Here was an interesting one. An M3 owned by a good client of ours came in with a rough running condition that happened suddenly. When we got it it was clearly running very rough and misfiring badly. We didn’t drive it much. Checking the DME for codes we found misfire codes for all 6 cylinders as well as vanos / valve timing errors for both the inlet and exhaust camshafts. We ran the vanos tests through the computer and it failed immediately. Knowing that the S54 has a problem with bolts breaking on the camshaft pullies (and causing vanos errors) we decided the next step would be to remove the valve cover and inspect the cam pullies. Valvetrain damage in this engine would get very expensive very quickly. To our surprise the cam pullies were still on nice and tight – no play at all. Next we checked the vanos assembly itself. Although it was hard to see we found total free-play between the vanos oil pump and the exhaust camshaft.
Here’s the broken part:
Here’s the Vanos assembly:
A broader view:
The repair required replacement of the Exhaust side pulley and variable valve timing adjuster as well as the vanos assembly itself.
Here’s the new Exhaust cam pulley next to the old one:
Servicing this pulley requires removal of the timing chain from the exhaust camshaft. To do this we have to lock the lower part of the engine (using a lock pin) as well as the camshafts. BMW have a special tool to do this:
With the engine locked the service is relatively straight-forward…
Install the new exhaust cam pulley:
Since these bolts have a reputation for breaking we opted for new hardware (BMW have upgraded the strength of these bolts):
We updated the hardware on both camshafts:
Our next step was to pull the engine oil pan to find any broken pieces of metal and make sure they didn’t circulate in the engine oil – here’s what we found:
Verification that we found what we’re looking for:
And then there was this part in the oil pan:
I suspect this little puck (it was approximately 10mm in size) is a valve adjustment puck – someone lost it during the car’s last valve adjustment?
Finally we installed a new Vanos assembly:
Once we got the engine back together we had a quick prayer for luck and started it up. It started perfectly! Got it up to operating temperature, ran the computer vanos test again – recalibrated the vanos through the computer and we were done!
We cannot take all the credit for this success however – we had GREAT help from Ramon LeFrancois of Bavarian Motorsport in Milpitas California. He was an invaluable asset – thank you Ramon!
Here’s a common, common problem with VW and Audi’s cooling systems. Their water pumps use plastic impellers to pump the engine coolant and, unfortunately, the impellers like to crack and freewheel on the pump’s shaft. This will obviously cause overheating problems. Sometimes this can be hard to diagnose because, if the impeller still moves a little, the car will only overheat under certain conditions.
This waterpump, like many in the VW/Audi world is driven by the timing belt and these two services should be done together to save on the labor costs as well as to ensure a more reliable engine.
Note: At Integrity First Automotive we have a great relationship with a parts suppler than can provide us with aftermarket water pumps that use METAL impellers – they are our preferred replacement for these engines.
Below is a picture of a VW water pump with a broken impeller. This one is from a New Beetle with the 1.8T APH engine:
Audi timing belts are always impressive looking jobs. They’re actually more bark than bite but, as these pictures will show, they do look like a pretty difficult job. They’re not as bad as they look.
One thing to know about Audi timing belts, don’t tempt their service interval. If your car is due for a belt – get it done. Some engines are less sensitive to their service intervals than others but Audis, unfortunately, are very sensitive. In fact, on the 4-cylinder engines, we recommend doing the belt early or you can have problems before you ever reach the service interval. If the belt slips or breaks it will cause expensive engine damage.
So roughly here’s the procedure to do an Audi’s timing belt. The pictures in this article are for a 2.7T (twin turbo engine found in the Allroad, the S4, and the A6). Other Audi V engines are very similar in their service procedure and the 4-cylinders are somewhat similiar too.
1- Get engine to TDC cylinder #1 on the compression stroke. There is a lock tool for the crankshaft that can be installed (it threads into the transmission’s bell-housing) but most technicians find this unneccessary.
