7A Spal coolant fan burnt wiring - causes?

[cgharibo]

Hello everyone,

My '91 7A with 300k miles experienced the autocheck red overheating coolant light for about 30 seconds. The coolant gauge was almost at the two dots that rest on each side of the thick line.

What's the experience with 7As and such overheating? I am just really concerned that the 7A experienced engine damage.

The car has had a relayed Spal fan for about a decade. When I investigated the cause, I found the Spal wiring insulation and it’s connector was burnt down to metal. What can cause such catastrophic wiring failure?

Thanks in advance.

CG

[Obli]

That is getting a bit high. The pair of dots are either side of 110 deg C. The thick line at 11 o'clock is 90 deg C, each line represents 10 deg C. Is you coolant level OK and with engine up to temp, are rad bottom and top hoses hot (coolant is passing through rad) ? Were you stationary? What was the outside air temp like?

My 7A is UK based and is running without the auxiliary rad. I've never had it overheat, although I don't actually know what is a safe, constant operating temperature. I've always presumed halfway on the gauge must be OK. Mine has been without the aux rad for about 50,000 miles. Runs a couple of deg C higher now, perhaps, but never goes past the 100 deg (thinner line at just after 12 o'clock), even when stuck in traffic. Needle sits at the thick 90 deg line (11 oclock) when at A-road or motorway speeds and outside temp is ~25 deg C. This is about right, I believe. I'd imagine the thick lines are of significance. I'm aware that different manufacturers of multi function temp sensor can give differing gauge readings.

Ensure your radiator cooling fan is kicking in at high 90s, and afterrun kicks in shortly after engine has been switched off and key removed. Is the rad fan motor turning freely?

[newsh]

The wiring damage is probably down to a poor connection or loose crimp. Cut the wire back, make sure terminals are clean and crimp or solder on some decent connectors. Are they 1/4” spades on the fan or similar?

If the car boiled over and you had steam everywhere you may have stressed the head gasket, otherwise I would keep an eye on water level, if it doesn’t drop you should be ok.

A few years back I lost the head gasket on my S2 when I had a leak under the header tank which allowed the water level to drop. It was a 3B and still had the original paper gasket so it was a no-brainer to replace with the later metal type, new header tank and no further problems after that.