Rear Main Leak Questions

[bishir]

I have a stock block and I'm sure the rear main is the factory one. I know our cars are prone to rear main leaks especially with the stock type seal. I have a few questions. First of all, I lose about a quart every 1000 miles. Now some of this may be oil blowing out of the PCV too though I don't know how much. What I want to know is if this is an excessive amount? Also, I'm currently I'm running about 20-21 lbs of boost daily on the street with a TA-49. Is this boost making my leak worse?

Thanks,

James

 

[markboss]

Check your valve cover gaskets...always seems to be the cause for me...

 

[Turbo6inKY]

First of all, you need to determine if you have a rear main leak. Get under the car and take off the cover over the torque convertor. If there is oil all over the flexplate and splattered on the back of the block, then you probably have a rear main leak. Replace the rear main seal.

But, as markboss said, it could be your valve cover gaskets. if you've got oil pooled in the bottom that torque convertor cover and down the sides of the block, but not on the back of the block or splattered on the flexplate, then change the valve cover gaskets.

Adding breathers on both sides (replace the oil fill tube and the filter on the other side on the front of the valve cover) will reduce the pressure inside the valve covers, and it'll leak less.

 

[bishir]

Thanks! I do have oil dripping out of the inspection plate and I plan on new valve covers soon anyways. Thanks for the tips!

I got a breather today.

James

 

[TurboJim]

Originally posted by Turbo6inKY
First of all, you need to determine if you have a rear main leak. Get under the car and take off the cover over the torque convertor. If there is oil all over the flexplate and splattered on the back of the block, then you probably have a rear main leak. Replace the rear main seal.

Be very careful with that diagnosis. A leaking intake or valve covers will do the same thing as oil drips down the back of the block and into the inspection cover. If you have access to a UV lamp, put some leak tracer dye in the oil, run it till its hot, then hold at 2k rpm for a couple mins. Then with the UV lamp, look for "glowing" oil. Tracer dye is one of if not the best tool for finding and pinpointing leaks there is.

FWIW, unless the rear main is PISSING, I wouldnt bother screwing with it. I have never seen one that didnt leak even a little.

 

[turbo nasty]

Recently, I installed the check valve(between the TB and PCV) for the PCV valve. And even though, a few years back I replaced the rear main seal and oil pan gasket. It still would use about a qt between oil changes. Well I have to say that since I installed the check valve my oil is just now getting to 1/2 qt low and it is due to be changed(miles) and I can honestly say that my oil has stayed alot cleaner. Same viscosity and brand of oil and I even drove it on a road trip about 400 - 500 miles round trip, running about 75- 80 the whole way with a few triple digit blasts.
Got it through Ramchargers...wish I would have installed it years ago !!!
No idle problems or tip in and vacum still reflects the same.

 

[bishir]

I have a check valve and new PCV sitting on my table at home. I guess I better install it soon. Hopefully, that is part of my problem. I have a layer of oil on top of the block that may be rollling of the back during takeoff.


James

 

[turbo nasty]

If original VC gaskets are on then they should be replaced. The felpro cork blends are awesome!!! And most everywhere has them.

The hose that came with my check valve was not good for the 90 bend down to the pcv.
Dayco hose # 87000 is stellar NAPA has em always...it has the 90 made into it.

 

[6 to go]

The valve cover breathers and the check valve
in line with the PCV worked wonders for me.