones (turbo return line, oil filler gasket) This is because the engine chamber where the oil is should have negative pressure (caused by PCV system) If the PCV system is clogged and there is positive pressure present in the oil chambers in the engine, there is force to push out the seals and cause leaks.
From reading the Volvo forums and my personal experience, it seems a clogged idle circuit don't usually cause seals to leak. I had some oil in my #2 spark plug as the oil forced its way past the seams between top and bottom half of the head. Note this is just the sense I get from reading these boards. Certainly not based on many hands on diagnostic and repair experience.
I will outline my directions below. I have found additional excellent online writeups and will share them here as well. Here is a link for a XC90 with the 2.5T engine. PCV system is basically identical to the XC70. This direction seems pretty good. You might look over my write up below on additional tips to handle the more difficult part of the job.
Servicing the PCV System
Now onto how to the service of your PCV system. A warning before you begin, this is one of the bigger jobs on this car and can take 6+ hours for a first timer with reasonable experiencing doing their own car's maintenance. This is because Volvo's design decided to bury the PCV components under the intake manifold.
First, there is a banjo fitting that commonly clogs. It clogs because there is only a 2mm diameter channel where the oil vapor runs through. So it doesn't take much to clog it.
What does the PCV look like on this car
Here is the airflow directions for reference
Cleaning the Banjo Fitting Under the Intake Manifold
This is the direction on an XC90. It is largely similar but may have slight differences. On my 2001 V70 T5 and 2001 V70XC, the differences are
This writeup will avoid the directions already in this document. Rather, just focus on the differences in my cars and tips for short cuts.
Here is the directions for removing the intake manifold
Simple Short Cut Without Removing Manifold
Here is a post on cleaning the banjo fitting nipple that often clogs without removing the intake manifold. It does require ETM/airpipe to come off. NOTE This direction appears to be for pre 2002 cars. More explanation below.
A few notes before you begin this job. You will need the following
Also take the belly pan off as this is a long job and you probably will drop a bolt here and there. Have a telescopic magnetic pickup would come in handy as well.
Fuel Line Disconnect
Remove Air Pipe and ETM
See the throttle body cleaning directions here.
Manifold Removal Short Cut
My 01's lower manifold bolt holes have openings on the bottom so the bolts don't need to be removed completely. I'm not sure this is the case on the newer year models. This makes the job very easy. You will need a universal swival for the tricky angles. For the bolt nearest to the passenger side, I used 2 extensions (6"+4" 1/4" extension) and snuck it just above the alternator to loosen this bolt.
You have to remove a couple of vacuum fittings and use a 17mm wrench to remove the banjo bolt from the bottom (near alternator). This step is blind and limited space with the wrench and your arm under the manifold (Disconnect the battery for safety since the starter's positive connecting is right down there where your arm will be) Remove/loosen the manifold bolt first so the intake manifold can move and give more space to access the banjo bolt. There are 2 copper washers between the bolt/round fitting and round fitting/manifold. Be sure not to loose the copper washers.
Removing and installing this banjo bolt is the hardest part of this job due to poor angle and limited space.
Volvo changed the banjo bolt design over the years. I believe 2005+, the banjo bolt evolved to include a check valve. This is to eliminate the pressure from entering the PCV system when intake manifold is pressurized under boost. I guess on cars without check valve, the boost circuit is expected to produce venting volume to over come this pressure.
I personally think the checked valve design is a better design rather than to rely on the boost circuit's vacuum to remove this pressure and blowby pressure. So if you have a banjo bolt without the check valve, you might consider replacing it with the new design on any Volvo PCV system for the turbo charge cars. The new design is part number 31325709.
Cleaning the 2 ports on the engine block
After the oil trap is removed, the 2 ports that connects engine block to the oil trap is visible. The top port is where the blowby gasses in the crank case need to exit into the oil trap. The bottom port is to drain back the filtered oil from oily vapor back into the oil pan. Usually, the blockages are found on the bottom port.
In addition, the bottom port runs through interior channels in the engine block that maybe plugged as well. This may require removing the oil pan to clean. Here is a link with a tip on how to clean this interior channel.
