Coolant always cold - but normal temperature

wolfe10 wrote:
Bodo,

Please share with us what coach/chassis you have.

Is the reservoir you are checking an integral part of the cooling system or an overflow reservoir?

Does the level in the reservoir change between cold (before engine started) and just after you shut it down (engine hot)?

And, with a pressure cap, coolant should NEVER boil. The function of the pressure cap is to raise the boiling point. Same for coolant-- the correct 50/50 mixture boils at a higher temperature than plain water.

It is a Fleetwood Fiesta 2006 - Workhorse Chassis W16
It is an overflow reservoir as I understand.
Orange Dexto Cool is inside, was always at level COLD, now after 3 months parking the level was a little bit under COLD (just a few millimeters). Beside the coolant there was also some black dirt inside that tank, some mixture of oil/grease/sand I guess. I opened that reservoir today, cleaned it and have add new coolant (50/50) into it.
I filled it to about 1/2 inch above the COLD mark.

Still, when I start the engine and bring it to normal temperature (takes about 2 minutes), the level in that overflow tank is always the same. It never rises to HOT.
But the manual says, that the level should be HOT when the engine is warm.

Bodo,

Please share with us what coach/chassis you have.

Is the reservoir you are checking an integral part of the cooling system or an overflow reservoir?

Does the level in the reservoir change between cold (before engine started) and just after you shut it down (engine hot)?

And, with a pressure cap, coolant should NEVER boil. The function of the pressure cap is to raise the boiling point. Same for coolant-- the correct 50/50 mixture boils at a higher temperature than plain water.

Take the radiator overflow tank out of the rig and wash it out. Most likely what you're seeing is not coolant but crud/rust in the tank.

If that's not the case, then the radiator is not sucking the overflow coolant back in when you cool down. This can be caused by a bad rad cap or a plugged or leaking pickup tube.

It depends on the vehicle. Many gas use a 193 thermostat. It would be nice to see numbers.