NitrousMan

I've had an oil leak on my 383 stroker 4 bolt main since the day I put it in the car a few years ago. Had the motor built by a well known shop but they are out of state so I've finally decided I need to fix it myself. It almost looks like it's coming from between the block and the heads. Are there any head bolts that go into an area that if the shop forgot to use sealer on them could cause it to leak oil? It has Dart Pro 1 heads on it and I've redone the valve cover gaskets a few times and it looks dry below the valve covers but at the edge of the block it looks like that's where the oil is located. It's not a major leak but will leave a few spots in the driveway when I park it. Thanks for any info.

73, Dark Blue 454

A neighbor with SB Camaro and AFR heads was telling me about his having some oil seapage between the heads and block. I dldn't believe him, but I guess it's possible.

Try re-torqueing the heads.

Make sure the valve cover gaskets are doing their job.

Use the oil detection kit (about $12 from any parts counter) and see if you can better diagnose the origin of the leak.

Good luck!

snoopykissedlucy

The two mystery oil leak places on the small block chevy:
1) a plug located on the top drivers side edge near the rear valley lip. The machine shop should install a plug with sealer....but sometimes forget or do it wrong

2) there are two bolt holes on the passenger side front near the fuel pump. One hole goes all the way through to the fuel pump push rod and oil gallery. I've never known a machine shop to place a bolt here, much less use sealer

MotorHead

Oil leaks usually end up being no near where you think it is coming from. The cheap oil detection kit is the only way to see where the leak is for sure

NitrousMan

I'll check those spots tomorrow. I don't have a mechanical fuel pump so there's just a plate with 4 bolts in it so are those the one's you're talking about?

Yea, the heads look dry under the valve covers but the edges of the block deck have oil on them. I wasn't sure if some of the head bolts go into any area of the block that could allow oil to be pushed out if the bolt didn't have sealer on it.

mysixtynine

If its at the back of the block (towards the firewall) my guess is your rear intake gasket is leaking. Those damn things have the tendency to slip into or out of position. Best to use a thick bead of RTV instead of the rubber gasket.

Then you get seeping and it starts at the back of the intake and would run down all the nooks and crannies especially where the block and heads meet.

Check this post out by MotorHead. Hes got intake fitment issues. http://forums.corvetteforum.com/c3-t...o-explode.html

7T1vette

Especially with an engine with non-stock parts. When engines get rebuilt, blocks get milled and the relationship between the heads, block and intake surfaces get altered...so the fit at the upper block rails (front and back of intake) and/or the head-intake junctions don't match up properly for 'normal' gaskets to seal properly. I'd bet on a bad 'valley' fit or intake gasket fit at the back of the engine.

Budman68

My buddy sprang a leak at the front of his motor. I thought it was the fuel pump rod hole, but after closer inspection it turned out to be oil coming through an acc. hole. I guess during the casting or machining the tap or hole was drilled to far into the oil gallery. Simple fix.

NitrousMan

It looks like it's leaking between the head and block, intake gaskets are dry and so are the valve covers. The very front edge of the block deck has oil on it but the head itself is dry. I'll have to put some dye in the oil to actually locate it but I'm wondering if any of the head bolts go into an area that could leak oil if the bolts weren't sealed by the assembler?

7T1vette

If the head bolts were replaced [with new ones] during the rebuild, there could be one that is bottoming out in the threaded hole and not pulling the head down completely. Not a high probability, but possible. If you remove valve covers and start checking out bolt torques, I'd suggest that you remove each bolt...one at a time...use a caliper gauge to measure the depth of the threaded hole and compare that to the length of the bolt [under head to end of shaft]. There should be about 1/8" of clearance in the hole. If not, grind of the end of the bolt and reinstall and retorque to specs.

MotorHead

That is a smart move Napa and a few other places sell these kits and they are the cat **** when trying to find a leak. The kit I got comes with dye you can use for oil or brakes and a flashlight and yellow glasses for so you can see the fluorescent colored fluid and where it's coming from.

I only paid about 35 bucks for mine and have used it many times, well worth the money. Here is what the kit looks like, not the one I got but it shows you what you get. Don't pay more than $35 for the kit

http://news.thomasnet.com/fullstory/...ion-Kit-553339

NitrousMan

I would have thought the speed shop would have done that but I'll check that after I use the oil leak kit to try and find it first. Thanks.