I have a 1991 Camaro with a 3.1L V6. The engine has a 132000 miles.

When I first bought the car in early 2001, I could hear a slight ticking sound coming from under the car, just behind the drivers front tire. You can only hear this noise when the car is at idle when it is at operating temperature (you cannot hear this ticking when the motor is reved up, nor can you hear it when the engine is cold).

Recently the ticking has gotten much louder, I took it to a technician and he said the noise was bottom end, probably a rod bearing. I was told by someone else it could be a timing chain.

I was told by someone to try runing "Marvel Mystery Oil" for an hour (to clean) and then drain and refill with regular oil. I did this, and while the marvel mystery oil was running in the motor, the noise was gone completely! (even when the motor was at operating temperature). But, as soon as I drained it and used regular oil the noise returned, just as loud as before. (I have tried almost every brand of motor oil known to man (except synthetic) and the noise is unchanged).

Any thoughts?

 

Sounds like a bad or sticking hydrolic lifter or oil pressure problem at idle if it clears up at higher RPMS. what does your oil gauge look like and what is it doing??

Try running 10w-40 or 10w-50 and see what happens. I bet that Marvel Mystery Oil was just thicker. Also put on a brand new oil filter.

 

Actually, the Lifters and Pushrods have been recenly replaced (was making same noise before and after).

I have tried thicker oils from 10-40 up to 20-50 (Valvoline Racing 20-50), but generally I just use 10-30. The noise remains constant with each of these oils.

When driving the car, the oil guage moves up to about 3/4 of max and while at idle the pressure fluxuates between 1/4 and 1/2 of max.

Wierd huh?

 

Interesting, are you sure the guy did everything he said he did and set the valve lash correctly? Not that the person that sold you the car just said that to make you feel better or something.

On my 1992 the oil pressure never moves, always the same last mark. Does it fluxuate after you put a new filter on?

What you might do is screw on a gauge right where the sending unit screws on. Requires that you take off the sending unit with the engine off of course. Then read the gauge and compare to what the manual says you should have, this will tell us if there is an oil pressure problem at idle.

And the ticking goes away when you rev it.... for sure? Does the ticking speed up when you give it a little gas. It comes from the engine not from the front pullies or something right?

Did you run 10-40 up to 20-50 for the full 3,000 miles not just a quick test?

The rod bearing he is reffering to is the bearing on the bottom of the piston not at the crank I think.

 

I know for sure the lifters and pushrods were replaced because I paid to have them done, and I have the old ones in a plastic wal-mart bag (haha).

The ticking sound does go faster with minimal increase in RPM's, but goes away or could be being drown out by the sound of the engine when the rpms increase to around 2-3k rpms.

Yes I did run all the oils for the full 3,000 miles and noticed no change in sound. I have thought of almost everything and still cannot figure it out. I have posted this problem to multiple message boards and no luck yet. I may just have to completely rebuild the engine to get rid of the noise.

I will try your suggestion with the oil guage. The oil guage on my dash does fluxuate at idle, not a whole lot, but it is noticeable.

The engine runs strong and has plenty of power, so whatever the problem is, it must not be effecting performance.

Thanks for your help, hopefully we will figure this out.

 

Yep check out the oil, pump, if it's not that then that guy is right, it's internal and I think your best bet would be to go ahead and rebuild OR upgrade to a 3.4L long block and put that in since it bolts right in. Would give you another 20 more hp too.

 

Where can I find a 3.4L long block? Should I look at junk yards? If so, then what vehicles came with the 3.4L?

Maybe I will just build a 3.4L and swap them when its done.

 

1993 - 1994 Camaros and Firebirds.

Do a search on the board, KED85 has posted a lot on this topic.

Or you can order a remanufactured long block from jasper or other engine rebuilders that come with a warrenty and be brand new since you don't need the other stuff that comes with a used engine because you will be using your emissions equiment and intake.