overheating 300tdi

magsnemma · Sep 6, 2006

My 300tdi overheats if i run it at more than 60mph ,below that its fine but over 60 its touching the red if i run for more than a few miles
Ive checked all the usual no water in the oil , no steam in the exhaust the cylinder head seems fine , fan is working ok , no blockages in the radiator, not using water at all , temperature gauge is not faulty thermostat ok
interestingly it still does it with no thermostat in!!!!!!!!
any ideas Im stuck

yella · Sep 6, 2006

change the temp sender in the block, possible its a bit haywire,you could try back flushing it through the heater hoses

Treev150 · Sep 6, 2006

Dodgy coolant temp sensor.

Cheap fix if it is.

magsnemma · Sep 8, 2006

No it realy is overheating the heater gets extremely hot so no air locks temp gauge seems to be accurate

Treev150 · Sep 8, 2006

Get it on a 4wd rolling road so they can check it out when it gets to 60mph.

Shouldn't cost much for the diagnosis.

magsnemma · Sep 10, 2006

Good idea

My usual guy seems to think its the cylinder head but even he admits there is nothing to prove this
and its an expensive guess if he's wrong (especially when it's my money!)
Towed a trailer with it yesterday but it still only got hot over 60

Waldothegreat · Sep 10, 2006

2 things.
1: Running without a thermostat can cause turbulence which causes bad circulation.
2: Remove the radiator and reverse flush it while it's upside down. Watch the muck come out and make sure it flows freely. I know it's a pain to get the rad out with the oil pipes and all that but, at the end of the day, this will have cost you nothing except your own time.

Best of luck and fingers crossed.

bonnybaggot · Sep 10, 2006

Could be your viscous fan coupling |Check it out before doing anything else. BB

magsnemma · Oct 8, 2006

Problem solved
bit of a nightmare though
I put rad flush in the radiator ran it then took it off and flushed it out no muck at all water flowing freely so I thought it was ok
put it back on and ran it same problem still there
I had the top cowel off the radiator and could put my hand down the front of it , there was a cold spot right in the middle of the radiator , it could cope at low speeds but not at high speed for long distance tried to shift the blockage but no joy so !
New radiator end of problem
Thanks for the ideas guys
cheers

overheating 300tdi

magsnemma

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yella

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