zz28zz

Getting bad burning oil fumes inside cabin with vent sucking in outside air. Seeing an oil puddle in garage.

I cleaned the underside of eng with solvent and dried.
Returned abt 1 hr later and no leaks.
Started eng for abt 3-5 mins. Oil is dripping from pass side near starter at one drop every 5 seconds.
Left side got oily near filter but only dripped a couple of drops over abt 10 mins.
See pics.

I double checked oil press sender and it's dry as a bone.

Pointed my light into large insp plug at bottom of case (where you can see flexplate bolts). Doesn't appear to be coming from rear main. I get a few drops from the insp plug hole area but nothing like I'm getting near starter.

What an I looking at here? The plate that holds rear main seal leaking?

Thx for any help. This 2000 model is my daily driver and has 96K miles.

Bill Curlee

You have a TWO piece oil pan... Check the UPPER oil pan bolts for proper torque. Retorque to OEM spec. The bottom bolts are torqued to INCH POUNDS so, don't over torque and snap the bottom pan bolts. Concentrate on the upper pan bolts for that leak.

There is also a cam sensor O ring that can leak in the same area as the oil pressure sensor.

Are you ABSOLUTELY SURE that the oil pressure sensor isn't leaking??

BC

zz28zz

A couple of weeks ago, I put the car on the lift, but couldn't find my solvent sprayer. I had abt a half can of brake cleaner so I did what I could to clean-up the bottom side. I put a socket on every pan bolt I could see. They were all tight.

The place I indicated on right side of eng, close to starter, is where I see oil running out. Looks like a narrow rectangular slot. I assume it goes to the flexplate cavity, but don't know for sure. That slot is above the pan gasket.

I've replaced the OPS last year (went with the brass bodied one I understand is more robust). When I saw a puddle in same spot under the car a couple of weeks back, I thought for sure it was the OPS and removed it. It was completely dry and very clean.

Today, I was able to get a quick look at the OPS with a remote camera before the batt died. It looked nice and dry. At the time I didn't know abt the cam position sensor but after researching a bit more, sounds like it may be the problem.

Looks like the intake will have to come off. I've pulled lots of intakes, but never pulled an intake from a LS eng. Doesn't look too bad at all.

From my searches, the cam sensor leaking doesn't seem to be a common problem. Is the o-ring available from GM or do you have to buy the sensor assy?

Bill Curlee

Normally,,,,,,,,,, the intake seals are reuseable... If yours are very compressed and non compliant,,,, I would replace them.
AutoZone ,, NAPA or Advanced sells them for around 25 bucks.

Intake removal is pretty simple.. The TWO rear bolts can NOT be removed. Just install approx 3/4 inch long split rubber 1/8" vacuum line between the head of the bolt and the manifold and that should clear the bolts from the block for removal and allow easy manifold extraction..

If you dont do that,, the extended bolts will NOT allow the manifold to be removed from the engine with out hanging up

BC


Bill

zz28zz

Thx for the tip on the rear bolts. Good stuff.

Any thoughts on suscess rate when replacing the cam position sensor o-ring only?

Bill Curlee

Before you do any disassembly and repairs, grab a couple cans of BRAKE PARTS CLEANER and flush down the rear of the engine, behind the intake manifold and area under the car around the oil pan/ bell housing and starter. Allow the solvent to evaporate.

Use a mirror and inspection light and get an eye on the area at the back of the manifold and look for leaks around the oil pressure sensor and cam sensor and see if there is any oil coming from under the manifold. If there are any leaks, you should be able to see it with the mirror and light.

It is also possible that one of your KNOCK SENSOR wells is spewing out oil because of a bad seal between the valve valley plate and the sensor pedestal.

zz28zz

I was able to clean around the OPS last time I was in there and it's still clean/dry around that sensor. The remaining area back there is pretty gunky, from prev leak I had possibly. Especially around the cam sensor.

The cam sensor o-ring doesn't hold back any real oil press does it? Hard to imagine just splash oil making it around the o-ring, up a couple of inches to the top of the block then running down the eng to create the leak rate I'm seeing (with eng at idle).

zz28zz

Just found this post and now I'm excited again.

http://forums.corvetteforum.com/c5-g...-oil-leak.html

May just get this repaired without disassembling the entire car.

Cybermind

Yep, that's where I'd look first. Let us know what you come up with. Take some pics and post them once you figure it out. I'm very curious to find out if it's the cam position sensor.

zz28zz

Got the intake off today. Does not appear that oil was leaking from the top hole.

Pulled the cam sensor out. Noticed just above (abt 1/2") the o-ring, there's some sludgy build-up.

There's a chamber abt 2" below the top surface then a hole from the chamber down into the area where the cam is. The o-ring seals the hole between the chamber and the cam area.
I see some oil in the chamber. Is there supposed to be oil in the chamber? Is that chamber open to the rear of the block so oil could leak out?

zz28zz

Installed a new cam position sensor, reinstalled intake, cleaned everything and fired it up. Still getting a leak on the right side near starter.

