Thermostat issue.

[norwoodboy]

Morning,

My thermostat gauge is not always working and the fan comes on, if i turn the engine off and restart it springs in to life.
I am assuming there is a sensor or probe that is failing? Any ideas?

E350 on a 10 plate.

Cheers

 

[onefortheroad]

When its at hot what does it read.

 

[norwoodboy]

Intrestingly it reads high between 70-90 although not in the red but it does come down after 10 mins driving or so to normal?

 

[onefortheroad]

Intrestingly it reads high between 70-90 although not in the red but it does come down after 10 mins driving or so to normal?

90 is the set point . If it drops when driving , you need a replacement thermostat .

 

[mioba]

Modern car temps dont fluctuate that much.
Unless its the middle of summer and your driving an air-cooled up and down the mountains and you need tge fan to cool the car.

Replace the stat. Merc stats not the best. 10 years seems their span.

 

[hmang]

Morning,

My thermostat gauge is not always working and the fan comes on, if i turn the engine off and restart it springs in to life.
I am assuming there is a sensor or probe that is failing? Any ideas?

E350 on a 10 plate.

Cheers

my s 350 cdi does that now and then in cold mornings I sometimes lose the eco setting . the gauge reads nothing and the fan goes full blast .
stop and restart the engine every thing goes to normal .

I do know that my thermostat is faulty so maybe the engine management is getting confused . Dunno .
Id be interested too

 

[mioba]

If you know your stat is faulty the get it changed

 

[malcolm E53 AMG]

If you know your stat is faulty the get it changed

Definitely, it feeds the ECU with engine temp data and affects fuelling etc so a bad stat will lead to all sorts of problems especially on modern DPF diesels

 

[sonic]

my s 350 cdi does that now and then in cold mornings I sometimes lose the eco setting . the gauge reads nothing and the fan goes full blast .
stop and restart the engine every thing goes to normal .

I do know that my thermostat is faulty so maybe the engine management is getting confused . Dunno .
Id be interested too

Never had that on my 212 E350CDI

 

[norwoodboy]

Thanks for replies guys, due MOT in a couple of weeks so will get a new stat fitted then.

 

[malcolm E53 AMG]

Thanks for replies guys, due MOT in a couple of weeks so will get a new stat fitted then.

A lot of problems with pattern parts best advice is to fit the original MB part, not cheap but without issues

 

[ajlsl600]

A lot of problems with pattern parts best advice is to fit the original MB part, not cheap but without issues

Sorry. If some of the parts were properly designed/made, we would not be looking pattern or any other in the first place.....

On service items I would agree.

 

[mioba]

Things are just designed not to last anymore otherwise the business would fail and there would never be any return of customers. I guess thats why we say they dont make them like they used too.

 

[EmilysDad]

..... I guess thats why we say they dont make them like they used too.

I'm glad they don't make things like they used to .... tappets that needed frequent adjustment, greasing king pins, greasing prop shaft u/js, adjusting points & replacing condensors every other week. I know that when the proverbial hits the fan on a modern car you might have top dig deep, but cars generally just keep going regardless of servicing.

 

[hmang]

If you know your stat is faulty the get it changed

yeah righto
struggling with that . the bottom housing screw is seized solid . I cant afford the car off the road at the moment so dont want to risk snapping it off .
Life ain't always simple is it

 

[hmang]

Never had that on my 212 E350CDI

but you have had the same problem as the op ?

 

[mioba]

yeah righto
struggling with that . the bottom housing screw is seized solid . I cant afford the car off the road at the moment so dont want to risk snapping it off .
Life ain't always simple is it

bugger....

give it a shot of wd40 twice a day for a week before you attemt to remove.

 

[sonic]

but you have had the same problem as the op ?

No problems at all. The thermostat on my CLK270CDI failed at 115K miles about a month before I part exchanged it so I just lest it.