Heater Doesn't Get Hot...

[Donagh]

Hi Kevin,
No, I can honestly say that this is the first time I've ever heard the two words 'blend' and 'door' used together a description of a car part. LOL. But I'll tell you what, I had the car repaired by some guys who specialize in Benz repair, not Land Rover. I had to tell them to replace the bolts on the intake manifold when they replaced the gasket. I did the research that they should have. So I have a suspicion that it may have something to do with their repair. I know they replaced the coolant, but they didn't replace the top hose clamp properly and I had a slow leak there until I replaced it myself. (they were probably in a hurry).

I saw someone had posted something about a 'flap' being stuck or jammed in relation to this sort of problem. Is that what you are speaking about? The point is, everything worked fine before I gave it to them, and now... so my first thought is that they might have done something inadvertently, to contribute to this issue.

Could that blend door motor be a 'fuse' that is blown?

[kevin-ct]

Den, Here is a description of the heater unit that I got from Rave.

The heater unit consists of a housing containing a
heater matrix which is connected to the engine cooling
system. As water is circulated continuously through
the heater matrix, the selection of hot or cold air is
controlled by servo operated LH and RH blend flaps
directing the air through or around the heater matrix.
The LH and RH blend flaps operate independently to
allow different temperatures to be set for the LH and
RH air vents. The servo operated distribution flaps
control the flow of air from the heater unit to the outlet
vents. Air distribution is common to both sides of the
vehicle interior.
The two temperature servos and the distribution servo
each incorporate a feedback potentiometer which
provides the Heater ECU with a flap position signal to
enable accurate control of air temperature and
distribution.

[Rovah]

I'm going to jump in on this thread because I have a mystery coolant system issue.

A couple years ago(yeah, I'm that busy, with that many vehicles), I lost heat in the cabin followed directly by the truck overheating. Odd thing was that the coolant level didn't drop.

I finally resurrected the truck last month(partially), and we replaced the following; head gaskets, lifters, valve seals, water pump, front main seal, thermostat.

So, drove the truck on a couple of short rides. Seeemed to be ok. Then we lost heat in the cabin and it started to overheat. Thinking we had air in the system, we let it cool, refilled, etc. Attempted another drive with similar symptoms.

Thinking the radiator might be bad(I've heard stories), I replaced it today. Refilled, warmed, refilled, etc. Drove for about 15 miles with no issue and then cabin heat became variable. Once again the truck got hot.

Our heads hurt from trying to think what is going on! Are we simply dealing with a air pocket in the system that won't go away. Is the water pump just pumping air? Did we get a bad thermostat?

ANY help/suggestions are welcome. I need this truck to work and I've run out of things to replace. Everything in the coolant system external to the block(except the hoses) has been replaced. I'm out of ideas and options. I don't really want to take it to my local cooling/radiator shop because I don't think they're any more mechanically inclined than I am. But if we are dealing with an air pocket-would they have the gear to get it to go away?

Thanks again in advance for any suggestions/help.

Cheers! John

[spacemutt]

Check your passenger....no...wait...you've got LHD cars...er...probably driver side carpet in the footwell. (check both sides just in case they run the pipes in a different direction)

Is it damp?

If so you have a real BAR STEWARD of a job. There are heater hoses running to the matrix that perish and leak causing fluid loss. This could cause an air lock in the matrix. You need long bendy arms to reach them. Either that or send in a small child...

[Rovah]

Thanks Spacemutt-I'll check. Not smelling any coolant in the cab, but I've read about the heater core o-rings over the past few years. I'm sure my day will come-maybe sooner than I want. ;-)

[spacemutt]

Yes! O-rings! Not hose lol. It's the o-rings that fail.