99 monte carlo ls engine ticking

Hello, I just recently bought a 1999 monte carlo ls with a 3.1 liter engine that has 137,000 miles on it. When the engine is cold there is a loud ticking that gets louder with acceleration. Once warm, the engine runs smooth without any unnormal noises. Does anybody else have this problem? Is there anyway to fix it? Are there certain oils or additives that will help or fix the problem? Or is it nothing to worry about?

If you know anything about this problem please let me know. Your help is greatly appreciated. Thank You.

Could be lifters or worse,a bad camshaft.The 3100 and 3400 are known for eating cams and washing out the cam bearings.The block is junk right away if this happens

Do not not be too quick to jump to cam issue here which would not clear up warm, piston slap, which is inherent to just about every 3.1/3.4 out there is much more likely.

I have seen 3100s and 3400s eat cams up and wash the cam bearing out.Jasper,the top of the line engine reman company found out,fixes it right and it is not because the camshaft is hollow in the center.The blocks were casted in China and the cam journals were casted offset with GM putting in the cheapest cam bearings.Jasper fixes this by alighn boring the cam journals and put in upgraded cam bearing.Jasper is the only one that does this and GM does not.A Jasper rep that comes in my father's shop told this since my father is a Jasper dealer bringing a sample of a portion of a broken cam from a 3100 with him.The Jasper rep that I know explained this very clearly.

And how does this help the OP determine what his engine noise is, a cam failure of this nature does not match his symptoms, ie: noise goes away when warmed up?

I have seen this many time in a 3100 with broken cams in half.one would not run and one ran with a chopping noise and quit.

I can just about guarantee that the problem is piston slap. Nothing to worry about.

How are the intake gaskets? Notice any leaking coolant, or, low coolant?

Try a quart of Marvel Mystery Oil. May help if you have stick lifters.

Ironic I should read this thread after just getting home from the mechanic working on my daughters car. It's a 96 Monte with the 3.1 engine. The thing has been running like absolute crap during warm up. The running like crap only happens under load (acceleration). I was at a loss so I had to resort to bringing it to the only shop I trust. The first thing they fixed was to replace the exhaust manifold at the rear of the engine. We thought because the crack was in the immediate area of an oxygen sensor, replacing it may fix the poor performance. Well after replacement and everything was quiet we found the engine has a very bad knock when cold. And it still ran like crap. They did a lot of testing of temperature sensors, air flow sensors and ox sensors and everything checked out ok. So they took the thing for a ride with the computer connected and collected a ton of data. What they found was all the noise the engine is making (mostly piston slap they said) is causing the knock sensor to retard the timing. A lot. I believe he said up to 18 degrees. Once the engine warms up and most of the noise is gone, it runs like a top. If you disconnect the knock sensor, the thing runs great when cold. He gave me some suggestions of things they could try but it all sounded like expensive but educated shots in the dark. So these are my questions. Could it be as simple as the sensor is old and hypersensitive? It's and easy replacement. Or should I look at running heavier oil than recommended? Like 10w30 or 10w40. What about any oil additives that actually work? The mechanic also recommended a professional fuel system cleaning.

Clearly the question here is what is the noise, anything to get around it is a patch, the knock sensor, if it is as loud as you say, is doing it's job. If it is slap and it is getting worse, than you may as well leave it off, unless you are going into the engine. This will cause pinging, possible detonation and in some states will fail the vehicle emissions test. Fuel sytem cleaning has no effect unless it was carbon build up on the piston domes, not a condition these engines experience. Again, if slap heavier oil may quiet it in some undetermined degree, but usually not signifcant.

The reason the noise becomes less when the engine warms up is because all the metal parts expand with increase in engine temperatures. This takes away alot of the clearance issues that creates rattles with the cold engine. If the rattles continue with the engine warm, then you have some real reasons to be concerned. Loose engines can self destruct from the stress of hammering parts. I would use a good synthetic blend or full synthetic oil to help reduce further wear and tear on components from friction.

Drove my 90, 3.1 Pontiac to over 350,000 with full synthetics and no problems. Now have 2002, 3.4 Pontiac with over 180,000 and no problems. I purchased both new. Also have 2000 DTS and my 1 owner 70 Nova 168,000. I'm a believer!!! Started with AMS OIL now use Castrol Syntec.

I don't want to look like I'm stealing someone else's thread but just one more question. About the knock sensor. Have they been known to get over sensitive with age? I can get one for $27 and it's easy to replace. When warm is quiets down to no knock or ticking at all.

The knock sensor is doing exactly what it is supposed to do. It will ony cost you $27 to find out if it is operateing out of range.