Porsche Enthusiasts Club Forum

Rebuilt my S2 after the previous owner neglected to change the tentioner pads. Everything was smashed to bits top end, so got a second hand head......and I dont know why but I also had the other head welded around the tentioner, skim because the welder got a blob of slag on the face and new valves - but have not assembled it ( due to the complex procedure in the book) Anyway put the second hand head on and all was spot on, done around 500 miles but the temp gauge was a bit up and down around the first mark, bled the system a load of times and also got a pressure bleeder. Went for a blast today to try and sort it one way or the other, it blew some water out of the header tank and was again full of air. So this after noon I removed the head.

Had a look at the head face and the gasket and all looks normal. Any thoughts as to the source of the problem, warped head or crack internally? I used an £80 gasket.

What to do next put old head on after putting the valves back in or get second hand head repaired/looked at?

These heads should be pressure checked after being overheated. One of our members had a cracked head on an S2 & it took some finding.
It also sounds a bit like an air lock TBH, these things are pigs to bleed.

My turbo did exactly that after changing the headgasket - it was an airlock.

Rich

OK, so I have now had all the valves out of the used head and all looks fine, other than some fair corrosion on the face, does not appear to be on the fire ring area, and no visible cracks , but without an x-ray who knows.....so I'm going to put new valves in my spare head that has been slightly skimmed. Read the book and taken some advice on setting up new valves in the head, they are all shimmed up, but not like a diesel theres 0.5mm tollerance.

Soak the lifters in oil overnight before fitting. This helps them pump up quicker on first start. Also bleed the cooling system carefully, it may require some concentrated effort & several cold/hot cycles.

Thanks Jim, any advice is greatly appreciated! Going to lap the valves in and then pressure wash the head. My work bench is clean and ready for the valves to be fitted. Have you heard about drilling a small hole in the stat to aid bleeding, read it on some amarican site.

I've drilled a 3mm hole in stats in the past & it can help. Rover V8s for instance, it doesn't do any harm & it may help. When I had a hose go on the 944 it bled out OK but I have heard of some people struggling. You have followed the book & removed the bleed screw on the housing haven't you? And left the heater on full hot.

Yes Jim, Did it loads of times, Im convinced there was an issue with the head or gasket. Anyway well on the way with the rebuilt head, just got to order the gasket set. Will post and let you know how I go.

OK so rebuilt the new head, new gasket, new pump and the found the time to bolt it all up, I recon I could whistle now and it would come to bits. Still the same minor problem,that being temp gauge moves a few mm and the fan some times runs when I stop. Also the header tank fills right to the top, and tries to spew all the water out if you remove the cap. So far I have drilled a 3 mm hole in the stat, this eased things, I have a presure bleeder and have bleed a thousand times with the car jacked up.............Pulling my hair out with this thing. Just had a look at the rad cap, the seal appears worn, would it give these symptom........Anyone?

Rad cap would definately cause problems as the system needs to be pressurised.

About a fiver I think.

Rich

got to be worth a go !

Replaced the cap with a new one.....just the same. Went to a mates garage and explained cap in hand.Out from his tool rack he pulled a piece of kit hes only used once in 5 years, it was a cooling system vacuum. Used it and it has solved the problem- Happy days!!! That was one big air lock.

good news