Mystery oil leak above exhaust manifold

[going4speed]

I have been searching for a mystery oil leak. It seems to be coming from above the exhaust manifold. Have new pcv elbow zip tied tight. Have new valve cover gasket. Oil feed on top of turbo is spotless.

This has me stumped.

**Solved**

[85boostbox]

One if the intake manifold bolts runs through an oil galley. Is it more towards the drivers side of the engine?

[going4speed]

toward passenger side

[turismolover22]

Ive found its a crapshoot on your manifold bolts and studs. If I recall correctly, 50-75% of the intake bolts run through some oil or coolant passage. If they werent sealed on install, or are just aged, they can leak. Beyond a stud leaking, the only culprit I could blame is a leaking valve cover.

[going4speed]

I put a new valve cover gasket on yesterday and cleaned the engine today to make sure I have a clean start for oil leak hunting.

The odd part is the car will sit there at idle with no smoke then all of a sudden it smokes like crazy rolling out from under the passenger side manifold by the ps pump. Then it stops. I ordered a boroscope. That will hopefully help and I've needed one for some time anyway.

Is it possible to remove the intake bolts one at a time with the engine in the car and reapply sealant?

[Chris W]

I put a new valve cover gasket on yesterday and cleaned the engine today to make sure I have a clean start for oil leak hunting.

The odd part is the car will sit there at idle with no smoke then all of a sudden it smokes like crazy rolling out from under the passenger side manifold by the ps pump. Then it stops. I ordered a boroscope. That will hopefully help and I've needed one for some time anyway.

Is it possible to remove the intake bolts one at a time with the engine in the car and reapply sealant?

You may have just answered your own question. I have had PS hoses leak intermittently. Sometimes they only leaked when the steering wheel was moved which was frustrating to pinpoint. If you are low on P/S fluid that might confirm it.

BTW- the lower exhaust manifold bolts can leak antifreeze, but not oil. I don't believe intake bolts would be an issue since they dead end.

Chris-TU

[4 l-bodies]

4 of the intake bolts intersect with head bolt holes on the 8V applications. They are on drivers side or left of each port. I have seen these leak slowly before. The 4 top exhaust bolts along with the other 4 intake bolts (pass. side) are all blind holes. These should not be issue. As Chris stated the bottom 4 exhaust bolts are drilled through into the waterjacket. Certainly could be PS fluid leaking through hose.
Todd

[going4speed]

There is a small plume of smoke coming from under the intake at times. How could this be a hose for ps?

[Chris W]

There is a small plume of smoke coming from under the intake at times. How could this be a hose for ps?

In my situation the pressure hose leaked right at the crimp whenever the steering wheel was moved even the slightest amount. Due to it's close proximity, the P/S fluid sprayed a small stream of fluid on to the exhaust manifold each time.

Check your fluids to see which one you are low on. That might help speed up your diagnosis.

Chris-TU

[Dave]

Do any of the intake or exhaust manifold fasteners require sealant then? I never knew this before but have occasionally seen oil on top of the #1 exhaust runner.

[4 l-bodies]

Do any of the intake or exhaust manifold fasteners require sealant then? I never knew this before but have occasionally seen oil on top of the #1 exhaust runner.

Yes Dave they do. That is what we are talking about. The 4 bottom exhaust studs penetrate the waterjacket. If you haven't sealed these before, consider yourself extremely lucky. See post #7. If in doubt, put some thread sealer on them all.
Todd

[going4speed]

Can I do this with the engine in the car?

[4 l-bodies]

Can I do this with the engine in the car?

I believe two of the intake bolts are not removeable without removing the exhaust manifold. Exhaust studs are usually not enough threads to attach jamb nuts on them with manifold attached. Sometimes they unscrew at head in lieu of jet nut loosening.
So what you would end up doing is trying to change out 3 of the 4 intake bolts (left side of port) that could be causing your oil leak. That should be doable in car. Hey it could be worse, you could be trying to do this in sub zero weather and not 60-70° weather that you should be enjoying.
Todd

[going4speed]

40's today...the next few days is going to suck for us or at least what we are used to.

My boroscope gets here tomorrow hopefully and I am going to see if I can see where this is leaking once and for all instead of just trying to seal random bolts.

[going4speed]

Got the boroscope and cant see any leak at all. Now the car smells like burning plastic under the hood. There is nothing touching the exhaust.

This really has me baffled.

[4 l-bodies]

40's today...the next few days is going to suck for us or at least what we are used to.

I hear yeah, But what I wouldn't give for a +40° day right now. High today for me was -4°. I was playing outside with the dog for a few minutes today and my Dr. Pepper can stuck to my tongue and lips when I tried to drink from it. Soda was already slushy. This was after maybe 5 minutes outside. Windchill was -40's in parts of the state last night. Cold even for a MN guy.
Todd

[black86glhs]

I hear yeah, But what I wouldn't give for a +40° day right now. High today for me was -4°. I was playing outside with the dog for a few minutes today and my Dr. Pepper can stuck to my tongue and lips when I tried to drink from it. Soda was already slushy. This was after maybe 5 minutes outside. Windchill was -40's in parts of the state last night. Cold even for a MN guy.
Todd

I don't mind the cold, but I don't envy you Todd.....hehe. BTW, the S60 harness and computer will be put to good use. Car is on a rotisserie as I type this. Thanks again.
Sorry for the hi-jack, Carry on.

[going4speed]

I really like rotisserie chicken. I think I'm going to swap the motor out of this car and put in the forged S60 turbo motor that was destined for glhs 313. Sick of messing with this thing.

[going4speed]

Okay. So. Got out the boroscope again tonight on a mission. So ran the car and while it was running had a high powered shop light and the boroscope going at once. Looking all over the intake and exhaust manifold to look for a leak. Then in the camera I could see wisps of smoke. Okay lets do this thing. So I'm watching and watching and cant seem to find where it's coming from them BAM. I see this dark mark on the exhaust manifold and the smoke slowly burning off the spot. Right above it is the intake manifold bolt and it's shiny black. So shut it down and fight getting the socket on that manifold bolt as it at a weird angle. The crazy thing. This thing is finger tight. The second crazy thing. Not a spot of thread sealant on the damn thing. So thread sealant on. Fired it up and ran it in the driveway for 30 minutes. My neighbors love me. I love them back believe me. Not a stitch of smoke. NON! Stills smells funny but hey its a 27 year old TD!!!

Cliff notes version: Victory..no thread sealant on intake bolt.

[4 l-bodies]

Yay! Another mystery caper solved. Looks like buying the right tool helped crack the case. Good job!
Todd