06stef

hello

I have changed the thermostat ( previous post :
https://rennlist.com/forums/996-foru...-too-high.html)

and now the water pump.

but the city road the temperature is still too high
this morning 24°C/75F indoor my temperature on average is 103°C/217F
on highway the water temperature is 94 °C/201F on average...

the water level is ok
radiators in front are clean.

has prolonged the stop in a car park,
the temperature water is 100/103°C (212/217F)


I'm confused I do not find the origin of the problem.
if you have ideas ...
thanks

crashclint

What did the impeller blades on the water pump look like on the one you took out of the car? Did it look like it had been rubbing? The next thing would be to pull the radiators and have them flushed and flow tested.

My son had a Pontiac Fiero, when we bought it, it had not been running for a while and the coolant lines looked a little dry rotted so replaced all the lines, installed a new water pump, 160 thermostat and radiator. It would run fine some days and other days it would run extremely hot. I removed the thermostat and put it into a pan of water and heated the water and I could see it open fine but since it was so cheap I bought another one, tested it and installed. Same thing as before and as hard as it is to pull the water pump, I did. I noticed a couple of the plastic impeller blades had some small nicks. I grabbed the old water pump to compare and noticed the impeller on the new pump was slightly past the shaft. I grabbed the pulley and was able to easily spin the impeller. Basically when it got hot the impeller was floating around, it would strike the housing and stop spinning then work its way back and spin again. I replaced the water pump and all was good.

Hurdigurdiman

A lower temp opening thermostat only keeps the coolant fluid temp down for a short time until the engine warms up. Then its the same temp as all other normal running cars. Hope you get my drift on that statement. On really hot days and when the car is running under normal circumstances, (Not standing with engine running) of course the coolant temps will rise. It has nothing to do with if you have a lower opening thermostat or not. Hope you realize that the higher the water mix have in the system, the cooler the car will run. Its not the antifreeze but the water that keeps the engine cool . The antifreeze does what the name says it does, ie anti freeze. It stops the water from freezing in the winter and that's all it does. If you are sure that all other factors are clear as you state, ie:- good water pump, rads and condensers free and clean and if you are really worried that your temps are still toooo high during the summer, then make a full change for the summer to distilled water. Then a partial change to 50/50 distilled water-antifreeze for the winter months.

dporto

"A lower temp opening thermostat only keeps the coolant fluid temp down for a short time until the engine warms up. Then its the same temp as all other normal running cars. Hope you get my drift on that statement. On really hot days and when the car is running under normal circumstances, (Not standing with engine running) of course the coolant temps will rise. It has nothing to do with if you have a lower opening thermostat or not. Hope you realize that the higher the water mix have in the system, the cooler the car will run. Its not the antifreeze but the water that keeps the engine cool . The antifreeze does what the name says it does, ie anti freeze. It stops the water from freezing in the winter and that's all it does. If you are sure that all other factors are clear as you state, ie:- good water pump, rads and condensers free and clean and if you are really worried that your temps are still toooo high during the summer, then make a full change for the summer to distilled water. Then a partial change to 50/50 distilled water-antifreeze for the winter months.
Today 08:18 AM"

^This^ is just wrong in so many ways...I won't start a debate about the lower temp thermostat as it's already been "run to ground" several times... As for "ant-freeze" - your statement is just silly. Firstly, "anti-freeze" is just a shorthand/lazy way of saying Anti-freeze/Coolant. So, you forgot the "Coolant" part. Here's a little refresher for you:

*Cars operate in a wide variety of temperatures, from well below freezing to we*ll over 100 F (38 C). So whatever fluid is used to cool the engine has to have a very low freezing point, a high boiling point, and it has to have the capacity to hold a lot of heat.

Water is one of the most effective fluids for holding heat, but water freezes at too high a temperature to be used in car engines. The fluid that most cars use is a mixture of water and ethylene glycol (C2H6O2), also known as antifreeze. By adding ethylene glycol to water, the boiling and freezing points are improved significantly.
Fluid - Freezing Point - Boiling Point

Pure Water: 0 C / 32 F - 100 C / 212 F
50/50 mix of C2H6O2/Water: -37 C / -35 F - 106 C / 223 F
70/30 mix of C2H6O2/Water: -55 C / -67 F - 113 C / 235 F

The temperature of the coolant can sometimes reach 250 to 275 F (121 to 135 C). Even with ethylene glycol added, these temperatures would boil the coolant, so something additional must be done to raise its boiling point.

