rattle when cold
03-12-2002, 03:51 PM
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Join Date: Dec 2001
Location: Milano
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rattle when cold
Hi to all,
I send this message to conclude a long odyssee of finding the real error for a symptom that seemed linked to the chain tensioners.
All started with a rattling noise when the engine was cold. This rattling noise was only noticeable from inside the car, coming from the right side; you couldn't hear by listening to the engine from the engine compartment, but only from inside the car. The rattle disappears completely once the engine is warmed up.
1. Assumption:
I assumed a chain tensioner had failed. Although I had hydraulic tensioners(considered bullet-proof), I replaced the right hydraulic tensioner and I updated to the later bronze bushed idler arms.
1. Result: Wrong, no change, rattle when cold does not change
2. Assumption: Timing chains worn out and consequently chain tensioner not effective.
So I changed timing chains (it is not difficult once you take off the chain housings), and redid the cam timing.
Result: The engine running very smoothly now (probably due to the readjusted cam timing), the once and then popping through the intake has completely disappeared. I also found out: Maximum travel of the tensioner is about 15mm, so when you see that the tensioner is out by more than ~10mm it is necessary to change chains and/or sprockets/intermediate gear.
But: Still there is the rattle noise when the engine is cold.
3. Assumption: Oil filter problem: Bingo, here we are: By changing the oil filter the rattle has disappeared completely. Examining properly I found that the safety valve in the oil filter was defective. You could hear rattling when shaking the oil filter in your hand. This rattling was then transmitted by the oiltank to the chassis and caused the noise. Replacing the oil filter has completely eliminated the problem. Once the oil had warmed up it was too liquid to cause the rattling, that's why the noise dissappeared.
Thank you for reading, and I will promise to myself that I will never open the timing gear again on this car in my life.
At least I hope that this description helps pinning down errors of one of you rennlisters more quickly
Ciao from sunny Milano
Andreas
I send this message to conclude a long odyssee of finding the real error for a symptom that seemed linked to the chain tensioners.
All started with a rattling noise when the engine was cold. This rattling noise was only noticeable from inside the car, coming from the right side; you couldn't hear by listening to the engine from the engine compartment, but only from inside the car. The rattle disappears completely once the engine is warmed up.
1. Assumption:
I assumed a chain tensioner had failed. Although I had hydraulic tensioners(considered bullet-proof), I replaced the right hydraulic tensioner and I updated to the later bronze bushed idler arms.
1. Result: Wrong, no change, rattle when cold does not change
2. Assumption: Timing chains worn out and consequently chain tensioner not effective.
So I changed timing chains (it is not difficult once you take off the chain housings), and redid the cam timing.
Result: The engine running very smoothly now (probably due to the readjusted cam timing), the once and then popping through the intake has completely disappeared. I also found out: Maximum travel of the tensioner is about 15mm, so when you see that the tensioner is out by more than ~10mm it is necessary to change chains and/or sprockets/intermediate gear.
But: Still there is the rattle noise when the engine is cold.
3. Assumption: Oil filter problem: Bingo, here we are: By changing the oil filter the rattle has disappeared completely. Examining properly I found that the safety valve in the oil filter was defective. You could hear rattling when shaking the oil filter in your hand. This rattling was then transmitted by the oiltank to the chassis and caused the noise. Replacing the oil filter has completely eliminated the problem. Once the oil had warmed up it was too liquid to cause the rattling, that's why the noise dissappeared.
Thank you for reading, and I will promise to myself that I will never open the timing gear again on this car in my life.
At least I hope that this description helps pinning down errors of one of you rennlisters more quickly
Ciao from sunny Milano
Andreas
