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kpasko · Joined: 25 Jun 2013 Posts: 35 Location: California

hey all, I recently have had a lot of overheating woes on my 78 N/A 924.

as long as the car is moving (i.e. speed-based flow across the rad) there are no problems with the temp at all. however, in stop and go (especially after being ridden for a while at speed) it can creep up to the red fairly quickly. This leads me to believe the radiator itself or the fans are to blame.

before jumping into replacing all of that, I checked the system and found a rusted out tube in the system right by the heater control valve, which I'm sure wasn't helping the situation. I did a system flush, and replaced the thermostat (motorad failsafe 82c) and aux fan switch (wahler, 82-77c)...(maybe that's the wrong combo? The fan does come on at what appears to be the high speed...)

I've removed the AC system (that never worked) except for the front exchanger, which could be blocking a decent bit of flow to the rad, but aside from removing that, thoughts on upgrading/rewiring just the fans? 924s/944/951 upgrade as mentioned on the forums here? Take it to a rad shop for repair/recore? Other things I'm not thinking of?

I'm hoping its not a leaky head gasket and exhaust is getting in, but I don't see any white smoke or other symptoms so I'll exclude that possibility for now.

For reference, this is just spirited street, so no heavy use on the track or anything.

thanks for any help!

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

Like I said in the other thread, the temp gauges on these cars suck. If there is a grounding problem under the dash or between the engine and the body, the gauge will read high.

You need to borrow a pyrometer to verify that the car is actually overheating.
_________________
Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

kpasko · Joined: 25 Jun 2013 Posts: 35 Location: California

ah!!! thanks for the tip, i'll check around under there and see if there's something loose/frayed/etc.

924RACR · Posted: Wed Sep 17, 2014 7:22 am Post subject:

I disagree that the gauges suck; I think the gauges and senders are excellent, and I use the same senders even on my purpose-built racecar (fully stock gauge and sender on the 924 racecar). It's only the wiring on the car that can be a problem, as correctly noted.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

A gauge is only as good as its wiring. . .my point is intact.
_________________
Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3