The cooling system uses pressure to further raise the boiling point of the coolant. Just as the boiling temperature of water is higher in a pressure cooker, the boiling temperature of coolant is higher if you pressurize the system. Most cars have a pressure limit of 14 to 15 pounds per square inch (psi), which raises the boiling point another 45 F (25 C) so the coolant can withstand the high temperatures.

Antifreeze also contains additives to resist corrosion.

So, to the OP - Disregard anything/all that Hurdigurdiman said, or just add WD-40...

LexVan

Are your fans working properly?

You say the front radiators are clean, are you sure, did you pull the bumper cover and clean??

Macster

Not sure what the problem is.

The engine coolant temperature doesn't seem all that high. And it remains rather constant as long as other factors are constant.

If the fans are running and both blowing the same amount of hot air -- and you confirm this amount matches that amount of air blown by the fans of another car -- and you confirm the fans can switch from low speed to high speed and coolant temperature drops to the point the fans shut off, what's the problem?

Coolant temperature is not a constant. It changes based on ambient temperature and how the car is being used.

As long as the coolant temperature doesn't keep climbing and there are no warning lights or signs of a leak I'm not sure what problem you are trying to solve.

06stef

thank you all for your experience,

I have two friends with an identical 996 and 986.
in the traffic city, it does not exceed 95 ° C. / 203F

my 996 fan ON and temperature 103° / 217F

I find the temperature water high in operation ->
my 996 is often a hair dryer (FAN ON).

I disassemble the radiators on the front (ac/engine) everything is clean on this side ...
the thermostat is new
the pump water is new
no fluid water leak
no oil in the coolant...

I used coolant -30 ° from Audi (less expensive for testing my water pump)
if I ride very quickly
on a small mountain temperature water,
can rise again
goal 2 fan speed
happens to set the temperature again
I never exceed 110 ° / 230

I found the water temperature High compared to other cars...
I thought the operating temperature of a motor was 90C°/194F
maybe you have reason my 996, works like this
and as it regulates the temperature with fan (no expensive temperature).

changing the front radiator
I do not see what I can do more.
I think you have very hot days
on the east coast of the US,
how is your temperature ???

to obtain the water temperature
I use the display with air conditioning
I check with Durametric is identical to 1 ° C...

regards
stephane

dgjks6

I am going to put my vote in the normal camp. I cruise at 93-94 degrees C on the highway and 97-104 degrees C in traffic.

My advice is quit looking at the gauge.

Schnell Gelb

Stefan,
Great post -lots of data -it helps the diagnosis.You have covered all the obvious items.Is your car Tiptronic? I ask because there are specific problems reported with that.
Now for some controlled tests & I hope others will propose better ones.
1. If you let the engine idle with the a/c on the lowest temperature setting+highest cabin fan speed ,2000+rpm, what happens to your (verified durametric-accurate) engine temperature reading ?
If there was a severe problem with the cooling system,it would overheat,warning light would come on .If that happens, immediately turn off the a/c and turn on the heater full speed- to provide short-term additional cooling for the engine.
2. Have you used the Durametric to test individually each fan individually throughout the car?High + low speed? I ask because a defective resistor(common) will prevent high speed fan operation.
Here is a mod that may help by "Jim" -the whole thread is useful:
https://rennlist.com/forums/996-foru...solutions.html
3. When you cleaned the radiators, did you clean between the a/c condenser and the coolant radiator? I ask because a lot of debris can get trapped there.It looks clean from the front,but in fact it is blocked in the gap between the condenser and radiator.This article and particularly the photos may help you:
http://www.pelicanparts.com/techarti...eplacement.htm
4. In theory the internal radiator coolant passages may be blocked ?Others may advise how to do a reliable diy flow test?
5.If you are still worried, can you fit a GT3 center radiator?
http://lnengineering.com/products/ot...2-gt3-996.html
http://www.pelicanparts.com/techarti...r_Radiator.htm
6. Water wetter ? Evans?

