940 heater cold

940 turbo estate, 95, UK, manual, non-air con

Recently my heater seems to be playing up. It was always a bit crap with it
still not hot when the temp guage is right at the middle, but now its
blatantly cold with the engine warm, moving the heater control up and down
seems to allow it to warm up.

The cooling system was drained when I replaced the heater control valve
during the summer and didn't seem silty, as usual I added anti-freeze.
There is plenty of water.

Is it common for these heaters to not flow very well or get air locks, or is
just a one off blockage somewhere?

 

Make sure that coolant is actually flowing through your new heater
valve. When you have no heat, see if the heater hoses inside the car
are hot to the touch. (I know, easier said than done.) Make sure vacuum
is getting to the heater valve (no vacuum = closed valve), and that the
visible lever is moving. Finally, there is a blend door that controls
the amount of air that goes through the heater core - make sure it's
moving to the right position.

--
Mike F.
Thornhill (near Toronto), Ont.

NOTE: new address!!
Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)

 

Mike, surely on non air-con equipped cars the heater valve is cable operated and
inside the firewall. Not nit picking, just have a 945 with ordinary heating and
cable operated valve.

Cheers, Peter.

: Tony Stanley wrote:
: >
: > 940 turbo estate, 95, UK, manual, non-air con
: >
: > Recently my heater seems to be playing up. It was always a bit crap with it
: > still not hot when the temp guage is right at the middle, but now its
: > blatantly cold with the engine warm, moving the heater control up and down
: > seems to allow it to warm up.
: >
: > The cooling system was drained when I replaced the heater control valve
: > during the summer and didn't seem silty, as usual I added anti-freeze.
: > There is plenty of water.
: >
: > Is it common for these heaters to not flow very well or get air locks, or is
: > just a one off blockage somewhere?
: >
: > --
: > Tony Stanley ++Always Learning++
:
: Make sure that coolant is actually flowing through your new heater
: valve. When you have no heat, see if the heater hoses inside the car
: are hot to the touch. (I know, easier said than done.) Make sure vacuum
: is getting to the heater valve (no vacuum = closed valve), and that the
: visible lever is moving. Finally, there is a blend door that controls
: the amount of air that goes through the heater core - make sure it's
: moving to the right position.
:
: --
: Mike F.
: Thornhill (near Toronto), Ont.
:
: NOTE: new address!!
: Replace tt with t (twice!) and remove parentheses to email me directly.
: (But I check the newsgroup more often than this email address.)

 

Actually you may be right. Over here, all Volvos have had the more
expensive heating system. Even in the few years that 740s came without
A/C as standard, they still had that system, which made adding A/C at
the dealer level possible. I just plain forgot that the rest of the
world had a different system sometimes. I would imagine that system
more or less works the same way (blend door and heater valve).
--
Mike F.
Thornhill (near Toronto), Ont.

NOTE: new address!!
Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)

 

Sure does, but manually operated, the cable operates the door and the valve
together. The valve is first then the rest of the cable goes up to the door.

Cheers, Peter.

: Peter Milnes wrote:
: >
: > Mike, surely on non air-con equipped cars the heater valve is cable operated
and
: > inside the firewall. Not nit picking, just have a 945 with ordinary heating
and
: > cable operated valve.
: >
: > Cheers, Peter.
: >
:
: Actually you may be right. Over here, all Volvos have had the more
: expensive heating system. Even in the few years that 740s came without
: A/C as standard, they still had that system, which made adding A/C at
: the dealer level possible. I just plain forgot that the rest of the
: world had a different system sometimes. I would imagine that system
: more or less works the same way (blend door and heater valve).
: --
: Mike F.
: Thornhill (near Toronto), Ont.
:
: NOTE: new address!!
: Replace tt with t (twice!) and remove parentheses to email me directly.
: (But I check the newsgroup more often than this email address.)

 

It is a manual cable, and I would expect the hoses are cold, I am reasonably
sure the water isn't flowing through. I have monitored it more closely over
the last few days and it is losing water. Possibly the water dropping is
causing a short term airlock.

