Oil dripping from the exhaust manifold bolt.

[spikeygg]

I have a small slow oil leak that is dripping from my driver's side exhaust manifold. Does anyone have any idea where this leak could originate from? I think I might have to take off the exhaust manifold in order to determine where the leak is coming from. Any pointers on removing the dipstick and manifold?

You can see the drop forming on the darkened bolt head from this attachment...
44646

[David T]

I have a small slow oil leak that is dripping from my driver's side exhaust manifold. Does anyone have any idea where this leak could originate from? I think I might have to take off the exhaust manifold in order to determine where the leak is coming from. Any pointers on removing the dipstick and manifold?

You can see the drop forming on the darkened bolt head from this attachment...
44646

It doesn't appear to be leaking from above. Did anyone ever drill that bolt hole? If it was ever drilled it could be they went too deep and hit an oil passage.

[spikeygg]

It doesn't appear to be leaking from above. Did anyone ever drill that bolt hole? If it was ever drilled it could be they went too deep and hit an oil passage.

That's a good question and point. I don't know the history so my guess is as good as yours. Hopefully, that's not the case but I've got no ideas beyond a leaking head gasket.

How many studs should be sticking out of the heads? I find it strange that there are bolts and studs with nuts on them for this exhaust. Makes me wonder about the status of the heads.

Do you know if the dipstick just pulls out after it is unmounted from the exhaust bracket?

[dn010]

Kind of odd that those two are an actual "bolt" and not a stud & nut like the rest. Only thing to do is remove it and see if there was drilling done/how deep the stud hole goes into the head compared to the rest. Stock configuration was 2 studs per exhaust port, installed so they are diagonal- one on top/one on bottom. I opted to utilize all 4 of the mounting holes so you may find some engines that are different.

Yes, the dipstick tube will pull out once the tab is unbolted.

[DMCMW Dave]

Normally the studs are into blind holes and no sealant is needed. The upper holes, being into the cam area, are very low pressure hot oil. The lower holes go into 15 PSI coolant.

When you see someone using bolts, that means they broke the studs and could not find new ones, so they screwed in 7MM or 8MM bolts. If the bolts they used were too long, or they drilled the holes too deep - well - it's not good.

What's really odd here is that the holes ABOVE the pipes would drill into the oily area under the cam. The holes BELOW the pipes go into the water jacket. Are you sure it's oil and not coagulated coolant? You can always remove the bolt, and see what comes out, but be prepared for a disaster.

They are supposed to be 7MM studs. Worst case you can put new studs in (assuming the holes aren't hogged out to 8 mm or such) with something like JB Weld to seal the threads from leaking. That will make the next replacement more difficult, but it sure beats trying to weld the head back together. If the holes are bigger/stripped, you need to look into time-serts as a thread repair.

[davidc89]

If they did drill too deep, another solution would be to wrap a set screw with Teflon tape and screw it all the way in. Preferably a short set screw with an Allen head. It basically just becomes a plug at that point but, it gives you the option to put studs in again.

[Ron]

If they did drill too deep, another solution would be to wrap a set screw with Teflon tape and screw it all the way in. Preferably a short set screw with an Allen head. It basically just becomes a plug at that point but, it gives you the option to put studs in again.I've had this work well, but Teflon tape is only good to ~500F, so we always used high temp, permanent, pipe dope/sealant (1800F and 2000F are easy to find...).

[davidc89]

I've had this work well, but Teflon tape is only good to ~500F, so we always used high temp, permanent, pipe dope/sealant (1800F and 2000F are easy to find...).

Yeah, probably a better choice in this situation.

[spikeygg]

I've had this work well, but Teflon tape is only good to ~500F, so we always used high temp, permanent, pipe dope/sealant (1800F and 2000F are easy to find...).

Good call, I'll have to get some of that high temp thread sealant.

I went out last night to pull the header and I didn't realize that the O2 sensor was on that exhaust pipe. I went to disconnect the sensor plug and I couldn't figure out the trick to separating it. Apparently, that wire runs through a couple of holes in the frame. I couldn't get a very good view nor grip of this plug and I was worried that just yanking on both ends might destroy the conductors. Tonight I'll just try to take that bolt out of the head and see if it's oily inside. Hopefully, I can tell... If it is oily, I'll try some of the high temp thread sealant on the bolt and see if that helps.

Thanks for the info guys.
-Greg