Water coolant Heater Core Radiator Flush

[Smith007]

2002 Ml320 Km 220 000.00
Cabin temp low Heater core??

* Standing and looking towards the firewall LEFT coolant or radiator hose is cooler than the the RIGHT coolant or radiator hose Therfore the Right one is the INLET correct??

* Because of the Y in each of the LEFT and Right coolant or radiator hoses I had to remove the hoses from the Firewall.
*I purchased 2 feet radiator hoses times two (I think 3/4 inch OUTER diameter and attached them to the firewall tubes using the Left side to blow into (opposite to the normal flow ??? correct) with the compressor @50 PSI.
* OMG i had clean coolant but there was black pieces of what appears to be silicone pieces coming out the Right coolant or radiator hose (bear in mind from a previous post of mine on changing my water pump, I can only conclude that it may have been reminisce or pieces from the warepump gasket)

WHAT IS THE MAX PSI of COMPRESSED AIR I CAN I USE TO BLOW?

* After running clean water and Compressed air numerous occasions and then put CLR descaler and let sit for while then thourougly rinsed that out.

* Genius!!! here did not flush out the rest of the coolant passages - the engine block passages etc.
* Mixed results now - looks like i have to redo and blow out the rest #@$~

PS there is no noise eminating from under the glovebox. Which if there was could mean the electical cam flap is stripped

In addition to the above questions and uncertainties - Any further ideas would be appeciated

Any other cleaning agents to be used for the flush would be appreciated

LESSON learnt here for me the genius - who only woke up years later that perhaps when changing a water pump flush and clean the system out - Da!!!

And another question is can one do harm (such as seal breakdown etc) from a very rich coolant or glycol mixture????

[mbdoc]

On a ML, coolant always flows thru the heater core.
So it is rather strange to have blockage there.

Have you removed the glove box & moved the heat knob & watched the "blend air" flap?

[Smith007]

Thank you very much !!! Doc for the time and experience.

No but now that u say i will look and see, however, Question if the blend air cam thingy is busted would one have zero no heat or some heat even when the engine block temp on the dash is reading about 80?

[mbdoc]

Yes, if the blend air motor is bad & can't move that flap, you will have whatever temp air
that is blended at that position.

Can be NO heat or full heat OR anywhere in between

[Oldernotwiser]

Hi
I have the same problem - no heat from heater, and one pipe in hot and the other one cold.

My question is - if it is a blemd door problem, would it stop the hot coolant coming out of the heater, and if it is a door problem is it a diy fix?

Thanls