IAmIronVan

My 2002 LS1 Firebird appears to have a slow oil leak coming from the bottom rear of the engine.

I tried my best to reach behind the engine from under the hood, but I couldn't feel any oil back there. Top rear of engine felt clean.

When I first looked under the engine, it was difficult to find the source of the oil leak. So I cleaned the oil off of the engine and transmission and waited a week before looking again.

During that week, my LS1 dropped two quarter sized drops of oil on my garage floor. I took these photos a week after I cleaned the oil off of the engine and transmission.

I'm not sure where I'm leaking oil from. I see oil around the window between the bottom of the engine and transmission, but I also see oil up by the filter. Please let me know what you all think. I hate to see my engine like this! Thanks!


Passenger side of engine


Window between engine and transmission


Window between engine and transmission


Passenger side of engine


Passenger side of engine


Passenger side of engine


Passenger side of engine


Passenger side of engine


Driver side of engine (aka oil filter side of engine)


Driver side of engine (aka oil filter side of engine)

.boB

iTrader: (1)

Oil leaks are always difficult to find. A leak almost anywhere usually shows up at the lowest point, which is the bottom rear of the oil pain. Even valve cover leaks show up there first, unless you're looking really close.

Clean the engine off really well, and then let it dry. Sprinkle corn starch or baby powder around places like valve covers, front cover, and oil pan. Then take it for a drive. Look closely for oil tracks in the powder.

You can also buy dye kits that use a black light. Put the dye in the crank case, and take it for a drive. Then in a dark garage look around with the black light and see what lights up.

I generallyu prefer to use corn starch, because I already have it in my kitchen. And I am very cheap.

CHEVELLEPOSSE

Rear main seal possibly also could be sensor behind intake manifold leAcking down maybe need tighten

JRENIGAR

iTrader: (37)

Rear seal cover gasket could be leaking. Mine was leaking at the top center and driped down the back of the block on both sides much like yours is doing.

GMC5.3

iTrader: (2)

It almost looks like my same problem, after my cam swap I thought I pinched the oil pan gasket because I had a leak on the back bolt right by the filter, changed the gasket and still leaks so I'm going with rear main also.

wantsum410

iTrader: (5)

That Lil Fitting above your Oil Filter is Bad about Leaking ...2 10mm Head Bolts...it has a Stem on it we Drill & Tap for Oil press on our Swaps . Easy Check to Pull Clean & Put a Lil Sealant on & go from There.

JakeFusion

iTrader: (7)

Any mods or did this just appear?

Likely culprits: oil pressure sender behind manifold drivers side, rear main seal, valve cover gaskets, or oil pan gasket, especially where oil pan and rear cover join (if ever replaced and a dab of RTV was not installed).

IAmIronVan

Leak just appeared. My car has a fair number of engine mods, but the latest mod was an auxiliary oil temperature gauge. That was about 2 years ago though and this leak is recent.

A buddy from work was over last weekend. We jacked the car up and used a flashlight to look up at the oil pressure sending unit from under the car. It looked a bit shiny, so he reached behind the engine from under the hood while I was underneath the car with the flashlight watching his hand. I watched his fingers touch the oil pressure sending unit and when he pulled his arm out, his fingers had a liberal coating of oil on them.

Is it typical for an oil pressure sending unit to begin leaking on its own?

We're going to pull the intake to have a better look. I'll keep you all updated.

Thanks for all the advice! This forum is awesome!

GMC5.3

iTrader: (2)

Any updates, wanted to see if your sending unit was the problem and if it was still working when it was leaking

IAmIronVan

Totally was the sending unit! Unit was mostly working, however every once in awhile it would stop sending oil pressure info for a second and cause the "check gauges" light to come on because sending unit would send an oil pressure of 0 psi to the instrument panel for a brief moment.

I replaced the sending unit back in 2014 when I made this thread, but I think I broke it again.

Maybe this time I'll try replacing it without removing the intake manifold. Anyone got photos of how the connector on top of the sending unit disconnects so that I can disconnect it without being able to see it?