Engine Tempreture Issue (z18xer engine)

[SteB13]

Hi guys.
Posted a while back that my temp gauge was reading 0, heaters where cold also. When in traffic the gauge will begin to increase to 90, however will revert back to 0.
Changed the thermostat and housing and I am still getting same problems.
Any ideas what's happening? Thanks.

[triple595]

when mine did that i changed the sat and housing which cured it

[disco dan]

have you tried changing the two sensors ?

[SteB13]

I haven't changed any mate no, which sensors are they?

[byebyeitsagsi]

Did you fit a brand new thermostat etc?

[rich r]

It's unlikely to be the thermostat - that has nothing to do with the gauge. Even if it's stuck open, the engine will still increase in temperature higher than the point at which the gauge starts moving with the car not moving. If it's stuck closed, it'll increase too but there's a risk of the engine overheating as the coolant will never go through the radiator.

More likely is a fault with the electrical sensors that drive the gauge.

[disco dan]

There's two sensors around the thermo housing, or their is on my one. I had similar syptoms to you, I replaced the thermostat, which comes a complete housing, with a sensor attached, at the cost of nearly 80 quid, partco couldn't get in so had to go to VX.

[disco dan]

It's unlikely to be the thermostat - that has nothing to do with the gauge. Even if it's stuck open, the engine will still increase in temperature higher than the point at which the gauge starts moving with the car not moving. If it's stuck closed, it'll increase too but there's a risk of the engine overheating as the coolant will never go through the radiator.

More likely is a fault with the electrical sensors that drive the gauge.

Doubt it would be just sensors to blame, ie blowing cold air.

[rich r]

Doh - missed that bit

Maybe air trapped round the thermostat and sensors?

Either way, I'd take the sensors out and test them (resistance range on a multimeter. See if the resistance changes when put in a cup of boiling water), and flush the cooling system again.

[eeyore]

Hi -

Thought I'd jump on the back of this post rather than starting a new one, as I have something similar...

1.9 CDTi 120 (pre-facelift '05)

My temp. gauge almost NEVER moves off zero, despite the length of journey (did 100 miles last night, with it sat on 0 apart from an occasional feeble movement up to maybe 40 degrees, then back down again).

Put the BC in to Testmode last night and kept an eye on the coolant temperature reported in there... which I assume is fed by the same sensors that drive the dash gauge... and it was running at 65 - 70 degrees, occasionally up to 80, which feels on the low side of normal I guess... but certainly more than reported on the gauge (zero!).

I noticed that, at anything below 70 degrees (as reported in the BC), the dash gauge was at flat zero, but even 71 degrees (reported in BC) would move the dash gauge up a bit !. I sat in a layby and cooked it, got it up to 80 degrees (BC) - and lo and behold, the dash gauge was also reading 80 degrees !.

I started to suspect simply a faulty dash gauge.. but the air from the heater is not nearly as hot as I'd expect, either. Have checked coolant levels etc and no problems there..

Any ideas please folks ?

Cheers -

Chris.