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Chris (aka- Moose)
Chris (aka- Moose), Pontiac Technician
Category: Pontiac
Satisfied Customers: 47273
Experience:  16 years of experience
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Pontiac Trans Am Firebird: Need someone with GM expertise (ASE

Customer Question

Need someone with GM expertise (ASE Master), performance ie 550hp regular gas, and hptuner experience for 2002 Trans Am 5.7 V8 that has a rebuilt LQ4 in it. Issue is a stubborn oil leak that has surfaced 7 mos after the build we can not get rid of. It's wet, but not enough to drip in the crease between the bellhousing and pan. Then a drop coming down from the starter. I put Blue Devil oil stop and now rear main seal stop in it over the past 3 days and also UV dye to see where it's coming from and what caused it. We used all new name brand gaskets with the rebuild. We also now just installed an air/oil separator. The car left with no leaks. The customer claimed they could tune it themselves with hptuner and he's been tuning in for 7 mos now, with it running rich the first 3 mos at least. It's been back 3 times with oil leaks and we when we removed the manifold gaskets they were clearly leaking and distorted this time. We replaced those and that took care of the majority of it. We then re-seeded the oil pan with gasket and sealant, but still have a wet spot at the location. What would cause this? and what else can we do to locate the leak. I've added uv detection, but need to drive it more. I'm at my witts end with this.
Submitted: 1 year ago.
Category: Pontiac
Expert:  Chris (aka- Moose) replied 1 year ago.
Welcome, I'm Chris (aka Moose). I normally log in after 3 pm central. Please make sure to let me know exactly what is needed from me so I can provide EXCELLENT 5 STAR service. Finding stubborn leaks is not easy though your on the right track with the oil dye. I like to use brake cleaner prior to wash it down so I have a clean slate to look at. I usually get my customers to drive a minimum of 100 miles and try to park it overnight aiming up hill then downhill and in some cases leaning to the left or right. The dye for me is 90% effective of tracing the origin down. Based on where your saying its coming from, I believe it may be the rear main which no stop leak is going to resolve. Have you checked the crank run out to see if its excessive? -------------------------------------------------------------------------------------On your screen at the top you should see a rating 1-5 stars and a green submit button. Please make sure to select one and press submit. I am not compensated by the website unless a customer rates. Rating only pays me from the deposit you have already made, it does not charge you more, nor close the post. Also all follow ups are free and welcome.Thanks Chris
Customer: replied 1 year ago.
I use brake cleaner also to wash down before every new attempt. And I've driven it 150 miles now. Even though I've added the dye, it's not showing up yet. I'm fearful it's the rear main also which we have replaced 2x already. 1 with the new build and then a 2nd time when we did some modifications. What would cause that?
Customer: replied 1 year ago.
He leaves and it's dry. Comes back a few months later with something new. Not always the same place.
Expert:  Chris (aka- Moose) replied 1 year ago.
Did you check the crank shaft run out that I mentioned prior. Are you removing the transmission and flexplate to use the UV light to search for the dye? Any proof the owner is running the engine rpms to high or the engine to hot?
Customer: replied 1 year ago.
Not yet on crank shaft. At this point I'm trying to avoid dropping the trans again. It's a 550 hp engine. I know he's running it hard at times. That's what we built it for.
Customer: replied 1 year ago.
and no on the engine running hot. I've been driving it for 4 days. steady temp, but yes I have had it at 110mph, fast acceleration etc.
Expert:  Chris (aka- Moose) replied 1 year ago.
Other than the things I have mentioned, the only thing I know left to check is crankcase pressure being to excessive and force oil out seals.
Customer: replied 1 year ago.
How do I check that?
Customer: replied 1 year ago.
And what's "excessive" for that hp?
Customer: replied 1 year ago.
and if it is...what can I do about it?
Customer: replied 1 year ago.
and could the fact that it was running rich for 3 mos have degraded the gaskets. We've had PCV leak, oil pan gasket leak, manifold gasket leaks. We fix it and a few mos later comes back again. That's why we just put the air/oil separator in it this visit, but not really a chance to see how that works because we can't get this last small/tiny leak resolved.
Expert:  Chris (aka- Moose) replied 1 year ago.
A low pressure pressure gauge dead headed on the PCV system is used to check crank case pressure. Over 5 psi would be excessive. If this is the issue then the combustion chambers are letting to much pressure by the rings and cylinder walls.
Customer: replied 1 year ago.
And if that is the case, how do we fix that?
Expert:  Chris (aka- Moose) replied 1 year ago.
That would mean you rebuild the engine.
Expert:  Chris (aka- Moose) replied 1 year ago.
Are you pleased with my assistance?Do you need more help?
Customer: replied 1 year ago.
I need to check these things today to see if I need more help and they make sense. I will let you know. Thanks.
Customer: replied 1 year ago.
If this is the issue and we have to rebuild...the combustion chambers are letting to much pressure by the rings and cylinder walls, then what would I need to replace etc? Attached is the build sheet. Can you see if anything looks out of whack? My Husband was an expert in performance builds. Worked on Kenny Bernsteins Racing team when they first went 300mph. We started our own performance shop in 2012 and he passed away in 2014 and a friend of his stepped into help me with the mechanical part and this was an engine he built. Ran great on the engine dyno, pulled over 500 etc, 5 guys in the business gave it the thumbs up, but we've had numerous issues when it went back in the car. It's never been tuned exactly right (customer's responsibility) and I'm trying to get to the root cause.
Expert:  Chris (aka- Moose) replied 1 year ago.
If crankcase pressure is to high from excessive blow by. Then there is a ring or piston to bore clearance issue. Your clearance was 0.030 was that inches or mm? https://dl.dropboxusercontent.com/u/90220402/pistontobore.png
Customer: replied 1 year ago.
I'm not sure, but that better not be the case because we had a high-end reputable performance machine shop do all the machining and they had the pistons etc we used.
Expert:  Chris (aka- Moose) replied 1 year ago.
Do you know the piston diameter if so where were they measured?
Customer: replied 1 year ago.
Yes, we are going to be over there soon. More to come. Thanks
Customer: replied 1 year ago.
Pistons are 4.000 checking to see how they were measured.
Customer: replied 1 year ago.
What is a good low pressure gauge tester to use for the PVC?
Customer: replied 1 year ago.
and measurements are in inches.
Expert:  Chris (aka- Moose) replied 1 year ago.
I use my vacuum gauge that can also measure pressure, like the one below.http://www.amazon.com/Carburetor-Valve-Pressure-Vacuum-Tester/dp/B00KRJFSFQ/ref=sr_1_1?ie=UTF8&qid=1460082496&sr=8-1&keywords=vacuum+tester
Customer: replied 1 year ago.
Hey Chris, I think we are onto something finally. Can you tell us where exactly to connect the hose? I know you said dead head on the PCV, but when we disconnect the hose and put on the gauge, it barely moves. That doesn't seem right. We have now also read that stock PCV valves shut off at 3psi, which would cause pressure to build up in a performance engine so it sounds like we need to update the PCV to something that supports at least 4psi. Does that make sense to you?
Expert:  Chris (aka- Moose) replied 1 year ago.
The PCV system allows filtered air to be sucked into the engine, normally in one valve cover and the other valve cover has the PCV valve that is routed to the intake which is under a vacuum, thus pulling filtered air through the crankcase to clean out fuel vapors. To check the pressure you would cap off the input and route the output to the gauge then start the engine to see if pressure starts to rise. The lower the pressure the better.