Engine temp varies

[Flackadder]

Have noticed of late that my temperature guage shows from 80 to 90 degreees. Has it always been like this the few months I have owned the car.......probably yes, though it is not something I keep an eye on.

I am reasonably confident I have no leaks ...no smell, no water on floor and water is at level. Also, was only a few weeks ago that MB fitted a new 'diesel cooler' (what ever that is) as it had a very slight leak.

Should I be overly concerned or just keep an eye on things?

Oh! It is either 80 or 90...never stays in between.

Thanks

 

[zipdip]

I would not think it was a big problem all the Mercedes I have known have a temp range about that, mine is about 84,interesting it is either 80 or 90, maybe putting on a new diesel cooler has caused this,I doubt it,but I suppose it depends on what is actually happening for this variance in temp,if it was a electric coolant fan being lazy cutting in you would get a top temp but then reduce to the normal one,these Mercs sure like to throw weird little problems.

 

[Bellow]

The heat into the coolant changes with load. More right foot means more fuel being burned so the water heats up by a small amount. Nothing I'd be worried about.

Diesel cooler AFAIK is in the return line to the tank and cools the fuel the engine doesn't need before returning it to the tank. Fuel metering of common rail diesels is by bleeding off pressure from the fuel rail hence the hot excess fuel.