W208 CLK230 - Overheating

[Mike2006]

Morning Folks,

I was stuck in terrible traffic for about 90 minutes yesterday. After about 40 mins, I noticed the temp rising on the display to ~95-100DegC. I took little notice as it was staying at that temp. I finally got moving and I noticed steam/smoke coming from under the bonnet. I pulled over and lifted the bonnet. The steam/smoke had stopped but there was a 'burn/rubber' smel from under the bonnet.
I gave it a few minutes and sat in again and drove off up a clear road for about 30 mins. The temp droped back down to ~80DegC and didn't rise any more.

1. Is this 'normal' to a car of this age (1998).
2. How/Why did it happen?
3. Is there anything I can do/check to prevent it happening again?

Thanks,

Mike.

 

[television]

Ideally cars should run at the 100c mark, you have electric fans that cut in at 100c

 

[Mike2006]

If I was not overheating, what would the smoke from under the bonnet have been caused by?
There was definately heat being generated from somewhere to cause the smale because the smell was a burn smell...

 

[David Nock]

Presume the temp displayed is a bit innaccurate and the problem is the fan. It's not cutting in on high water temp. If you noticed it rising above it's normal running position in the jam then that's the key clue that it's overheated. There will be others on the forum who can tell you where and what to check better than I, but I would start by locating the electric fan control switch in the cooling circuit and checking it/getting it checked. Also check no loss of coolant has occurred.

 

[MIW615]

Firstly check that the electric cooling fan is cutting in, you need to pressure test the cooling system to check for leaks, also check the rad cap is holding pressure.

 

[television]

Just leave it running with some cardboard over the rad, it will soon get up to 100c for testing

 

[Mike2006]

Cheers guys,

Can anybody tell me/show me on a pic where the Cooling fan is located?

Thanks,

Mike.

 

[television]

208--- the next 3 numbers please

 

[Mike2006]

Any ideas to what the smoke would have been??

Mike.

 

[television]

Any ideas to what the smoke would have been??

Mike.

If the engine has not ever been that warm before it could just be residue oil misting smoking

 

[David Nock]

Cheers guys,

Can anybody tell me/show me on a pic where the Cooling fan is located?

Thanks,

Mike.

The fans the big thing in the shroud (plastic housing) normally fastened inside the engine bay against the rad. It pulls air thro' if overheating occurs.
It's the control switch I think you need to be looking for. If you give Television the next numbers of your VIN code he'll no doubt send you a link to one of his magic diagrams to show you where it is.
WATCH OUT WHEN POKING ABOUT NEAR THE FAN THAT IT DOESN'T START UP AND TRAP YOUR HANDS/TIE ETC. On most car makes they can start up without the ignition key being even in the car!

 

[Mike2006]

Cheers Folks,

Malcolm, VIN as requested - 208-3472


I had a quick look last night. There was 1 big fan on the engin side of the radiator and 2 smaller fans on the other side of the radiator. I put the car in park and left the engine running for 30 mins but the temp did not go above 90 at any stage so I could not see if the 2 smaller fans would cut in at 100DegC.

I tried the 'carrott test' on the main fan and the carrott stopped the fan quite easily. I don't know if this is a reliable guide to the quality of the fan or not? Opinions welcome.....

Mike.

 

[David Nock]

Assume that the main fan is running strongly? So the control switch IS cutting in? That tends to rule out the switch I guess? Then I would make sure that the coolant level is all OK and then assume that in your jam you'd got in a situation where perhaps there was a traffic blockage of fresh air, or a tail wind just able to nulify the fan cooling. Also the rad might be clogged or the rad grill full of debris.Plastic Bag? Like you say, opinions welcome.....