high water temp?

[jhandy]

Hi, I have been watching my water temp with the "scangauge" now for a while and I have noticed that on warm days, the temp goes up to 198-205 and stays there. The fans are on of course, but it stays at least 198.
Is there a way to lower it?
Should it be lower?
Are the radiators not working well?
62,000 miles and the system has not been flushed, never had to add any coolant.
The dealer swears that the system is sealed and life time coolant does not need to be changed.
Thanks

[Lil bastard]

Not lifetime coolant. Should be no more than 5yr./150k mi. whichever comes 1st.

Also, when was the last time you cleaned the radiators? They clog up fairly easily after a few years.

Also, are both fans working? Turn on AC and go to the front to check. It's not uncommon for the ballast resistor on one or both of the fans to go. Replacement is available and you need to splice it into the original harness, not a big deal, but you need to pull the bumper, a good thing is to plan a radiator cleaning at the same time.

[jmatta]

This is not unusual, which is why LN Engineering designed the lower temp T-stat, which is a simple bolt on replacement.

Please take a moment and read the article by Charles Navarro as to why this could be a valuable upgrade. I will install one in my '02 S as soon as I have time and can figure out what to do with spent coolant. LB is correct, lifetime coolant doesn't forever, but there are other steps you can take to protect your engine.

http://www.lnengineering.com/lowtemperaturethermostat.html

[jhandy]

I read the article and I have a question. Maybe Mr. Raby can chime in (hint hint).

How would this be better? Opening sooner would just make the motor take longer to warm up. Factory thermostat is open at 186 and the motor still goes to 205. The way I look at it, Open is open. sooner or later, the engine will get as hot as the radiators allow it to.

I was thinking..... is there a bigger better fans to install? Better ducting? Clean the radiators ( thanks Lil bastard).

I would think that cooler is better to a point, but how cool is too much?, IE: "dont drive hard until the car is at normal operating temps"

The dealer would not even set up a time to flush the system. They where emphatic that the system does not need it and even suggested that it would do more harm than good. dont ask me why....I dont understand. They said that they only do it if the system needs to be repaired.

Also is there a hack to make the engine bay fan turn on sooner? Or I guess I could hot wire it to be always on.

[Cloudsurfer]

I am with you on the lower temp T-stat- once it is open, it is open and the system will regulate itself based on the cooling capacity of the radiators. Now, opening sooner will give the system more time until it reaches this point of equilibrium, but still, assuming the car is to be driven for more than 20 min it becomes a moot point.

If you want to wind up with cooler operating temps you would need to add cooing capacity- either with larger radiators and thus more coolant volume, or by taking the oil cooling out of the liquid cooling loop (by eliminating the laminar flow oil cooler and installing a conventional air/oil cooler) or some combination of both.

The coolant Porsche fills is absolutely not lifetime fill, and you certainly cannot do any harm by changing it- provided that you do it correctly (when bleeding mainly).

[Jaxonalden]

I think there's one other thing your not addressing, the thermostat itself. Is it opening all the way? Flush water through the radiators for a quick cleaning and start the car and allow to run up to temp. Do not run the A/C.

1. Do the fans kick on? Yes, does the temp cool down and the fans stop? Yes, no problem.

2. Do the fans kick on? Yes, does the temp cool down and the fans stop? No, Possible coolant flow problem.
a. Bad pump (impeller blades coming apart and not moving fluid).
b. Thermostat not opening all the way (replace).

3. Do the fans kick on? No, troubleshoot electrical problem. Not enough airflow to cool the coolant.

Our radiators are well away from the engine, unlike most cars where the coolant is in and out of the radiator in just a couple of feet. Ours travels the length of the car and cools on the way to the nose and cools on the way back. There is no way you should have a temp of 200-205 degrees. Living in TX you're going to want to fix this before it gets really hot.

Good luck

[Lil bastard]

I've read both Jake's and Charles explanations and remain somewhat skeptical, no offense guys.

I get it that the t'stat opens sooner. I get that the gauge is both inaccurate and not indicative of temps in the engine's hot spots.

What I'm unconvinced about (though am ready to be) is whether or not the OEM t'stat actually cycles, that is, opens/closes within the normal temp swings of the engine and within the difference between it and the low-temp t'stat. I'd like to see someone test one in a pan of hot-to-boiling water and accurately record the temps at which it opens and closes. Even if it does cycle, udner most operating conditions, it will nonetheless stabilize at some point.

While they report cooler operating temps, or at least temps lower than 186° (OEM t'stat) with the low temp unit, they have not reported the operating temps with the oem unit vs the lower temp one.

Nor has any info been posted as to how 'bad' this actual operating temp difference is to the engine and it's components. I mean we're talking about materials like steel and alloy, but temps of only between 160° and boiling (250° under pressure), well under any critical temps for these materials. Even the oil is resistant to such relatively low temps.

To me, it sounds like a belief in the concept that anything lowering temps is better. While theoretically this sounds good, it may have no practical effect, especially if the higher temp is not in itself destructive, or more destructive.

All t'stats pose some degree of flow restriction due to their outlet diameter and their size. Could it be that the low-temp t'stat has a larger outlet, or is a smaller unit allowing more flow?

I would think that switching to a waterless coolant, such as Evans NPG because of it's much higher boiling point, would provide much more protection and, because of reduced hot spots would also give a lower overall operating temp. Plus, it's rated to 500k mi., instead of the 5yr./150k mi. of the Porsche coolant argueably making it more economical.

Whatever, these are just some further questions I'd like to see answered. I do hope the debate continues and that more accurate info is passed along.