Technical SBC Oil Everywhere...

I have a SBC 350 that has developed major oil leaks. Seemingly from basically all possible areas. And yet because the motror is in the vehicle it is very difficult to piknpoint the major source of the leak. Biggest issue seems to be from the back of the motor leaking down onto the starter and also similarly down over the other side. I checked the rear of the intake and actually plugged the oil sending unit for the gauge. I had no problem when the motor was initially installed. I dide put aluminum heads on it. Any help would be appreciated.

 

If you installed aluminum heads, did you put a large bead of RTV between the intake and the block?

Also could be valve cover gaskets

Does it have a PCV system? That helps relieve crankcase pressure that will push oil out of the weak areas.

 

^^^^^^^^
Like Dan said

 

just clean it, then watch to see where it's leaking... I use blue shop paper towels.. where it's leaking will turn the paper towel dark blue.. my bet is manifold , plus valve covers...

 

Thanks everyone for the suggestions. Yes, I have checked the PCV and it appears to be working. I also have a breather on the other valve cover. I amy replace the PCV just to rule out that it has failed. I have put dye in the system and so have a better idea of where the oil is coming from. With a mirror and light I can see that the back of the motor is an issue. However getting to where I can see that area is a problem. But it does not appear to be coming from the valve covers or the back of the intake.

 

Gasket at the base of the distributor? Oil pressure sending unit or tube?

 

It might be leaking out the distributor hole. There should be a small round gasket under the collar to seal against the intake manifold. Although I still would check extra for the China wall to intake, and the valve cover gaskets. It's also possible to have leaking from head gaskets or intake gaskets.

 

Pretty simple really...
Just check every place that there is an oil related...gasket...!

Go buy some Brakleen (or other engine wash chemical), hose everything down well to clean/dry all of the oil that you can see. Then take the car for a drive.
Come home, open the hood, get a flashlight and start looking for fresh oil.

Mike

 

A couple of friends of mine have had difficulty finding the source of their oil leaks. They bought a dye that goes in the oil and a flashlight so that you can find the source of the leaks easily. It's fairly inexpensive and they both rave about it. Might be a good option for you.

 

You said you checked the PCV, but did you check that breather? When I worked at a Dodge dealership, we had cars coming in with oil leaks everywhere and even milky oil. 99% of the time the problem was the valve cover breather for the PCV system. It happened often enough that we kept a supply under the parts counter along with the dual ballast resistor.

Mike VV gave you good advise. You really can't track down an oil leak until you get the engine clean and dry.

 

Another possibility. Don't know about your aluminum heads; but on stock heads the intake bolts go into the valley and oil can wick up the threads and leak out around the bolt heads.

 

Leak at the back of the intake is my best guess - as he put on new heads (gasket slipped or there is too big of a gap due to the new heads) . . . . with valve covers being my 2nd guess.

 

put a piece of paper over the breather hole opposite of the pvc valve and the paper should stay sucked on the cover.

 

Thanks again, I had not thought about the gasket for the distributor. And the brake clean idea is a good one as well. Get a better sense of just where this is coming from. I did put the dye in and that helps.

 

I have plugged the oil pressure sending unit.

 

Do you have leaking galley plugs on the back of the block in the flywheel/flexplate area ?

 

Sounds weird but works. Right Guard arm pit stuff sprayed over everything. Leaves a chalky residue.
Run it and oil leaks show up good.
And you engine wont stink for a bit.

 

When the engine is clean and dry, spray Arid extra dry deordorant around areas of possible leaks. The oil will leave a trail in the powder.

 

Don't worry about it! Think of it as a built-in rust preventative measure for anything below and behind the engine...

 

You said motor was pulled out & then reinstalled ,
what brand heads / model ,& & same for intake ?
There are different Intake gaskets ,they look close but are different.
Any Machine work done to block? Decked ?
( head surface of block )
Oil galley/passages cleaning done?
On rear of block , cam plug & 3 other oil passages plugs..
On passenger side ,of block ,rear on head surface ,there is a oil galley plug , recessed down in the deck /block , that I have seen left out a few times
On front of block , passenger side front of block 2 3 /8 vertical bolts holes the top one needs to be installed
1/4 -1/2 long ,that hole goes into the fuel pump gallery,
Most of time Oil will go from leak reward , & also from leak down ward .

 

Or use Secret. Strong enough for a man but made for a woman.

 

Did you remember to install the oil pressure sending unit?

 

Sounds like a flathead or a Harley! LOL

 

Be sure , you have air flow , not pressurizing the crankcase . Happens a lot , easy to do easy to fix

 

I have a tired 283 in my car. I bought a new PCV that attached to the base of the carb and it leaked a lot in the same areas youre saying (bellhousing/oil filter area). I cleaned the motor where there was oil and put in a different new PCV, a standard ignition V100 model, that plugged into the base of my rochester 2bbl carb and havent had the issue anymore. Could be worth a shot before going down a rabbit hole.

Gordy

 

THIS. There can be a pretty large difference between the height of the valley area of the block and where it meets the intake surface of aftermarket heads. It can take a 3/16-inch bead worth of RTV to seal up the ends depending upon the parts being used. If you used the end gaskets when you installed the intake, take it back apart and put a bead of RTV that's TALLER than where that surface meets the head, just in case. Then reassemble.

 

On oil leaks that are hard to confirm the exact source I use an oil dye kit. The kits with the small illumination light are not expensive. Most of the time you can diagnose in the driveway.

 

I used The Right Stuff sealer on my intake, great shit no doubt. I still have a few mystery oil leaks, although we were careful with everything.

I had an issue with valve cover gaskets being sucked in at the short ends, I went to billet valve covers that captured the gaskets. I recently went with an extra valve cover breather. I have to get some miles on it to see if it did work.

 

Thanks again everyone.

 

On the SBC 350 I had in my old truck it would leak out the rear main seal. Changed myself and had the dealer changed it but it would still leak.