Thread: Another 300 tdi overheat!

Originally Posted by steveG

Also, the youngest production 300tdi's are nearly 15 years old now, so if they still have the original coolant hoses......

Steve

Yeah something I have just started to consider! I will replace the hose and see how it goes but I am not optimistic

We are getting another vehicle in the interim.... I was quoted $1600 for a locally supplied reconditioned head but paddocks advertise OE heads for £310 + £130 delivery.

Originally Posted by Blknight.aus

yep, thats the copression gasses coming straight past the fire rings

Bad luck there Matt, I agree with Dave that the head gasket is gone.

After the problems I had sorting the cooling system out in 'Fred', along with replacing the headgasket I would do the following.

Check for cracks, warping of the head and if the motor was badly cooked get the top of the block checked for distortion.

Make sure that the air bleed hose from the thermostat housing is clear by blowing through it into the expansion tank and into the radiator tank, the plastic venturi is easily cleaned out by running a small 3mm drill bit through it .

As the Coolant is gone and needs to be refilled, I would be taking the radiator in for a rodding out and also think about doing the tropical mod as well.
When the head gasket goes, rubbish gets circulated around and lodges inside the tubes of the radiator core, this isn't obvious at first, but on a long pull the temperature rises slowly and when you stop and run the motor the temperature drops slow as well and this is due to the fact that the baffle in the radiator tank has a bleed hole big enough that you can poke your little finger through, the tropical mod is reducing that bleed hole size down to about 3 mm.

Check to see that the thermostat is opening by placing it in some boiling water on the stove, it should be fully open when the water nears boiling point and just as important, when it is cold make sure that the valve is closed completely and you can't see light coming past the sealing face.

Refill with 50 - 50 mix of coolant concentrate ( Green type for 300TDi ) and water .

If the heater is not effective, then the heater core is blocked as well, as it is a awkward job to remove and put back, the radiator repair bloke I took mine to for servicing suggested that I replace the heater core for a longer service life.
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