Vanos seals solution

Just ordered a set. I will post my results after winter break.

just bought the kit. thanx

Rejaie, if I'm not experiencing any stalling or fault codes, and my car seems to be running pretty smooth, is it still possible that my 99 323i w/ 89k is suffering from these bad piston seals? I have occasionally felt a hiccup in acceleration, and very rarely a shaky idle upon cold startup. Plus I'm pretty concerned about my car for this winter, I feel like shes not ready for it.

Did not receive the order.

Originally Posted by smokedOUTbimmer

Rejaie, if I'm not experiencing any stalling or fault codes, and my car seems to be running pretty smooth, is it still possible that my 99 323i w/ 89k is suffering from these bad piston seals? I have occasionally felt a hiccup in acceleration, and very rarely a shaky idle upon cold startup. Plus I'm pretty concerned about my car for this winter, I feel like shes not ready for it.

I can tell you that all the vanos seal O-rings are failing. In every seals repair case the O-rings were badly deteriorated and the pistons had a loose fit. Also in every case the owner gained great performance improvements. These improvements have also been noted by owners who replaced the vanos with a new vanos.
There are many owners who have idle and performance problems who will install the solution. Hopefully they will report back and in time everyone will receive the feedback needed for a fuller assessment.

Not all European M52TU engine cars are experiencing the cold idle symptom. This is surely related to the DME programming. This might be regional and related to environmental laws. The idle problem is created when the DME utilizes the vanos to help warm up the cats to bring to operating temperature faster. This feature might not be implemented in all DME software versions.

If you are not experiencing symptoms then maybe you can just wait and see what others report.

Here is something I recently wrote on another E46 forum.

The major aggravating symptom from the failing vanos is the cold weather cold start idle jolts and possible stall. This is only found on the M52TU engine (99-00). BMW became aware of the problem and patched up the next version engines, M54 & M56, software to address the symptom. M52TU owners usually indicate the symptom returns after two years from replacing the vanos.
I bought my car, 528i 06/00, in the summer of 2003 with 51k miles. At the first sign of cold weather I started experiencing the cold ideal symptom. In early 2005 I bought a new vanos. I replaced the pistons from my old vanos with the pistons from the new vanos and reinstalled the old vanos. My idle problems resolved. I also gained some wonderful performance improvements. I used to say my car now drives like its on steroids. I noted that I lost these performance improvements in ~6 months. In two years, ~20k miles, I started experiencing the cold engine symptoms again. I removed the seals and inspected them. The O-rings had significantly deteriorated. During my development and testing process I purchased several new BMW vanos units. I installed one of them for testing, but didn’t get to removing it for 3 months, ~3k miles. Upon removal I was disgusted to see the seal fit had notably degraded. I removed the seals and found the O-rings had already suffered notable compression set.
The Buna O-rings simply are not appropriate for the engine environment. They are not compatible with engine synthetic oil or engine temperatures.
All the vanos units in all the engine years have these Buna O-rings. All the newly sold vanos units have the Buna O-rings. I bought a new vanos unit a year back and tested the O-rings for material makeup and the result was Buna.

One of my Beta installers had a 2003 330xi 77k miles. In his case I actually did the install myself since I wanted to take pictures and document the E46 specifics. The owner complained of hesitations at lower RPMs and a lack of passing power on the highway in 5th and 6th gear. He simply thought that’s the way the car drove. I drove his car and noted the hesitations and the lack of low end torque and power. Once I removed and opened his vanos, I noted the piston (seals) were very loose in the cylinder. I could simply insert the piston in the cylinder and let it go and have it drop without resistance to the cylinder bottom and clunk. It doesn’t get much worse than this. Once I removed the seals I noted the O-rings had completely plasticized and turned into plastic. They had flat top and bottom surfaces and had shrunk.
Once I completed the repair and took the car for a drive, with the owner, we noted improvements in the lower end torque. We also noted the lack of hesitations. After driving for a period and breaking in the seals, he has indicated significant improvements in torque and power, and that his car drives like “a different animal”. Here is his post on the vanos forum.
http://www.bimmerboard.com/forums/posts/440307

M54 & M56 (01+) engine owners do not experience the cold idle symptoms. They are also often not aware of their power losses. But after repairing the vanos they are quite pleased with the performance enhancements.
In time, enough M54 & M56 owners will perform the repair and indicate their results that the remaining owners will become more convinced.

Here’s a method for attempting to gage the vanos failure degradation. Get the car in third gear at ~1500 RPM on an incline. Fully depress the throttle. With a failing vanos unit the car will bog and clime very slowly. With a well functioning vanos, the car will have good torque and acceleration.

