OVERHEATING

[lanz127]

I have a 78 124. I have an overheating problem that can not seem to be cured.

I have replaced the water pump and the radiator fan thermal switch at the bottom of the radiator. The thermostat is working fine.

What occurs is that between 190 and 260 on the temp gauge in the car the fan will kick on. Occasionally it will turn itself off when it has been on for a long period of time. But the main issue I have is that if I have been driving the car for a bit of time the temperature (with the fan running) will shoot to around 260 per the reading on the gauge in the car.

My question is: Why, even with the fan running, is the engine getting so hot?

[So Cal Mark]

your radiator is probably plugged. Do you have an infrared temp gun? If so, check each tube across the radiator and I'm sure you'll find tubes that are much colder than others

[courtenay]

It could also be the temperature sender that "spikes" the needle. Again, in infrared thermometer will help to see if the engine itself is actually overheating.

[4uall]

I had this exact same problem with mine.


Why she was overheating by itzebtze, on Flickr

This remedy worked great for me and I have had no issues since.

http://forum.fiatspider.com/f08/viewtop ... =5&t=16398

I had a friend help me, so we started with the thermo which was new, then checked the rad temp with an i.r. thermometer, all hoses, there should be two sensors in the engine block (checked them), then checked the flow and it was next to non existent, that's how we found the internal thermo stuck closed

[courtenay]

Do all 1980 fi's have an internal thermostat? Mine has an external t-stat and I've never thought to even look for an internal one.

[4uall]

truth be told I have no idea All I know is that mine only has an external one now and I have never gone above 190F

[So Cal Mark]

there should only be an external stat

[124JOE]

lanz127
do you have a tee in the heater hose at the back pass side of the motor?
these are aftermarket but nesesary on these cars
its for burping the air out and filling ALL of the system

you need the heater valve open to fill it all the way up

prestone makes these coolant flush kits GET ONE if you dont have one

as well as see if someone installed a second Tstat on the head

[Fi8spider]

Hi lanz127,

If the system is getting up to 260 you'd be getting a whole heap of steam and action happening at the overflow bottle.
Is this the case?

Do you run a 7lb cap or is it heavier.

A 7lb cap would release pressure to the overflow bottle at that temp.

If you are running a 7lb cap and you're not getting any action at the overflow bottle at 260deg I'm THINKING it could be your sender unit in the head, there are two of them. I'm aware if the wires are connected to the wrong ones ...i.e mixed up that that would make the gauge read incorrectly. Have you worked in this area recently and maybe accidently connected them up the wrong way around. I'm aware that the original wiring loom wont allow this but we are dealing with an old car with previous owners and who knows if the back wire has been lengthened in the past to reach the front switch???

From what you posted originally you said that the fan does cut out even when the temp is reading high, if the system was overheating as high as you mention while the car is running the fan shouldn't cut out at all.

Good luck with it and hopefully you get to the bottom of it soon.