H20Vette

I have a bone stock '04 coupe with 6300 miles on it.

Last time I changed the oil at 3300 miles, I noticed there was a thin dusting of oil on the bottom of the pan. I thought maybe I hadn't tightened the filter enough. So I cleaned it off and moved on.

Today I changed the oil again (6300 miles). This time, there was oil on the pan again. There was also oil around the filter (and whatever sensor that is by the filter), around a sensor on the opposite side of the pan from the filter (oil temp or level sensor?), oil on the exhaust by the pre-cats, oil around the drain plug, and a little up under the main pulley.

I cleaned it all off with brake cleaner and I'm going to check to see what gets dirty first, but I'm not sure if it will be easy since wind may blow it around.

Is there a common place that leaks on LS1s? Thanks for any help.

JEEP/C5

My pan is always clean (01 with 30K) but maybe some others guys can chime in and let us know what they think. Two question I have: Do you seen any puddles of oil under your car? Is it blowing under the whole underside? If it real minor and just moist around the filter area then maybe (MAYBE?) its not a big deal. Keep track of your oil level and keep us posted.

H20Vette

There's never any puddling under the car, and the oil residue is confined to the areas I listed in the first post -- basically no further back than the cats. Whatever gets back as far as the cats gets onto the cats and burns off there. I've been noticing an oil burning smell lately, so that explains it.

Anyone have any ideas where it might be coming from (based on common LS1 trouble spots)?

runamuk

Did you change the O-Ring on the drain plug?

Mine leaked also until I realized there was an O-ring.

H20Vette

Nope, never have. There is definitely one on there but I've never changed it. How often are you supposed to change it? The car is 1 year old.

H20Vette

Update: I drove the car after cleaning the oil off and put it back on ramps to have a look underneath. Fresh oil showed up on the rear passenger side of the oil pan near the bellhousing. Are there two oil pans on the C5 LS1? Upper and lower or something? It looks like the leak may be coming from just above the lower pan. Then there is also the rear main seal possiblity... Is there a way to rule one of the two (pan or rear main) out?

LoneStarFRC

The oil pan is one piece. One thing worth looking at is the oil pressure sender. It's behind the manifold (which btw, has to come off to change sender) and just a little towards the driver's side. You may have to use an inspection mirror and a good strong flashlight to see it. Removing the driver's side fuel rail cover helps. When my sender failed a couple years ago, causing an unusually high pressure reading, I found that it had also been seeping some oil too. The small amount of oil was running down over the bellhousing and then the wind took over from there. I'm thinking that maybe the sender is possibly leaking, even though you may be getting normal pressure readings. BTW, after changing mine, the oil leak stopped too. HTH

BTW, to rule out the rear main, you might try removing the lower flywheel inspection cover and looking up at the back of the block.

H20Vette

Which manifold are you referring to? intake, exhaust, other? Can you post a pic or service manual drawing of the location? Thanks.

runamuk

On early 97's the oil pan was a 1 piece but since then it is a 2 piece. I haven't heard of them leaking unless you've removed it. I had removed mine lower half 4 times reusing the original gasket with no leaks.

If you have a "thin dusting" of oil I wouldn't worry about it it could be a porosity problem but if you have a thin dusting leading to drops on the floor then I'd be more worried about finding the source.

H20Vette

Any oil leak on a new car is unacceptable to me. I agree it's probably not a major problem but still annoying. Thanks for the info on the pan.

I'm looking into the oil pressure sending unit possibility now. Does anyone have a service manual drawing scanned or a pic they could post of its location?

LoneStarFRC

Sorry, it's the intake manifold I was referring to. Once it's either moved forward or removed, the sender is very easy to get to. I have seen several posts from guys that used the GM replacement, and found it also to be leaking within a short period. I used an aftermarket unit that I bought from RockAuto.com and it's been no problem at all. It's a PS308, made by Standard Motor Products. HTH

ghost.rider

My 99 needed a new rear main seal.

The tech said this was very rare in C5's because they are usually pretty tight but mine leaked almost from day one, very slightly, until I had it fixed just as it was about to run out of the 3 year warranty

Obviously I don't mind a little oil in my garage, maybe I had to add half a quart between oil changes

Patches

Oil pressure sender


Oil level sender


Oil temperature sender