New head gasket - heaters STILL cold - disco 300tdi

it does not matter what I'm suggesting is the water pump can induce air into cooling system. A coolant pressure test would expose this and any other leaks.

Ah right! But theres no drips, however I have been told that they may not work to full capacity and therefore not beable to force the water round correctly.
Would that be true?

Had this problem over xmas couldnt get the matrix warm after doing the head, bleeding mine was the problem I had done it by the book temp needle was reading half way, how i did it in the end was ran for 3 mins out with the tstat housing plug topped up tiny amount back in pump all hoses by hand repeated this about 5 times and next thing I know matrix starts getting hot hope yours is the same just very hard to get the air out I thought the worst to, best of luck

Hi I hope so too. The heater matrix has now been flushed both ways, and there was a clear flow! Had the inlet pipe from the bulk head to the heater matrix off today and the water trickles, rather than "pumps" out, even at high revs? It just gives coughs and splutters the higher the revs get?
Is this the water pump that is not working correctly?

New update, water flow seems ok now HOWEVER thermostat housing is relatively HOT the pipe from the thermostat housing to the rad is warm (but I can hold it) but the pipe from the bottom of the rad is cold.
BUT when the engine is turned off, that bottom hose gets warm!!!!!
Could this be that the water is flowing too fast, i.e. thermostat open just a little!!!

remove the stat and put back together, and give it a good run... if some pipes are still cold, probly air lock. the heater pipes usuly spur off and have a valve which could be faulty. make sure its hot and give the pipes which are cold a good squeze to see if u can move the air lock, or move some water around. if still cold... water pump. still cold then block problem.
hope this helps

is the whole of the radiator surface getting hot, mine used to go into the red on a hill climb. turned out the rad was partially blocked and stopping the flow of water and stopping the heater from getting hot

I'm not an expert or claim to be brilliant but have you checked if the thermostate works properly? I'm sure this can be tested by removing and putting in a pan of water on ya cooker and then wait to see if it opens etc. Please tell me shut up if i'm wrong but just a suggestion as i had the same problem in my old car.

check that bypass valve on thermostat is working

ill swap u for my non running p38 including the gremlins lol

My 300 TDI auto also has proved to be very difficult to fill properly.
Now sorted though .
Advice from this forum was to replace the thermostat housing PLUG with a HOUSE radiator air bleed vent (B&Q) about £2.50.
Back flushing the cab heater matrix on first try looked as there was a good flow .Second try however with a longer flushing time worked .It looked like there was more water coming out then the hose pipe was putting in .
I will soon change the radiator vent soon as that is plastic and its just good to see water pumping out when chasing these air locks.
After 2 years of moderate heat from the cab heater the difference in getting it primed correctly is huge .Can just hold my hand in front of the face level vents when hot.
Hope this helps good luck

why did it over heat in the first place? change the thermostate and i think it will be fine. when you first start her take the top off the expansion tank/res and if the water is fllowing / pumping around the system its the stat. good luck.

my mate had similar thing on his 200 tdi, i used a running hose pipe through his heater matrix, i undid the rubber hose near the stat and also undid the rubber hose off the end of the metal pipe that runs back along the head to the front of the engine, i let it run for a good minuit then re conected the pipe back to the metal pipe let it run some more then pull the hose pipe off and reconect the first pipe this should shift the air in the matrix, its to fidderly to do it at the back of the engine, take it for a good spin with the header tank cap off.. this made things a good 50% better on his, but he was still not happy so we replaced his hole heater box now its 100% good luck..

good thinking batman!