After my long trip to Detroit for the Camaro Superfest I found a little puddle of oil on the top of my fuel pump (2-1/2 year old Holley 110 gph mechanical). It was not the gaskets or the bolts being loose because I checked them before I left on the trip. The fuel pump supplied plenty of pressure and the car seemed to run fine.

Today I pulled the fuel pump and it turns out that there are two small ports on the side of the pump (near the rear bolt) that were leaking oil. Yes oil - and definately not gas. I sprayed gummout in the ports and the more I squirted in the more oil/gummout came out.

Could oil also have leaked into the fuel system? or worse yet, gas leaked into the oil?

Bizzare huh. Any ideas?

ps. Already replaced the pump with the Edelbrock 110 gph which looks identical to my old Holley except it says Edelbrock on it.

I have seen pumps leak oil and gas to the outside the worst though is gas in the engine you dont usually discover it until the engine starts spinning bearings.

Those are vent holes. Never had oil leak from them though, but anythings possible. Seems like it would have to be getting past the diaphram.

Jody

Engines will leak from these "vents" if there is pressure building up in the crankcase. The pressure needs to vent somewhere and it can force oil out throught the vent.
The only other cause I've run into where weird oil leaks came into play was a car with a Big(!) scratch in the front cam bearing - it pi$$ed oil out of the crankseal (even after a new one was put in) and the fuel pump vent. Still don't know why the pump vent was leaking on that one - could have just been a 'co-inky-dink'. I didn't do the 'rebuild' - I was just called on to fix the leaks.

There is an oil seal on the pump shaft to seal out the engine oil, if that leaks, the oil comes out the vent hole, if the diaphram leaks, the fuel comes out the hole.
I had a 70 BB Camaro that would leak oil on hard left hand turns only.

Cut one apart and see how it's made.
David

David, You lost me on the seal part - you are saying that there is a seal on the pump shaft!? on the pushrod in the engine!?!? Never seen one there before and don't understand where one could go . . . or maybe you are talking about inside the pump.

I'll take the old pump apart today and see what I can find.

I had the same pump and the same problem it's a bad design on that pump. My pump leaked after a couple of months of use. There is a seal inside the pump that fell out on mine, it's a **** poor design. I did buy another Holley because I wanted the same fuel line size, but I did check and Holley started buying them from a different vendor. I was told to send mine in and they would replace it but I did not want to wait for shipping it back and forth because I had bought mine from Summit. You can take yours apart and try to center punch the seal better so it won't come out again but it is a bitch to load the spring back in there without tearing the seal.

Thanks for the info. I tried taking it apart last night and only got the bottom apart. Everything looked fine there. Where is that seal at? and how did you get the spring off the top half of the pump? I didn't want to force anything so I left it alone when the top of the spring didn't want to pop loose.

ps. You are right, Holley pumps are different now, but Edelbrock now uses this same design. I went with a new Edelbrock pump so my lines would fit :rolleyes:

Eric the diaphram hooks thru a hole in the top of the pump. It is hard to compress the spring to unhook the diaphram but if you unhook it the hard part is hooking it back after you fix it. The seal is in the top part of the pump look under the diaphram in the top part of the pump and you can see it.

Bill T