I know there's no proper way of bleeding the coolant system for a 200tdi defender but think have got air in the system and can't bleed it out. Whats the best method am thinking run the engine till thermostat opens then loosten pipes off heater matrix make sure is no air bubbles etc and just coolant seeping out.
Have bled it upto the rad and now I'm not too sure. Have searched and spoken to various machanics and all have been a little stumped.

Some say just leave it and have the heater flat out. This has made no difference for last few days still doing it as described below..

I'm driving along for 10mins odd and somthing will cause the thermostat to shut causing engine to heat up and no hot air out the heaters??
I'm thinking it air in the system as I've just changed the thermostat over for new one.

Am not sure if head gasket has gone or not but I wouldn't thaught that would be sucking air into the system, as air is blown out of header tank when engine switches off when the engine gets hot??

Good news, started 10am this morning and just finished a clutch change, new gearbox, new tranny box, and me new props put on.
Cheers

Have had enough of the annoying-ness!!
Head gasket change one night this week..
:hurt:
Only changed bloody thing 3months ago, and yes the head was checked all fine..
Might have to turn me turbo&pump back a tad if she's gana keep going..

MaxyMan said:

I know there's no proper way of bleeding the coolant system for a 200tdi defender but think have got air in the system and can't bleed it out. Whats the best method am thinking run the engine till thermostat opens then loosten pipes off heater matrix make sure is no air bubbles etc and just coolant seeping out.

Click to expand...

I'd be cautions about doing this as the cooling system will be pressurised and could end up spraying very hot water out

No presure if cap is off the header tank. Just the actual force of the water tying to escape.

Fair enough, however probably better to do it with the engine cold (thermostat closed), that way the pump will just be forcing water around the block/heater rather than through the radiator too.

Yes agree with ya there fella, but ideally want to do it with the stat open so that is also bled and not missing the stat housing and top rad hose etc. head gasket has gone I believe, that's why I'm struggling to bleed the air out and no hot air from the heater.
Another job to do this week.

You might try removing the thermostat altogether? That would at least eliminate one of the possibilities.

I have recently had the same problem. My 200TDI defender head gasket went, during it being repaired I replaced the thermostat, water pump, cambelt and heater matrix. The first thing I had go wrong was a drop in mpg from 25mpg to 19mpg and the thermostat gauge reading red hot.

Since carrying out all the above repairs iv had various mpg readings all around 22mpg. The gauge reads anything it wants from cold (nothing) to middle or just outside red even after 10 miles on a cold day like today.

I can't get heat into the cab at all, the fan is either two weak to push the heat in or so fast it cools the air first. Iv checked for air locks and found nothing.

That all said this weekend I found that the seal between the heater matrix housing and bulkhead was leaking air. I didn't want to drain the system again so I undid the housing and manoeuvred it around so I could see the seal.
I couldn't get a replacement locally so I made one using windscreen foam seal. This and a load of duck tape around the matrix housing has helped. What has helped the most was the moving of the matrix, I must have had air trapped in that, as it has improved a little.

I obviously do not know if this is of help as I'm still searching my self but it might be worth a punt.

Please let us know how you get on, if you find it. I will be most interested as it might be worth me trying too, like wise if I find anything else I will let you know.

Just to add when my head gasket went, their was no visual sign. Cylinder three had gone, leaking oil and water into the cylinder, this kept the pressure to a point that it ran just using a lot of extra fuel.