Hello, I am brand new to this forum. I have a 99 Disco 2 that has the new head gaskets, new water pump, flushed cooling system, gray t-stat from AB, installed everything per the RAVE manual. Here is the problem. Idles at about 95 degrees Celsius with the defrost on full it is COLD, rev motor and the temp drops to 85 ish Celsius and the heat comes out nicely. So I let off and back to no heat cold!!! The res is full and no leaks. The lower hose below the t-stat is cool compared to the the upper hoses and the the two heater hoses go cool too.

Heads were milled and checked, water pump was dealer installed, radiator seems to flow water easily.

It feels as if the heater core has an air bubble in it but how could the rpms not force the air through?

Any suggestions? Thank you all for your time.

 

You are low on Antifreeze I bet.
OR you have a lot of air in your system.

Fill it up with Antifreeze.
Then bleed the system.

 

Well lets go back a minute.

Do you hear the waterfall sound coming from your dash when reving up your engine? If so that means you cooling system has air in there. If thus is your case go up to the top of the page to the search bar and search "how to bleed cooling system " If not then you could have clogging going on in your heater matri or radiator which would also be the reason it is only blowing heat as more force is causing the coolant to circulate threw the blockage. You could have caused blockage or sediments to all pile up in one area from flush not allowing your coolant to circulate properly.

 

X2 with above. The thermostat is a "bypass design" that allows flow to heater core at low RPM, but at high speed the opening of the main stat forces the bypass disc closed. If during the work the sludge in cooling system was allowed to dry out, you could have blockage in both heater and radiator.

You can reverse flush the heater core with a garden hose. See https://landroverforums.com/forum/at...025_105723-pdf

Can also have crud from inside the system blocking the holes in the bypass disc.

 

Stop driving it till you properly bleed the coolant system, then pressure test the coolant system to rule out another coolant leak.

 

Thank you Mike for the phone call this morning. I will try your tests and report back.

 

OK, coolant filled and bleed done as per Disco Mike's phone help today. Dead cold filled to top of coolant bottle with bleed screw out. Replaced screw, replaced cap, started up and set heater to highest temp. Cold air is all I got as temp came up to 187 degrees, slowly brought up rpm to about 1500 and back down several times. Heat would come and go just as the rpm would. Idle temp was around 195 and would drop with increased rpm. I do think I do need to replace the fan clutch but that is not causing my heater core not to get coolant?

 

Do you not understand my post?

 

LR2001, I did bleed it correct, no waterfall sound, I can blow through all parts with my mouth too. So I am baffled.

 

Try switching the hoses that enter the heater core at the firewall. Drive around like that and see if it gets better. If it does you may have had a partially blocked core. I would then flush the cooling system again to get out whatever may have been blocking it and putting the hoses back to their original location.