Anything else I can try short of removing the engine? I'm about ready to throw in the towel and send it to the shop..

Frank_Nesta

I hate to suggest this but, I have had 2 friends who had to have the rear seal replaced. I hope that is not the problem.

zz28zz

Well the saga continues.. Convinced the rear main or the rear cover plate was leaking, I ordered up a rear cover plate. Pulled the tranny/diff and all the related stuff just to find the leak is still coming from the new cam sensor I just installed.

With the flexplate removed you can see into that "chamber" the cam sensor passes thru. Cleaned out the chamber. Started eng and the chamber had a puddle of oil within a couple of mins. For some reason the new sensor and o-ring failed to seal the hole leading down to the cam.

When I replaced the cam sensor last week, I grabbed a clean rag with a set of mechanical fingers, stuck it down into where the o-ring should seal and spun it around to wipe away any debris in the sealing area. I lubed the o-ring with eng oil when I installed it. Not sure what to try next. Thinking maybe I could coat the o-ring with RTV or something similar.

zz28zz

Picked-up a couple of exh flange gaskets at the dealership today. While I was there I spoke to the Vette mech and asked abt the cam sensor leaking issue. He had only seen it a couple of times. He said occasionally the machining isn't perfect in the hole where the o-ring seals and recommended some sealant they use made by Delco.

I cut the end off the old cam sensor so I would have something to block off the hole leading to cam. Drilled a couple of holes thru it and attached some aircraft safety wire so I could get it into the hole and retrieve it later. Inserted the modified sensor in the hole and gave the chamber a good rinse with solvent then air dried. Then pulled out modified sensor and inserted a rag wet with brake cleaner using mechanical fingers and cleaned out the hole where the o-ring seals.
Used the remote camera to confirm all was clean.
After that dried, I applied the Delco sealant to the new cam sensor o-ring and installed it. Tech at dealership recommended waiting at least 24 hrs before starting. Guess I know tomorrow if it worked..

DougBoost

I'm also in Austin and my 2002 just started having the same problem. Not much oil but car has never leaked, so want to fix it.

I have to pull the intake anyway to replace the oil pressure sender since it failed awhile back (am going to relocate it while at it). May well just be that sender but am definitely watching your experience.

Thanks,

Doug

zz28zz

Hey Doug;

Since your oil sender quit working, it's very likely that's where the leak is coming from.

I've replaced mine a couple of times without pulling the intake using a long 1/4" extension, a universal joint and a sender socket. Getting the wire on and off is the hardest part. However, over the last 2 weeks, I have discovered pulling the intake is pretty quick and easy. Got it down to abt 10 mins now.

I started mine up this evening. Got a few drops after eng warmed up, but then it appeared to stop. Hoping it was just some residual I missed during clean-up. I'll know for sure when I get stuck in rush hour traffic on 183 tomorrow.

zz28zz

Drove the vette to work today. It's still leaking. Not as bad but still leaves a golf ball size puddle when parked for a few hrs.

Suppose I can try again with more sealant, but cleaning the sealant out of the hole is going to be tough.. I'm a little concerned abt getting bits of dried sealant in the oil, but I guess that's what filters are for...

Any other ideas??

DougBoost

10 minutes, it took me at least that long just to get the stupid coolant air bleed hose off the bottom of the throttle body!

I sure hear you about sitting on 183...just keeps getting worse and worse, with those 1200+ people per week moving here.

Wish I could help you on your stubborn leak but that's going to have to be someone who's been there before.

zz28zz

Ok, think I got it this time. Pulled cam sensor again today. It was a bear to get out with the eng sealant gluing it in.

Once it was out I needed a way to clean-up the dried sealant if I ever wanted it to seal again. Raided the shotgun cleaning kit. Seems the 12g bore is pretty close to the cam sensor hole. Had to cut off some of the brass extension so it would fit into the hole with a angle drill attached.

Used the brass brush attachment then followed-up with the cloth attachment wetted with brake cleaner. Got the cam sensor bore clean as a whistle in no time. Only bad part is I got some dried sealant bits inside the crankcase, but I don't think it will hurt anything.

After cleaning the sealant from the cam sensor and re-installing the o-ring, I gave the o-ring a light coat of eng oil and popped it back in. Slapped the intake back on and idled it for abt 15 mins, didn't see a single drop or any wetting even. ***Fingers crossed***

LoneStarFRC

Sure do hope you got it and it's not the dog bone (oil restrictor) o-ring. It's the only thing I could think of in the area you are saying is leaking. It's on the left side and directly above the bolt/area you show in your pics. It's rare, but can happen. GM made a re-design, not sure when, and the new part number is 12573460. Problem is, the drivetrain has to come out to access it inside the rear engine cover.