I originally posted on Tech Help, but seems no one has any input. I thought I'd see if anyone here has any info:

http://www.peachparts.com/shopforum/tech-help/343000-1983-280ce-question-cooling-system.html

BTW, this is the car that I mentioned in this other post:

http://www.peachparts.com/shopforum/open-discussion/342435-question-m110-280e.html

Thanks!

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"Time's never wasted when you're wasted all the time"

Forget the fan...

Overheating during hard driving speaks to the radiator or water pump (eroded vanes), not to anything to do with the fan (which is more likely to make the car overheat at idle). Oh, and clean the radiator honeycomb and change the antifreeze to the proper coolant with proper coolant/water ratio before doing anything more drastic.

110 C isn't critically hot, but it does point to something being a bit wonky. As Speedy said, high speed overheating is a function of the radiator and/or water pump. Incorrect (too much ethylene glycol) coolant mixture will mimic some of the same symptoms. Start with a coolant flush and good external cleaning of the radiator. Also, use an IR thermometer to double check the actual running temperatures. 30+ year old gauges aren't always accurate.

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.

Have you scanned the radiator with an IR gun to see if there are cooler spots or not? Maybe the radiator is clogged? Assuming you have no debris blocking the cooling fins.

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01 Ford Excursion Powerstroke
99 E300 Turbodiesel
91 Vette with 383 motor
05 Polaris Sportsman 800 EFI
06 Polaris Sportsman 500 EFI
03 SeaDoo GTX SC Red
03 SeaDoo GTX SC Yellow
04 Tailgator 21 ft Toy Hauler
11 Harley Davidson 883 SuperLow

I posted a comment on the thread linked.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

I had to rethink about this again, and I realized I did not describe the problem correctly.

When I was crusing at highway speed, the temperature stayed between 80-100*. However, when I exited the highway I ended up idling for a while, and it so happens I live in the LA foothills so the engine was already under load climbing hills in traffic. That's when the temperature crept up to 110* until the auxilary fan kicked on. I did not notice this before as everytime I've exited it was on flat surfaces.

I haven't checked the radiator with a IR gun yet (don't have one).

Thanks again for all the input!

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"Time's never wasted when you're wasted all the time"

As my teacher used to say when we forgot our pens or pencils, I don't care how you get one. Beg, borrow or steal but get one.

Seriously, go see if someone will lend you one. I would take the radiator shroud off and drive to a garage and see if someone has one. You want the radiator hot anyways so it might work. If you were in the Milwaukee area, I would probably lend you mine assuming I could find it in that box of electronic trash and valuables I have.

__________________
01 Ford Excursion Powerstroke
99 E300 Turbodiesel
91 Vette with 383 motor
05 Polaris Sportsman 800 EFI
06 Polaris Sportsman 500 EFI
03 SeaDoo GTX SC Red
03 SeaDoo GTX SC Yellow
04 Tailgator 21 ft Toy Hauler
11 Harley Davidson 883 SuperLow

Sounds good aklim - I will grab one from HF this weekend and check it out.

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"Time's never wasted when you're wasted all the time"

Preferably BEFORE your engine is toast. I wouldn't drive it till I know for sure.

__________________
01 Ford Excursion Powerstroke
99 E300 Turbodiesel
91 Vette with 383 motor
05 Polaris Sportsman 800 EFI
06 Polaris Sportsman 500 EFI
03 SeaDoo GTX SC Red
03 SeaDoo GTX SC Yellow
04 Tailgator 21 ft Toy Hauler
11 Harley Davidson 883 SuperLow

Yup - I'm not driving it. It's sitting in the garage; it will likely be a weekender anyway, so there's no real urgency.

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"Time's never wasted when you're wasted all the time"

That's different. Check your fan clutch.

__________________
Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.