HEATER CONTROL VALVE

Just found the coolant leak on my 960 turbo, it's been loosing water
slowly since I bought it 2 years ago. I was told that it was probably a
head gasket but over the last two weeks it's got to the point where I
need to top it up every 40 miles, looking under the bonnet tonight I
tried revving the engine and above about 4 thousand revs water is
spraying out of a crack in the vacuum operated heater control valve.

What will happen if I replace this temporarily with a short piece of
copper pipe? Our local Volvo pattern part dealer can't get one so it
looks like main dealer after the holidays. Will this just make the
heater operate flat out(Car has climate control) or do I risk any damage?

Steve H

Stev eH wrote:
> Just found the coolant leak on my 960 turbo, it's been loosing water
> slowly since I bought it 2 years ago. I was told that it was probably a
> head gasket but over the last two weeks it's got to the point where I
> need to top it up every 40 miles, looking under the bonnet tonight I
> tried revving the engine and above about 4 thousand revs water is
> spraying out of a crack in the vacuum operated heater control valve.
>
> What will happen if I replace this temporarily with a short piece of
> copper pipe? Our local Volvo pattern part dealer can't get one so it
> looks like main dealer after the holidays. Will this just make the
> heater operate flat out(Car has climate control) or do I risk any damage?
>
> Steve H


Your heat will be on full, it won't hurt anything though. I did this on
my friend's 940 a few years ago and it worked fine, in fact the
temperature control still worked due to the climate control operating
the AC. Not very efficient, but ok for temporary use.

James Sweet wrote:
> Stev eH wrote:
>> Just found the coolant leak on my 960 turbo, it's been loosing water
>> slowly since I bought it 2 years ago. I was told that it was probably
>> a head gasket but over the last two weeks it's got to the point where
>> I need to top it up every 40 miles, looking under the bonnet tonight I
>> tried revving the engine and above about 4 thousand revs water is
>> spraying out of a crack in the vacuum operated heater control valve.
>>
>> What will happen if I replace this temporarily with a short piece of
>> copper pipe? Our local Volvo pattern part dealer can't get one so it
>> looks like main dealer after the holidays. Will this just make the
>> heater operate flat out(Car has climate control) or do I risk any damage?
>>
>> Steve H
>
>
> Your heat will be on full, it won't hurt anything though. I did this on
> my friend's 940 a few years ago and it worked fine, in fact the
> temperature control still worked due to the climate control operating
> the AC. Not very efficient, but ok for temporary use.

Just ordered a replacement on line from Euro Car Parts, a call to the
local main dealer sounded like it was a major job to replace and they
wanted to book it in for repair rather than sell me the part. Looks
like a couple of hose clamps and a push on vacuum pipe to me. I will
bodge it tomorrow as we need to do a few hundred miles the day after
Christmas, nice to find the problem now rather than on the motorway.

Steve H

Stev eH wrote:
> James Sweet wrote:
>> Stev eH wrote:
>>> Just found the coolant leak on my 960 turbo, it's been loosing water
>>> slowly since I bought it 2 years ago. I was told that it was
>>> probably a head gasket but over the last two weeks it's got to the
>>> point where I need to top it up every 40 miles, looking under the
>>> bonnet tonight I tried revving the engine and above about 4 thousand
>>> revs water is spraying out of a crack in the vacuum operated heater
>>> control valve.
>>>
>>> What will happen if I replace this temporarily with a short piece of
>>> copper pipe? Our local Volvo pattern part dealer can't get one so it
>>> looks like main dealer after the holidays. Will this just make the
>>> heater operate flat out(Car has climate control) or do I risk any
>>> damage?
>>>
>>> Steve H
>>
>>
>> Your heat will be on full, it won't hurt anything though. I did this
>> on my friend's 940 a few years ago and it worked fine, in fact the
>> temperature control still worked due to the climate control operating
>> the AC. Not very efficient, but ok for temporary use.
>
> Just ordered a replacement on line from Euro Car Parts, a call to the
> local main dealer sounded like it was a major job to replace and they
> wanted to book it in for repair rather than sell me the part. Looks
> like a couple of hose clamps and a push on vacuum pipe to me. I will
> bodge it tomorrow as we need to do a few hundred miles the day after
> Christmas, nice to find the problem now rather than on the motorway.
>
> Steve H


Yeah it only takes about 10 minutes to change, and you can even do it
without spilling a lot of coolant. On a 240 it's a much bigger job, but
still not too bad.

