1999 Mercedes CLK 230 Kompressor - Idle overheating problem

[rizzla]

Hi all! New to this forum and also new to owning a mercedes! Its great I have to say.... but only yesterday while sitting in traffic I noticed a problem

The temperature gauge rises to about 80 when not moving. I got the car home and done some tests:

1) Started the car and left it idleing
2) Popped the bonnet to check all fans were working - yes they were...
3) Checked the water/coolant - all good and topped up

Attached to the engine is a big fan pointing towards the radiator and that was consistently going round and when I put the air fans on inside the car, the two fans in front of the radiator at the front of the car came on.

Now the weird thing is, if I set the heating to HOT inside the car and then turned on the air fans, the temperature gauge went right down to below middle. Once the internal air fans were turned off, the gauge slowly moved back to 80 again!

The car has had one owner and has got full mercedes service history and looks well kept but I can't help but think that this is a problem, that all cars temperature wise should sit level at all times, and not rise to one notch away from the HOT level if left idleing.

Has anyone got any advice or know what the problem maybe?

Kind regards,

Matt

 

[BlackC55]

80deg is normal and nothing to worry about.

At 100deg the fan will be on full yield and then the temp should drop. If you switch the heaters on the engine temp WILL drop as you are taking some of the heat away from the engine.

Welcome BTW.

 

[rizzla]

Hi, Thanks for your reply. I think I've got my measurements wrong when left idleing, the most it went up to last night was just under 100c. Sometimes when driving, as I noticed today, it goes over the 80c mark and moves its way to 100c but if left for a good 20 minutes or so, then only then it goes near to 100c. Once I put on the internal fans, the temperature does drop but I don't want to keep doing that as it makes me think there is something wrong with the heating system .

One thing I noticed today (as we've only had the car a few days) is that it gets hot very quickly. I mean, within minutes it'll be up to 80c. Is that normal?

Also if the car temperature goes up to 100c and then down to 80c all the time, is that normal for a supercharged engine or do you think there is something else wrong? And could this affect the engine in anyway?

Thanks and kind regards,

Matt

80deg is normal and nothing to worry about.

At 100deg the fan will be on full yield and then the temp should drop. If you switch the heaters on the engine temp WILL drop as you are taking some of the heat away from the engine.

Welcome BTW.

 

[grober]

If you have a viscous coupled fan at the front of the engine it will freewheel most of the time. If the engine gets too hot it will engage and will start to cool the engine down. It will sound far noisier when this happens-when its freewheeling its pretty quiet. From cold the engine heats up quickly to 80c while the engine thermostat is closed- effectively no cooling is going on thro the front radiator. Once the engine temperature is up the thermostat opens and the temperature of the coolant will drop because the engine is now cooled by the radiator. To reassure yourself everything is OK you should read up on the basics of car cooling systems. You will then understand what you are observing is normal. try the section on engine cooling here http://www.carbibles.com/fuel_engine_bible.html