Leaky Head on 3.6 ??

drola · 07-02-2020, 07:49 PM

i pulled the motor out of 964 for some while you're in there stuff. the motor is a late 1991 with plastic intake and after the serial # of commencement of head gaskets. not sure of the mileage since it is not original to my car.
i found this evidence of oil on the #6 cylinder to head mating point. i have not done a compression test since i didn't realize i may have a problem. all head studs are intact without issues. and the motor runs like a bat out of hell, even stronger than the 3.8's in the area. but yet i found this oil stain right at that spot which does not make me very happy. is this something of concern?

Tyson Schmidt · 07-02-2020, 07:56 PM

Judging by the dirt build up on there, I’d say it’s seepage at most.
Nothing to worry about. Clean it off, and keep an eye on it, but definitely don’t lose any sleep.

yelcab1 · 07-03-2020, 05:34 AM

I rather be driving it than chasing oil seepage anyway. You will never stop an old air cooled engine from leaking and seeping oil.

drola · 07-03-2020, 07:46 AM

I am not at all worried about leaking oil. What I am worried about is potential head damage. Like the type that happens with broken head studs. Also possible loss of compression in that cylinder.
And I agree, I’d rather drive it then rebuild it

GH85Carrera · GH85Carrera's Garage

I had one head seeping like that on my 3.2.

It turned out to be two of the head studs had become loose. Not broken, not pulled, just somehow not tight. I had to had all 6 heads surfaced. Of course "while yer in there" and the heads of off it is silly not to do a full top end. And the cylinders just slide off, and the rod bolts are there, and well "while we are in there" lets do a full rebuild.

drola · 07-03-2020, 07:59 AM

and that's exactly my fear...

i guess my next step would be to check torque on the studs. is there a sequence for just checking and/or re-torquing those suckers or just go by the normal procedure as if putting them new?

RedCoupe · 07-03-2020, 08:09 AM

I would just use the normal tightening sequence. IIRC, the 964 uses all dilivar studs so there's always the possibility of a broken one. That being said, when I disassembled my 964 the studs were all okay.

GH85Carrera · GH85Carrera's Garage

It likely would have destroyed that head and more damage if I just kept driving. In the end, as I was looking at the bearings for the shaft of the oil pump, it showed signs of wear and a few of the rod bearings had hot spots. It was good to get a fresh engine with all ARP bolts and other tweaks.