924Board.org

jebe · Joined: 16 Dec 2002 Posts: 39

1988/924S/Europe

a couple of months ago I bought this car and had it serviced (belts, all fluids etc. by porsche specialist). They also changed the temp switch; the one on the radiator, because it was running a little hot they said.

Then I noticed it was hungry for coolant (0,5 ltr / 1000 miles). Thought it could be an air bubble from refilling the system. Checked by opening the bleed plug; no bubbles but steady stream of coolant.

But I still notice in stop and go traffic that the temp gauge is creeping onto the edge of the red area (!!!), and just before I want to get of the road the fans turn on (freaks me out). And then it cools, the needle gets to the middle quickly. But one time the fans didn't come on quick enough so I parked out of safety. Now it's working again, but just on that freaking red-zone.

Any suggestions so I know what's wrong (major/minor), what to buy, or order to fix if to complicated (thermostat? pump? radiator? relay?)

TNX again
JB.

Paul · Posted: Thu Dec 04, 2003 12:36 pm Post subject:

I would have my cooling system pressure checked to rule out a leak in the system (radiator, heater core, hoses, head gasket, etc).

Make sure the radiator cap is pressure checked or replaced.

It is not normal to lose coolant.

Once the cooling leak is found, you could install a lower temp radiator fan switch to turn the fans on earlier. If you have A/C, turning it on activates the fans any time you wish.

gohim · Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA

A loss of that much coolant signals a leak of some sort.

Check your hoses carefully, and try sniffing the tailpipe to see if you can detect any coolant. Any coolant smell at the tailpipe indicates a blown head gasket.

Here in the U.S. I noticed that many of the used 87 924S models that I looked at starting about 3-4 years after the cars were made had a very high incidence of blown head gaskets. Many/most of the cars that I looked at that had between 70K-90K miles had already had the head gasket replaced, or had blown head gaskets when I saw them.

Zuffen · Posted: Thu Dec 04, 2003 2:09 pm Post subject:

I would have the service shop do a temp test and fan switch check,

basically they would use an infrared gun to measure the radiator temp to the point of the fans coming on to determine whether you had a cooling problem or sensor gauge problem.

You didn't say anything about the thermostat being changed?
_________________
Bob Dodd - 924turbo@cox.net
931 1982, 944 1982 euro, 924S 1988SE, 93 968 tip 06 Silver Cayenne S, 06 Black Cayenne S

I have Way too many cars, parts for the 931,944 and 951

jebe · Joined: 16 Dec 2002 Posts: 39

Thermostat has not been replaced yet. When I called them about the problem they said 'oh probably the thermostat'.

And about refilling coolant; I can't see more than one tiny spot of it at the temp-rad switch, no dripping. And no oil in coolant (so no signal of blown gasket I suppose)

ZV · Joined: 27 Nov 2002 Posts: 297

jebe · Joined: 16 Dec 2002 Posts: 39

OK,
the service station didn't find signals of a head gasket problem. They already had replaced the temp switch for fans on the radiator. Now they put in a new thermostat and a new engine temp sensor for the gauge, to be sure the meter accurate. But still the fans kick in just before the red zone. What is it? Do I need a lower temp switch fans?

TNX

MAAS · Joined: 19 Jan 2003 Posts: 72

"But still the fans kick in just before the red zone. What is it? Do I need a lower temp switch fans?"

This is normal!!! I owned an 87 924S for over 2 years and it did this from the first day I had the car. It concerned me too.

Also, the temp range reading on the gauge is actually smaller than it looks. This is why when the fans kick in, the temp can drop from Red Zone to 1/2 in only a few seconds.

-MAS

Lizard · Posted: Fri Dec 19, 2003 6:16 am Post subject:

I was waiting for someone to state the obvious, yes it is meant to run like that, if you want the engine to run way cooler then change the thermistats and the temp switch in the rad, the early 924s had a temp switch that was very low, that is what I have in mine, it sits right at the 1/4 bar when it hits this, as per the loss of coolent that is not good, it could also be the oil cooler on the head/block (not sure which) it has some seals in there that go, but try checking the oil for contamination, it is possible to be the head gasket, and not mix the oil and water, it could just burn it out the exhaust, have you retorqued or checked the torque on the headbolts?
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3 928s,

Lousailor · Joined: 04 Sep 2003 Posts: 16 Location: San Diego

Yes it seems strange but usually the culprit is the thermostat. I have a lower temp fan switch and the thermostat was not working properly. The car would heat to well past the halfway point on the guage and the fan would run constantly, even when driving. I spent the whole day removing the thermostat because the bleepin PO had broken a tab from the retaining spring ring and there was no way to get it out. Finally was able to coax it, but didn't have a replacement, so I buttoned it back up sans thermostat. No real problem here in sunny Socal, but wouldn't advise it in an area that gets really cold. Car runs super cool now. Only gets to halfway when sitting in traffic, then fan kicks on and it drops right down to a quarter. Hopefully when I do re-install the thermostat it'll work as well.
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'87 924S (Crunch/Rebuild)
'85 944 (Beater)