ALL the vanos units are failing. The O-rings simply do not handle the engine environment. There can be grades of failure. This will depend on time of use and spirited driving. Sports driving will cause the engine oil temperature to peak and will intern cause increased damage to the O-rings.
In my experience from inspecting many O-rings and speaking with many owners who have performed the repair, ALL the vanos O-rings are badly damaged.

Originally Posted by smokedOUTbimmer

Rejaie, if I'm not experiencing any stalling or fault codes, and my car seems to be running pretty smooth, is it still possible that my 99 323i w/ 89k is suffering from these bad piston seals? I have occasionally felt a hiccup in acceleration, and very rarely a shaky idle upon cold startup. Plus I'm pretty concerned about my car for this winter, I feel like shes not ready for it.

VANOS failure isn't an "all at once" occurence. The VANOS seals wear and break down over a period time. The best defense is to change the oil and filter more frequently than digital readout tells you to. I change mine every 4-5K miles. And, use an oil that is compliant with BMW Long Life 2001 (BMW LL-01) specs.

In you case, I would start with a bottle of injector cleaner. Chevron Techron is a good product; so good, BMW dealers stock it (with a BMW label, of course). Follow the directions on the label. I would use this stuff a couple of weeks before you change the oil as it doesn't burn at the same rate as does the fuel/air mixture. As a result, some of the cleaner doesn't completely burn and can get by the piston rings. This contaminates the oil.

If that doesn't do the trick, I'd look at changing the air and fuel filters. I change these every 2 years, regardless of mileage. Also, the connectors between the coils and the sparkplugs have a tendency to "age" from the engine's heat. This can cause an occasional arc that feels like a single misfire. They're cheap so change them the next time you change your plugs. Plugs - they could be another source of "hiccups."

Your car is approaching the magic 100K mile mark, so oxygen sensors could also be at fault. As they age these sensors don't "track" as well as when they were new. By "track" I mean the accuracy of the sensor's output (to the ecu) in reaction to changes in the engine's exhaust stream.

Isn't owning a BMW such fun!!!

Yesterday night I switched on my car to warm it up a little bit. Once I switched it on I heard a Hissing sound, So I opened up my hood and tried to track down the sound. It was coming from the left side of the engine with me facing the car. Does this hissing sound relate to the Vanos. If it does is my Vanos messed up.

Thanks for your help.

How long are you expecting these seals to last relative to the ones that come in our VANOS units?

Originally Posted by memonlarka

Yesterday night I switched on my car to warm it up a little bit. Once I switched it on I heard a Hissing sound, So I opened up my hood and tried to track down the sound. It was coming from the left side of the engine with me facing the car. Does this hissing sound relate to the Vanos. If it does is my Vanos messed up.

Thanks for your help.

Your noise is not caused by the vanos. The vanos is at the front of the engine and is an extension of the engine head.

A hissing noise might be a vacuum leak. The left side of the engine (at hood) is the exhaust side. At the top left side of the engine run several cables that clip onto the engine cover. One of these cables is a plastic vacuum hose used to engage the secondary air valve. The valve looks like a puck at the front left of the engine (at hood). On cold weather cold starts the DME turns on the secondary air pump and enables the vacuum through the hose which opens the valve. This floods the exhaust with oxygen which helps bring the cats up to operating temperature faster. If the hose has a crack and the vacuum is turned on, there might be hissing sound. My hose cracked at 100k miles and I got a secondary air fault code.

This is just speculation. You might pose your question in a new post and see what others might suggest.

Originally Posted by zeshon

How long are you expecting these seals to last relative to the ones that come in our VANOS units?

The OEM Buna O-rings are fairing quite badly in the engine environment. As I noted, I inspected new OEM seals after only 3k miles and found them to have a notably loose fit. I removed the seals and found the O-rings had notable compression set. The OEM O-rings I drove on for 20k miles were significantly deteriorated.
It's not just that the replacement Viton O-rings are better than the OEM Buna O-rings. The Buna O-rings are simply not compatible in the engine environment. By spec they should not be in there. Use the following link to gauge the O-ring materials compatibility with the engine synthetic oil. For chemical choose "Oils: Hydraulic oil (synthetic)". For material choose Buna-N and then Viton. Click the submit button and see the compatibility level.
http://www.coleparmer.com/techinfo/chemcomp.asp
Buna is rated to 100C (212F) and Viton to 204C (400F). Engine oil temperatures can easily reach 200F and can peak to 250+F. Buna is also notably more susceptible to compression set than Viton, especially at the higher engine temperatures.
I spoke with the head of the automotive seals division of the largest US manufacturer of seals (a significant company). He could explain to me the seal materials GM and Chrysler use in their variable valve timing units (vanos). When I told him that the BMW vanos seal O-rings were made of Buna, he said, "now why would they go and do something like that!". He recommended Viton.
The next better material to use after Viton is Kalrez. It costs ~100 times more than Viton and is only used in very special extreme applications. It is way overkill for the vanos application.