2- drain the cooling system
3- remove vehicle’s front clip – the bumper, grill, and the radiator support assembly. Note that the a/c system doesn’t have to be evaculated – the condensor can be just ‘folded’ off to the side without removing any lines. **This is the step that scares a lot of people who haven’t done the job before. The truth is Audi built these cars to have the front clip come off easily so don’t be afraid. Be careful not to scratch the bodywork or damage a fender. Also, technicians who have done this job more have found that they can save time by not always removing the front clip competely. Consider this as a short-cut if you think you can get away with it. My favorite trick is to bring a padded chair in front of the car and rest the bumper on it.
4- remove the drive belt and any tensioners, pullies, etc that are in front of the timing belt covers
5- remove the timing belt covers. Note that they come off and go on in a certain order / they interlock. You also have to pull the main crankshaft pulley to get the lower cover off – there are 6 or 8 or so hex-head bolts that hold it on. Remove them and pull the pulley off.
6- mark the timing belt’s alignment to the camshaft and crankshaft pullies
7- remove the hydraulic tensioner and compress and lock it using a pin. Remove the tensioner pullies and the belt
8- replace the waterpump and the thermostat. Note – this isn’t absolutely necessary but it is a great cost-saving step since these parts will probably need replacing before the next time the timing belt is due anyway
9- Replace the pullies. IMPORTANT: the tensioner pulley has a known defect – the bolt that holds it should NEVER be reused. It can and will snap later and cause big problems. If you buy a replacement pulley buy it from a professional supplier – if you do it will come with a new bolt and with installation and torque instructions – follow them carefully.
10- transfer timing marks to your new belt (I recommend counting the teeth twice to be certain that you have the marks transfered correctly)
11- install your new belt / make sure your alignment is right – actually removing the tensioner and other pullies can sometimes help in getting the belt on / use your discretion
12- if available, set the cam timing using the timing tool. Not totally necessary but recommended.
13- put the hydraulic tensioner back on and release the tension (pull the pin)
14- roll the motor a couple of times with the cranshaft and double-check all the timing
15- reassemble everything else!
16- fill and bleed the cooling system
17- you’re done!
Here’s some pictures:
Front Clip Off Car (Audi A6):
Bad Idler Pulley – This engine was luck to survive with this pulley like this:
New Waterpump Installed:
Timing Belt Camshaft Alignment Tool Installed:
Timing Belt Installed:
Timing Belt Pullies:
Generally we love Volkswagen’s TDI engines. They produce great power, are much easier to live with than the older Turbo diesels that VW made, and have amazing fuel economy. They really only have two weaknesses: they HAVE to have their timing belts serviced on time. AND they like to coke-up in their intake manifolds thanks to the EGR (Exhaust Gas Recirculation) system. Here’s some before and after pictures of the decoking we did on a 2000 VW Jetta TDI with the ALH TDI engine. The car has approx 130,000 miles on it. The power difference from before we did this service to afterwards was amazing. Here’s the pictures:
PLUGGED EGR VALVE
CLEANED INTAKE (AGAIN)
If your TDI is feeling like it lacks power – particularly at high RPMs it may be time for you to do this service too. EVERY TDI needs this sooner or later.
Here is a deceptively simple timing belt job. This engine, built by Daewoo, is found in the 2002-present Chevrolet Aveo. The timing belt has a notorious reputation of failing early and we strongly recommend you replace yours before you get to 50,000 miles. This engine design is an interference engine which means that if the belt breaks or slips it will cause (expensive) internal engine damage.
Generally this is a simple procedure: disassemble the front of the engine, remove the engine mount, and roll the engine to get to Top-dead-center on cylinder #1 on the compression stroke. The cam pullies have marks that will point towards each other when in the correct position – see picture:
Also note the marks on the timing belt – it is our shop’s practice to mark old timing belts before removal and then to transfer these marks to the new belt. They serve as a back-up system for ensuring that the new belt is on correctly. (NOTE: You have to be very careful to be sure the marks are copied correctly from old belt to new / count belt teeth twice!)
The belt tensioning is the tricky part of this service. The waterpump (the toothed pulley with the special tool on it in the pict above) is used to load and unload the tensioner.