Check Engine's Internal Oil Trap Drain Channel Is Clear
Really important not to forget this diagnostic step!!!
Some of these cars have the internal drain channel for the oil trap completely clogged (Probably likely if the oil trap is completely clogged and filled) If this clog isn't cleared, then replaced PCV system will be healthy until oil backs up the trap and clog the air vent ports.
A easy way to test this is the blow some air into the trap port on the block and see if you hear oil bubbling inside the engine block. The air won't pressurize the block and blow seals because the block and head venting ports are all open with the oil trap out.
Here is what a clogged oil drain channel looks like
Replacing the Oil Trap and Hoses
Here is where the oil trap and hoses are located
Big Expensive L Shaped Hose
Since this hose is expensive, it is often asked if need to replace it. Here are some info on this answer
2001 may not be necessary.
2002+ has a design change where it attaches to the banjo fitting nipple uses a plastic hose that is super brittle after many miles of use. It will likely break during removal. So the hose will need replacement or repaired. The plastic brittle hose is maybe a few inches long so might be fixable with aftermarket parts.
Since I had 2001s, I replaced everything except the big L shaped hose/pipe assembly with the banjo fitting on it (#8 in this diagram). I just cleaned the banjo fitting on it and blew air through it to make sure it was clear.
Reattach The Banjo Fitting (Hardest part of the job with tips to make it easier)
This is probably the hardest part of this job. Here is how I did it without loosening the alternator and AC pump.
First, you need 2 new copper washers or resand the surface of the old ones.
Don't connect the hose between the banjo fitting and the oil trap. This gives the intake manifold a little more room to move and allows the banjo bolt thread to catch the thread in the intake manifold. Your entire arm will be under the manifold trying to get the bolt's head to catch by feel without loosing the top washer. It seems right handed person is required to do this given the space allowed.
Put in a new intake gasket, thread in the lower IM bolts a little bit so the IM can rest on it (if you have the manifold with an opening on the lower bolt hole).
Now put the IM in its near final position resting on the lower IM bolts. The 2 coolant hoses connecting the banjo fitting will prevent it from moving very far from the engine block. But disconnecting the connection at the oil trap give you a little more freedom to move.
The angle of banjo bolt hole is aimed towards the alternator. Therefore alternator blocks the bolt from threading straight into the hole. The trick is to tilt the IM upwards slightly on the driver side. You can do this by putting the driver side IM on top of the bottom IM bolt. Once you have IM at this slight tilted angle, its much easier to thread in the banjo bolt without being blocked by the alternator. Even then, its not so easy without dropping the top copper washer. Once I catch a few threads, I take a good look at the banjo bolt to make sure both copper washers are on before tightening rest of the way.
Just FYI, I tried for 6 hours without success once without tilting the IM, then I tilted the IM and was able to catch the thread in about 2 tries or within 5min.
You can get a 17mm box wrench under the banjo bolt from top of the engine just below the PS pump. It is only possible to make 1/8 of a turn at a time so it will take awhile to fully thread in and tighten the banjo bolt.
Loosening The Alternator
If you are unable to reattach the banjo bolt per direction above. You may have to loosen the alternator. Serpentine belt has to come off (read here). There are 4 bolts that hold the alternator and AC pump together. The top 2 bolts is easy but the bottom 2 bolts are harder. You probably have to take off the rubber hose that connect the intercooler to the charged air pipe (the one over the top of the engine) The top 2 bolts need to come out and the bottom 2 need to be loosened to tilt the alternator forward and get it out. Now finally, you can get to that banjo fitting if you weren't successful before.
Reconnecting The PS Tube
Put the new o-ring on the PS pressure side metal tube. Don't over tighten as it will smash the o-ring and PS fluid will leak out. The o-rings are cheap so get a couple just in case. There is not way to tell how tight other than by feel.
My oil trap was clear and all of the hoses and engine block inlets were clear even at 122k miles on the V70 T5 (the banjo fitting was cleaned at 90k or so). There was only a 1/16" thick of gunk at the bottom of the 2 engine block inlets. I just used a paint can opener to scrape it outwards. I always ran synthetic and I'm guessing that helped. Here is a picture, it looks worse in the picture, I should have taking a picture face on to show you how clear the engine block inlets were.