The OEM Teflon seals are fairing well, but unfortunately this information is of no significant value. As noted, the OEM O-rings are experiencing compression set in very short order (3k miles). This reduces the radial force of the O-rings against the Teflon seals, and in turn the Teflon seals against the vanos cylinder walls. Thus there will be significantly less wear on the OEM Teflon seals than in a properly functioning system.
The replacement Teflon seals have carbon filler like the OEM seals. The replacement seals carbon filler is a tougher grade than the OEM softer carbon grade and thus will last longer. The replacement carbon filler still does not risk damaging (wearing) the vanos aluminum cylinder walls. A tougher filler that would last even longer like glass/moly or bronze would run the risk of damaging the vanos cylinder walls.
It was suggested by one manufacturer to use bronze. Bronze is known to damage aluminum cylinder walls in hydraulic reciprocating piston applications (vanos). But it was suggested that it would not be a risk in the vanos application due to the slow piston reciprocating speed. I elected to not take this risk. Other seal experts recommended against bronze. It was broadly acknowledged that glass/moly would damage the aluminum cylinder walls.

The vanos is a hydraulic actuator. It utilizes a hydraulic reciprocating piston scheme. The vanos is considered a "light application". The piston reciprocating speed is slow. The oil pressure is very low (comparatively to the normal 2.5-5k psi). The seals are significantly lubricated with the engine synthetic oil. The operating temperature is no where close to the 575 F temperature range of the carbon Teflon seals.

Given all the above, I do really believe the replacement seals solution is the best solution. I also expect it will last the life of the car. I base this mostly on the vanos being a "light application".
Of course only time will tell. I plan on inspecting the seals at 20, 40, 60, 80, 100k, etc, miles.

I know this was a long winded answer, but I thought some might appreciate the discussion.

I appreciate all the info. This is a very interesting job you have done here. I've been informed that my kit has arrived. I can't wait to post results.

Hey Rajaie,

Great info on the dual Vanos issues. I will be purchasing and installing one of your kits as soon as I get the tranny back into the car.

Was wondering if you had heard of BMW issuing a software upgrade for M54's experiencing stalling problems that essentially locks out the exhaust side Vanos?

Even if one were to fix the seals the software may not enable the Vanos to operate to its fullest extent.

I ask because the PO of my car experienced a stalling issue at some point and the receipt shows the repair as a DME re-flash.

Matt

Please better define the stall problem you are speaking of.

The cold weather cold start idle jolts and possible stall is usually found on M52TU engines. I expect BMW patched the software for the M54 & M56 engines to address this symptom. I know there is a software update to the M52TU to also patch this symptom.
I have seen a reference on this forum about cold weather first start stall. I thought this might be vanos related.

It is impossible to know what these software patches do without having specific information from BMW. Due to the spring in the vanos exhaust side, significantly leaking piston seals can render the exhaust side dysfunctional. Eventually engine fault codes are generated indicating this. I've referenced these codes above. Owners are now beginning to receive these codes. I wouldn't be surprised if BMW implemented a software patch to completely disable any use of the vanos exhaust side to address this symptom.

The problem with these software patches is, first they don't address the failure, second once the vanos is repaired the DME might not utilize it appropriately due to the software patches. I don't have faith that BMW changed the software in a way that detects and adapts to the vanos condition and performed thorough testing.
This whole thing is such a mess! BMW should be addressing the hardware problem, not continuing to generate software patches to circumvent the escalating failure symptoms.

Rajaie, thanks for all the work on this; amazing that you found the problem and how you came up with a very viable and affordable solution! I do have a question for you since your experience with this issue seems to be second to none. I also am having the cold rough idle (lasts for about 15 seconds after the secondary air injection pump shuts off) and the stuttering/hiccups under heavy throttle input in low RPM (especially trying to accelerate uphill). However, in my case, I have noticed that the stuttering and loss of torque problem all but disappears when temperatures are between 60F and 75F. Anything below 60F or above 75F and the problem returns. Another thing I am experiencing is severe hesitation in low RPM for a minute or two after driving off from a cold start, even with very light throttle input - then driving fine once warmed up a little. I never had a CEL appear and never had any pending codes. The car is a '04 325Ci with 30K miles (original owner) and I have been using Mobil1 0W-40 changed every six months since the first oil change. I am guessing that I am in need of a vanos repair but I am wondering if my specific symptoms may indicate other or additional problems as well. Any ideas? Do the vanos seals cause a variety of performance/hesitation issues depending on the degree of deterioration? Is it normal that a certain ambient temperature range causes the problem to be less noticeable if any? Thanks.

