Mysterious oil leak on my 289

fasttback · Dec 19, 2005

Tim65GT said:
Sorry I did not catch this post the first time.

I had this EXACT problem before. I replaced the filter and the oil pressure sending unit extension making sure it was tight and sealed with teflon tape.

Nothing I did helped until one day I revved it up while looking carefully at the area right in front of the oil filter. It was getting sprayed by an oil mist out of the fuel pump "bleed hole"!

I don't know if all fuel pumps have this hole. (I don't have the original type fuel pump anymore with the screw-on filter) I think the purpose of the hole is to let the fuel run out onto the ground in case the diaphragm ruptures, instead of pumping the oil pan full of fuel.

Anyway whatever seals the crankcase from this hole failed and it was allowing the oil (assisted by excessive blow-by pressure) that lubes the pump arm on the cam eccentric in the timing cover to flow into the pump and out the hole. The hole is on the back side of the pump facing right at the oil filter and sending unit/extension.

I took the pump back to Checker Auto Parts and they exchanged it for free. No more mysterious oil leak.

Hope this helps.

I'm sold. Called on fuel pump this afternoon. Will replace and post the results later on. As for the oil filter - it is new and I gave it the usually 3/4-1 full turn after engaging and I did apply oil to both sides of the rubber gasket before installing.

I did note in an earlier post that I have switch to Redline synthetic oil, but the amount of oil I lost the last time (covered parts of the fuel pump, oil filter, oil sending unit, power steering hoses, headers, and drive way) would probably happen with conventional or synthetic oil.

Rapid · Dec 20, 2005

I had a similar problem and recieved help finding the answer here a few weeks ago. I had oil in the same areas that was being blown by the fan from where the leak started. The oil was coming up the dipstick tube. The solution was to change the pcv from the drivers side front to the passenger side rear valve cover location. No leak after that.

fasttback · Dec 20, 2005

Tim65GT said:
Sorry I did not catch this post the first time.

I had this EXACT problem before. I replaced the filter and the oil pressure sending unit extension making sure it was tight and sealed with teflon tape.

Nothing I did helped until one day I revved it up while looking carefully at the area right in front of the oil filter. It was getting sprayed by an oil mist out of the fuel pump "bleed hole"!

I don't know if all fuel pumps have this hole. (I don't have the original type fuel pump anymore with the screw-on filter) I think the purpose of the hole is to let the fuel run out onto the ground in case the diaphragm ruptures, instead of pumping the oil pan full of fuel.

Anyway whatever seals the crankcase from this hole failed and it was allowing the oil (assisted by excessive blow-by pressure) that lubes the pump arm on the cam eccentric in the timing cover to flow into the pump and out the hole. The hole is on the back side of the pump facing right at the oil filter and sending unit/extension.

I took the pump back to Checker Auto Parts and they exchanged it for free. No more mysterious oil leak.

Hope this helps.

This did help - looks like we do have a winner (Tim65GT).

I purchased a new Carter fuel pump yesterday and installed it today. I took her for a spin this afternoon while mimicking the conditions that caused her to leak before. So far, no signs of oil in the problem area.

When you think about it, fuel pump = oil leak...just doesn't seem right, but it works for me!

Tim65GT · Dec 20, 2005

Glad I could help! :SNSign:

67coupe351w · Dec 20, 2005

If you find the problem isnt gone:

One thing that I didn't see suggested yet is the oil seal from timing chain cover to harmonic balancer.

This type of leak will spray oil like you describe and are fairly hard to see without getting a facefull of spatter.

Repair kits are fairly cheep if it is problem.

Mysterious oil leak on my 289

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Mysterious oil leak on my 289

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