Camshaft Plug Leak On Small Block Chevy

[c3po]

I have 375,000 miles on my small block chevy, at 330,000 miles I had the rear main seal replaced.

I have read that there is a rear camshaft plug above the rear main seal on small block chevy's and that they may leak, I have a feeling that since I cleaned up this motor so good, that there was probably some crud around this camshaft plug and now that it has been cleaned up I have more of a leak on the back of my oil pan, it used to be just wet, now I have oil all over my drip tray.

I know the old saying, if you clean the inside of your engine you will have leaks, this oil that has leaked out is clean looking, does the transmission have to be dropped to get to this camshaft plug.

Are there any other plugs in the back of the block that I need to look at, all of the oil pan bolts are tight, maybe I need to get the car on the lift and also make sure my valve cover gaskets are not leaking.

 

[ADFD1]

I'd check the VC gaskets and pan gasket again, then make sure its not the rear main seal again. How bad is it leaking? With those kind of miles if it is a small leak I might be inclined to leave well enough alone. JMO

 

[c3po]

Originally Posted By: ADFD1
I'd check the VC gaskets and pan gasket again, then make sure its not the rear main seal again. How bad is it leaking? With those kind of miles if it is a small leak I might be inclined to leave well enough alone. JMO


I am going to clean up the drip tray and keep an eye on things, I will also check the valve cover gaskets as they have been on the car for awhile, if they need changing I can also take some photos of the valvetrain.

 

[Trav]

There is one that looks like a small freeze plug and a couple of threaded galley plugs.Its very rare for these to leak.
I would look at the valve covers or the rear main first.
With that many miles on it the crank sealing surface may not be perfect and it started leaking again.

 

[Herz]

change the valve covers for peice of mind.

They are cheap and easy to replace and may solve your problem.

 

[c3po]

Originally Posted By: Trav
There is one that looks like a small freeze plug and a couple of threaded galley plugs.Its very rare for these to leak.
I would look at the valve covers or the rear main first.
With that many miles on it the crank sealing surface may not be perfect and it started leaking again.


If the crank sealing surface is not perfect then maybe I just need to live with it.

The other thought I had was, this car came with a 4 quart oil pan, so the total oil capacity was 5 quarts. I then added a 5 quart oil pan which brought the capacity up to 6 quarts, maybe on my next oil change I could run it half a quart low, maybe at 5.5 quarts.

 

[Trav]

Think it could be the oil pan leaking?Check the bolts,the gasket may have compressed since you installed it leaving the bolts a little loose.

 

[c3po]

Originally Posted By: Trav
Think it could be the oil pan leaking?Check the bolts,the gasket may have compressed since you installed it leaving the bolts a little loose.


I'll check the oil pan before I change the valve cover gaskets.

 

[JetStar]

Don't forget the rear intake manifold seal as well.

 

[Chris142]

Oil pressure sending unit is tucked back there under the edge of the distributer.

 

[demarpaint]

First thing I'd look at are the VC gaskets, next the oil pan gasket, and oil sending unit. I would re-tighten things just to be sure, before I start pulling things apart. If it really bothers you clean the engine and try to trace where it is coming from. With close to 380,000 miles on an engine I would be a little hesitant about doing a rear main seal, there could be a groove worn from dirt and you could end up with a bigger leak. Now that you've done all those A-Rx treatments and cleaned things up with MMO try a High Mileage oil without any additives in it.

 

[JohnBrowning]

I had a distributor O ring that was leaking tht drove me mad!!! It was not leaking where it goes intothe block that would be too easy. No this one was filling the inside of the HEI distributor with oil their is a little notch cut inthe aluminam on the back side I am guessing as a vent the oil was leaking out of that notch on the back side of the distributor then running down the block making it look like valve cover's.......For some strange reason I was going to remove the distributor to check the Oring seal and when I took the cap off I saw that the inside of the distrubotor was full of oil! SO take the cap off and make sure the inside of the distributor isn ot full of oil!

 

[c3po]

Originally Posted By: JohnBrowning
I had a distributor O ring that was leaking tht drove me mad!!! It was not leaking where it goes intothe block that would be too easy. No this one was filling the inside of the HEI distributor with oil their is a little notch cut inthe aluminam on the back side I am guessing as a vent the oil was leaking out of that notch on the back side of the distributor then running down the block making it look like valve cover's.......For some strange reason I was going to remove the distributor to check the Oring seal and when I took the cap off I saw that the inside of the distrubotor was full of oil! SO take the cap off and make sure the inside of the distributor isn ot full of oil!


Thanks John, I will check this tommorow.

 

[demarpaint]

Originally Posted By: c3po
Originally Posted By: JohnBrowning
I had a distributor O ring that was leaking tht drove me mad!!! It was not leaking where it goes intothe block that would be too easy. No this one was filling the inside of the HEI distributor with oil their is a little notch cut inthe aluminam on the back side I am guessing as a vent the oil was leaking out of that notch on the back side of the distributor then running down the block making it look like valve cover's.......For some strange reason I was going to remove the distributor to check the Oring seal and when I took the cap off I saw that the inside of the distrubotor was full of oil! SO take the cap off and make sure the inside of the distributor isn ot full of oil!


Thanks John, I will check this tommorow.


I completely forgot about the distributor location on the SB Chevy. Ford had them up front it was Chevy that had them in the rear of the engine.

I would have a look at the O ring. I had an old Chevy that was leaking from that O ring it drove me nuts too.