Stev eH wrote:
> James Sweet wrote:
>> Stev eH wrote:
>>> Just found the coolant leak on my 960 turbo, it's been loosing water
>>> slowly since I bought it 2 years ago. I was told that it was
>>> probably a head gasket but over the last two weeks it's got to the
>>> point where I need to top it up every 40 miles, looking under the
>>> bonnet tonight I tried revving the engine and above about 4 thousand
>>> revs water is spraying out of a crack in the vacuum operated heater
>>> control valve.
>>>
>>> What will happen if I replace this temporarily with a short piece of
>>> copper pipe? Our local Volvo pattern part dealer can't get one so it
>>> looks like main dealer after the holidays. Will this just make the
>>> heater operate flat out(Car has climate control) or do I risk any
>>> damage?
>>>
>>> Steve H
>>
>>
>> Your heat will be on full, it won't hurt anything though. I did this
>> on my friend's 940 a few years ago and it worked fine, in fact the
>> temperature control still worked due to the climate control operating
>> the AC. Not very efficient, but ok for temporary use.
>
> Just ordered a replacement on line from Euro Car Parts, a call to the
> local main dealer sounded like it was a major job to replace and they
> wanted to book it in for repair rather than sell me the part. Looks
> like a couple of hose clamps and a push on vacuum pipe to me. I will
> bodge it tomorrow as we need to do a few hundred miles the day after
> Christmas, nice to find the problem now rather than on the motorway.
>
> Steve H

Steve,

My 'bodge' for this same failed valve on my '86 740 frankencar, was to
replace it with a short length of 15mm copper plumbing pipe held in
place with hose clips, 4 years later, the 'bodge' is still doing its
duty, more trustworthy in my opinion than the dodgy split plastic valve
that it replaced.
The heater still works well, blowing both cool, hot and everything in
between (aircon is knackered), with the heat output well controlled by
its air flaps.
I've never really noticed the fact, that without the coolant flow
control valve installed, the heater matrix is always hot, but, thanks to
your research I can now replace my valve (after a short motorbike ride
to Preston), and make the heater work as it was originally intended to.

Merry Christmas,
Ken Phillips

Ken Phillips wrote:
> Stev eH wrote:
>> James Sweet wrote:
>>> Stev eH wrote:
>>>> Just found the coolant leak on my 960 turbo, it's been loosing water
>>>> slowly since I bought it 2 years ago. I was told that it was
>>>> probably a head gasket but over the last two weeks it's got to the
>>>> point where I need to top it up every 40 miles, looking under the
>>>> bonnet tonight I tried revving the engine and above about 4 thousand
>>>> revs water is spraying out of a crack in the vacuum operated heater
>>>> control valve.
>>>>
>>>> What will happen if I replace this temporarily with a short piece of
>>>> copper pipe? Our local Volvo pattern part dealer can't get one so it
>>>> looks like main dealer after the holidays. Will this just make the
>>>> heater operate flat out(Car has climate control) or do I risk any
>>>> damage?
>>>>
>>>> Steve H
>>>
>>>
>>> Your heat will be on full, it won't hurt anything though. I did this
>>> on my friend's 940 a few years ago and it worked fine, in fact the
>>> temperature control still worked due to the climate control operating
>>> the AC. Not very efficient, but ok for temporary use.
>>
>> Just ordered a replacement on line from Euro Car Parts, a call to the
>> local main dealer sounded like it was a major job to replace and they
>> wanted to book it in for repair rather than sell me the part. Looks
>> like a couple of hose clamps and a push on vacuum pipe to me. I will
>> bodge it tomorrow as we need to do a few hundred miles the day after
>> Christmas, nice to find the problem now rather than on the motorway.
>>
>> Steve H
>
> Steve,
>
> My 'bodge' for this same failed valve on my '86 740 frankencar, was to
> replace it with a short length of 15mm copper plumbing pipe held in
> place with hose clips, 4 years later, the 'bodge' is still doing its
> duty, more trustworthy in my opinion than the dodgy split plastic valve
> that it replaced.
> The heater still works well, blowing both cool, hot and everything in
> between (aircon is knackered), with the heat output well controlled by
> its air flaps.
> I've never really noticed the fact, that without the coolant flow
> control valve installed, the heater matrix is always hot, but, thanks to
> your research I can now replace my valve (after a short motorbike ride
> to Preston), and make the heater work as it was originally intended to.
>
> Merry Christmas,
> Ken Phillips
Fitted it today, the old one fell apart when I removed it. The plastic
body had become very soft and brittle. Total cost 18.89 GBP. and about
half an hour.

