R129 500sl over heating

[BAZ-500SL]

Ello guys, got a bit of a problem on stand still my r129 500sl begins to over heat, the car has only covered 800/900 miles in like 3/4 years, I have bleed the system for air form a nut above the thermostat, but it still is the same I dunno if it could be the thermostat problem, there's no lots of white smoke coming from exhaust and there is not buckets if water coming from exhaust so I don't think it could be a head gasket, is there any other way if checking what I could be thanks in advance guys

 

[brucemillar]

Probably the stat. Cheap to buy and easy to replace. Is the bottom hose getting hot or staying cold? If it's getting hot after 15 minutes or so then the stat may be ok.

Sent from my iPhone using MBClub UK

 

[RichardF]

If it overheats when stationary but cools down again once your driving it's more likely to be the fan clutch.

 

[BAZ-500SL]

Il have another look at the pipe, and what is the fan clutch ?, when I start the car the fan for the radiator comes I'm to as it's off the aux belt

 

[brucemillar]

Overheating whilst driving could be a blocked or rotted radiator. But it could also be the thermostat (or both). Start with the simple things that you can see and feel.

Is the car overheating when started and left to run up to temp at idle?

If yes? Then have a look at the thermostat after checking that the bottom pipe is heating up. If it is not then the stat is not opening.

If it is heating up. Then the stat is opening but you are not moving enough coolant through the radiator/engine to keep in range. This could be a blockage, like a rotten rad.

 

[RichardF]

Check thermostat as above. Unless your in a hot climate it's probably this.

The engine driven fan has a clutch which locks up when hot, otherwise it just freewheels to save fuel. They fail, this causes overheating in traffic/stationary, but the engine temperature will drop once your moving again. The fan does nothing @ speed, airflow through the radiator is enough.

You should hear the fan cut in with a whoosh. To check the clutch get the car really hot, over 100c. With the engine idling carefully try to stop the fan with a rolled up newspaper. If you can stop the fan easily the clutch is faulty, if it shreds the newspaper the clutch is good.


You haven't given a lot of info to go on. Is it normal when driving and overheats when stationary, or does it overheat all the time? Is the heater working? I assume your in the UK with the current low ambient temperatures.

 

[BAZ-500SL]

Thanks guys I will get on to this like I mentioned it's not been driven much so I could be the radiator or thermostat every thing seems all good no throwing water out the exhaust like a head gasket or huge clouds of smoke. once I have done the above I will come back with a update lol it might be a little while as work and Xmas so let's all have a merry Xmas and a happy new year all the best for 2016

 

[BAZ-500SL]

Sorry Richard missed some of your text, it does it on idle at standstill about 20-30 in to standstill it just rises with the car so basically it rises as the car warms up, the heaters are hot from what I recall, I hope to do some more test that are mentioned so I can feedback what information I gather hoping to solve the problem thanks again guys

 

[RichardF]

Does the car cool down again when you drive it?

 

[BAZ-500SL]

Yeah it begins to cool down once driven it's only at standstill it rises up and continues to rise so if I'm at stand still I usually put heaters on which only slow the heating up process, but over time of still idling at standstill it does rise

 

[RichardF]

My money's on the fan clutch.