Thread: Coolant Flush and Heating Problem

Probably need to bleed the system.
Don't know about the TD5, but in my 300td D1 refilling the system as follows:

first radiator (which is the lowest point) -close when full
then through the thermostat housing (which is the highest point) with the overflow tank open until coolant is at level in the tank -close tank
then fill up thermostat housing until full.

after this I need to run the engine until warm, turn the heater on and open thermostat housing plug and bleed until no air bubbles (and until heater is warm) - this can take a little while (30min)

Hope this helps.


I also keep an eye on how much coolant I fill in (plus a bit that spills while waiting for the air to escape) so I know how much I am off the total capacity

If you find coolant on top of the radiator again, check the lenght of the plastic tank where it joins the core.
I had a sticking thermostate and the extra heat caused it to leak around the rubber seal that join these two parts. It was the coolant on top that drew my attention to it.
Also after you have taken it for a longish drive, check both ends of the radiator. If the drivers side is cold and the other end hot, than water is not flowing through and it could mean the thermo is not working. ie opening.
If after the drive both ends are cold, than it could mean the thermo is stuck fully open. And this may account for the cold heater.
A Nanocom will give you a better reading of the ENGINE temperature. Dont trust the in dash one.
Also check the hoses that go through the fire wall, next to the clutch master cylinder (and fuel block on the engine) Both hot, than the water is flowing to the heater.
Best of luck.

Just checked the Rave disc and water should allways be flowing through the heater. When it leaves the heater it travels to the fuel cooler. It opens at 82c.
Check these hoses to see if warm water is flowing.
If these hoses are cold than a blockage must be present.

If you are getting hot heater lines in and out, the problem is more likely to be in the heater matrix, probably the blend motors. Read section 80 of the RAVE worshop manual for details.

Originally Posted by Zute

If you find coolant on top of the radiator again, check the lenght of the plastic tank where it joins the core.
I had a sticking thermostate and the extra heat caused it to leak around the rubber seal that join these two parts. It was the coolant on top that drew my attention to it.

Does that mean that you can replace that rubber seal and not necessarily the whole radiator?

Originally Posted by biggin

If you are getting hot heater lines in and out, the problem is more likely to be in the heater matrix, probably the blend motors. Read section 80 of the RAVE worshop manual for details.

Don't think it is the blend motors, as all combinations of Feet, Demist, Aircon at 16 C on left and "hot" air on right etc. seems to work, so think it is coolant flow, I may just have to bite the bullet and place all hoses, drain system properly and flush.

if its second hand make sure that someone hasnt bypassed the heater matrix.

Originally Posted by DCPAus

Does that mean that you can replace that rubber seal and not necessarily the whole radiator?

You can, But..
Its all crimped together. Ive been told that it dosnt like being done a second time.
Mine hasnt leaked since replacing the thermo. I now have a Nanocom and can better keep an eye on the temp if pushing it hard.