It's been a few weeks since I've posted on here but I'm still chipping away at the ol' girl.
The latest task completed was a good overhaul of the cooling system to address overheating problems when the car was stationary.
After having had an oil cooler seal fail, there was quite a bit of oil in (what little) coolant was left in the system. So, I drained the system of all the sludgy brown stuff, removed the expansion tank (which had been painted black - go figure!) and all the associated hoses for a good clean. What I had't planned on doing was completely removing the radiator and fan, but seeing as the PO had it loosely attached to the car by nothing but cable ties, it practically fell out...so out it came for a more thorough clean.
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Unfortunately the old expansion tank was way beyond repair so a cheap used one bought from ebay and couple of hours shaking with hot water, uncooked rice and Sterodent(!) as advised on numerous forums and it came up suprisingly well! There seems to be fiercly divided views on many of the forums about this, but I decided against forking out for a brand new bleached white one as I feel that it would stick out like a sore thumb in my particular engine bay! - especially given everything else that needs attention/££'s.
Next up was the radiator which was flushed/backflushed, bent 'fins' carefully straighened out to improve airflow and finally scrubbed up the aluminium edges to get them nice and clean. The fan got a wipe clean and a quick spray of contact cleaner on the electrical connections. I also fitted a new OPC bought fan switch as the old one was dead - the main cause of the overheating!
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Another little suprise I discovered was that there was no thermostat present at all!...yet another frustrating bodge by the PO/mechanic.
Anyway, a new OEM thermostat and circlip bought and fitted and we're good to go.
Refitting the rest of the system was straight forward enough. Replaced all the old corroded hose clamps with new JCS items bought from eBay, along with replacement screws for the fan mount and new OEM rubber mounts for the radiator.
Next step was a system flush with Forte Biodegreaser to get any remaining sludge out of the radiator and block, final water flush then fill/bleed with 50/50 coolant and de-ionised water.
Result: a 924S which reaches temperature more quickly from a cold start, fan kicks in when the temperature creeps just above the 1/2 way point (83 degrees I assume)which then cools it down to just above the 1/4 mark.
...and a much more clued up Porsche owner (with regard to cooling systems at least!)
Next job: address the idling vibration with a new set of engine mounts