Steve H

Stev eH wrote:
> Ken Phillips wrote:
>> Stev eH wrote:
>>> James Sweet wrote:
>>>> Stev eH wrote:
>>>>> Just found the coolant leak on my 960 turbo, it's been loosing
>>>>> water slowly since I bought it 2 years ago. I was told that it was
>>>>> probably a head gasket but over the last two weeks it's got to the
>>>>> point where I need to top it up every 40 miles, looking under the
>>>>> bonnet tonight I tried revving the engine and above about 4
>>>>> thousand revs water is spraying out of a crack in the vacuum
>>>>> operated heater control valve.
>>>>>
>>>>> What will happen if I replace this temporarily with a short piece
>>>>> of copper pipe? Our local Volvo pattern part dealer can't get one
>>>>> so it looks like main dealer after the holidays. Will this just
>>>>> make the heater operate flat out(Car has climate control) or do I
>>>>> risk any damage?
>>>>>
>>>>> Steve H
>>>>
>>>>
>>>> Your heat will be on full, it won't hurt anything though. I did this
>>>> on my friend's 940 a few years ago and it worked fine, in fact the
>>>> temperature control still worked due to the climate control
>>>> operating the AC. Not very efficient, but ok for temporary use.
>>>
>>> Just ordered a replacement on line from Euro Car Parts, a call to the
>>> local main dealer sounded like it was a major job to replace and they
>>> wanted to book it in for repair rather than sell me the part. Looks
>>> like a couple of hose clamps and a push on vacuum pipe to me. I will
>>> bodge it tomorrow as we need to do a few hundred miles the day after
>>> Christmas, nice to find the problem now rather than on the motorway.
>>>
>>> Steve H
>>
>> Steve,
>>
>> My 'bodge' for this same failed valve on my '86 740 frankencar, was to
>> replace it with a short length of 15mm copper plumbing pipe held in
>> place with hose clips, 4 years later, the 'bodge' is still doing its
>> duty, more trustworthy in my opinion than the dodgy split plastic
>> valve that it replaced.
>> The heater still works well, blowing both cool, hot and everything in
>> between (aircon is knackered), with the heat output well controlled by
>> its air flaps.
>> I've never really noticed the fact, that without the coolant flow
>> control valve installed, the heater matrix is always hot, but, thanks
>> to your research I can now replace my valve (after a short motorbike
>> ride to Preston), and make the heater work as it was originally
>> intended to.
>>
>> Merry Christmas,
>> Ken Phillips
> Fitted it today, the old one fell apart when I removed it. The plastic
> body had become very soft and brittle. Total cost 18.89 GBP. and about
> half an hour.
>
> Steve H
>
Glad the replacement went well, just out of interest how much coolant
did you loose? I often wonder how many times that a failure of this
valve has actually killed the engine by unnoticed or otherwise overheating.
I once got an entire 740 turbo sedan, from a scrap dealer for 50 GBP,
got all sorts off it before taking it back for crushing, including the
entire heating system (to upgrade my manual gle estate), the gearbox
(auto, now dead, my fault, oops! So cars a manual again lol), the
steering rack (still working very well, the 100A alternator (still
working and bloody brilliant!), the electric seats, etc. ......,
however, the only thing I actually found obviously wrong with the car,
was that wretched valve!
Split open, obviously, the car had bled all it's coolant.
Whatever possessed them to make it out of plastic? The earlier
thermostatic ones in the 84ish 240's were metal, so why not now? It's
almost as if some apparently insignificant parts are designed to fail,
with catastrophic results.

