Car is UNDERheating , temperature gauge reading stays very low, why ?

[Rightboy91]

Urgh! You don’t know what’s been going on in the passenger seat of that car!

Or simply stuck wide open.

Hi John , I don't think I've seen you here before, nice to meet you. Please ignore the trolls, I do although it's not always easy they will soon realise they are not getting fed and move along.

So can thermostat s suddenly become stuck open or whatever ? It only started happening about a week ago , after replacing the cooling pipe everything was ok for the next 2 weeks, no dodgy thermostat readings or engine Undercooling etc..

Could it be because it just has tap water in it ATM ? ( I have actual coolant here for it I was waiting to obtain new radiatior plug which I now have for it )
Could it be anything tondo with changing that cooling pipe about 3 weeks ago ? ( Although everything was fine with the temperature readings 2 weeks after fitting it,. Thanks

 

[Rightboy91]

Urgh! You don’t know what’s been going on in the passenger seat of that car!

Or simply stuck wide open.

Hi John , I don't think I've seen you here before, nice to meet you. Please ignore the trolls, I do although it's not always easy they will soon realise they are not getting fed and move along.

So can thermostat s suddenly become stuck open or whatever ? It only started happening about a week ago , after replacing the cooling pipe everything was ok for the next 2 weeks, no dodgy thermostat readings or engine Undercooling etc..

Could it be because it just has tap water in it ATM ? ( I have actual coolant here for it I was waiting to obtain new radiatior plug which I now have for it )
Could it be anything tondo with changing that cooling pipe about 3 weeks ago ? ( Although everything was fine with the temperature readings 2 weeks after fitting it,. Thanks

 

[Rightboy91]

no it wouldn't. There is no hole for it to pour out of. It would be circulating very freely, losing more heat than usual to the radiator, so would not get up to normal running temperature quickly, if at all, now the weather is getting cold.

There is a a big coolant hose that goes onto the thermostat so if the thermostat was not present then water would be pouring out of the cooling hose as nothing will be connected to it

 

[JohnD]

if the thermostat was not present then water would be pouring out of the cooling hose as nothing will be connected to it

Have you disconnect the hose from the radiator and/or cylinder head and/or water pump?

If not, water will not pour out of it.

The thermostat is inside a sealed housing. You can't see it until you take the housing off.

 

[Rightboy91]

Have you disconnect the hose from the radiator and/or cylinder head and/or water pump?

If not, water will not pour out of it.

The thermostat is inside a sealed housing. You can't see it until you take the housing off.

I was replacing the long front metal cooling pipe about 3 weeks ago to upgrade the pipe to stainless steel. Everything was ok 2 weeks later temp gauge was all working fine etc up until about a week ago.

I understand what he meant now, I was muddled up thinking he meant removing the thermostat housing, of course the thermostat is inside of that. The thermostat is present because I haven't removed it

 

[johnny2007]

The engine not reaching operating temperature should be the last of your worries.
Did you fix the brakes or did you fit a crucifix on the dashboard so to pray every time you need to press the brake pedal?
Anyhow, as already mentioned, you need a new thermostat and as you're there, use coolant on the correct concentration, not tap water.

 

[HERTS P&D]

This 'car' is a death trap!

Andy

 

[Burnerman]

Hi John, thanks for this.

So would a stuck thermostat cause not only the temperature gauge to barely move but also cause the entire engine to remain very cool even after long journeys ? It doesn't even get hot to the touch.

2 - could it be an airlock or anything to do with me changing the long metal cooling pipe a few weeks previously ? The thing is ,the temperature gauge was working fine 2 weeks after changing the pipe up until about a week ago.

3 - what did you mean by asking if the thermostat is still present ? If not the water would be pouring out of the engine and the car would be out of water within a minute

1) Yes - even in full summer the engine would be running too cool.....it needs to run at 90 to 95 degrees C at all times. This minimises pollution and evaporates nasties out of the oil.
2) I very much doubt it - check the heater pipes are getting warm by hand. Air locks occur at the top end of the engine.
3) If the thermostat is stuck open (or someone has left it out on purpose) the engine will over cool. Usually they are at the engine end of that bottom hose unlike early designs where the stat was at the top of the engine. The thermostat is within a plastic housing.
John

 

[Mottie]

Rightboy. As your main concern is that the engine is running too cool, are we to assume that you’ve sorted out the trivial matter of the brake fluid loss?

 

[Rightboy91]

Rightboy. As your main concern is that the engine is running too cool, are we to assume that you’ve sorted out the trivial matter of the brake fluid loss?

did I say I am treating the engine under cooling as the main issue ? No

I told you, I went to kwik fit the guy said leave it with us it will take over an hour for a complete check and take off all the wheels. I walked around town for 2 hours and then went back and the guy said we didn't take wheels off, it is leaking from the brake pipe near fuel tank or something.
I remember asking about this on the forum and you said if it was leaking the pedal would be soft, so I took it to ATS and they had a look and they said they could see no leaks so now I am taking it to a 3rd garage for it to be looked at.
So yes it is still losing brake oil but as you can see I am doing the right thing by getting it looked at and diagnosed.

 

[Rightboy91]

1) Yes - even in full summer the engine would be running too cool.....it needs to run at 90 to 95 degrees C at all times. This minimises pollution and evaporates nasties out of the oil.
2) I very much doubt it - check the heater pipes are getting warm by hand. Air locks occur at the top end of the engine.
3) If the thermostat is stuck open (or someone has left it out on purpose) the engine will over cool. Usually they are at the engine end of that bottom hose unlike early designs where the stat was at the top of the engine. The thermostat is within a plastic housing.
John

Hi

No, as I say the thermostat hasn't been taken out as I haven't removed the thermostat and nobody else has had the car to mess about with. the temperature was all ok up until about a week ago.

 

[HERTS P&D]

Take it to a scrap yard and see what they say.



Andy

 

[Mottie]

Hi

No, as I say the thermostat hasn't been taken out as I haven't removed the thermostat and nobody else has had the car to mess about with. the temperature was all ok up until about a week ago.

Sounds like you have another claim against Kwik-Fit or ATS in the pipeline then.

 

[Harry Bloomfield]

So yes it is still losing brake oil but as you can see I am doing the right thing by getting it looked at and diagnosed.

The point is that with such a dangerous fault, it should not be driven on the road at all, putting yourself and everyone else at risk.

 

[Harry Bloomfield]

Hi

No, as I say the thermostat hasn't been taken out as I haven't removed the thermostat and nobody else has had the car to mess about with. the temperature was all ok up until about a week ago.

When the weather turned really cold!