: Engine Tick after oil change - very concerned



joeveto
03-10-04, 07:41 PM
Hey all, I bought this 97 Eldo two weeks ago. At the time of purchase, I noticed a mild ticking noise. The shop manager said "Have you ever owned a Caddy before? They all do that." He was a jerk. A bit of a know it all. The kind of guy that "has been doing this for 30 years" and you're not going to tell him a damn thing. I bought the car anyway, deciding the noise wasn't that bad, and was most likely something harmless.

At any rate, before it was too late, I decided to have the oil changed. I had them put 10W-30 Mobil 1 in the crankcase. The car took nearly 8 quarts.

When I got the car home, I noticed a loud tick when the car is in idle. Accelerating, cruising, whatever, I don't hear it. But when the car is sitting in the drive, in park, the tick has gotten to be a lot louder. If I goose the throttle, the the tick / knock speeds up, becomes louder, and then settles back down to a softer, but still audible level.

What do you think it is? Should I lose my mind? I can still buy the warranty...

BeelzeBob
03-11-04, 12:18 AM
Hey all, I bought this 97 Eldo two weeks ago. At the time of purchase, I noticed a mild ticking noise. The shop manager said "Have you ever owned a Caddy before? They all do that." He was a jerk. A bit of a know it all. The kind of guy that "has been doing this for 30 years" and you're not going to tell him a damn thing. I bought the car anyway, deciding the noise wasn't that bad, and was most likely something harmless.

At any rate, before it was too late, I decided to have the oil changed. I had them put 10W-30 Mobil 1 in the crankcase. The car took nearly 8 quarts.

When I got the car home, I noticed a loud tick when the car is in idle. Accelerating, cruising, whatever, I don't hear it. But when the car is sitting in the drive, in park, the tick has gotten to be a lot louder. If I goose the throttle, the the tick / knock speeds up, becomes louder, and then settles back down to a softer, but still audible level.

What do you think it is? Should I lose my mind? I can still buy the warranty...

Hmmm....they do NOT all do that.....

If it is a light tick that sounds like a lifter I wouldn't be too concerned. Personally I would take it out for a good spin. It sounds like there is either air in a lifter...which is hard to purge out...or possibly a tiny piece of debris is holding a lifter check ball open causing the lifter to collapse and tick. Driving it may get rid of it. Worst case is to have the lifter diagnosed and replaced.

Try removing the PCV valve and the oil fill cap and listen to the cavity to see if you can hear the lifter noise inside the cam cover and determine which side it is on.

The other possibility here is that the engine was babied quite a bit and has a lot of carbon build up. If that is the case the carbon builds up inside the combustion chamber until it gets thick enough in the squish areas to actually contact the piston at TDC... The carbon contact upsets the motion of the piston causing it to rock in the bore or "slap". This is more a rap or knock...commonly called carbon rap. Lots of Northstars that get babied develop this....the cure is easy....just get on the throttle. Drive it the way it was designed to be driven. Hard and fast. Some full throttle accels to 80 with WOT upshifts will quickly eliminate the carbon and the noise. Do the WOTS occasionally to keep the carbon at bay.

I would doubt that anything serious is wrong. The Northstar is pretty bullet proof in the lower end and the valve train. It is designed to be run hard so it can easily take it.

joeveto
03-11-04, 12:39 AM
Hmmm....they do NOT all do that.....

If it is a light tick that sounds like a lifter I wouldn't be too concerned. Personally I would take it out for a good spin. It sounds like there is either air in a lifter...which is hard to purge out...or possibly a tiny piece of debris is holding a lifter check ball open causing the lifter to collapse and tick. Driving it may get rid of it. Worst case is to have the lifter diagnosed and replaced.

Try removing the PCV valve and the oil fill cap and listen to the cavity to see if you can hear the lifter noise inside the cam cover and determine which side it is on.

The other possibility here is that the engine was babied quite a bit and has a lot of carbon build up. If that is the case the carbon builds up inside the combustion chamber until it gets thick enough in the squish areas to actually contact the piston at TDC... The carbon contact upsets the motion of the piston causing it to rock in the bore or "slap". This is more a rap or knock...commonly called carbon rap. Lots of Northstars that get babied develop this....the cure is easy....just get on the throttle. Drive it the way it was designed to be driven. Hard and fast. Some full throttle accels to 80 with WOT upshifts will quickly eliminate the carbon and the noise. Do the WOTS occasionally to keep the carbon at bay.

I would doubt that anything serious is wrong. The Northstar is pretty bullet proof in the lower end and the valve train. It is designed to be run hard so it can easily take it.
I guess my concern surrounds the timing of the noise. Why would it present itself after an oil change? Especially an oil change to lighter weight oil...My thought, is that the dealership may have been trying to cover something up, and threw some heavy weight oil into the motor to disguise the issue.

The upside, is that I went outside and started the car, and did not hear the noise. So maybe it was a lifter. Tomorrow, I plan to make a few hard runs (I already have, as I love the sound of the motor).

I'll keep you all updated...Thanks for the response. I trust your opinion.

BeelzeBob
03-11-04, 01:18 AM
It sounded like from your original post that the noise was there before the oil change and just seemed to get worse after the oil change...???


If the car was for sale for a while and not driven then it could have bled a lifter down while sitting...and then injested air when it was started. That air in the lifter takes a long long time, hours sometimes, to completely purge. Drive it.

joeveto
03-11-04, 01:04 PM
It sounded like from your original post that the noise was there before the oil change and just seemed to get worse after the oil change...???


If the car was for sale for a while and not driven then it could have bled a lifter down while sitting...and then injested air when it was started. That air in the lifter takes a long long time, hours sometimes, to completely purge. Drive it.
I took your advice, I got it out on the freeway, and I ran it up to the redline. I also ran a few top gear accelleration runs. I'd go up to 100, back it off to 50, go back up to 100, etc. I don't currently hear the noise. Let me also say, I suspect the A/C compressor. I notice it a lot more with the compressor pumping. Which is great and bad. Great because it's probably a noisy compressor. Bad because I didn't think of this possibility sooner.

I'm just freaked out and looking for things to go wrong. This tension is brought about by the pressure of knowing I can still get the warranty. But I think buying the warranty is probably a bad idea. When you look at what the warranty actually covers, and what it doesn't, well, I'm not sure it's worth the cost.

So thanks again for the help and advice. I really appreciate the assistance.