Happy new year! Don't waste that leap second.
TTFN,
Ken Phillips

Stev eH wrote:
> Ken Phillips wrote:
>> Stev eH wrote:
>>> James Sweet wrote:
>>>> Stev eH wrote:
>>>>> Just found the coolant leak on my 960 turbo, it's been loosing
>>>>> water slowly since I bought it 2 years ago. I was told that it was
>>>>> probably a head gasket but over the last two weeks it's got to the
>>>>> point where I need to top it up every 40 miles, looking under the
>>>>> bonnet tonight I tried revving the engine and above about 4
>>>>> thousand revs water is spraying out of a crack in the vacuum
>>>>> operated heater control valve.
>>>>>
>>>>> What will happen if I replace this temporarily with a short piece
>>>>> of copper pipe? Our local Volvo pattern part dealer can't get one
>>>>> so it looks like main dealer after the holidays. Will this just
>>>>> make the heater operate flat out(Car has climate control) or do I
>>>>> risk any damage?
>>>>>
>>>>> Steve H
>>>>
>>>>
>>>> Your heat will be on full, it won't hurt anything though. I did this
>>>> on my friend's 940 a few years ago and it worked fine, in fact the
>>>> temperature control still worked due to the climate control
>>>> operating the AC. Not very efficient, but ok for temporary use.
>>>
>>> Just ordered a replacement on line from Euro Car Parts, a call to the
>>> local main dealer sounded like it was a major job to replace and they
>>> wanted to book it in for repair rather than sell me the part. Looks
>>> like a couple of hose clamps and a push on vacuum pipe to me. I will
>>> bodge it tomorrow as we need to do a few hundred miles the day after
>>> Christmas, nice to find the problem now rather than on the motorway.
>>>
>>> Steve H
>>
>> Steve,
>>
>> My 'bodge' for this same failed valve on my '86 740 frankencar, was to
>> replace it with a short length of 15mm copper plumbing pipe held in
>> place with hose clips, 4 years later, the 'bodge' is still doing its
>> duty, more trustworthy in my opinion than the dodgy split plastic
>> valve that it replaced.
>> The heater still works well, blowing both cool, hot and everything in
>> between (aircon is knackered), with the heat output well controlled by
>> its air flaps.
>> I've never really noticed the fact, that without the coolant flow
>> control valve installed, the heater matrix is always hot, but, thanks
>> to your research I can now replace my valve (after a short motorbike
>> ride to Preston), and make the heater work as it was originally
>> intended to.
>>
>> Merry Christmas,
>> Ken Phillips
> Fitted it today, the old one fell apart when I removed it. The plastic
> body had become very soft and brittle. Total cost 18.89 GBP. and about
> half an hour.
>
> Steve H
>
>
>


I think I'll replace mine as a preventative measure, I don't like having
something as vital as engine coolant circulating through anything made
of plastic. It all becomes brittle and fails eventually, and unlike
metal, when plastic fails, it fails catastrophically.

>>
> Glad the replacement went well, just out of interest how much coolant
> did you loose? I often wonder how many times that a failure of this
> valve has actually killed the engine by unnoticed or otherwise overheating.
> I once got an entire 740 turbo sedan, from a scrap dealer for 50 GBP,
> got all sorts off it before taking it back for crushing, including the
> entire heating system (to upgrade my manual gle estate), the gearbox
> (auto, now dead, my fault, oops! So cars a manual again lol), the
> steering rack (still working very well, the 100A alternator (still
> working and bloody brilliant!), the electric seats, etc. ......,
> however, the only thing I actually found obviously wrong with the car,
> was that wretched valve!
> Split open, obviously, the car had bled all it's coolant.
> Whatever possessed them to make it out of plastic? The earlier
> thermostatic ones in the 84ish 240's were metal, so why not now? It's
> almost as if some apparently insignificant parts are designed to fail,
> with catastrophic results.
>
> Happy new year! Don't waste that leap second.
> TTFN,
> Ken Phillips


Yeesh, converted *to* an automatic? If only you saw all the effort I've
gone through to replace several perfectly working (and a couple wonky)
auto boxes with manual! Fuel economy improvement of several mpg alone
makes the job worthwhile, even if the manual wasn't so much nicer to drive.

Ken Phillips wrote:

>>
> Glad the replacement went well, just out of interest how much coolant
> did you loose? I often wonder how many times that a failure of this
> valve has actually killed the engine by unnoticed or otherwise overheating.
> I once got an entire 740 turbo sedan, from a scrap dealer for 50 GBP,
> got all sorts off it before taking it back for crushing, including the
> entire heating system (to upgrade my manual gle estate), the gearbox
> (auto, now dead, my fault, oops! So cars a manual again lol), the
> steering rack (still working very well, the 100A alternator (still
> working and bloody brilliant!), the electric seats, etc. ......,
> however, the only thing I actually found obviously wrong with the car,
> was that wretched valve!
> Split open, obviously, the car had bled all it's coolant.
> Whatever possessed them to make it out of plastic? The earlier
> thermostatic ones in the 84ish 240's were metal, so why not now? It's
> almost as if some apparently insignificant parts are designed to fail,
> with catastrophic results.
>
> Happy new year! Don't waste that leap second.
> TTFN,
> Ken Phillips

I don't think it ever ran dry, I noticed the coolant level was low when
I topped up the windscreen washers. The heater never failed to work and
I kept it toped up but if the failure had happened in the summer then i
think it would have damaged the engine. The new valve is plastic and a
made in Sweden pattern part but looks to be a lot stronger than the
original. The car is 18 years old next week so probably past the end of
it's design life but still going strong after 2 years of daily use, I've
done 37,000 miles in it and it only cost me 245.00 GBP, over here in
England second hand cars are very cheap.

Steve H