Heater box blowing lukewarm

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Ryan_mag said:
Thanks for all the help so far!

Tried parking on a hill and running for about 40 mins with the radiator plug off and going to buy a self bleed valve but still not difference

All heater controls are definitely adjusted properly now and the box to bulkhead seal was replaced when I changed the matrix and its sealing correctly. Tbh the fan is working deadon I think im just being fussy.

However it's still only blowing like warm air. Both pipes seem red hot from heater matrix to me it seems like the bottom of the matrix is airlocked so the water is only getting into part of the matric then flowing out again.

Other things: landrover build temp normally and guage sits bang in the middle and the thermostat was replaced 500 mile ago along with a full coolant flush

Anyone any other ideas?
Click to expand...

Might need to back flush the matrix ... when you changed the matrix did you flush the scale through ?
 
v8250 said:
This, there's a need to know that there's good flow rate and that there's input flow AND return flow. If an engine has a blockage within the the water galleys there's the risk that the flow rate to it's furthest point of heat use [the heater matrix] will not get enough water flow :. thermal store, to give enough heat output from the heater matrix to provide enough heat irrespective of the fan air volume. I've only seen this happen once and it took me an age to fault find

ps when isolating from the matrix it's worth keeping the pipes on back of engine an adding a tap to each - this enables testing of water flow, one should be full flow, the second near zero flow.
Click to expand...

I did mean put a hose on the matrix, its a straight forward way to check if its blocked or gummed up ;)
 
My 90 heater was pretty poor. I disconnected both pipes at the engine end and jammed a garden hose in one of them. All sorts of brown crap came out and eventually it went clear. Next was to seal up all the gaps around the heater box to prevent loss of hot air, and clear any accumulated rubbish from the inlet side.

The best way I found to clear air was to loosen the hose clamps with the engine running and warm, then prise the hose away slightly until coolant starts to come out. Ideal would be to solder a proper bleed screw to the top of each pipe.

If that's all been done, it's worth disconnecting the cable and moving the bypass flap by hand to see if it's moving all the way over. If it's not fully closed then cold air will enter the mix.

The heater flaps in the lower dash, and the pipes leading up to the windscreen are also prone to leaks.
 
Ryan_mag said:
Not sure what temperature I just got it from the landrover parts supplier near me. What temperature would u reccomend fitting? Is there a way to test what temperature she is actually at I've one of them infrared thermometers if thats any help?. Could my water pump be causing the probelm either it dosent seem to leak but just a thought
Click to expand...

Can you remember what the stat looked like?
You want the type of stat with the bypass shut off.
88 degc is the temp Iirc, waxtstat was th emake to have but think no longer in business.

The 200 is so efficient it takes an age to warm up and even when the gauge says its at running temp its not, unless you are working it hard.
The 300 apart from being way gayer:D is also less efficient and that goes for every disco engine after the 200 newer = less mpg.
 
Thanks again everyone for the help

Going to check my water pump next for leaks then remove the feed pipe to the heater when running and see how much water it's pumping. If all else fails I'll replace the water pump and reflush the coolant again, including washing the feed and return pipes on the engine
 
To be honest It might just be easier to take the heater box off the bulk head and test it. That way you’ll know if it’s the heater unit itself or something else.
 
lynall said:
Bet it has the correct temp stat in it.
Click to expand...

Yeah do oh remember I brought about 5/6 different stats including genuine waxstat (x2) and doing some testing of them.

Of the 6 only one worked within spec. All the others started to open to early (like mid 70’s) or to late (like mid 90’s)

Certainly opened my eyes to the totally varying quality and the massive deofferwnce it made to both the heater and general running

Will look for the thread
 
My heater was crap for years until I investigated. As already said there was a gap letting warm air out into engine bay which I solved with a sleeve and foam strip. Secondly the fan, although working, was too slow. Cobbled together a fork shaped adapter to a long spade bit, spray fan with electrical lube, spin it up manually on a variable speed drill till going really fast. Spins brilliantly afterwards.
Solved! Loads of heat and great airflow. First time the soft top has ever been warm in winter
 
Stat is 88 degree but going to test it in water now. Pulled the return hose of the heater and it is pumping water but not at a mad rate how much water should be pumped through? It's no trickling out but it's certainly not shooting accross the engine bay lol
 
Ryan_mag said:
Stat is 88 degree but going to test it in water now. Pulled the return hose of the heater and it is pumping water but not at a mad rate how much water should be pumped through? It's no trickling out but it's certainly not shooting accross the engine bay lol
Click to expand...

Got a pic of the stat?
 
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