Cyl 6 oil leak - what is "normal"

[MeteorMetal86]

Hi,

been trying to identify the source of this leak on cyl 6 on my 3.2l '86, in order to estimate whether it is an engine out kindof problem or not.

Photo from below, where you can see the symptom - a small slow leak onto the exhaust flange and bolt. It is a very slow leak, and in itself not a problem, but I don't want it on the hottest part of the exhaust for obvious reasons.

Closeup on Cyl 6 exhaust area:


In order to find this, I went and got an endoscope, so I could get into the area below the air shroud on top of the cylinders. I filmed through the fan and into the area and you can see the larger cooling fins on the right. I know its hard to make out but it's the best I could do. In the gap between the cylinder head and the smaller cylinder wall fins I had expected a pool or trace of oil from somewhere but alas... the only thing I can see is that the back wall (the side of the oil cooler?) is kinda dirty, indicating oil and thus dust sticking to it. That's my conclusion, that the oil cooler is leaking, would anyone care to agree? I don't know what is "normal" in here. hence my ask for a second opinion.

https://youtu.be/XcN0flS_hhM

Thanks in advance,

Mike

[Nditiz1]

I have a similar leak on my 82 engine. I'm not saying it is the same, but in my case the lower head stud has broken. Easiest way to check is pop the lower cover off and see if you can put any torque on the head stud. Mine spun and unfortunately was broken.

[MeteorMetal86]

Thanks for your input. Sounds a little daunting but I am in good company here it seems.

[yelcab1]

That is an engine out, but the engine out on a 3.2 is actually pretty easy to do. Don't sweat it, just do it.

[ErrorMargin]

Originally Posted by MeteorMetal86

...been trying to identify the source of this leak on cyl 6 on my 3.2l '86, in order to estimate whether it is an engine out kind of problem or not...

Whether it is an oil cooler leak or a broken head stud, or just about anything else it might be, it is an engine out job.

I pulled the engine on my 84 3.2l a few weeks ago and am going through the process of cleaning everything up, replacing parts, fixing leaks, etc. It was not too bad getting the engine out and it now enables me to address many current and potential issues.

https://forums.pelicanparts.com/porsche-911-technical-forum/1153485-pulled-engine-my-84-targa-now-fun-begins.html

If you are not going to do it yourself, I'd start talking with local shops to see what they would charge.

One way to get a handle on what you are getting into is to have a shop adjust your valves and then run a leak down test, both can be done with the engine in the car. The shop can very easily check for broken head studs while adjusting the valves.

After adjusting the valves, have the shop run a leak down test. If your engine passes the leak down test and you don't have any broken head studs, then you know your engine is good and you don't need to open it up. You could be fairly confident that pulling the engine to fix your leaks will not turn into a rebuild.

On the other hand, if your engine fails the test, then you know what you are getting into and can start talking to shops for either a head/valve job and/or new cylinders depending on what the leak down test says is wrong.

Let us know what happens.

[MeteorMetal86]

Thanks - appreciate the good advice.

I'm a DIY'er so likely attacking this on my own.

Looks like I might need a new tool then, a leak-down tester

Both leak-down and compression is done with a warm engine right? do I remove the wire on top of the ignition coil when I run the compression test? That should keep it from building up energy right?

I have started getting my head around having to remove the engine, but testing it first is the right thing to do.

[theiceman]

the one thing i would absolutely check that can show here are the rocker shafts. That is NOt an engine out job, but if you are removing the covers to check for a popped stud , id definitely get a close look at each end of the upper and lower rocker shafts, they should be bone dry.

[MeteorMetal86]

I’ll have a look once engine is out

But first is to run the tests, anyone know how to disable the charge to the ignition to avoid damaging anything.

[john walker's workshop]

Inboard of the left rear shock top is a plug that relates to injectors. Unplug and it won't start.

[ErrorMargin]

Originally Posted by MeteorMetal86

Both leak-down and compression is done with a warm engine right?

Franny did a great video series on engine removal, work and reinstall on her 3.2 Cabriolet. Here is her video on the leak down test:



Here is a link to her full series on the 3.2: https://www.youtube.com/watch?v=-2rvMKMqQ2k&list=PLESd2KXwHSVKKl3FxYSFB3rGKZTsfWpQp

[pmax]

Originally Posted by MeteorMetal86

I’ll have a look once engine is out

But first is to run the tests, anyone know how to disable the charge to the ignition to avoid damaging anything.

Don't have to drop anything or run tests to pop the valve covers.

Hope it isn't the head stud(s).

[ErrorMargin]

Here are Franny's videos on checking the head studs and adjusting the valves:

Head studs: https://www.youtube.com/watch?v=uG9cFxtSfQg

Valve adjustment: https://www.youtube.com/watch?v=6ciw3mDjz0k&t=315s

The valve adjustment is ideally done before the leak down test.

All of these are doable with the engine in the car.

As for a leak down tester, I'd post your location here and see if someone has one they will loan you.

Tom also has a great video series for the 3.2 and the 911 in general, here is his video on valve adjustment and a leak down test:

[MeteorMetal86]

Thanks guys!

I'll have a look at those videos

I am off in a far region of the world (literally on top of it) and I don't mind an extra tool, it's good to have for diagnostic purposes, and it's not my first and only car that needs help from time to time.

Also, I need to do the fuel lines at some point, so an engine out is easier than fiddling with all of these things in cramped spaces, I'm not a young spruce anymore

Actually a part of me is looking forward to the challenge now that I have got used to the idea and spending some quality time in the mancave can be a little carthartic.

[wazzz]

Oil cooler can be removed with engine in. No need to drop engine.
It is worth checking it, as the leak could come from the famous engine block foundry fault that is easily addressed with a bit of JB-Weld. See the Porsche Bulletin about this. My leak was worse than yours and I cured it this way. I now have a clean underside.

[MeteorMetal86]

Originally Posted by wazzz

Oil cooler can be removed with engine in. No need to drop engine.

Hi, ehm, can't see how I can get to it without major removal of intake, shrouds etc. Can't be easier than removing the engine first, surely?

[MeteorMetal86]

To keep the momentum up, I've decided to take the cover off the head on the 3-6 bank and have a look, before I do any engine drops, it shouldn't be too hard to get in there and evaluate the head bolt failure source. I need to set the valves anyway as I don't know when that was done last.

[Discseven]

Suggest putting your endo around the breather hose where it connects to the cap for look. If hose is old enough, it will be brittle and possibly cracked. Oil vapors will escape and trickle down. I hope this is it. Simple fix relatively.

[MeteorMetal86]

Cheers, I’ll have a look

[ErrorMargin]

Originally Posted by MeteorMetal86

Cheers, I’ll have a look

have you made any progress?

[MeteorMetal86]

Yes, somewhat…

My diagnosis led me to a clear conclusion of a leak between the cylinder and the head. Exactly why I will see, suspect is an exhaust side head bolt, but I needed it decently driveable to get it out of the garage hence I did not remove the camshaft covers. I loaded it on a flatbed and took the car to a Porsche specialist. Awaiting for him to tear into it.

He has a few customer 964 engines on the stand so that will probably take a few weeks he said then he would look at my car. He has an identical ‘86 3.2 himself so I feel pretty comfortable he knows what he’s doing. I will get to come see it whenever I want as he gets into it, which is comforting.