Oil leak

[Jayro]

Hey guys,

So had the 73 in the shop to get the C4 serviced to stop all the transmission oil leaks. All good but still have one relative substantial leak I’d like to get fixed.

Seems to be engine oil but is dripping off the bottom of the bellhousing. Any suggestions?

Cheers
Jase

 

[Stanglover]

Hate to say this, but it sounds like your engine rear main seal is shot.
If so, it can be fixed in the car, but a real pita. I did a rear main on a previous Mach 1 4 speed, when I exploded a clutch. I was able to drop the pan to do it, but had to raise the engine to get the pan off. And I did that with the car on jackstands, laying on my back!!
Good luck, hope I'm wrong.

 

[71ProjectJunk]

Clean everything up from the top of the engine all the way down, and then you will need to look to see where the oil is leaking from. It could be anywhere from the top of the engine, like the valve covers gaskets, or intake manifold area, to the oil pan gasket, or rear main seal. Only way to tell for sure is to clean everything off and then start looking where it is coming from. Regrettably Stanglover above is probably right, but check, you may just get lucky.

 

[Stanglover]

Clean everything up from the top of the engine all the way down, and then you will need to look to see where the oil is leaking from. It could be anywhere from the top of the engine, like the valve covers gaskets, or intake manifold area, to the oil pan gasket, or rear main seal. Only way to tell for sure is to clean everything off and then start looking where it is coming from. Regrettably Stanglover above is probably right, but check, you may just get lucky.

+1

 

[will e]

check the oil pressure sending unit at the back of the block too.

 

[DAverkamp]

Hey guys,

So had the 73 in the shop to get the C4 serviced to stop all the transmission oil leaks. All good but still have one relative substantial leak I’d like to get fixed.

Seems to be engine oil but is dripping off the bottom of the bellhousing. Any suggestions?

Cheers
Jase

If there is nothing obvious as previously mentioned and you park it downhill engine first, the oil sitting in the BH (from the rear main seal) will drip out of the weephole and confirm. Like SL'r said it can be done in the car but not having a 360 view on installing is a bit of a risk for a do-over.

 

[Cleveland Crush]

Hey guys,

So had the 73 in the shop to get the C4 serviced to stop all the transmission oil leaks. All good but still have one relative substantial leak I’d like to get fixed.

Seems to be engine oil but is dripping off the bottom of the bellhousing. Any suggestions?

Cheers
Jase

Could you tell if this "bell housing leak" was happening before the tranny fix or started after the fix? Point being, if leaking before, mechanic should have noticed the leaking/wet rear main seal while tranny was out. Especially since you brought it in for leaks. So maybe, just maybe, if lucky your leaking from up top as fellow members said.

 

[71coop]

Seeping from the valve covers is very common - I'd start there and make sure that you have a good seal up top (valve covers and oil sending unit, as well as the back of the intake). My experience is that valve covers - especially thin metal covers - often get over-tightened and fail to seal well. Oil runs down the back of the engine and collects/drips at the lowest point.

 

[Retired2014]

I found the source of a leak by adding a UV dye to the oil and searching for the leak using a UV flashlight (Harbor freight cheapie), AFTER thoroughly cleaning the area of the leak (and above it) as previously mentioned. UV oil dye is available at most auto parts stores.

 

[midlife]

And where was the leak?

 

[Retired2014]

Mine was coming from the weep hole behind the (recently replaced) fuel pump. The internal rubber diaphragm ruptured. Almost impossible to visualize the hole with the pump mounted. Kept thinking the oil was coming from the oil filter sealing surfaces. The UV dye really provided a glow-in-the-dark tracer to follow using the UV flashlight. Also helped pinpoint a leak in the power steering system previously. It proved a handy diagnostic tool.

 

[Jayro]

View attachment IMG_3546.MOV

 

[Cleveland Crush]

Hard to tell where the oil is coming from based on the video. I guess the "good" thing is the leak appears off center from the rear main; possibly meaning topside leak ( VC, rear intake, oil sender area). Feel around those areas with a clean paper towel and inspect it for fresh oil.

 

[Jayro]

Hard to tell where the oil is coming from based on the video. I guess the "good" thing is the leak appears off center from the rear main; possibly meaning topside leak ( VC, rear intake, oil sender area). Feel around those areas with a clean paper towel and inspect it for fresh oil.

It’s no drama degrease in and around there is it?

 

[Cleveland Crush]

Spray it down with carb or brake cleaner. An inspection mirror and good light will help get a good view back in that area.

 

[Blayne9067]

Are you sure it’s oil and not tranny fluid? Previously mentioned cleaning suggestion is where I would start as well, but I have seen carb and brake cleaner strip paint, personally would stick with an engine degreaser, rinse and dry real good. Take car for very short drive and inspect with good light and mirror as suggested.
I have seen more than one freshly overhauled automatic transmission leak from front seal because the tranny dipstick read incorrectly and trannies were way over serviced.

 

[Jayro]

Yeh certainly oil leak. It’s engine oil not trans fluid. Had a few leaks from transmission but they are fine now. This engine leak has been there since by prior to transmission leaks being fixed. Will give it a good clean up and do a drive line you mentioned and go from there.