The pulley above the waterpump and below the intake camshaft is the actual spring loaded tensioner – see picture below:
To properly tension the belt (with engine in top-dead-center #1) loosen the waterpump and turn it (using special tool) until the tensioner pointer is pointing to position 1 in above picture – then tighten down the waterpump. Next roll the engine through two full rotations to get back to top-dead-center #1, loosen the waterpump and reduce the timing belt tension until the tensioner’s pointer is pointing to Position 2 in the above picture. Re-tighten the waterpump and roll the engine a few times and verify that all of your timing still lines up. If so ensure everything it torqued down properly, reassemble the engine, and enjoy it for another 50,000 miles!
The special tool – shown below – is almost necessary for this procedure:
You *can* get away with using a 41mm crow’s foot and a short extension but it’s tricky. The important thing is to be sure the belt is tensioned properly before starting the engine. Remember: if the the belt is too loose it can skip and cause internal engine damage.
We bought our tool here:
Please email if you have any questions!
Here’s a fun one: a Land Rover Freelander’s timing belts. This engine is a 2.5L double-overhead cam with three (count them: three) timing belts. Moreover these should be serviced every 60,000 miles or so. Since this engine is an interference design if a timing belt breaks or slips you will have internal (expensive) engine damage.
Although this is probably a service that can be done without special tools we don’t recommend it. The key to getting the job right, as with any timing belt service, is to mark everything. If you mark the old belt, transfer the marks to the new belt, and get the new belt on exactly where the old one was you’ve obviously got the new belt on correctly. It is easy to get off by a tooth though so count twice and install the belt once. Any timing belt job done this way can get scary and if you find you cannot get things back where they belong you then have to have the correct tools to align the engine.
Timing Tool Kit:
Starting Point – air filter housing removed.
Note that you cannot fully remove the serpentine belt without removing the ‘front’ engine mount seen here below the alternator. What this means is, if your serpentine belt is even slightly worn you’re smart to replace it while doing the timing belt since the labor completely overlaps.
Next Step: Remove Upper Intake
Note that when removing the upper intake it can feel like it has gotten stuck and you’ll go hunting for hidden bolts underneathe the back side or something. Most likely it is just stuck on the large green o-rings you see in this picture. Also note the shop-rags inserted into the intake runners. We do this to protect the engine from something falling down into the intake. Even a small bolt dropped in the wrong place here could ruin the engine.
Next step is to be sure our engine is in the ‘safe’ position:
The camera angle makes it look like these marks are mis-aligned but when viewed from directly in front of the harmonic balancer the marks line up perfectly.
To keep the crankshaft in the safe position you use your first tool from the tool kit to lock the crank:
Not easy to see here and not easy to install but here is the tool – once this is installed the engine is locked. You’re probably wise to disconnect the negative battery terminal at this point since someone hitting the starter motor at this point could be very bad!
Here’s the flywheel tool from futher back:
Here’s the front belt coming off / notice we still mark belts at our shop even when we have the alignment tools.
Right Side Cylinder Head:
And the left side:
To replace the front belt you need to remove hydraulic tensioner assembly and lock it. The tool kit comes with a pin for this but really any pin would work. Before remove the tensioner we recommend you remove the idler pulley on the left side of the engine – this will slacken the tension on the tensioner and make it easier to remove. Land Rover recommends that if the tensioner bolts are too tight you should soak them in some type of penitrating oil. If this does happen it is also recommended that you replace the bolts.
Next you can pull the old belt off, partially install the new belt, and then align it. Before installing the new belt be sure to inspect the tensioner and idler pulley and replace them if they are even slightly questionable. Also check the hydraulic tensioner for any signs of leakage – again play it safe and replace it if it’s even slightly questionable.
Putting the front belt back on we use the upper alignment tool to ensure everything is aligned correctly:
The tool kit comes with two of these tools so that you can lock both front cams at once.
Once the front belt is back on and you’re satisfied that it is aligned correctly it is now time to tackle the rear belts.
Above is the front cylinder bank’s rear timing belt. Notice that it doesn’t have any tensioner assembly. To replace it first mark both cam pulleys and the belt then remove both pulleys and the belt as an assembly.
