Series 2 cooling system

[LMF]

Hello, hoping someone can advise, I bought a series 2 earlier this year and noticed the rad fans on all the time and the temp gauge barely moving when the car was warmed up. Had a thermostat fitted to the fans but still the temp gauge barely moves and also no hot air coming though the heater which makes me think the cooling thermostat is stuck open rather than a faulty gauge.
Hoping someone else might have any other ideas and if it looks like the thermostat needs changing how big a job is it?
thanks in advance

Mark

[politeperson]

Do the fans come on immediately when you start the car?

If so it sounds like a faulty or a by-passed sender unit on the radiator.

Have you an airlock on the cooling system?

Have you a low coolant level?

Is you coolant circulating?

Is the temp gauges receiving the correct voltage supply from the voltage regulator? Are the other gauges wrong.

Before startup, squeeze the top hose, it should feel full of water-not air! Check your water level at the radiator, should be at the top of the fins. Unscrew the cap and have a look. The rad cap has no spring, the expansion bottle does.

When the thermostat opens, water will quickly circulate through the radiator if it is not clogged. Feel this temperature change with your hands.

If the water pump is defective (no impeller), you may be getting no water circulation. I have seen this on stood XK engines.

When the system is operating correctly, water should also be circulating around the heater matrix. Check the valve on the bulkhead is opening and feel the temperature oF the 2 hoses going in and out of the heater box. They should be hot after a few minutes.

If you have hot water circulating, that is the important thing.

If you need to change the thermo switch, Fossway do a reliable one.

Changing the thermostat is pretty easy, takes about half an hour.

[LMF]

HI James

Thanks for your reply.

To answer your first question the fans did use to come on straight away and that's why i had a thermostat fitted.

I will do as you suggest re the other checks.

Thanks again


Mark

[cactusman]

Wise words above and important to make sure the cooling system is working. If you have not yet done so I would drain, flush and refill too. Use glycol based antifreeze. If what comes.out is brown and very sludgy you may also have silt build up in the radiator. Worth removing it and flushing through separately. If the gauge does not work, as mentioned...the instrument voltage regulator may be faulty although if dead the fuel gauge will be too. It should produce 10 volts. Due to the way it works a modern digital meter will probably dance about randomly. Use an old analogue instrument...an avo meter being the rolls Royce of such devices

[politeperson]

What I mean Mark is, do the fans come on straight away?

ie Do they come on when the ignition is on and the engine isn't running? ie when the engine is cold.

This means a wiring issue.

James

[LMF]

Hi James

yes they used to come on when the ignition came on but I've sorted that now.

Thanks

Mark

[drcarrera]

Hi James

yes they used to come on when the ignition came on but I've sorted that now.

Thanks

Mark

Hi Mark

Can I ask what you did to resolve this? Just taken mine out prior to a run and the fans came on immediately - never had the problem before. Presumably it's a faulty radiator switch but was just wondering what you found with yours.

[LMF]

Hi Chris

yes it was a faulty switch, pretty easy to replace

Regards

Mark

[drcarrera]

OK, thanks. Just ordered a new one. I guess it's better to have the fans running constantly than not at all!