However, my V70XC had a clogged PCV system at 116k miles. The banjo fitting was completely clogged and hardened. When I took the banjo bolt out, a little puddle of oil came out. I guess they had collected inside that portion of the intake manifold unable to get vacuumed out due to the clog.
Before reassembly, it is probably a good time to use some carb cleaner and clean the butterfly and the throttle body opening.
Nothing too tricky about reassembly. Read the ETM and air pipe directions to familiar how to reassemble the ETM and reconnect the pipe to ETM's intake.
Here are some more notes on this job.
Got a couple of these for my car. I noticed the chrome plating flaking off during one of my oil changes. Having loose chrome flakes in your engine probably does more harm than good.
Had this problem and read that it is likely the thermostat. Bingo, changed that and both are back to normal.
To change the thermostat, you can drain the whole engine of coolant following these directions
Or just open the petcock below the bumper and drain about 1/2 gallon of coolant and proceed to open up the thermostat housing to change the thermostat.
See here for the type of coolant to use.
I had minute coolant loss along with engine temperature reading lower than normal when warmed up (1 tick to the left of center on the temp gauge. Center tick is normal on both of my 01s). I also had random no cabin heat unless cabin temp dial is at max (And it isn't due to the clogged ECC temperature fan). All of these were due to a bad thermostat. Replaced that and everything is back to normal.
See here for the type of coolant to use.
For this car, it is best to use HOAT (G-05) coolant. Zerex G-05 is a common replacement to the more expensive Volvo coolant. Its probably a good idea to not mix the other types of coolants (OAT, IAT). So if you are not sure, you probably want to flush the old coolant+some water and then add the HOAT coolant.
Here is an explanation I found on IAT, OAT, HOAT coolants
Here is a table with specs for most aftermarket coolants out there
I've been running Prestone Extended Life in my cars without any problem. But since it is an OAT coolant rather than HOAT, I plan to drain it, flush my system with water followed put putting in Zerex G-05.
If you have this code, it is likely the car has well over 150k miles and the catalytic convertor (CAT) is no longer efficiently cleaning the exhaust.
General Background on O2 Sensors
There are 2 O2 sensors on this car. One before the CAT commonly called the upstream O2. This O2 basically samples the exhaust and provides input to the ECM to control the proper air fuel mixture ratio. The 2nd O2 is after the CAT and commonly referred to as the downstream O2. This O2 samples the exhaust to check CAT is operating at good efficiency to clean the exhaust.
Some times you will read about bank1 and bank2. These are for V configuration engines. There will be 2 CAT systems (one for each bank) and therefore total of 4 O2s for V banked engines. But this doesn't apply to these inline 5 cylinder Volvos.
If you get the P0420 code, it means the downstream O2 thinks your CAT is no longer meeting the efficiency requirements.
Cheap Easy Fix
There is a cheap easy fix for this. They sell O2 extenders that basically pull the downstream O2 sensor out of the exhaust stream for a few dollars. While this doesn't improve CAT's efficiency (and therefore continue to pollute the air) it does trick the ECM to think everything is fine and not trigger this error code to passing emissions test. Emission's test on modern cars with ODB2 port just read the ECM's error codes and trust car's built in downstream O2 sensors rather than sample the actual exhaust from the tail pipe.
The extension you need can be found on ebay. I believe it is M18 thread x 1.5" length for a straight one and they also make an L shaped one. Which one works depends on how the O2 is mounted and the clearance necessary. A straight one worked for me on a 2000 V70XC while others comment a L shaped one was necessary for 2005 XC70.
Some online threads suggest buying a spark plug extender from your local auto parts store. But these need to be drilled to provide sufficient opening while the ebay parts are plug and play.
More Proper Fix
A more proper fix is to replace or clean the CAT. Replacement is expensive and runs well over $1000. I've read people successfully clean the CAT on various cars. Basically soak the CAT in some citric acid solution for few hours. I think this likely removes some of the gunk on CAT's catalytic reaction surfaces to expose them to do its work again. I've not tried this but thought I note it for those interested.