Thomo1927

Thomo1927

Active Member
My 300 tdi discovery heaters are blowing cool ,Head gasket has been changed. Not loosing any water or overheating. Pipes are very warm but it's blowing cold. Heater matrix blocked maybe or something else.

I know you haven't got a crystal ball but any tips for me ? Cheers
 
Trying bleeding and rebleeding at the stat housing valve with the engine ticking over.
 
blue beasty said:
Trying bleeding and rebleeding at the stat housing valve with the engine ticking over.
Click to expand...

I have bb many times ,I can put up with it but my Mrs who is 5 months pregnant is having none of it.Just trying to sort it out myself to save some baby money. Cheers
 
Maybe you should say what you have tried then people can suggest things you haven't?

Back flush the matrix? Check the fins aren't gummed up?
 
Is the engine running any cooler than before, if so the thermostat could be stuck open, rare I know.
Are the pipes to the heater matrix hot as they should be, "very warm" how hot is that? I only know cold, warm or hot.
Then there's the blending dampers, is the heater output the same on both sides with the controls set equally?
 
discool said:
Is the engine running any cooler than before, if so the thermostat could be stuck open, rare I know.
Are the pipes to the heater matrix hot as they should be, "very warm" how hot is that? I only know cold, warm or hot.
Then there's the blending dampers, is the heater output the same on both sides with the controls set equally?
Click to expand...

What I have noticed is from start up when I go to work ,The engine temp gets up to just under halfway quicker than it used to. The pipes are hot
 
Thomo1927 said:
What I have noticed is from start up when I go to work ,The engine temp gets up to just under halfway quicker than it used to. The pipes are hot
Click to expand...

Well if the "pipes" are hot that's a good sign, it means that hot water is flowing through the heater matrix.
 
Tried bleeding the system for 10 mins and can't see any bubbles coming out. The 2 hoses on the rear of the head that go into the matrix ,One is hot and the other is noticeably cooler ? Is that right
 
Obviously there will be a temperature difference between the two pipes, but noticeably ? Both should be hot, did u have the fan blower on full.
The flow-in pipe will be the very hot one.
 
discool said:
Obviously there will be a temperature difference between the two pipes, but noticeably ? Both should be hot, did u have the fan blower on full.
The flow-in pipe will be the very hot one.
Click to expand...

Yes one was noticeably hotter than the other,Heaters were on full.
 
Turn the blower off how's it then? if the same it seems if the water isn't flowing through the matrix, but there's only one way to find, disconnect the return pipe and check the flow.
 
Update ,Just for the sake of it I put another thermostat in and flushed out the matrix. Lots of black stuff come out ? Took her for a run and bled the system,Loads of air come out .Heaters now very warm .Now I have a happy pregnant Mrs. Cheers everyone
 
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