Coolant temperature - Golf Mk2

[Tod]

1989 Golf Mk2 1600 EZ auto.
I think my engine is running too cool. Temp gauge has no numbers but never
goes beyond first division (ie quarter way through 'normal' range, beyond
the 'cold' band, of course.)
Today I tried a piece of cardboard covering 2/3 of the radiator and now I
get half-way across the temperature range.
I'd like to calibrate the dashboard temp gauge.
- Where and how can I measure the temp of the coolant with a thermometer?
- What is a good running temperature?
- Perhaps the thermostat is worn out. (I thought the water-pump thermostat
was only for the first few miles of a journey and that for the rest of the
journey it was just fully open. Is this wrong? Does it actively regulate the
flow throughout the whole journey?)
(The radiator fan is fully functional, but hardly ever has to come on.)

Cheers,
Tod

[Chris Bartram]

Post by Tod
1989 Golf Mk2 1600 EZ auto.
I think my engine is running too cool. Temp gauge has no numbers but never
goes beyond first division (ie quarter way through 'normal' range, beyond
the 'cold' band, of course.)
Today I tried a piece of cardboard covering 2/3 of the radiator and now I
get half-way across the temperature range.
I'd like to calibrate the dashboard temp gauge.
- Where and how can I measure the temp of the coolant with a thermometer?

You could beg/boorow/steal one of those fancy infra-red ones (I think
machine mart sell them) and point it at the rad perhaps.

Post by Tod
- What is a good running temperature?

90 deg C ish, probably

Post by Tod
- Perhaps the thermostat is worn out. (I thought the water-pump thermostat
was only for the first few miles of a journey and that for the rest of the
journey it was just fully open. Is this wrong? Does it actively regulate the
flow throughout the whole journey?)

I'd say the thermostat is knackered. I used to think the same, but years
ago I ran a mk1 without a thermostat for a while (after it seized
closed) and I round that I had to pull the choke back out if I was
cruising, as the engine got cold again and din't idle well. Replacing
the stat cured it. They are very cheap and should be quite easy to
replace, so I wouldn't even think about mucking about with the
thermometer. Just replace it. Do you know for definite there's one fitted?

Post by Tod
(The radiator fan is fully functional, but hardly ever has to come on.)

I'm not surprised.

Post by Tod
Cheers,
Tod

[Iain Miller]

Post by Tod
1989 Golf Mk2 1600 EZ auto.
I think my engine is running too cool. Temp gauge has no numbers but never
goes beyond first division (ie quarter way through 'normal' range, beyond
the 'cold' band, of course.)
Today I tried a piece of cardboard covering 2/3 of the radiator and now I
get half-way across the temperature range.
I'd like to calibrate the dashboard temp gauge.
- Where and how can I measure the temp of the coolant with a thermometer?
- What is a good running temperature?
- Perhaps the thermostat is worn out. (I thought the water-pump thermostat
was only for the first few miles of a journey and that for the rest of the
journey it was just fully open. Is this wrong? Does it actively regulate the
flow throughout the whole journey?)
(The radiator fan is fully functional, but hardly ever has to come on.)

Sounds like a knackered thermostat - the return spring gets old & lazy & so
they stay open further than they should.

To test start the car and let it sit at idle until the temp guage comes up
to somewhere near the middle. You can rev it to 2-3000 to speed this process
up a bit. Then take it for a drive down the nearest bit of freeway at a
reasonably constant speed - i.e. go fairly quickly but don't work the thing
too hard. If the temp starts to drop back its the Thermostat - it might take
a few miles to start dropping. Temperature senders don't last forever
either - they get lazy & slugish so you might look at replacing that as
well.

rgds

I.

[phk]

Post by Tod
1989 Golf Mk2 1600 EZ auto.
I think my engine is running too cool. Temp gauge has no numbers but never
goes beyond first division (ie quarter way through 'normal' range, beyond
the 'cold' band, of course.)

Are you freezing when driving in city trafic? If you are itŽs the
thermostat. Buy a Winter thermostat, itŽs marked about 3 degrees Centigrades
higher than the Summer ditto ....

I can tell you, 3 degrees makes a hell of a difference and the Winter
thermostat is no problem not even in Italy (been there done that with Golf
and Mondeo).

[Tod]

Thanks for advice.
I changed the thermostat yesterday. (The job would have been very easy if I
didn't have power-steering!) Both valves were stamped with "87 degrees".
Now the temp settles to just below half-way on the gauge. Engine seems
quieter and more powerful. A successful job!

Tod

[Dave Hall]

I thought the ease was being overstated, having checked the thermostat when
changing the water pump on our power steering Mk 2. It seemed far from
accessible to me. That explains it.
--
Dave.
UK VW Type 3 & 4 Club
http://www.hallvw.clara.co.uk/
------

Post by Tod
Thanks for advice.
I changed the thermostat yesterday. (The job would have been very easy if I
didn't have power-steering!) Both valves were stamped with "87 degrees".
Now the temp settles to just below half-way on the gauge. Engine seems
quieter and more powerful. A successful job!
Tod