I have a 2001 Pontiac Firebird 3800 with about 106,000 miles on it. After an oil change gets to be about 2500 miles on it I get valve noise (tick) at start up and it goes away after a couple of min. My concern is the fluctuation of the oil pressure when engine is cold. drops/ rises from 40 to 90 psi. depending on the engine RPM. It fluctuates like the tach. when engine gets warm, ticking gone and pressure stabilizes. Also after fresh oil, pressure on average higher than when oil gets a few miles on it. I have changed presure sensor already and same results. Wondering if could be pressure regulator. Have changed oil trying different types and cleaners about 4 times in last 10000 miles. Noise goes away a day or two after new oil and comes back at about 2500 miles after oil change. Presure stabilizes after fresh oil as well. Oil sceems to be ok before the change (no coolent or water in it.) Anyone have any ideas. Noise is pretty loud as far as valve tick. Once noise goes away( and even when noise is thier) car runs like a champ!!! Anyone help?

amfornal, welcome to GMForum

Take a look around and enjoy the stay!

One ticking lifter tells me its the lifter not the oil.

If it is low oil pressure, the first thing to check is if the oil pressure relief valve is stuck open. I would disassemble the relief valve, and check it out to make sure it is not sticking. There is a picure below. You are looking for items 74 and 75.

If it is a sticking or collapsed lifter, I would try Seafoam in your oil 100 miles before your next oil change. It may or may not clean it up. If not, you may have to replace the lifter.

Is it worse in the colder weather?

Welcome to the forum! Your thread was moved to the Pontiac mechanical and maintenance section, where it can get a targeted response to your issue.

Well, I think I found my problem. On a hunch, and thinking oil pressure regulator/ clogged filter,I changed the oil filter only and saw that it was full of crud!!! Only thing I can think of is that after running some sea foam and various products before previous oil changes, that I losend up a whole lot of sludge. I bought this car about 15000 miles ago and Ill bet since it was fairly low mileage for its age, it only saw short " sunnday drives" and built up alot of sludge over the years. Now, what would anyone suggest from hear? The car is in great shape and runs fantastic.

ls crate engine. lol. just run it and see with out the additives, the filters have alot to do with pressure, if they are getting gunked up thats your reduction in pressure and that will cause lifter noise. you arent using a fram filter are you?

Sludge in the filter is a good thing. That means whatever you did got the sludge out of the engine. If you are concerned things have been stirred up that are still floating around in there, increase your oil change frequency for the next couple of changes. Another shot or Sea Foam before your next change wouldn't hurt either.

No, not useing Fram filter. This one was a purilator (Gold one). I put a cheap filter on it temporarily just to see if that was problem. Going to seafoam again this weekend and change oil and filter with Purilator and Mobil 10w-30 synthetic. While changing the oil going to go ahead and replace pressure relief valve and spring. May take valve cover(*) off to see how bad sludge may be. Anyone ever take oil pan off firebird/ Camero 3.8 v-6 before? Lookes like a big chore.

If the pressure relief valve is sticking, a good cleaning will probably correct the problem. Read the post at the start of the thread at this link in which Dan describes a mod where you add a washer under the pressure relief valve and it will increase your oil pressure:

https://www.gmforum.com/showthread.p...t=oil+pressure

The above thread is also good because it describes how to get to the pressure relief valve.