s5benzo

Im just curiuos my moms 02 s500's temp gauge will be at 80c while crusing and then when im its idling at a stoplight itll slowly climb to 90c-rarely to 100c and then back down as the car starts to cruise again. im not sure if its a clogged radiator / water pump issue or this normal? car doesnt overheat at all just want to make sure if its a normality with this car. thanks guys

bamberger_1

Where do you operate the car? In Saudi Arabia when it's 40°C outside I would consider this as normal. If you are operating the car under normal condiotns like N-Europe or the USA in Winter this may be a sign of a malfunctioning motor fan controller. My guess with the year 02 you have still the belt driven main fan on the passenger side (left hand driver) of the radiator. Check if the little belt is still there,. If yes then the electronic speed controller may have a prob or the fan motor itself. Check if it is running and driving the fan with the belt. If you have a newer version then this fan is directly driven by the motor (in the centre of the fan) and has an electronic controller somewhere.

s5benzo

thanks bamberger ill definately check it out and see what version it is and then test it for operation.
thanks again

Quadcammer

this is totally fine. Don't worry about it.

Corsa9000

As OliverK said, this is perfectly normal. As long as the temp gauge hovers within limits, all is fine. Think about it, at idle there is little airflow to the radiator thus temps go up slightly and vice versa.

tusabes

perfectly normal. 80-100 is where mine moves too.

s5benzo

ok perfect guys lol i appreciate it...just wasnt sure because my lexus has 250k miles on it and the temp has always stayed in one spot. thnks for input no more worries haha

bamberger_1

This is not okay, if you driving in normal conditions 70-80 degrees F or 20-30Celcius. I have MB's since 1987 and the ~80°C mark is held within a +5°C tolerance for 90% of my driving experience. City stop and go or mountain roads under normal conditions don't drive the gauge over 85°C. I'm pretty sure your main fan is defective.
Where a re you living? As I said, if you operate the car in an ambient of >40°C or >104°F you might see the gauge go up to 100°C. But you operate the car in colder areas and it goes to 100°C it would never survive Saudi Arabia, which is however a large market for those cars, and they are working just fine there???

s5benzo

i live in sacramento california , 40-50 farenheit in winter and 100-110 in the summer.

Quadcammer

don't be ridiculous. The thermostat only opens at 87 degrees C. Running up to 95 degrees C is no big deal whatsoever. Thats only about 204 degrees F.

cameraman123

It is perfectly normal. I run anywhere from 85-95 on a regular basis. Theres a reason the 120 mark has a red line and not the 100 mark

s5benzo

im not worried , i was just making sure thats how it functions. none of my other cars vary temp like that...bamberger saying its a problem but im cool with ur input.. car runs fine. thanks guys

cameraman123

Well bamberg doesnt know what hes talking about. When you let a car idle or sit running with little or no airflow the temperature will increase as the motor is sitting in a closed compartment with no hope of cooling down. Once it hits a certain temp and the fan kicks on, the it will begin to cool, once cooled the fan will kick off, then the process starts all over again. Of course the engine will run cooler if you then take it out and drive it because your forcing air over the engine. Stop at a stoplight? It'll go right back up. No airflow.

Quadcammer

Your other cars probably have "idiot gauges"

in other words, in a temp range between 180 and 210 degrees F, the needle will not move out of the "normal range"

Reason: People freak out when things like oil pressure and temperature gauges move too much. MB tends to believe its buyers (or at least it used to) were smart enough to realize that oil pressure and temperature rising and falling were normal. (not implying that you aren't)

s5benzo

thank you cameraman and oliverk, i completely understand what both of you are saying and it is true , iv worked at toyota for a long time so im used to looking at those..most of em reach operating temp and stay there. 07 e350 doesnt change much at all nor does my roommates 08 c300 . thats all i was just wanted to kno if my 02 s5 was good. thanks guys

bamberger_1

...thats all i was just wanted to kno if my 02 s5 was good. thanks guys [/QUOTE]

and it's not. Why would one out of the many cars you own and know do something totally weird. You know why? because either the fan or its controller is dead.

BTW Cameraman:
I'm sorry, but I exactly know what I'm talking about. The reason the car has a cooling fan is exactly that, to cool the radiator, when driving slow or just sit and have the engine idling. The air over engine cooling has practically no effect for the coolant temperature. The gauge tells you the coolant temperature not the engine temperature. The control circuit is designed in such way to keep the coolant temperature constant within small limits for the regular driving situation, and keep headroom for extremes. If S5Benzo is running the car presently in ambient temperatures of 40-50°F and a little stop and go traffic the coolant temperature will never rise over 83-85°C.
You can check the fan speed:
Let the car idle, press RES and 0 simultaneously for about 10 sec.In the little display of the A/C about 99 data set appear, scroll up with the temperatur up/down button and one of the data sets shows you Main Fan speed. When the coolant temp. is over 85 -90 °C this fan shall definitely show a certain speed, if not either the fan or the controller is dead!!!!!!!!!

