98 1.25 heater only blowing cold air - Newell24
hi, i have noticed similar posts but i need help, not long ago i changed the heater control valve as it was leaking and it was broken... the new one worked fine until recently when all that i get is cold air blowing. both the pipes on both sides are hot as i have the heat turned up, they run hot water... is the HCV likely to be the problem here?

thanks

Edited by Pugugly {P} on 15/01/2008 at 17:32

98 1.25 heater only blowing cold air - DP
I thought HCV before even opening this post, as 99% of the time, that's exactly what causes lack of heat on a Fester, but that doesn't fit with your description.

The two pipes on the engine side of the valve will get hot regardless of whether the heater is set to cold or hot. However, the two on the rear side would normally stay cool if the HCV was causing your lack of heating. If these two rearward pipes are hot as you describe, this suggests the HCV is working correctly, and that hot water is making it to, and through, the heater matrix.

Is the heater stone cold, or is there any trace of heat at all? Do the two rear pipes run cool if the heat is turned off? Is the blower working normally?

The only possibility I can think of is that the heater matrix housing has become clogged up with leaves and debris, and is preventing air from being drawn through the matrix to be heated. However, I seem to recall the matrix is quite well tucked away in the bulkhead with a nice sealed cover over the top of it. It's possible something has got in through the pollen filter I suppose.

Cheers
DP

Edited by DP on 16/01/2008 at 08:51

98 1.25 heater only blowing cold air - Newell24
i thought that, i dont think it is clogged up as you said the heater matrix is tucked away... is it possible it is the thermostat? the heater appears to blow normally except for the obvious fact its blowing cold air... and yes the air is cold as it can be,,,

Thanks...
98 1.25 heater only blowing cold air - Screwloose

Very odd one. I wouldn't rule out a faulty new valve; but if you temporarily bridge it out with a couple of pieces of suitable pipe, then that'll prove it one way or the other.
98 1.25 heater only blowing cold air - topbloke
the theory is that one should be hot and the other a lot cooler, as the hot water flows through the marix the cold air from fan flow through the matix and pulls the heat from the hot water so if the hoses are the same temp it isnt flowing through the matrix so its blocked or the pump is not pushing the water through you could remove the pipes from the valve and revese flow through the matrix and see what comes out if its clear then that would prove its a flow issue
98 1.25 heater only blowing cold air - Newell24
Hi all, i have corrected the problem and the heater is now blowing hot air, i found that the heater control valve was blocked as one of the pipes had become jammed. i replaced this and now all seems fine... although now i have a completely different problem to do with my reverse light so ill be posting again... Cars!

thanks all
98 1.25 heater only blowing cold air - Turtle1966
Some advice, please!

I have the same problem - no heat at all in the heater.

Looking into the engine comp from the front, the nearest (frontmost) pipes are both hot. The left rear pipe is also hot. The right rear pipe is stone cold. This is with the engine warm and the heater turned on to hot.

Can anyone tell me which direction the water flows to and from the matrix?

I will replace the HCV anyway - it just looks like a matrix problem may be what I have?

98 1.25 heater only blowing cold air - trevoryz426
its more then likely your hcv is at fault but sometimes the heater controll module is faulty lets hope its not that as that will cost you more money