1.9DG... Interesting Tem Scenario.

[ozman]

Evening all,

Interesting scenario for you WBX boffins...

1984 1.9DG...

Replaced Waterpump
Replaced Temp Sender
Replaced Thermostat
Flushed Coolant
Added extra Temp Gauge Inline after Thermostat Housing in Waterpipe.

Now...

Guage now idles round middle (used to be on the line 1/3rd up)
New Guage Shows 90 degs on idle, but dash guage is bang on middle... New Guage went up to 95 when stationary after hill climb.
Rad fans did not kick in at all.
Fuse for fans still ok.

Suspect

Fan switch is dead allowing coolant to heat up too much. But odd that dash guage is happy...

Thoughts?

[Mocki]

You do realise that the engine temp has no direct connection to the rad fan , the rad fan only switches on when the temp of the coolant reaches the trigger point actually in the rad , so the rad is 8 or 9 litres behind the engine

[ozman]

Hi Steve.

Yes. What's confusing is the coolant temp in the engine bay being at 96 and the fan at the front switching on. As I understand it, the fan should come on at 85... Surely there can't be a drop of circa 10 between coolant in the pay and the rad in the front?.

[Aidan]

If thermostat is closed then coolant isn't really circulating between the rad and the engine
just because you have replaced the thermostat doesn't mean it is working correctly, so at idle temp creeping up in the engine isn't odd, it will only drop once the thermostat opens and you circulate some coolant, with a little revs. What was the temp spec of the thermostat ?
The gauge was under reading previously, now it reads correctly, could just be corrosion on the contact(s) or poor earth that was causing the low reading, changing the sender may have cured that

[keynsham1]

After replacing the sender I wouldn't expect the gauge to read the same. They are inherently inaccurate which is why most cars don't have numbers on the tem gauge but just colour or width bands. It is more important that is always returns to the same place and is consistent!

[ozman]

Thanks both. Dash seems to be fine.

Just the reading over 90degs on the additional temp guage which caused me concern.

I need to run it up till the fans kick in or short it to check out it's still working