Heater blowing cold air only

[Hoopy_Frood]

I took the van out for a shake down run last night and noticed that my hot air blower isn't putting out any warm air. My radiator is getting hot, and the temp gauge sits in it's usual spot. I have also been a bit of losing coolant from the top up tank.


Having done a search on this here forum, it appears that I might have an airlock in the system, possibly due to a small leak somewhere.

Is the standard bleeding procedure enough to clear the airlock in the heater matrix?

[MidLifeCrisis]

Does the heater control lever feel 'normal'?
It's possible that the cable from that lever has become detached from the heater control valve.
If you get under the van, remove the spare wheel and look up behind the radiator you should be able to see the two heater pipes (that go to the heater) disappearing up into the van - you should then be able to see the heater valve .... looks like this (ignore the drawing bit on it - it's from an old post)

You need to check that when the lever in the cabin is moved that the lever on this valve is also moving?
Worth a quick look just to be sure?

[Hoopy_Frood]

Hmmm. I'll have a look and see - that would be a nice easy solution if it's just that.

What has me a bit concerned is that the little vents nearest the side windows on the dash and the vents that sits next to your knees always used to put out warm air, regardless of what the heater controls were set to. Now they are only putting out cold air. For some reason, I always thought that the warm air was a good indicator of a working radiator and that it would go cold if the rad was cold. But, my rad gets hot and the temp gauge looks normal, but still I have cold air.


It's painful sitting in the office when all I want to do is get the van ship shape for going away on Saturday.....

[gary1998]

try topping up the coolant first
i have a water leak haven't got around to fixing yet
when it gets low but not low enough for warning light to come on or temp gauge to go higher than normal
i get cold air in stead of usual warm air i just top up and warm air comes back

[Hoopy_Frood]

Right then,

I checked the blower controls and the lever definitely moves the valve.

I had a shot at bleeding the air out of the system. I got some bubbles coming from the rad, but the heater pipes still feel cold/empty. I kinda wussed out of revving the nads out of it as it was getting quite late last night, so will have another go this evening and properly go for it. On the good side, the rad was getting hot all over and the fan was cutting in and out beautifully.

I'm hopeful I can get whatever airlock is in the heater pipes/matrix shifted - if not, should I reconsider my plan to drive to France?

[kevtherev]

Oh is it very cold in France?

[Hoopy_Frood]

Hah, not where we're heading to seemingly. 21 degrees max on the forecast.

I read on tinterweb that if an airlock makes it way into the engine it can be very bad. If that's not the case, then it's happy days.

[Hoopy_Frood]

I've just had another thought.

I removed the fuel tank to do some welding. Is it possible I might have crushed/blocked the heater pipes when I put it back on?

[MidLifeCrisis]

I've just had another thought.

I removed the fuel tank to do some welding. Is it possible I might have crushed/blocked the heater pipes when I put it back on?

It's possible I guess - they are in the same area - can you give the pipes a 'wiggle' to see if they seem free?

[Hoopy_Frood]

Progress report.

The heater pipes don't appear to be crushed but they are not getting warm/hot at any points under the van.

Also, it looks like there's a small leak coming from somewhere near the heater matrix itself.

At this point, I need to just hope it's not going to develop into something more serious.

Off to France tomorrow - wish us luck!

[MidLifeCrisis]

Good luck!!
And maybe google the French for 'Heater Matrix'!!