Rear seal leak

[vincelc]

My 350 Mr. Goodwrench motor's rear main seal is leaking after 42,000 miles and 24 years.

I've tried Barsleak HD RR main seal repair p/n 1040 per the instructions with inconclusive results.

Any suggestions other than replacing it?

 

[Ricko1966]

My 350 Mr. Goodwrench motor's rear main seal is leaking after 42,000 miles and 24 years.

I've tried Barsleak HD RR main seal repair p/n 1040 per the instructions with inconclusive results.

Any suggestions other than replacing it?

Look at your oil pressure sender at least 1/2 of the home diagnosed sbc rear main seal leaks end up being the oil pressure sender. Also do you have the proper valve covers on it with a working PCV valve in the drivers side valve cover and a vent or a vent tube to the air cleaner in the passenger side valve cover. Without that, the crankcase will create pressure and cause leaks. Not saying you don't have a leaky rear main seal,but I ve seen the 2 above situations turn out to be the real problem way too many times

 

[vincelc]

Thanks for the reply. I can eliminate the valve covers--both original mr. goodwrench gaskets began leaking long ago and been replaced by aftermarket ones with inner metal stiffening reinforcement.

I will check out the sender and pvc-- much easier than pulling off the trans and clutch...

 

[Ricko1966]

Thanks for the reply. I can eliminate the valve covers--both original mr. goodwrench gaskets began leaking long ago and been replaced by aftermarket ones with inner metal stiffening reinforcement.

I will check out the sender and pvc-- much easier than pulling off the trans and clutch...

Wasn't saying the valve covers themselves was saying not vented with pcv properly as described in my above post. Lots of people don't realize it is important to vent them and have working pcv. Without a vent and PCV valve it is common to pressurize the crankcase and blow oil past the rear main seal. Problem with aftermarket valve covers is not all sbc use the same valve covers or vent the same. So it is a common problem when they change valve covers not knowing the differences.

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[vincelc]

I got what you meant. I was just adding that the gaskets that mr. goodwrench put under the covers were junk that began leaking bad in short order

 

[Rickf]

After the above advice, there is a dye you can put in the oil, you'll need a UV light.

 

[vincelc]

Interesting. Is there a brand name or perhaps a kit with the dye and blacklite? It would be nice if Harbor Freight offered something like that...

 

[Moodyalaskan]

Interesting. Is there a brand name or perhaps a kit with the dye and blacklite? It would be nice if Harbor Freight offered something like that...

They do sell a small flashlight that is UV. Braun is the brand and it takes 3 AAA batteries. Should be able to buy dye from an auto parts store.

If I remember the flashlight was around $10.00.

 

[Oldbear42]

They do sell a small flashlight that is UV. Braun is the brand and it takes 3 AAA batteries. Should be able to buy dye from an auto parts store.

If I remember the flashlight was around $10.00.

Just never shine that UV light in a hotel room...

 

[Sad Sack]

https://www.amazon.com/dp/B09HH64G4G/

https://www.amazon.com/dp/B002M4G24U/

But as @Ricko1966 check PCV system!!!

If you want to take the poor man's way out, add some ATP205 to your crankcase.

https://www.amazon.com/dp/B000NVW1LM/

 

[Moodyalaskan]

Just never shine that UV light in a hotel room...

Are you speaking from experience?

Seen enough crime shows, I know not to.

 

[vincelc]

How does ATP205 compare to the Bars leak Rear main seal repair product I've previously tried?

 

[squaredeal91]

How many miles on the engine? And What oil are you running?

 

[vincelc]

350 Mr. Goodwrench motor
42,000 miles and 24 years.
NAPA 10/30 conventional

 

[squaredeal91]

Im kinda surprised it is happening. But I guess 24 years could be why lol. I had a 305 in a 1990 caprice start leaking immediately after an oil change once. Changed oil again to what I normally used and it stopped leaking.