Mk3 Cavalier Owners Club | Vauxhall Cavalier Dot Com

My coolant level light has decided to come on and my car gets hot (on the temperature gauge) quickly so I drive round with the heater set to hot all the time....However, the coolant level sensor has been disconnected for months so what would cause this?
I'm presuming the sensor is on the top of the filler bottle cap as I have a connection there
I'm getting ready to give up and go back to VW as I've had nothing but trouble with this car since buying it

It's a 2.0 ecotech

Ah - I have seen this before where the alternator has started to go wonky.

Possibly over charging.

I am sure that was on a diesel with check control.

Does the car acually overheat, or is it just an indication of over-heating?

Possible alternator or voltage regulator issue.

I would get the alternator checked out.

Cheers
The temperature gauge goes right up and the heater starts blowing hotter than normal to the point where it's unbearable
I've had no steam coming from anywhere to suggest overheating
Head gasket was replaced and head skimmed in February if that would affect it any way

If you are still in a position where you can return the car, then I would threaten the dealer with this.
Hopefully they will have another look in an attempt to sort the problem, rather than give you your money back in return for getting a "lemon" back on their forecourt.

Was a private sale unfortunately

Ah - I misunderstood you as it suggests you got it from VW.

No I used to have VW cars then came over to Vauxhall

Okay...
Lets wind this back a bit.

The car gauge says it is getting too hot
The air coming through the heater is also too hot.

This implies that the coolant is indeed getting very hot.
Potentially too hot.

The garage has done the head gasket.
Did they also check for cracked cylinder bores?

Is the level of coolant in the header tank going down over time?
If it is, then you are still losing coolant.

Possible losses could be via the radiator, one of the many hoses, the heater matrix or an internal crack in the engine block.

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Firstly I think the following is unrelated to your hot engine situation.

Coolant level switch wires. Have you insulated the plug ends to prevent shorting to each other or from touching the metal work.

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If the instrument check control lights are coming on when they shouldn't... again possibly an alternator over voltage situation.

Head and engine were all checked, skimmed, pressure tested etc as and where needed.
I'm not losing any fluids and the wires have been insulated with tape..I have checked them again today in case it had split or come off.

Yes the gauge is reading maximum until I start moving again (only goes right up if standing in traffic) then drops back down to 90 - 100 degrees

The car itself runs fine and the engine sounds fine

It could be a duff gauge sender then.

Well I have no idea why the level sensor had been disconnected and bypassed as my mechanic popped round this morning to look at another issue I had and checked this while he was here.
After reconnecting it and testing it with various meters or whatever he used (I have no idea) the light went out and it works perfectly
The only thing he could come up with was that the previous owner disconnected it to hide the water loss due to blown head gasket while he was selling it