Overheated - panic stations?
 

My 1.8t ZT got a little warm on Sunday afternoon during a drive back from a hospital appointment. The temp gauge blipped into the red, the warning flashed up for a second and then immediately went back to normal.

I’ve not been well so only had the chance to check on things properly this afternoon. Oil levels seem fine, but coolant levels were way down. I’ve filled that up and will see if it goes down again.

There’s no sign of the dreaded mayonnaise, but I know that’s not the be all and end all of HGF diagnosis.

Is it likely the cold snap and fast thaw we experienced this last week could have caused a leak somewhere? Or is this just wishful thinking? The only other symptoms I’ve had are the heating taking a while to kick in, but I put that down to the weather.

What other checks and precautions should I take? I’m just looking for advice and reassurance really.

My 1.8 n/a overheated once due to low coolant but after a quick garage stop & top-up there were no further issues.

Do the "demist test" Tom to check that your fan is working on slow speed.

1. Start the engine from cold.
2. Press the windscreen demist button on the air con./heater control panel.
3. Get out of the car and walk to the radiator grille.
4. Can you hear the fan running continuously?

Simon

Yeah the fan seems to be working ok. I decided to drive it to the shop and back this morning, (only around a mile or so.) Didn’t skip a beat, and there was no issue with temperature.

It’s lost all the coolant I stuck in it yesterday though, so there’s an issue somewhere within the coolant system I’m guessing? Any suggestions on what to look at next?

It sounds like a coolant loss issue to me - when the level is low, the heaters will feel 'lukewarm' as they're quite high up in the coolant circuit.

A good place to start with a 1.8 (assuming you have the plastic inlet manifold) is the inlet manifold gasket - these go hard with age and start to leak.
Sometimes they leak into cylinder 1, so there's no external indication you're losing coolant!
We have the revised Viton gasket designed to last a lot longer here: https://www.dmgrs.co.uk/products/k-s...sket-lkj101110

Another source of coolant loss is the O Rings in the coolant cap; they flatten with age, allowing steam to escape at higher pressures when on the move.
Again, hard to spot as the loss is often gradual.
You can get replacements here: https://www.dmgrs.co.uk/products/rov...to-fix-esr1480

These issues probably account for a good 50% of K Series coolant loss episodes we're asked to help diagnose these days - very common, but thankfully both relatively simple repairs. :)

Activate the instrument pack diagnostics, test 7.0, to monitor the actual coolant temperature whilst driving. It should rise to the low nineties and stabilise there unless you're stationary in traffic. In that event it will creep up to 104˚ when the fan should bring it down.

I need to ask whether anyone's been working on the cooling system recently or whether K-Seal has been put in to the cooling system.

Simon

Not to my knowledge. I’ve had the car for about 18 months, and was told it had already had the head gasket done previously. So I’m hoping it’s not that again.

How do I activate the instrument pack diagnosis?

See "How to use diagnostic mode" here. You want test 7.0.

Simon

Thanks will top it off and take it for a spin tomorrow and see how it gets on.

Thanks will look into this too.