Check with other Forum members before you do any of theses things I am no expert and they may have much better suggestions/experiences.

crashclint

I haven't paid much attention to what the actual temp is of my 02 but on the gauge my needle sits between the 8 & 0 of the 180 mark. I was on I-540 in stop and go traffic for about 7 miles on a 98 degree day and the temp never went higher.

I do know if you didn't get all the air out of your coolant system temperature will bounce around when it hits an air pocket. I followed the steps below when I change the pump in my Boxster. On the advice of a Porsche mechanic, if the temp light comes on, turn the car off and let it cool awhile before starting the procedure again. Mine did come on during the process so I let it cool for about an hour and went back to it. This process should be a little easier on the 996, less to remove.


1. Consider covering the trunk with plastic in case of a coolant overflow.
2. Remove the radiator cap, oil filler cap, and dipstick.
3. Pop the cover trim plate off the filler access area. This reveals the bleeder valve. If you remove the little screw above the trim plate to do this, be extremely careful to not drop the screw into any of the filler necks.
4. Flip the bleeder valve locking clip up to release it.
5. If you have an automatic transmission, remove fuse B1 (the ATF cooler valve).
6. Fill with coolant up to the bottom edge of the filler neck.
7. With the engine idling, occasionally revving the engine, fill up with coolant until there's no more room when the engine is revved. (Revving may raise the level a bit.)
8. Replace radiator cap.
9. Warm up engine until you are sure the thermostat is open. 10 minutes at 2500 RPM should do it, and you should hear the radiator fans come on.
10. Run 5 more minutes at 2500 RPM, revving to 5000 RPM every 30 seconds.
11. Carefully open the radiator cap, and top up the coolant.
12. Replace the radiator cap.
13. Run 5 more minutes at 2500 RPM, revving to 5000 RPM every 30 seconds.
14. Idle until the radiator fans cycle on and off once.
15. Carefully open the radiator cap, and top up the coolant.
16. Put everything back the way it was.

Macster

Well I can tell you that based on my experience a Porsche engine that doesn't exceed 203F in city traffic (assuming this involves stop and go driving) even on a mild day is not "normal".

My Boxster's coolant temperature can climb high enough even in a fast food restaurant drive through to cause the fans to switch on. They switch on at 212F.

Even with temps in the mid 70's (F) running around town in and out of store parking lots not only the radiator fans are running at times but even the engine compartment fan comes on once in a while.

There can be differences in the temp sensor. These are not precision sensors. They are pretty good but I would think that a few degrees of variation is within the realm of possible.

T-stats likewise can have different reactions to the same temperature. One might open a bit quicker or open more fully at a slightly lower temperature than another one so two otherwise "identical" cars might operate at different temperatures because of normal variability of the T-stats.

Based on what you have posted I think you are chasing some imaginary problem.

As long as both fans work and both blow the same amount of *hot* air and you can not detect any temperature difference between the two coolant lines to or from the two radiators and the fans come on at a reasonable temperauture (212F but this can vary from MY to MY and I do not know what is normal for your car) and both fans switch to high speed at the "right" temperature (216F in my car's case) and the temperature comes down and both fans shut off at (again a number based on my observation) 205F, I think there is nothing to worry about.

Every MY one of the things Porsche touts is improvements to the cooling system. Thus I would expect to find earlier 996 models run a bit hotter perhaps than later model 996s. And treating the Boxster and 996 engine as the same may cause you some grief.

Of course I have monitored my Boxster's coolant temperature behavior a number of times over the miles and years. But as I mentioned above though my car's fans come on at 212F and switch to high at 216F and shut off at 205F some or all of these numbers may be different for your car.

This doesn't mean your car's coolant system is bad you are seeing the normal variation that can arise due to normal variability of manufactured items.

06stef

I want to thank you all for your answers.

my car 996 year 2000 gear manual.
this clean between the a/c condenser and the coolant radiator.


the temperature water display never alarm (no warning light LED "engine too hot"),
and the 2 speed radiators, always down temperature for the water.

the car regulates correctly, and as it regulates without alarm or overheating
is that the operation should be good.

you are probably right, I can be me too much trouble.
thanks tou for your helps, good driving