Oil Leak Diagnosis Photo

[dantye]

While I had the heat shield off, I took this photo of the exhaust manifold "crud," which only accumulates above the rear port. I have always had an oil leak which apparently originates here - not a rapid leak when on the road - less than a quart in 500+ miles, but it does drip for a while when parked after running, and that side of the block stays oil-coated all the time.
From the photo and other reading here, it appears it may come from the gasket between the Cam Housing and the cyl.head. The compression measures in range: within 5% on the front 3 cylinders and within 10% on the rear cylinder.

Does anyone have an experienced observations on likely source based on this info and photo? It runs well enough now, that I hate to tear into it, but would like to get some feel for what might be ahead. THANKS!

[redcars]

It would be nice to have a picture from the side of the engine. I can't realy tell where your oil is coming from with the one picture. The crud on the side of the engine looks like is coming from above the picture. From what I can see in your picture it looks like there is an exhast manifold stud missing, if this is true, that is one that goes into the head where there is oil. I have replace the exhast cam box gasket on my 82 spider because of leaking. Mine had a piece of the gasket missing and it was leaking so bad that after 5 mimuites it looked like the engine was going to chace on fire from all the oil leaking on to the exhast manifold. It took me, with no experiance on the Fiat, about 8 hours. I replaced the timing belt and belt tensioner at the same time. I am sure that a mechanic would be able to do it much quicker.

[vandor]

You could clean the area, and then watch where the oil is coming from. The most likely sources are the cambox to head gasket, or the distributor. Other possible culprits are the cam cover gasket, oil filler gasket, and the #2 and #4 exhaust studs which thread into oil return galleries.

[dantye]

You could clean the area, and then watch where the oil is coming from. The most likely sources are the cambox to head gasket, or the distributor. Other possible culprits are the cam cover gasket, oil filler gasket, and the #2 and #4 exhaust studs which thread into oil return galleries.

Thanks. The cam cover gasket has been checked and is OK. I guess I could run it long enough without the heat shield to perhaps get a good look at the leak location(s). I did replace the distributor seal last year. Then I discovered the crack in the 30 yr old coolant hose to the heater, which was spraying coolant when the engine torqued. After replacing it, as you can see in the photo below, there was still oil slowly leaking between the cam housing and head under the back bolt. (The blue sealant was just in case the oil leak was through the bolt hole in the cam housing - it was not.)

After replacing that, I was hoping the liquid on the engine was ALL coolant, but about 700 miles, it was evident there was also an oil leak.

This car keeps giving me something to do - as long as I can afford to (or know how) do it!

[dantye]

More Photos:

[azruss]

classic symptoms of a leak at the dizzy gasket (dizzy to camtower). should be a paper gasket there. there is also an o-ring on the dizzy base that needs replacing as well. before pulling the dizzy, mark carefully its location (both the rotating shaft and the cap base). the dizzy will twist out, so pay attention to where the twisting stops and the dizzy is free. you will want to start at this point at reassemble.

[DaveT]

My '78 had the identical leak. It turned out to be the cam box gaskets. Replaced those and the leak was gone.

[dantye]

I am thinking that the distributor related leak "crud" might be "archival," from before the seal was replaced early last year. The photos below seem to show that the area around the cam housing-to-head gasket seems to be more "wet," but the higher area around the dist. area seems dried, and what dried crud is there may be left over from before the seal was replaced. Also keep in mind that, before the hose shown below was replaced (before a major road trip last Fall) coolant had been periodically "spraying" on that area from a small split just above the clamp! Everyone's comments are helping. Thanks!

[divace73]

i think I heard somewhere that some of the studs that hold the exhuast go straight through to the cam box, if this is the case and the studs are not sealed properly oil will leak out (i have a small leak on the front stud but haven't done anything about it yet?)

[131]

i think I heard somewhere that some of the studs that hold the exhaust go straight through to the cam box

Not through to the cam box, they all screw into the head about 15mm. But a couple go into an oil gallery and should have a sealant applied before they're installed. As for the photos, I'll go with cambox to head gasket, although trying to identify an oil leak with a motor covered in oil is like trying to herd cats. Give it a good clean and one 5 minute drive will show you exactly where the oil is coming from.

[Zippy]

Give it a good clean and one 5 minute drive will show you exactly where the oil is coming from.

I would agree. That is how I found my transmission leak.

[dantye]

Down to brass tacks: What do you think?

Two rear exhaust ports seemed to have oil leaking around one or both studs, that portion of gasket was oily on both sides, part of the metal seal around port 3 was missing and port 4 seal was mis-shapen. You can also see completely different color on manifold surfaces for those ports, showing "oil curing" of the surface. Must have been blowing out oil - apparently quite a bit - until it warmed up, then collecting dirt and baking it on (See photo #3.).

Rear Stud here appears to not be fully inserted (hopefully not stripped!). Will attempt to remove and seal, or rather than strip or break them off, just clean and seal around both of these studs. This aluminum mating surface was oily on these two ports only. [EDIT: Turns out rear stud (on left) was clean, but the other removed easily, as it was being continuously "oiled" by a leak.]


Pattern appears as though oil was blowing UP from exhaust manifold. Wondering if this is related to 10% lower compression is rear cylinder? It's pretty amazing it didn't burn more oil!

[124JOE]

yes it does look like the studs is leaking

[dantye]

Yummm ... Fresh baked Exhaust Manifold! Now to figure out replacing the lamda (Oxy) sensor. And sealing studs through the Cam Housing etc. etc. etc.

[dantye]

Getting there! Should be able to see any leaks now, as long as I get it running.
(Have to wade around the piles of melting snow.)