Quadcammer

and it's not. Why would one out of the many cars you own and know do something totally weird. You know why? because either the fan or its controller is dead.

BTW Cameraman:
I'm sorry, but I exactly know what I'm talking about. The reason the car has a cooling fan is exactly that, to cool the radiator, when driving slow or just sit and have the engine idling. The air over engine cooling has practically no effect for the coolant temperature. The gauge tells you the coolant temperature not the engine temperature. The control circuit is designed in such way to keep the coolant temperature constant within small limits for the regular driving situation, and keep headroom for extremes. If S5Benzo is running the car presently in ambient temperatures of 40-50°F and a little stop and go traffic the coolant temperature will never rise over 83-85°C.
You can check the fan speed:
Let the car idle, press RES and 0 simultaneously for about 10 sec.In the little display of the A/C about 99 data set appear, scroll up with the temperatur up/down button and one of the data sets shows you Main Fan speed. When the coolant temp. is over 85 -90 °C this fan shall definitely show a certain speed, if not either the fan or the controller is dead!!!!!!!!![/QUOTE]

Actually you aren't right, and since you like to nitpick, let me do some of that.

The cooling fan is not there to cool the radiator. Its there to flow air over the radiator, which cools the coolant inside the radiator. Regardless of how awesome your cooling fan is, it will never replicate the amount of airflow that you would see while driving 40mph+

If the fan was not spinning at all, his car would most likely climb above 100c pretty quickly.

Considering the thermostat opens at 87c, operating temps between 85 and 100c are perfectly fine.

bamberger_1

Hi OliverK
if our friend already sees readings of almost 100°C, and the outside temp is 40-50F (~7 °C) What would be the coolant temp. reading then in Summer with 100F (~40°C), just calculated (as per your theory), around a theoretical value of 133°C (270F). This means stop at the curb and call road assistance, right?

Why would our friend's W221 show a pretty much constant temperature of ~80°C, and the W220 fluctuates between 80-100°C? The cooling circuit control for the W220 and the newer W221 are not any different, from the basic design lay-out.

The thermostat short cuts the radiator as long as the coolant temp. is <87°C, then it opens and uses the full cooling capacity of the radiator (and in winter even of the heater). In summer this cooling capacity of the heater is not available, and additionally the A/C condenser delivers a lot of heat, so the coolant temp. will even rise much higher, when the main fan is off. The threshold of the thermostat has nothing to do with what is discussed here.

He should just do the check I proposed, and also check the little belt between the fan motor and the fan itself. There are two version of main fans used, one motor is located on the upper right corner of the radiator and belt-driven. The other (newer) version is a centrally attached motor right on the fan hub. Both have an electronic speed controller.

BTW: If the thermostat is gone, the temp. gauge will float between 70-<80°C in an ambient of 40-50F(~7°C). This is the value everyone will confirm having a dead thermostat.

cameraman123

Again on the nit picking subject, OP if you wish to check you hold the REST button, not the 0 button. And the A/C must be on for it to go into the menu.

Bamberger maybe your S320 is seeing pinpoint temperatures, but the larger V8s healthy run between 80-100C. And if you claim that that info is incorrect, then all W220s on the market today must have dead thermostats. Simple FALSE.

And aside from that. The cars computer is programmed to warn the driver on the I/C if engine temp ever exceeds what it should be.

bamberger_1

Yes, and it will warn when summer comes!

cameraman123

I drove around all summer in Houston with above 100 temperatures AND NEVER ROSE ABOVE 100 OR GOT WARNINGS. Bamberger you are one ignorant ***-clown. You've been proved wrong by everyone here. Just get over the fact that you are not right about this.

shellshock

Bingo, you hit the nail on the head sir.

Reason I know this is because I'm in to Volvo's too, and many of the 80's and early 90s models (mainly 240s) had a temp compensation circuit board that kept the temp needle always smack in the normal spot unless it it overheated, then it would peg out. It's a common modification to remove this to see a accurate temperature reading on the gauge. This is probably what your Lexus has.


FWIW, my S500 stays right at or a little over 80c all the time. Even after driving hard and even drag racing all night with the ambient temps in the high 70''s (Fahrenheit), I've yet to experience a hot Oklahoma summer in this car yet. (Bought it this past fall)

Quadcammer

one of the most unusual and nonsensical posts I've seen in a while.

congrats.

benzat17

mine shows 85-90c too this is normal when i go on the highway it drops to 80 in city it goes over 80 by a lil
i think this is normal i had a 03 c240 and it did go up and down depends on the air flow not by much.
main point i dont think you have a problem my 06 expedition never went up or down lol.

tusabes

From what I read, it seems the Ford "gauges" arent really gauges... they stay in the middle at all times unless something is out of spec, when they go to the ends when something is wrong.