The rear cylinder bank is a little harder to deal with but take your time and be sure you have your timing belt marked:
Here’s the front bank with the alignment tool installed and the intake cam mark showing:
Here’s the new belt installed on the pullies before installing back on the engine:
The tool kit comes with nice ‘pegs’ that you put into the cam bolt holes. You can then slide the cams in place using the ‘pegs’ as guides. BUT – here’s one of the trickiest parts of the whole process: the EXHAUST CAM WILL HAVE MOVED and you’ll have to roll it back to get the cam pulley back on. With the tool kit there is a bolt on the front lock tool that allows you to turn the exhaust cam with a wrench – without this we recommend using a chain wrench over the large smoother outer section of the exhaust cam to allow you leverage to roll it back. BE VERY CAREFUL!
The rest, as they say, is simply the reverse of removal.
Once all belts are on remove the flywheel lock and roll the engine a few times then recheck all alignment marks to be sure everything is aligned. Then reassemble the engine. Once starting the engine if you get any abnormal noises shut it down immediately and recheck everything. If you get a check-engine light on recheck your timing and read the computer error codes to see what it is complaining about.
Like every timing belt job it just takes cautious work and double/triple checking everything.
Here was a fun one – we swapped out the 1600cc engine from a 1974 VW Beetle and put in a built-up 2100cc. Should make just over 100 horsepower. Not bad for a Beetle!
Take a look:
The 22RE is a legendary Toyota engine. Used in many of Toyota’s smaller pickup trucks this engine has longevity to spare (what Toyota engine doesn’t?).
Despite its great reputation and low maintenance it isn’t perfect. After years of service the timing chain will start to loosen and contact the chain’s cover. Below are pictures from a 1993 Toyota pickup truck with over 230,000 miles on the clock. As you can see by the dark oil deposits on the inside of the cover this engine worked hard for its living. The track you can see on the inside lip of the cover is the machining of the cover by the loose timing chain. If left too long this would have worn its way into the cooling jacket of the engine. This would have caused the coolant and oil to mix and ultimately would have destroyed the engine.
When caught early enough a new timing chain kit will solve this problem and will give the engine countless more miles of service.
New Timing Gear Installed:
This is engine work on a 2002 Volkswagen Jetta VR6. The VR6 engine is a brilliant engine design where the cylinders are in a ‘V’ design but the engine still only uses one cylinder head, instead of the traditional two heads that all other V engines use.
The ‘R’ in VR6 stands for ‘narrow angle’. Rumor is that VW jumped on this when the patent for this design expired. The VR6 first saw production in the VW Corrado, followed by the GTI. It recieved mass acclaim from the automotive news press and was considered by many to have saved the hot-hatch market segment that was basically invented by VW’s first GTI – marketed in the US as the Rabbit GTI.
Here’s the cylinder head – it isn’t much bigger than an inline four cylinder:
Here’s the engine block:
Note here that it is mounted transversely in the Jetta and again isn’t much bigger than a four-cylinder.
A common service challenge with the VR6 is the timing gear. This engine came apart because it had blown a head gasket from overheating. However, like many VR6’s with some milage on it, the timing chain guides were damaged. If left unrepaired this would likely have caused timing chain failure and severe engine damage.
Here’s a shot of the old and new rear guide:
The complication with this engine design is that the timing chain is on the REAR of the engine. So, to service the chain requires removal of the transmission.
Here’s the new guide in place. Notice that the timing gear consists of two chains – an upper (hanging loose in this picture) and the lower.
Notice the new (clean) upper chain guide installed? The really unfortunate part about this design is that, to replacd this guide, the lower chain cover has to come off the engine. This requires removal of the transmission and either the flex plate (automatic transmission cars) or the clutch and flywheel (manual transmission).
Here’s some shots of this engine going back together.
Head Gasket Installed:
Head installed – notice the camshafts and the timing chain.
Here’s the head before installation of the intake manifold:
Here’s the lower intake installed (with Fuel Injectors):
Here’s the Upper Intake Installed (Starting to look like an engine again!):
This particular VR6 is the simplier of the two main designs that VW made. This one only has one camshaft per cylinder bank so it is technically a single-overhead-cam design (even though it ‘looks’ like a double cam design). VW also made a double overhead cam version where the engine has a total of four camshafts.
Other derivatives of this engine design include the W design where two cylinder heads, both using narrow-angle pistons, are used. This design made it into the W8 Passat. There are also exotic W16 engines and other high power designs made by VW.