Chain noise triggered by oil change - then clears

aigel · aigel's Garage

My pal bought an 84 Carrera w/ 138k miles in decent shape. Not much with respect to records, so we started a complete tuneup. We got as far as changing the oil, cap rotor and the passenger's side plugs and wires. Filled the tank with 9 quarts 20W-50, and fired it up. At idle, all was fine. Pal went around the block and returned few minutes later with a rattle at higher rpm 2000+, but not at idle.

After checking cap and rotor with nothing coming up, we traced the rattle to the driver's side chain housing. Very clearly from that area. We listened through a breaker bar and could practically sense the vibration, even with our hands. It was a rattle, not a valve tap or knock. I figured the oil change - and the short time without oil pressure from that - had triggered an event that pushed the tensioner over the edge.

After this dissappointing diagnosis, we were maneuvering the car around the house to stow it. Sure enough, during this action, the noise went away. Pal drove home, 10 minutes, driving normally and there was no more noise!

What's going on? Do you think air or debris got into the tensioners and now got bled out?

And finally, after this experience, would you keep driving the car? More importantly, would you take it to a DE if it behaves itself until the weekend?

TIA,

George

GB83SC · 07-01-2004, 06:17 AM

9 qt. oil change?

My 83SC 3.0 takes 10.5qt. to fill after oil and filter change.

If the oil pressure was low, it could keep the tensioner from full extension.

aigel · aigel's Garage

9 qt puts it above the low mark on the dipstick. That is definitely NOT low on oil! I never fill higher than mid way. One more quart got it midway. That can't be it.

George

widebody911 · widebody911's Garage

I've had this as well after an oil change; I suspect it's something akin to having to 'burp' the tensioners.

Zeke · 07-01-2004, 07:17 AM

The way I understand it is the spring holds the tension on the chains and the oil pressure is a fail-safe back up. What I do know is the tensioner should at no time release pressure on the cam chain. I would be in the engine removing and checking the tensioners if it were my car.

aigel · aigel's Garage

Quote:

Originally posted by widebody911
I've had this as well after an oil change; I suspect it's something akin to having to 'burp' the tensioners.

Did you do anything abuout it? Did you just keep driving it?

aigel · aigel's Garage

Quote:

Originally posted by Zeke
The way I understand it is the spring holds the tension on the chains and the oil pressure is a fail-safe back up. What I do know is the tensioner should at no time release pressure on the cam chain. I would be in the engine removing and checking the tensioners if it were my car.

The spring holds the tension, the oil is the dampening part. Just like a shock absorber. So, if there isn't enough oil, there isn't enough dampening and the chain can move enough to start making a noise. That's how I understand it.

I'd love to hear from more people that had this problem before and what they did about it.

John Walker would be a good resource here - someone with a lot of experience!

George

Vipergrün · 07-01-2004, 08:58 AM

Yes, some times the oil-pressure fed tensioners can do this. I would pop the chain housing covers off and take a look. You may want to put on those tensioner collars to prevent a complete collapse of the tensioner. I hope you meant that you drained and re-added the 9 qts

widebody911 · widebody911's Garage

Quote:

Originally posted by aigel
Did you do anything abuout it? Did you just keep driving it?

I just kept driving it. It was fine for another year or so until [iBANG![/b]. Of course that was due to a friend of mine redlining it in 2nd then shifting to 1st...

rhaas · 07-01-2004, 09:26 AM

It wouldnt hurt to take the timing chain cover off that side of the engine and check to make sure the chains have not stretched too much. That is about the symptoms that I had when my timing chains were stretching. It was the idler arm tapping the case.

RoninLB · 07-01-2004, 09:54 AM

maybe the pressure on the tensioner lid will give way a little after removing chain tension. Then use a tool to try to compress it? I'd like to hear what a pro says.

aigel · aigel's Garage

Quote:

Originally posted by bb80sc
Yes, some times the oil-pressure fed tensioners can do this. I would pop the chain housing covers off and take a look. You may want to put on those tensioner collars to prevent a complete collapse of the tensioner. I hope you meant that you drained and re-added the 9 qts

No collars available for the oil fed tensioners. You have to shim them internally to achieve that effect. Certainly will be done as soon as we can go in there. Now it is too late. DE Saturday! I am leaning towards attending with that car.

George

aigel · aigel's Garage

Quote:

Originally posted by rhaas
It wouldnt hurt to take the timing chain cover off that side of the engine and check to make sure the chains have not stretched too much. That is about the symptoms that I had when my timing chains were stretching. It was the idler arm tapping the case.

Interesting that you say this. My friend had intermittend chain noises and had the chains and other components replaced. Cured it.

The thing that still puzzles me is the fact that the oil change tiggered the symptoms. My pal has put about 1k miles on the car with never hearing the noise.

Any more input on the oil change part and if this will (likely) be fine for a DE?

George