Thread: Heater not getting hot

Double post.

Sounds like an air bubble, I found with mine the best way was to pulse it , so rev it a bit then let it settle, then rev again and so on, not recommended but I used to do it while driving when I heard it gurgle in the dash. I would drive it on the freeway put it in neutral down a hill, then back up to speed, at night with no one around.

Originally Posted by Ace

Hi all, long time no post.
Doing up a TD5 Disco 2 and have fitted all new silicone hoses and having issues bleeding the system up and getting the heater to blow hot air. I've been over the whole cooling system and made sure i've got all the hoses and the new thermostat plumbed up correctly and everything checks out. But having idled the car for a decent amount of time and the temp guage sitting smack on half way the bottom rad hose isnt getting overly hot and the heater wont blow warm air.

I've pulled the thermostat and checked it is opening and closing and it is working fine, but nothing I seem to do will get hot air coming out of the heater.

Any ideas?

Matt

manually flush the heater make sure its flowing adequately and isnt bypassed.

Conduct the coke bottle bleed to establish a correctly cooling system fill (or do a vac fill if you have the kit)

it the issue persists its likely to have started to have head gasket issues.


If all thats working as its a constant flow heater matrix, Are the control flaps working correctly?

Hi. Happened to me too not long ago, i'm 99.9% that the heater core is clogged, undo both pipes from it in the engine bay, attach two not too long suitable garden hose sections to both ports, let the outlet hose pointed upward, poor hot water mixed with some good radiator cleaner agent in the feed port untill it comes out the other side, let it work for an hour then flush it well, fill it with coolant mix while the hoses are attached then reatach the vehicle's hoses, start the engine, lift the coolant tank as much as you can, undo partially the bleed screw as to see bubbles then keep the revs around 2000rpm(the thermostat's bypass valve stays open this way) untill a clear flow comes at the bleeder then tighten the screw back and refit/ top up the reservoir... job done. Next time i'll replace the heater core with a new one which i have for spare already but it involves a lot of contorsionism and handyness with the dash in situ.

Originally Posted by Blknight.aus

manually flush the heater make sure its flowing adequately and isnt bypassed.

Conduct the coke bottle bleed to establish a correctly cooling system fill (or do a vac fill if you have the kit)

it the issue persists its likely to have started to have head gasket issues.


If all thats working as its a constant flow heater matrix, Are the control flaps working correctly?

Hi mate,

I have flushed the heater core, that was my first thought but it flushed clean, no issues there.

The engine had a full top end rebuild not that long ago by James at Yorkshire 4x4 so head and head gasket etc should be all good.

It has been sitting for a while so doesnt have rego so taking it for a test drive is hard.

I've just drained it to check the thermostat was working correctly so i'll bleed it up again and see how i go.

Thanks for the feedback everyone.

Matt

Originally Posted by sierrafery

Hi. Happened to me too not long ago, i'm 99.9% that the heater core is clogged, undo both pipes from it in the engine bay, attach two not too long suitable garden hose sections to both ports, let the outlet hose pointed upward, poor hot water mixed with some good radiator cleaner agent in the feed port untill it comes out the other side, let it work for an hour then flush it well, fill it with coolant mix while the hoses are attached then reatach the vehicle's hoses, start the engine, lift the coolant tank as much as you can, undo partially the bleed screw as to see bubbles then keep the revs around 2000rpm(the thermostat's bypass valve stays open this way) untill a clear flow comes at the bleeder then tighten the screw back and refit/ top up the reservoir... job done. Next time i'll replace the heater core with a new one which i have for spare already but it involves a lot of contorsionism and handyness with the dash in situ.

I've flushed the heater core, all is good there. I'll try the 2000rpm trick when bleeding and see how i go.