There are pros and cons but if your car is genuinely running hot during normal operation then an LTT will assist it in running cooler, however a car running hot under normal conditions is doing so for a reason which probably warrants further investigation.

 

One additional thermostat comment - and then I'll shut up - is that neither thermostat (OEM and low-temp) is binary - i.e. they don't go from 0% open to 100% open instantly. I point this out only because it can help make sense of the numbers if you're fixated on operating temp and trying to figure out why things happen when they happen.

 

If the radiator fans didn't come on until the coolant temperature reached 226F that's a problem. (Not the 226F but the fans not coming on before then.)

My info is the fans should have come on low speed way before 226F (by my observation they come on at 212F) and should have been at high speed if the coolant temperature climbed to 216F (again by my observation).

Based on what you posted I believe you need to investigate a possible problem with the fan electrical system stages of the ECU/DME with a bad T-stat or water pump also possible. (There are always 2 problems, unless there is just one or 3 or more problems...)

If the car's cooling system is correct there should be no reason to install a low temperature T-stat or make any other changes.

The car's cooling system, as it comes from the factory provided everything is ok should keep the engine reasonably cool -- though under some high ambient temperature conditions or on milder days with severe, err spirited usage the coolant temperature might climb to 226F (my observation more than once) and in high ambient temperature stay there but the engine will suffer no harm.

If the temperature reaches 226F on a milder day but during spirited usage as soon as the spirited usage stops the coolant temperature should drop and when it reaches 205F (my observation) the fans should turn off.

 

Don't know if this will help, but I have no idea when my front fans kick on, but my rear fan kicks on at 95C.

And my car has not crossed 100C yet.

 

Right on Macster.
Low speed mode is not working, per my ears.
Also, passenger side fan is not working, per me walking around it and kneeling down and listening.

 

Can I run without A/C condensers?

I don't use A/C anyway.

I figure removing those condensers would increase airflow to the radiators, until such time as I can diagnose the fan problems.

I removed the bumper etc. and will be cleaning the rads today. They're a little dirty but not too bad. Compressed air's not gonna cut it, coz it's more like caked on dust/dirt. So I'm gonna use soap and water and a brush. Hope the brush doesn't damage anything. Rads are pretty cheap, maybe just buy new ones?

Dealer appt. Monday for coolant flush and general look-see. I was gonna just drain/fill myself, but want to ensure it gets pressurized correctly, no air pockets etc., and I don't have the tools and it would be my first one.

 

Fixing the cooling fans should give you big improvements from where you are now. Next stop will be the water pump and thermostat.

 

Probably not a good idea to disable the AC system. Even if you don't use it for cooling, I believe most vehicle AC systems assist in keeping your windshield clear of fog when the defroster is on - and you never know when you'll need it. Case in point, I had an old 2 seater without AC. Had friends over for the evening and a buddy and I were sent out to pick up pizzas for the whole crew. On the way home, my buddy carried the 8 steaming hot pizzas on his lap in the passenger seat. As soon as we pulled out onto the street, the pizzas fogged up the entire windshield - holy crap, it's nighttime on a busy street and all I can see is a wall of fog - no AC available to quick clear the windshield.

 

The 996 also uses the AC to cool the fuel - one more reason to leave it in place.

 

Um, are you sure? I think only 996 turbos have it.

 

+1

With the 996 cooling system it's the "sum of the parts" that make the difference. When I bought my car with 86K miles on it all those things were original. New WP, coolant, belt and cleaning the rads made a substantial difference in lowering the peak temp.

I've also put a low temp Tstat in as well and while it won't stop your car from hitting peak temps it does run cooler a lot of the time and allows the car to warm up a little quicker.

 

Per The Essential Companion, "a fuel cooler is installed in the engine bay in all US market 3.4 L 996 models and all 3.6 L turbocharged models worldwide."

This applies to OP's car (and mine)...

 

That is interesting. I've only seen it on 996 turbos (photo in the link below) but not on the 3.4 . Maybe someone has a pic of it on the 3.4?

http://www.autoatlanta.com/porsche-p...section=813-26

https://rennlist.com/forums/10549141-post8.html

 

You'd better go back to T-stat class. A lower temp T-stat opens at a lower temperature but the engine will take longer to warm up to its nominal operating temperature.

It will be interesting to see how engines that have been fitted with a low temp T-stat fare over time after having to deal with colder and thus thicker oil and oil that because it is colder can't shed the build up of unburned fuel and water.

 

...especially since many of us are using incrementally more viscous oil than the factory fill...