SL/R230: loud knocking starting a cold engine.
Thread Starter
Junior Member
Joined: Nov 2018
Posts: 21
Likes: 4
From: Europe
SL500 2003
loud knocking starting a cold engine.
SL500 2003. Engine no 113.963
I have a loud knocking sound when starting a cold engine. Lasts about 10-15 seconds and then this sound disappear. It comes from the left valve cover. The sound follows the engine speed and agrees that it knocks half the crankshaft speed. There is certainly something about the camshaft or rocker arms, valve lifters.
My question is does anyone know this problem and what was the fault on your engine?
I have a loud knocking sound when starting a cold engine. Lasts about 10-15 seconds and then this sound disappear. It comes from the left valve cover. The sound follows the engine speed and agrees that it knocks half the crankshaft speed. There is certainly something about the camshaft or rocker arms, valve lifters.
My question is does anyone know this problem and what was the fault on your engine?
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Joined: Jul 2018
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From: USA Tennessee
2008 SL550 R230, 2004 E320 W211
It might be a lifter going bad that quiets down once the oil flowing as @Rudeney suggests (I have found his advice to always be spot on). How many miles are on it?
We have a 2004 Lexus LX470 (190K miles, V8 gasoline) that makes a clacking noise for the first 10 seconds on a cold engine, and I assumed it was a lifter. It has done this for the past 3 years and seems a little worse (lasts longer) in the winter and less noticeable in the summer. The research on the Lexus/Toyota forums indicated that it was "piston slap" and is a common (normal) issue with older Lexus/Toyota V8 (UZJ100) engines, and to just drive it and not worry about it unless it got worse (louder or lasted longer). However, we also have a 2000 Toyota Landcruiser 160K miles (identical to the Lexus LX470 but with fewer miles), and it does NOT exhibit this behavior (yet?). I don't know if this is common in Mercedes or not, I not aware of it. But you might do some searching for piston slap.
In either case, @Rudeney 's advice of thinner oil might help.
Lee
We have a 2004 Lexus LX470 (190K miles, V8 gasoline) that makes a clacking noise for the first 10 seconds on a cold engine, and I assumed it was a lifter. It has done this for the past 3 years and seems a little worse (lasts longer) in the winter and less noticeable in the summer. The research on the Lexus/Toyota forums indicated that it was "piston slap" and is a common (normal) issue with older Lexus/Toyota V8 (UZJ100) engines, and to just drive it and not worry about it unless it got worse (louder or lasted longer). However, we also have a 2000 Toyota Landcruiser 160K miles (identical to the Lexus LX470 but with fewer miles), and it does NOT exhibit this behavior (yet?). I don't know if this is common in Mercedes or not, I not aware of it. But you might do some searching for piston slap.
In either case, @Rudeney 's advice of thinner oil might help.
Lee
Thread Starter
Junior Member
Joined: Nov 2018
Posts: 21
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From: Europe
SL500 2003
Thanks for all suggestions.
The car has now 71000 mi. I don't drive much, aprox 2000 mi/year. Talking about oil I usually use Mobile 10W-30 synthetic oil. But have also tried different brand.
What oil quality do you use your cars?
The car has now 71000 mi. I don't drive much, aprox 2000 mi/year. Talking about oil I usually use Mobile 10W-30 synthetic oil. But have also tried different brand.
What oil quality do you use your cars?
Senior Member
Joined: Aug 2019
Posts: 340
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From: Europe
09 SL500, 03 E320 CDI Wagon
My engine has now 216K km on the odo, and still use no oil.
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Member
Joined: Sep 2013
Posts: 157
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From: Walpole, MA USA
2004 SL500
Is it possible that the knocking is from the belt tensioner which I believe is also oil pressure driven. If the oil pressure is low until warmed up, it could conceivably cause a knocking. Then again I may be confusing it with my old SLK350.
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Senior Member
Joined: Aug 2019
Posts: 340
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From: Europe
09 SL500, 03 E320 CDI Wagon
But I don't see how the chain or it's driven components could create a knocking sound ?
Member
Joined: Sep 2013
Posts: 157
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From: Walpole, MA USA
2004 SL500
Got it, and you're right, chain tensioner. I believe the theory is that at start up, until oil pressure builds, the tensioner can bounce a bit causing a knock. I never had it with the SL, but I want to say that my SLK exhibited that behavior occasionally.
Senior Member
Joined: Aug 2019
Posts: 340
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From: Europe
09 SL500, 03 E320 CDI Wagon
Severe slag in the chain, and it hitting the engine block or chain cover housing, could explain it, but normally less slag sounds like a rattle, not like knocking.
If you are right, the chain tensioner should be changed, it's a known issue on the M272/273 engine, not that much on the M113 engine.
My money is still on a clogged up lifter.
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I use Mobil 0w40 because it's on the approved 229.5 list and readily available (about $26 for a 5qt jug at Walmart).
The chain tensioner on the MM12/M113 engines is hydraulic, so this could get noisy. Replacement is fairly simple - just remover engine covers and the alternator for access. Torque is 80Nm.
The chain tensioner on the MM12/M113 engines is hydraulic, so this could get noisy. Replacement is fairly simple - just remover engine covers and the alternator for access. Torque is 80Nm.
Senior Member
Joined: Aug 2019
Posts: 340
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From: Europe
09 SL500, 03 E320 CDI Wagon
[QUOTE=Rudeney;7952321
The chain tensioner on the MM12/M113 engines is hydraulic, so this could get noisy. Replacement is fairly simple - just remover engine covers and the alternator for access. Torque is 80Nm.[/QUOTE]
Rodney, think about it, knocking from the chain, I doubt it, but on the other hand, sound is deceptive. What is knocking to one person is ticking to the other, and wise versa.
By the way, Mobil 1 ESP 5W30 have the following approvals.
MB-Approval 229.31
MB-Approval 229.51
MB-Approval 229.52
The chain tensioner on the MM12/M113 engines is hydraulic, so this could get noisy. Replacement is fairly simple - just remover engine covers and the alternator for access. Torque is 80Nm.[/QUOTE]
Rodney, think about it, knocking from the chain, I doubt it, but on the other hand, sound is deceptive. What is knocking to one person is ticking to the other, and wise versa.
By the way, Mobil 1 ESP 5W30 have the following approvals.
MB-Approval 229.31
MB-Approval 229.51
MB-Approval 229.52
Last edited by SLcharge; Jan 13, 2020 at 05:20 PM.
Thread Starter
Junior Member
Joined: Nov 2018
Posts: 21
Likes: 4
From: Europe
SL500 2003
Well for me it very clear the sound is knocking and nothing else. It can also be heard that it is just one lifter or rocking arm knocking.
I will try the thin Mobil 0w40 oil and perhaps also add one can of additive. This should be interesting to hear the result.
Thanks for now
I will try the thin Mobil 0w40 oil and perhaps also add one can of additive. This should be interesting to hear the result.
Thanks for now
MBworld Guru
Joined: Dec 2009
Posts: 10,782
Likes: 1,011
NO LONGER ACTIVE
Yes, it makes much more sense that the sound is a lifter (a not uncommon problem on the M112/M113 engines). A bad timing chain tensioner might still make noise, but probably not a paced knocking sound.