This is excellent news. My 328ci had a new vanos installed at 33K... iVe been having the cold start problem again since 80K. I was going to just get a new vanos, but now I can do this DIY.

Ill be ordering a set of these seals by years end!!
THANKS!

Hi Rajaie, is the crackling sound at 1200RPM related to the seals also? I have the timming chain tentioner crackling sounds problem and at times my car stalls when coming to a stop or turning at idle...also my idle RPM is not stable. I have a 2001 325. Thanks.

Originally Posted by Rajaie

Please better define the stall problem you are speaking of.

The cold weather cold start idle jolts and possible stall is usually found on M52TU engines. I expect BMW patched the software for the M54 & M56 engines to address this symptom. I know there is a software update to the M52TU to also patch this symptom.
I have seen a reference on this forum about cold weather first start stall. I thought this might be vanos related.

It is impossible to know what these software patches do without having specific information from BMW. Due to the spring in the vanos exhaust side, significantly leaking piston seals can render the exhaust side dysfunctional. Eventually engine fault codes are generated indicating this. I've referenced these codes above. Owners are now beginning to receive these codes. I wouldn't be surprised if BMW implemented a software patch to completely disable any use of the vanos exhaust side to address this symptom.

The problem with these software patches is, first they don't address the failure, second once the vanos is repaired the DME might not utilize it appropriately due to the software patches. I don't have faith that BMW changed the software in a way that detects and adapts to the vanos condition and performed thorough testing.
This whole thing is such a mess! BMW should be addressing the hardware problem, not continuing to generate software patches to circumvent the escalating failure symptoms.

The software patch does not address the Vanos at all if vanos has an issue the software patch won't help. It does change the cold start enrichment as these cars were to lean cold.

can a failing vanos cause a lean condition?

have you run into any early m54 engines that experience this cold start lean condition due to software issues?

Originally Posted by e46gp

Rajaie, thanks for all the work on this; amazing that you found the problem and how you came up with a very viable and affordable solution! I do have a question for you since your experience with this issue seems to be second to none. I also am having the cold rough idle (lasts for about 15 seconds after the secondary air injection pump shuts off) and the stuttering/hiccups under heavy throttle input in low RPM (especially trying to accelerate uphill). However, in my case, I have noticed that the stuttering and loss of torque problem all but disappears when temperatures are between 60F and 75F. Anything below 60F or above 75F and the problem returns. Another thing I am experiencing is severe hesitation in low RPM for a minute or two after driving off from a cold start, even with very light throttle input - then driving fine once warmed up a little. I never had a CEL appear and never had any pending codes. The car is a '04 325Ci with 30K miles (original owner) and I have been using Mobil1 0W-40 changed every six months since the first oil change. I am guessing that I am in need of a vanos repair but I am wondering if my specific symptoms may indicate other or additional problems as well. Any ideas? Do the vanos seals cause a variety of performance/hesitation issues depending on the degree of deterioration? Is it normal that a certain ambient temperature range causes the problem to be less noticeable if any? Thanks.

I expect your main problem is not the vanos. Your severe hesitation after cold start is the clearest indicator.
At 30k miles your car is not a candidate for the usual suspects that cause this type of issue.
My first guess is a vacuum leak. This is often caused by the CVV and associated hoses, but it’s too early for them to be a problem in your car. You should check the vacuum pressure. Also check the long term fuel trim values. They shouldn’t be more than +/-2.
This might be the MAF (mass air flow) sensor. After market oiled air filters can foul this sensor. You can clean it with a MAF spray cleaner. Be sure to allow it to dry thoroughly.
Try throwing a bottle of fuel injector cleaner in the gas tank.
Late model engines had Bremi coils that have been problematic. Not sure of you have these.

Air temperature and humidity do affect the engine. Also an engine acts differently when it’s cold. To me your varying indications point to an air/fuel issue; likely vacuum leak or MAF sensor.

At your miles, you’re still under warranty. You should take it in to the dealer.

Hope this helps.

Originally Posted by mpower325

This is excellent news. My 328ci had a new vanos installed at 33K... iVe been having the cold start problem again since 80K. I was going to just get a new vanos, but now I can do this DIY.

Ill be ordering a set of these seals by years end!!
THANKS!

Please tell us more about your experience so that others can learn from it.

What year is your car? At what mileage did you start experiencing the first vanos problem? What were the symptoms? Please be specific. Did the dealership perform the repair under warranty? What changes did you notice after the repair? Did you have performance gains? How many miles after the repair did you notice your performance gains disappear? What are your new symptoms?

Thanks.