Anyway my question is now what might be leaking. It is losing about 1.5
litres over a 25m trip, but sometimes loses it overnight. Its strangley
inconsistent and I can't identify the leak. The only thing I can see is a
small damp patch ontop of the join from the exhaust manifold to the turbo
after the engine has been sitting cold overnight. Are there any waterways
in there?

I was worried initially that it was the head gasket, not helped by the
overboost, but there is less evidence of that.

 

Manual cable?? All 700 series cars that I'm aware of use a vacuum operated
heater valve, did they change this on the 900's?

 

Tony

Check the small hoses that feed coolant to the turbo. I had one that leaked
straight down on the turbo, and it being really hot would evaporate the
water instantly. I looked for this one for about a month, and found it by
chance.

Harold

 

There was a different heating system we never saw in North America that
did not have any place to install an evaporator, and so A/C was not
possible in these cars.

--
Mike F.
Thornhill (near Toronto), Ont.

NOTE: new address!!
Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)

 

Generally when coolant disappears it's a problem with the head gasket.
The heater seems to empty first when coolant levels drop.

--
Mike F.
Thornhill (near Toronto), Ont.

NOTE: new address!!
Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)

 

Ah, didn't notice the poster was elsewhere. That always seemed weird to me,
that such stripped down models were available elsewhere than here. As far as
I know, *all* 700 and 900 series cars in North America came from the factory
with power steering, power windows, power locks, air conditioning and heated
seats. Every one that I've ever seen had a sunroof as well, though I've
heard rumors of a few without.

Were some/all of these options over the years in Europe? I'd be curious to
see the statistics.

 

In 1985 all 740s in Canada had manual sunroofs, manual mirrors and no
A/C. In '86 A/C was added. A little later came the power mirrors and
sunroof. In 1990 they started selling lower content plain 740s (no
letters) that had A/C (and sunroof) optional again. All our 740s did
have the vacuum heater system that could have A/C added. We did get
some 240s in '77 and '78 that had a cheaper cable heater system that
didn't have provision for A/C to be added though.

A friend of mine had a 1983 760 GLE without a sunroof, it must have been
a special order, the owner wasn't the first and didn't know the history.

--
Mike F.
Thornhill (near Toronto), Ont.

NOTE: new address!!
Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)

 

I'm actually in N.Ireland which has even more miserable weather than
England. Sunroofs are a pain on older cars I avoid them if possible, they
either jam or leak. My 940s is very leaky, from the drain hoses being not
tight enough to other leaks I can't identify. I consider it a bad feature.
Air con is a bit of a waste here although more cars are appearing with it as
a sales feature. Its nice for about 3 days a year but not essential, the
rest of the time the system is slowly seizing up and alot of cars it just
doesn't work as the owners havn't bother to fix it. I even suffered my
(manual) heater valve that wouldn't turn off fully for a summer.
Temperature varies from occassion below zero, but mostly 3-4C this time of
year to about 25C max in the summer.

I certainly wouldn't call it stripped down, air con is the only difference,
and mostly not justified in this country especially in older cars.

 

Checking again in the daylight (not much at the moment), I definately saw it
comming from the join between the turbo and the exhaust manifold. I'll have
to check now if its dribbling down from somewhere but it did seem to come
from inside. It is a water cooled turbo, Mitsubishi I think from the Haynes
manual and the direction of the wastgate pressure hose connection

There doesn't seem to be a gasket, is this right, could it be dribbling down
inside from the head?

If weather allows I may atempt my first turbo removal at the weekend. Any
advice?

 

No hands dirty this weekend, but a fill up with antfreeze seems to have
stemmed the flow, I guess the increased thickness may help, but yet to see
how it copes with the longer work journey.

 

Water you see coming from between the turbo and exhaust manifold is
generally combustion condensation and is fairly normal. As you suspect,
there is no gasket in this joint.

If this was coolant dribbling down from the head, the head would have to
have a serious crack (very unlikely) in it somewhere, there's no gasket
or seal that could leak coolant anywhere near there.

Broken studs are almost a given around turbos. Heat each nut cherry red
before any attempt at removal. At least on your later style turbo you
can remove the turbo from the manifold without removing the manifold
from the head first. Other than that, it's fairly straightforward.

--
Mike F.
Thornhill (near Toronto), Ont.

NOTE: new address!!
Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)