Overcooling? Where does your temp gauge sit?

[lnparry]

Hi everyone and seasons greetings.

Query on my '97, 945 SE, LPT.

Back in the summer I had my local independent garage fit new water pump and aux drive belts plus timing belt, idler and various front engine seals using genuine Volvo parts. Everything was fine and the temperature gauge continued to sit about 60% of the way between the "C" and "H" marks once warmed up.

Now that winter is here I find that when cruising the gauge typically sits about 40% of the way between C and H and the heater is not as hot as it was. If I dawdle in traffic the gauge will creep up to the 60% mark again and if I sit stationary for long enough the electric fan will kick in to maintain the correct temperature.

I'm wondering if the cooling system is now more efficient with the new pump and the engine is being overcooled in the winter. I can remember a time when people used to mask off part of the front grill in the winter and wonder if I should experiment with this?

Would appreciate any thoughts especially from even colder parts of the world than Surrey!

Cheers,
LeeP

[griston64]

Mine sits bang in middle all year round

[griston64]

Originally Posted by griston64

Mine sits bang in middle all year round

In Glasgow

[nutco]

Mine moved around a bit a few years ago then somehow the top of the temp sender unit got broken off, I fitted a new temp sender unit and since then mine stays near enough in the middle all year round, I cant remember the temp from the heater in the car changing much tho

[Dippydog]

On both my 960 and V70[both n/a engines] the gauge sits just a gnats past half way no matter what[unless I stand in traffic for quite a while in which case they go up slightly until the fan kicks in to help out] I'd suggest that the thermostat is getting lazy.

[omc 47]

Having had 940's for many years they've always read bang upright on the Temp gauge....................until the one l bought this Spring which was always @ 11 o' clock.
Winter came and heater was luke warm so......changed the stat and back to Normal literally.
But be aware the stat housing is cast alloy and due to studs being quite small you may need to spray them and be gentle taking the housing off as electrolasis can set in (reaction between studs and alloy)

[Laird Scooby]

It seems the only thing your garage didn't change was the thermostat!

That's almost certainly where your problem lies and it should get up to temperature within about 5 minutes (10 at a push) if the 'stat is ok.

Once up to temperature, it should, as all others (except the one with the broken sensor) have said, sit more or less bang upright, no matter what. If you get stuck in traffic, it might go up a little until the fan cuts in (if you have an electric one) but shouldn't drop below halfway.

Why did you have a new water pump fitted? Was it overheating by any chance, particularly when you got up to motorway speeds? I'm wondering if the radiator needs a good back flush and the rest of the system too.

One last thought - the garage didn't use that horrible red OAT antifreeze did they?

[loki_the_glt]

The Valdez's gauge sits bolt-upright, sometimes even when the car's been sitting for a few days without being used!

[lnparry]

Thanks everyone - looks like I need to add a thermostat to my to-do list. I'm just surprised it didn't show up as a problem in the summer as I presumed a dodgy 'stat would have lead to overheating rather than over-cooling?

Agree with OMC 47's point as have had problems with other cars in this area previously.

To answer Dave's points; I had a leak from either the rear gasket or gland on the old (original) pump. No overheating but as the timing belt was way past its sell buy date and I had a leak from the front camshaft seal, decided to have the front end of the motor all sorted. Plain "blue-green" antifreeze not OAT.

Cheers,
LeeP

[kelvinp]

Originally Posted by Laird Scooby

It seems the only thing your garage didn't change was the thermostat!

That's almost certainly where your problem lies and it should get up to temperature within about 5 minutes (10 at a push) if the 'stat is ok.

I had the same problem a while back with my 740. Temperature gauge would sit quite happily at 12 o'clock around town but on faster runs down the motorway or dual carriage way it would drop down to near C.

I took the thermostat out and stuck it in a saucepan and tested it and found that it was sticking slightly open, so that was probably why it was cooling down on faster runs.

Fitted a nice, new 92 degree stat and has been good as gold ever since. Temperature gauge sits at 12 o'clock under all conditions.