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Heater control valve

2448 Views 17 Replies 8 Participants Last post by  RevorTD
On my 400, the heaters blow warm but only for a short while, i.e you have to charge it up by holding it on cold for a few minutes then you get a couple of minutes of heat and so on.

Initially I suspected an airlock, so I bled the coolant and filled up carefully.

Many months have passed with the car mostly idle and as I had the manifolds out of the way today I decided to have a gander at the valve to make sure it was opening fully, it operated as suspected but I noticed a solitary drip when adjusting it either extreme. So it's leaking very slightly (no noticable coolant loss though!)

My first step is to replace this. Any other things to look at? Don't like the idea of running with an airlock but i'm confident there isn't one. The heaters do go warm - it just goes lukewarm after a minute.

No overheating, no coolant loss, thermostat okay. Blocked matrix maybe?

(Can you tell i'm bored tonight?) :dddc:
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On my 400, the heaters blow warm but only for a short while, i.e you have to charge it up by holding it on cold for a few minutes then you get a couple of minutes of heat and so on.

Initially I suspected an airlock, so I bled the coolant and filled up carefully.

Many months have passed with the car mostly idle and as I had the manifolds out of the way today I decided to have a gander at the valve to make sure it was opening fully, it operated as suspected but I noticed a solitary drip when adjusting it either extreme. So it's leaking very slightly (no noticable coolant loss though!)

My first step is to replace this. Any other things to look at? Don't like the idea of running with an airlock but i'm confident there isn't one. The heaters do go warm - it just goes lukewarm after a minute.

No overheating, no coolant loss, thermostat okay. Blocked matrix maybe?

(Can you tell i'm bored tonight?) :dddc:
This will be of no comfort whatsoever, but if I can do 2 coolant changes without creating an airlock, then I'm sure you wouldn't have made one either :lol:
Haha I was hoping it was simple.

If it's none of the usual suspects then it has to be down to the weedkiller solution.
Remove the valve and give the matrix a flush through in both directions by attaching it to the garden hose.

Lots of crud is likely to come out.
No, pressure doesn't help, flow does.

If you put that much pressure into it, it'll leak and then you have a pig of a job to change it as I think the dash has to come out.
4000psi do it?
I wondered what it's like when a heater matrix goes bang....haha...
I'm just curious as to what comes out of it, i'm expecting a few carp!
Hahaha just take a second and actually try and visualise fish leaping out of a heater matrix sorry if it sounds ridiculous bit that tickled me :)
Think I'd better check the waterpump? :dddc:

In all seriousness it wouldn't surprise me. When I stored her outside last, the expansion tank had a nit of a colony, and I've just had to defumigate her of spiders. Many house, few gardens, and a species i've not met before with a very yellow rounded body.
na they will be smooshed by the impellar. i can imagine one or two swimming about in the header tank though lol. maybe you should drain the rad again and make sure you dont have any "loose fish" kicking about in your system lol

as for the valve might need a new one as the seal might have gone.

on the plus side if you do flush your matrix through with 4000psi it would pop and you would have a foot well full of water for your fish to live in
Ha. What a wacky service schedule!

Then it's on to drain the sump and find out where George Bush has been hiding!
Haha.

Dunno if I can be bothered dealing with the heater tomorrow, but if I'm at a loose end I'l get it done as winters coming, though I've absolutely no hesitation to warm her up with the right foot!

Plenty of jobs to do :( That's what you get when you ignore a car for a few months.

Need to get my hands on a universal steering joint as the gear linkage is a bit saggy too, I've a pas leak to find, a cv joint to replace due to a cracked reluctor ring (I'm tempted to disable abs in all fairness as I intend to rip the dash out to fix a blown bulb)

In all she's not bad though. Bodywork is now good, though there's some corrosion at the rear that could turn serious, but the vandal damage is all gone.

She severely needs better brakes. The current discs and pads are awful.

Most of these are going to be solved as and when I can be bothered, as MOT standard is of only second priority. Most active work is going into smoke limitation and, predominantly boost control. I do beleive that the time for planning solutions is a bit 'last year' so I'm just going to get on with it I think. *rubs chin and thinks*

The problem with ohms law is everything on the triangle must balance out and that's not the way I work.
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I had an airlock once in mine when flushing the system. Only time in 7 L series coolant drains and refills that it has happened. Refilling more slowly cured the problem, obviously have the heater set to hot as well.

MOT standard brakes can leave a bit to be desired. The Halfords concrete pads on mine were legal, but scary. Good luck with it!
I've not got a lot on so I think I'l look at the coolant and do the brakes tomorrow, as I want her ready to move at the drop of a hat. Never had a problem changing the coolant, so I think this is a one off.

Got a few of the more tedious jobs done today though :)
EBC Utramax pads are good and are a good price on ebay too.
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