Discussion Forum - Northstar Chevelle Club

69SSConv · Active Member

Oil leak, need suggestions?

Tony Hoffer · Moderator

on a small block there is a bolt hole on the front of the block that threads into the passage for the fuel pump pushrod.. it that is loose or missing you will have a huge mess. Im not real well versed on Big block stuff.. is there anything like that on a BBC?

-- Edited by Tony Hoffer on Saturday 13th of August 2011 07:17:48 AM

Chris R · 2K+ Club

It actually could very well be the oil pump. I had the oil pump leak on my 396. Is it a stock pump or aftermarket?

69SSConv · Active Member

It is a Holley mechanical fuel pump. There is two bolt holes on the face of the block, but do not appear to go through to the oil gallery like on the small block. The big blocks have a plug just below the fuel pump mounting to access the fuel pump rod.

bowtie · Secretary

check the timing cover to oil pan area too

John D · 2K+ Club

It might be something as simple as just going around the pan & timing cover and giving the bolts a "re-tweak". After a bunch of hot/cold cycles and soaking in lube, the oil may just be wicking through. Don't go nuts, just 1/8 to 1/4 turn on the bolts - you don't want to squish the gaskets out.

Chris R · 2K+ Club

69SSConv wrote:
It is a Holley mechanical fuel pump. There is two bolt holes on the face of the block, but do not appear to go through to the oil gallery like on the small block. The big blocks have a plug just below the fuel pump mounting to access the fuel pump rod.

Ding, ding, ding. Ill bet thats it. I had the exact same pump on my 396.

69SSConv · Active Member

I have tried two different Holley pumps and have had the same issue. What did you do to get the leak to stop?

Chris R · 2K+ Club

I put the same type of pump on but it was an Edelbrock pump. Meaning, both pumps are identical to each other. They just put thier own name on it.

John D · 2K+ Club

Just for S&G's, get a couple of 1/2" long bolts, goober the threads with sealant, and thread them into the 2 block holes "that don't go into the oil galley".

Depending on core-shift, machining tolerances, or porosity, one of those holes just may have a pinhole or something.

If this solves it, paint 'em orange and be done with it.

dashboard · 2K+ Club

After you try John Ds suggestion, try this.
https://www.napaonline.com/Catalog/CatalogItemDetail.aspx?A=NFPM6628_0199774038&An=599001+101972+50012+2012020

Lost in the 60s · President

John D wrote:
Just for S&G's,
LMAO, I'm wondering how many people know that OLD saying....

SShink · 3K+ Club

Lost in the 60s wrote:
John D wrote:
Just for S&G's,
LMAO, I'm wondering how many people know that OLD saying....

I do!

Chris R · 2K+ Club

It cant be that old if I remember it.

69SSConv · Active Member

I think I have finally gotten to the bottom of my oil leak. Two things contributed. First found a small pinhole in the gasket to block area behind the first bolt on the front of the oil pan, passenger side. Smeared some RTV on that and appears to have stopped that leak.

Still had a leak, and just found it today, with the help of my dad. We started the car, ran it up on the hoist and watch from underneath will it was running at hi idle for about 15 minutes. When we were about to give up, we noticed that a drip was coming out from the bottom of the harmonic balancer (and blowing left towards fuel pump) every 5-10 seconds. I believe we have concluded that it is the from timing cover crank seal, because it is not coming from the front pan seal, that area remains dry, at higher RPMs the oil drip is being thrown to the passenger area around the fuel pump etc.

Looks like I found another winter project to add to the list.

jim larson · 2K+ Club

Looks like I also have some winter oil leak to tend to. A small leak around the large "O" ring between the housing and the pump of the PS Pump. Not to back. And the pesky leak from the front of the counter shaft and the main-case of the muncie 4 speed.

There is also a little leak at the front pass side between the intake and head that works it way down the edge of the head, then runs back along the head to the rear of the engine, then down the the starter. Maybe if I clean it good and then smear some RTV that will help.

69SSConv · Active Member

Looking for opinions, short route or long route? Would you recommend changing the pan gasket at the same time? I am thinking if I do of going to a 1-piece? Any thoughts? recommendations? What experience have you had with 1-piece?

I have reviewed several posts on the web, most have had good experience, key things are well cleaned surfaces, light application of RTV in the corners and about 1/2 of torque spec's for cork gasket.

Chris R · 2K+ Club

If your pulling the engine entirely out. Then I would replace the pan gasket if its leaking. Otherwise, if its not leaking, I wouldnt mess with it. Reason being, the engine has to come out to replace the pan gasket. Even if you lift the engine up "just enough". Just enough still means you have to disconnect nearly everything that would have been required to pull the motor anyways.

