fbgh2o

Tom, it does not move much at all with the heater on full blast. When I had the 90C thermostat in it did move a bit, but with the new 80C one, almost no movement at all.

hosrom_951

In Dubai, i saw a max temp of 95C in heavy traffic, ac running on full blast and it was well over 105F outside. Once the car started moving a bit, it dropped down to 90C )then to just below 90C during highway driving).

My personal opinion, replace that radiator if it is the factory one (that is what i did eventually and the car runs a tad cooler now). But, if you want a more accurate water temp reading, install a secondary coolant gauge, such as an Autometer one and compare it to the in car gauge. You can also use a non contact thermometer to see the in vs out temps of the radiator, but i would use those readings for a guide not as an exact water temp reading.

Note: I purchased a new radiator in January-Febuary, and i got it for $250 from Vertex Auto. Now, i see the prices have rocketed to over $350 from several places........i can see how this is a tough decision for you.

You never mentioned how old or new is the water pump?

gregeast

My car has had inconsistent running temps for the past couple of years even after a major overhaul of the cooling system.

To cut to the chase, it turns out that the new overflow cap I installed along with everything else was not holding pressure. I had pressure tested the system but never the cap, so, despite the fact that your cap is new it's worth pressure testing it as well.

fbgh2o

Hosrom - wp has 5,000 miles on it and was replaced 4 years ago - so I think it is okay.

Greg - good point. I have another one and will put it on.

Papamurphdog

fbgh, my daughter blew up the car before I could trace the issue for a final fix; but, the core can become constricted and reduce coolant flow and also allow air into the system from leakage points, or both. The heater valve can also allow air into the system depending on how it is failing. I changed all kinds of crap on that car and still had high temps (evident from boil over and screaming hot fluid discharge) and then I discovered the core was leaking into the passenger compartment, via the hoses just above the footwell, but I couldn't trace the exact source. Thankfully, it blew before I dumped more $$ into attempting a fix. I also, had a '90 944S2 coupe that had a similar overheating issue, but sold that before fixing. My "crew" and I were speculating that air was entering the system causing the occasional overheat condition after prolonged drive times. The rest of the system on both cars was otherwise perfect (mostly new everything.) Happily, my two current 944's do not have this issue. Wheeeew! Good luck. Check the core inlet/outlet hoses, etc. for leaks. If none, please tells me what the fix was so I can save the info for next time!!!!

fbgh2o

So in the end it appears to have been a bad temperature sender.

To eliminate the gauge itself, I used Clark's (http://www.clarks-garage.com/shop-manual/elect-19.htm) to test the gauge and it is "bang on" accurate. FYI you can get a POT for about $10 at most electronics stores.

That left either the sender or a ground. I had cleaned most of the grounds and did not have any other issues that bad ground seem to create.

As suggested by Lee101315, I got an infrared themometer. Idled the car for 10-15 mins and checked the temperature just after the fans came on. 82C at thermostat inlet, 80C radiator inlet and 88C at the outlet on the top of the head while the gauge was showing 102C. I am inclined to think the sender is wonky. Am having the belts done next week, so I will have them change it at the same time.

A big thank you to all that contributed to the thread. There are lots' of great ideas and experiences this thread. It is one to book mark, because it offers a wide range of potential issues that result in the engine running too hot.