Coolant Temp Gauge Reading Too Low?

[ian610]

Hi,

I have a Focus mk2 2.0 auto.

I've noticed that the temperature gauge never really gets to the mid point (normal) of the gauge.

The temperature range is 60-120 degrees and the highest it gets to whilst driving is the dash between 60 and 90, so about 75.

If I put the blowers on it can drop lower.

I drove back from work today which was 14 miles and it didn't go above 75 until I got home and parked up idling for a while which then caused it rise to half way (90).

Then if I drive off again it will go back down.

My previous car was a 1.4 mk6 Fiesta which had a digital coolant gauge which always reached 'normal' after about 2 miles.

Also my fuel consumption isn't that good at the moment (averaging 26.5 - 28.5 mpg).

I knew a 2.0 auto would be quite poor on fuel, but I was expecting at least low 30's considering my commute is a reasonable distance.

Could this be caused by the coolant not reaching optimum temperature?

Any help would be much appreciated.

Thanks,

[Dee_82]

Mine only ever goes above the half way mark when its baking hot, an the gauge is always is slightly lower than what is shown via OBD

[GMX]

Foci never seem to get past half way on the temperature gauge, unless you're stuck in gridlock, on a hot and moving terribly slowly in a low gear. It does go down when you put blowers on.

Mine reaches operating temperature with about 4 miles of starting.

When did last change/or have changed the air and fuel filters? My mpg has always been worse than expected in the time leading up to my filter service.

[daryl_hurst]

Sounds like a dodgy thermostat, recently changed mine for an aftermarket one and its doing this so replacing it with an OEM part. Managed to get a refund for the rubbish one.

[Enduser]

Outside temp about +3 to 4, sat in my 1.6TDi with the engine ticking over, to prevent me getting hypothermia whilst waiting for the Misses, and the temperature gauge goes from the usual 90 degrees down to min reading which is 60 degrees. The climate was set to 21 degrees both sides, and the fan was running. The gauge went back to it's normal reading when I drove away.

Question is, why did the gauge go back to it's minimum reading ? None of my previous fords did this.

[artscot79]

its all about how the engine works sitting idling the heater is sucking all the heat from the coolant hence why it goes down you start driving which increases fuel bigger bang more heat engine heats up quicker

also this is how a coolant gauge works so the above post that you changed it for an aftermarket and its still doing it means its working as it should the coolant goes through the engine the thermostat stays closed the coolant bypasses the thermostat and the rad to get the engine up to temp on a cold day below 5 degrees it pretty much stays that way it will open the thermostat qhen up to temp youll see the gauge drop this is overcooling as the air is over cooling the coolant so the thermostat shuts again and the process is repeated using the heater draws heat from the coolant meaning its harder to maintain the temp this has nothing to do with the engine temperature its the coolant temp unless it doesnt move at all or hits red its best left alone many people cause issues by mucking around with the system

[ian610]

Just to update; had a new oem thermostat fitted and this appears to have solved the issue. 

Gets up to temperature now and stays there, regardless of the blowers being on or driving at speed etc. Sits slightly left of the centre line which is miles better than what it was like before. Hopefully this should also add a few more mpg.

Looking at the old thermostat it appears to have failed in a slightly open position which would explain why the needle would barely reach the second dash, if doing NSL.

Thanks again to everyone that contributed on this topic.

[james1089]

Plenty of rubbish thermostats about, Gates are good, should have a small bleed valve in them which needs to face the top. That said I would never change a thermostat without housing on a Focus.