Thread: td5 heater, blowing air fine but not heating.

Howdy Wicks

I've got the same problem. My 99 Defender Td5 is exactly the same. Ran the heater on full for 10 minutes. In the end all I got was a very slight touch of warmth.... No worries tho, all I do is close the front vents and chuck a jumper on. 10 minutes later the cab is warmed up from the heat from the engine bay lol.

Originally Posted by Wicks89

No prizes for guessing why this is now an issue.

The heater in my td5 130 is blowing great but not heating the air. At all.
Are there any simple checks or things to look for? I have no idea how these heaters work.

Whats the temp gauge reading and or doing

I would suggest you either have a blocked heater core or the cable that opens the vent (the lever on the left of the dash who's cable runs to the LHS of the heater box) is disconnected or broken.
Regards,

G'day!

I've just fixed an issue with our heater system on our TD5 Defender, so a little familiar with it.

If you have no alterations to the plumbing, then I would suggest Phil B is on the money. Simplest thing is to first see whether your cable that operates the door is connected and working, you can test this by looking at the assembly on top of the heater box as you (or somebody else) moves the lever up and down.

If this is working, the next thing I would check would be a blocked core. Disconnect the outlet hose from the heater box with the engine running and warmed up, and see if coolant is pushed through?

If all that is good, then you might need to pull apart the heater box and see if the door mechanism is working correctly - I haven't needed to get to this stage before.

A previous owner has put a bypass line and taps to and from our heater matrix - ostensibly to try and keep the heater matrix (and subsequently blown air) cooler when in summer. What it did more effectively than that is allow a diverting path for the coolant, reducing the effectiveness of the heater.

Good luck!

Automotive heaters generally consist of a heater core (which circulates engine coolant) and ducting which blows air thru the core to give heated air. The coolant flow thru the core is regulated with a valve, which is usually actuated by a cable or a servo. Defender is cable operated (we have the poverty pack, lol, but easier to fix if SHTF)

While my experience mainly lies with other makes, the defender should be no different.
If it stopped working all of a sudden, then my money is on the heater tap mechanism being faulty. On the puma this is on the firewall, slightly left of the middle on the passenger side. Trouble diagnosis would be something like:
1) operate the heater controls in cab, check for any significant resistance, or lack of resistance.
2) while operating lever, have an assistant watch for movement on the cable which operates the heater tap. Chances are the wire which operates the tap has come out of its hole, as its usually just a dog-leg bend of wire which is fed thru a hole.
3) Check the heater tap. If it's old and brittle, it could have damaged the actuating lever. If you are in a fix, you could either manually operate the valve by hand (always on, or always off), or booty-fab it with gaffer tape, zip ties, tie wire etc until you can effect a proper repair.

A blocked heater core would be a more gradual demise, they usually caused by blockage at the small capillary sections of the core, which means only a row of the heater matrix will be blocked. If this is the case, consider taking it to a radiator shop for a power flush, or try running a bottle of radiator flush thru the system to loosen any rust, silicone, or calcification which has accumulated. Back-flush with a garden hose.

Hope this helps.

I think the td5 are getting to the point where the heaters are starting to play up , there has been a few people now that have had heater problems , me included . First you can't turn off coolant side " water " unless there has been a valve added . So let your engine warm up and feel the two hoses that go into the heater , there easy to find there high up in front of the fire wall " bulk head " If there both warm , or hot then you have flow through them , If Not there is a problem with heater core . Now if there is circulation through the core , then the problem is with the vent . That opens and closes by the heater hoses , you can see the cable on the top of the box , check to see that It opens and closes . They are the only two things I can think of that will stop your heater working ! You could have an air lock , check your top hose at the bleed screw . plus expansion tank level !!. Jim

Its funny I just logged on to ask about my TD5 heater problem a see they have a few issues haha.

My problem is I have hot air and fans running as they should but as soon as I get moving I hear a thud like a flap is slamming shut and get stuff all air out of either the demist or foot vents doesnt happen all the time but is now happening more often than not now as to why im here to ask...

When I operate my cables it all looks to be working but obviously something is doing it own thing So was wondering if anyone has come accross this b4 and a simple fix i was thinking that maybe they had a vacuum operated flap that might be playing up that i couldnt see but reading up looks to be all cable operated...

Sorry to hijack but need to be warm again

cheers Brian