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Cold Start Rattle: All models

18K views 12 replies 11 participants last post by  khomer2 
#1 ·
This update relates to ALL engines from 1995 to today. Cold srart clatter, clanking, rattle: It's not the chain tensioner or the timing chain at all. Unless you have over 250k on odometer or have not changed the oil every 5,000-7,000 miles, the noise you hear is from the VVT valve timing system and is easily remedied. All VVT engines will make a noise after sitting for more than 3 days. However, some do not make the noise by which we can hear them. The noise is indicative of a lack of full oil pressure at the lifter sprockets on the cam and VVT mechanisms.

There is nothing wrong with the engine. It probably has been making this noise since day one. If your windows are shut when you start the car after sitting for a few days, or even overnight in temps below 70 (f), you will hear that noise after a second past ignition and it will last for 1-2 seconds and stop.

To fix the problem, simply press the brake pedal firmly, not by smashing it, but by pressing it as if you were traveling at 40mph and had to slow down a bit. Press the pedal 2 times, and before starting, press the brake pedal firmly and start the car while pressing that brake pedal. The result will be to create a "vacuum pull" in the valve train and intake manifold, simulating the sane vacuum force created within the engine when it's running.

Simply press firmly on the brake pedal twice, then prior to turning the key, simply press the pedal firmly a third time, but hold it, start the car, and release the pedal. No more noise; guaranteed.

I learned this when I had the same cold start noise on a 2002 Lexus GS 300 as well as a 2007 Lexus GS350. Both had VVT valve systems. You see, all VVT engines use vacuum as well as hydraulic and electric/mechanical aspects to the variable valve timing.

It's not really a design flaw in any of these engines, at least not the SLK or any other car I've owned. Usually, a TSB will be issued if customers complain enough about the fears that their engines are grinding. Most TSB's for valve clatter on cold start involve changing the vacuum orifices in either the power brake systems or at the camshafts. It's so much easier just to create a simulated vacuum pull by pressing firmly on the brake pedal a few times then holding the pedal firmly when cold starting. Once the engines fires, let go of the brake pedal and you will not hear a rattle, clank, etc.

I've found this out by studying engine schematics on Mercedes, BMW, Audi, Chevy, Ford, Toyota and even Chrysler products. Each time a friend would complain about cold start clanking/clatter, I would advise them to try my method and they all reported that the noise was gone.

Why don't the dealers or other mechanics tell you this procedure? I have no idea, but it works.

Try leaving your car for as long as it takes to simulate that clatter. (for my R170) it was always 5+ days. If it is only 24 hours, overnight, or three weeks, just try my method and you'll see your noise is gone. My friends R171 has 272k on the odometer, and he replaced his timing chain tensioner three times and it did nothing to stop the clatter. Once he started the car using my 2 second fix, his noise went away.

Now, if you allowed OCI's of 10k miles for 150,000 miles and used a less than wonderful oil blend, you could have a partially clogged timing chain tensioner. However, the difference between cold start valve clatter and timing chain clanking is night v. day. Timing chain clatter does NOT appear only on cold starts and sound much different.

Please let me know how this starting procedure works. Oh, no need to ever bother with a warm engine. Vacuum remains in all engines for up to 12 hours.
 
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#5 ·
Has anyone above tried this? Care to post results. I’ve been scouring the internet looking for a solution that didn’t include $2600 leaving my bank account. I’m going to try this in the morning.
Thank you in advance if this solves the issue. It’s been freaking me out the last couple days since it started.
 
#9 · (Edited)
First tried your method this morning, it works!!! Mine has a really loud rattle for 2,3 sec at cold start and then goes away. The noise has been going on for just a couple week. I don't mind pumping the brake pedal a couple time before starting in the morning if that's what it take. Thank you.

Update: It works most of the times. It's just a temp solution.
 
#10 ·
In Fords with drive by wire, applying WOT when turning key will run starter motor without firing engine. This builds oil pressure in dry lifters and cam phasers which eliminates start up rattles and lifter knock. The OP's vacuum building technique is different but has similar goal. Wondering if there is a way in Mercedes to crank motor without firing up?
 
#11 ·
This update relates to ALL engines from 1995 to today. Cold srart clatter, clanking, rattle: It's not the chain tensioner or the timing chain at all. Unless you have over 250k on odometer or have not changed the oil every 5,000-7,000 miles, the noise you hear is from the VVT valve timing system and is easily remedied. All VVT engines will make a noise after sitting for more than 3 days. However, some do not make the noise by which we can hear them. The noise is indicative of a lack of full oil pressure at the lifter sprockets on the cam and VVT mechanisms.

There is nothing wrong with the engine. It probably has been making this noise since day one. If your windows are shut when you start the car after sitting for a few days, or even overnight in temps below 70 (f), you will hear that noise after a second past ignition and it will last for 1-2 seconds and stop.

To fix the problem, simply press the brake pedal firmly, not by smashing it, but by pressing it as if you were traveling at 40mph and had to slow down a bit. Press the pedal 2 times, and before starting, press the brake pedal firmly and start the car while pressing that brake pedal. The result will be to create a "vacuum pull" in the valve train and intake manifold, simulating the sane vacuum force created within the engine when it's running.

Simply press firmly on the brake pedal twice, then prior to turning the key, simply press the pedal firmly a third time, but hold it, start the car, and release the pedal. No more noise; guaranteed.

I learned this when I had the same cold start noise on a 2002 Lexus GS 300 as well as a 2007 Lexus GS350. Both had VVT valve systems. You see, all VVT engines use vacuum as well as hydraulic and electric/mechanical aspects to the variable valve timing.

It's not really a design flaw in any of these engines, at least not the SLK or any other car I've owned. Usually, a TSB will be issued if customers complain enough about the fears that their engines are grinding. Most TSB's for valve clatter on cold start involve changing the vacuum orifices in either the power brake systems or at the camshafts. It's so much easier just to create a simulated vacuum pull by pressing firmly on the brake pedal a few times then holding the pedal firmly when cold starting. Once the engines fires, let go of the brake pedal and you will not hear a rattle, clank, etc.

I've found this out by studying engine schematics on Mercedes, BMW, Audi, Chevy, Ford, Toyota and even Chrysler products. Each time a friend would complain about cold start clanking/clatter, I would advise them to try my method and they all reported that the noise was gone.

Why don't the dealers or other mechanics tell you this procedure? I have no idea, but it works.

Try leaving your car for as long as it takes to simulate that clatter. (for my R170) it was always 5+ days. If it is only 24 hours, overnight, or three weeks, just try my method and you'll see your noise is gone. My friends R171 has 272k on the odometer, and he replaced his timing chain tensioner three times and it did nothing to stop the clatter. Once he started the car using my 2 second fix, his noise went away.

Now, if you allowed OCI's of 10k miles for 150,000 miles and used a less than wonderful oil blend, you could have a partially clogged timing chain tensioner. However, the difference between cold start valve clatter and timing chain clanking is night v. day. Timing chain clatter does NOT appear only on cold starts and sound much different.

Please let me know how this starting procedure works. Oh, no need to ever bother with a warm engine. Vacuum remains in all engines for up to 12 hours.
I have a 2011 e350 v6 petrol and this worked essentially once pressure in the pedal occurs it’ works ....wow
 
#13 ·
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