190D 2.5 runs hotter than normal - PeachParts Mercedes-Benz Forum

Mxfrank · #1 06-28-2016, 08:03 AM

The lower radiator hose should always be cooler than the upper hose. But if the delta T is more that 20 degrees, then the thermostat is closed or the radiator is clogged. Since you've replaced the thermostat, it's a good bet that your radiator is clogged. You can try another flush (I hope with citric acid, not hydrochloric), if that doesn't do it you'll have to replace the radiator.

One more thought. There could be debris trapped between the a/c condenser and the radiator.

alghamedGT · #2 06-28-2016, 02:26 PM

thanks my friend for your replie

i flushed the radiator for 2nd time in a radiator shop
the radiator is working good
also they instpected water pump , ac condenser
and now there is slightly very tiny improvement in cooling but not sufficient to keep oil cool
you know om602 N/A dosent have an oil cooler so all the work is for coolant system . god damn Mercedes-Benz engineers
even tiny Naturaly Aspirated cars now had oil cooler

some guys in the radiator shop told to flush the engine block with their engine flushing machine

so tommorow after flushing engine block i will buy again a new thermostat
or drill some holes in thermostat like Diesel Giant

Diesel911 · #3 06-28-2016, 08:37 PM

Quote:

Originally Posted by alghamedGT

thanks my friend for your replie

i flushed the radiator for 2nd time in a radiator shop
the radiator is working good
also they instpected water pump , ac condenser
and now there is slightly very tiny improvement in cooling but not sufficient to keep oil cool
you know om602 N/A dosent have an oil cooler so all the work is for coolant system . god damn Mercedes-Benz engineers
even tiny Naturaly Aspirated cars now had oil cooler

some guys in the radiator shop told to flush the engine block with their engine flushing machine

so tommorow after flushing engine block i will buy again a new thermostat
or drill some holes in thermostat like Diesel Giant

If your Oil Filter Housing has a thermostat it could be the thermostat is ot opening.

Carefully check your Oil Cooler Hoses and see if they are getting hot.

Also I have had new Thermstats not open right out of the Box.

I used to test them before installing them because it is alot of mess and work to replace the new but defective one after it is installed.

Thermstats can also be installed backwards.

I suppose it is possible for a combustion gas leak from a leaking headgasket to create gas pocket that would keep the coolant from circulating and thereby the upper Hose does not get hot.
Try driving without the pressure cap on as that should allow the gas an escape route.

GregMN · #4 06-28-2016, 08:28 PM

Quote:

Originally Posted by Mxfrank

it's a good bet that your radiator is clogged.

X2