SShink · 3K+ Club

It's best to pull the engine if you are going to replace the gasket. I had this dilemma 2 summers ago when my green Chevelle slipped off the jack that was in the center of the cross member and dented in the front of the oil pan. Had to pull the engine to replace the pan. fyi-I don't ever jack it this way anymore. Thanks to my Navy buddy, I jack up one side at a time under the lower control arm and put some 2 X 6's under the tires. Safer and no risk of damaging the oil pan...

For the pan seal, I've used the fel-pro one piece rubber seal and love them. I've installed 2 now on different Chevelles, and neither one leaked. You can buy it from O'Reilly's.

jim larson · 2K+ Club

According to service manual you can replace oil pan gasket and timing cover without removal of engine. Don't have to remove hood, tranmission, exhaust pipes.

After jacking up engine you have to place two 2x4x15" wood pieces under the bottom of the engine mounts. No falling off the jack. If you get that far and don't like it, you can always pull the engine.

Most guys recommend engine removal; but you need a engine lift and extra guys to handle the hood removal/install.

I imagine there were lots of oil pan gaskets and timing cover seals replaced in the 60's. Wonder what the shop sheets allowed for time.?

69SSConv · Active Member

Well, tonight I tackled the job, and we will have to see tomorrow if I was successful. I pulled the radiator, fan, etc to make it easier to get at everything. When I pulled the harmonic balancer and inspected the seal, it looked good, but it almost appeared like it was leaking around the seal? I took the seal removal tool and gave it two gentle prys and the seal popped right out of the cover, almost too easy?

The cover is one of those inexpensive chrome aftermarket covers, so it is possible the tolerances were not as good as they should have been? I installed the new seal, with a thin coat of RTV around the outside, and put everything back together. I plan to let it sit tonight and will take it for a test drive tomorrow to make sure all the fluids are topped off, and that I do not have any leaks.

If all is well, looks like we may be able to make the fall cruise with the Chevelle? But I will reserve the final word for tomorrow night.

Lost in the 60s · President

Very possible it was leaking around the outside with an aftermarket cover. I always rtv the outside on all cover seals, just to be sure. Hope you oiled the new seal lip and balancer snout before re-assembly.

John D · 2K+ Club

Unfortunately it's a common problem with the aftermarket timing covers. The tolerances are (being nice) a little "loose". The steel used is usually of lighter gauge, the plating is "Monty Python Wafer Thin", and I'm guessing they really didn't do the math (factoring plating thickness & deformation) when building the die to stamp/punch out these items.... and who knows how "round" the hole/receiver for the seal really is.

Even with a factory cover, and a new seal (with the coating on the shell) as a matter of course I'll lay a bead of sealant around the perimeter of the seal, and (especially) in the bottom radius of the bore on the timing cover (where the seal bottoms out against). I want to see "squeeze-out" between mating surfaces when the seal is driven home - then I know all the voids are filled.

Hope you got it nailed.

69SSConv · Active Member

I did put a light coating of white lithium grease on the seal and balancer, before sliding them in so that the surfaces were not dry.

I believe the cover had the seal installed when I got it, so I never even thought about it and just put on the timing cover. That will be one mistake I won't make twice.

SShink · 3K+ Club

Hope it works! We're hoping to see you and Lisa Sat.!

Lost in the 60s · President

69SSConv wrote:
I did put a light coating of white lithium grease on the seal and balancer, before sliding them in so that the surfaces were not dry.
I believe the cover had the seal installed when I got it, so I never even thought about it and just put on the timing cover. That will be one mistake I won't make twice.
The lithium is perfect !!
The cover coming with the seal would explain a lot about the leak. I'm betting you got it stopped.

SShink · 3K+ Club

Kevin and Pushrod metal smithed my stock timing cover into near perfect flatness, and replaced the seal when I dropped in the engine this Spring. Delke supervised to make sure the minimal amount of RTV was used, and no leaks there.

In my experience, the chrome aftermarket stuff is typically marginal and should be checked before installing it. A lesson we all seem to have learn on our own...

I'm hoping we hear good news after your test drive today! Keep us posted.

69SSConv · Active Member

Well......... I believe we are good to go. Took it for a drive tonight, pulled it back in and checked underneath, and it was dry, no oil leaks.

Lisa and I will be there on Saturday.

SShink · 3K+ Club

69SSConv wrote:
Well......... I believe we are good to go. Took it for a drive tonight, pulled it back in and checked underneath, and it was dry, no oil leaks.
Lisa and I will be there on Saturday.

That's GREAT! See you Sat.!

Lost in the 60s · President

Way to go, Loren...

Now can you fix mine ? I have the same exact leak and I did put a new seal in the original cover. ...

dashboard · 2K+ Club

Great news, glad you can make it.

Do we need to get Loran and John D together and have them do some oil leak training.