1984

New Member
Hi all, I'll post up the details in the hope somebody can help.

1995 Landrover Discovery 2.5 300TDI

The blower air was always cold even with the engine warm, then it would over heat for a minute... then all of a sudden the temp would go back down to normal and at the same time the blower air would go hot :confused:

Had a leak from P gasket so changed that and water pump (which was nackered) - and also put a new thermostat in. Same problem.

Noticed that the radiator was cold? I got a radiator today from High Range in Canock, it was second hand £50. Got back and fitted it in, started to fill with water and the radiator was peeing it out, big hole in there :doh:

So, put the old radiator back on for now.. thermostat has been removed for testing as we thought that was the problem.. and very oddly after bleeding, the rad was fully hot, and the blower air was hot like it should be?? drove for half hour, blower air went cold and the engine over heated again, i got out to check the radiator and it was cold again!!

No signs of head gasket. I am tempted now to buy a NEW radiator, but confused how it suddley worked fine for half hour.

Any ideas, I'm going mad. Cheers
 
have you tried re-bleeding? sounds like an air lock but I'm surprised that I would effect anything other than the heater matrix.

if its not that it has to be a partial, shifting blockage. I'd try flushing the whole system under some pressure, not just the rad. I've seen some pretty gunked up bottom hoses.
 
I had an airlock that happened like that before, all of a sudden gauge would shoot up, put blowers on and nothing, then all of a sudden red hot blowers and gauge went down.
I just kept bleeding it over about 4-5 days and it eventually sorted itself out.

Sy
 
Sounds like an air lock to me . I had someting similar once. I always have the front end of car higher than the back when I top it up and squeeze the top hose as I do it. Regards Jonathan
 
replace, if you havent already, the plastic bungs on the rad and the thermostat cover with brass bleed versions. those plastic ones are notorious for breaking at inopportune moments :(. That will enable yu to bleed it when hot and under pressure.
 
Thanks for the replys, I have bled it lots and lots so if it is an air lock I really can't get rid of it , :confused:
 
Am I right in thinking that the radiator must be fine as it did get hot ALL over, the only reason I was replacing it as it was staying cold so i assumed it was blocked up?
 
Its a bit of a leap of faith....radiators should be the same heat all over,but if the rest of the system is faulty then I wouldnt rely on that alone.Do as above and bleed.Get the brass plugs,they are the same as domestic radiator valves so go to a hardware store and buy a blank for the rad and a drain-key one for the top of the stat.Flush the fcuking hell out of the whole cooling system and keep doing it,section by section,then reassemble and keep flushing till clear.That includes the heater matrix.

Fill the system by the top of the rad (with your shiny new brass plug!) and then the stat.

Unbolt the mounts of the header tank and suspend it as high as the hoses allow with some string from the bonnet frame.This will give some header pressure to push things round (so the book and my old dad say) while you run the engine and bleed air as usual from the top of the stat,through your fine new valve.

As has been said,you may have to keep bleeding for a few days (avoid the obvious pun here!) until things straighten out.

THEN see if your rad is hot all over.
 
An update, oh and a huge thanks for all the information it is very much appreciated.

Well I purchased some flush stuff etc, then whilst driving home I noticed that for a while the blower air has been hot and the engine has not over-heated.. so I kept driving, and driving.. and driving...

For over 70 miles! and it has not over heated once?? the blower air was nice and hot and the radiator was all hot as it should be each time I pulled over to check?

Confused, nothings changed. I am now thinking I don't want to touch it incase it has fixed itself?? I'm going insane. I'll keep driving it and see what happens I think???
 
Have you tried a new thermostat??

no there is still no thermostat in there, I tested the old one with boiling kettle water and it did work. I'll see what happens and if it has solved the problem all on it's own I'll put the themorstat back in
 
An update, oh and a huge thanks for all the information it is very much appreciated.

Well I purchased some flush stuff etc, then whilst driving home I noticed that for a while the blower air has been hot and the engine has not over-heated.. so I kept driving, and driving.. and driving...

For over 70 miles! and it has not over heated once?? the blower air was nice and hot and the radiator was all hot as it should be each time I pulled over to check?

Confused, nothings changed. I am now thinking I don't want to touch it incase it has fixed itself?? I'm going insane. I'll keep driving it and see what happens I think???

I'd still fit a new thermostat if I were you. :)
 

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