Z3 Newby - overheating issue

[HunterZ3]

Good evening,

I have just bought a 2002 1.9l 8v Z3 (66k miles) and I’m having some issues with overheating. After around 15 minutes of fairly standard driving the temperature gauge continues to rise until eventually triggering the red light. When I stop and take a look under the bonnet, everything appears normal and does not feel particularly hot (the bonnet is cold to touch). The only thing that seems to sort the issue is turning on the interior heater full blast.

I have tried bleeding the coolant system (without raising the front), this doesn’t seem to have made any difference.

Does anybody have any ideas on what could help?

Thanks in advance

 

[t-tony]

Best guess would be thermostat not opening, or not opening fully allowing coolant to circulate. This can be isolated by removing the thermostat. Next possibility is water pump impeller come off the shaft so not pumping coolant round the engine.

Tony.

ps. Welcome to the forum. Where are you located please?

 

[HunterZ3]

Thanks Tony, I’ll take a look at those. I’m from London !

Out of interest, do you know how turning on the heater rectifies the temperature issue ? (It seems to go from red light to 12 o’clock position within around 30 seconds once the heating is on!)

 

[Synclare]

Is your electric cooling fan cutting in? The temp switch is on the side of the rad near the top (drivers side). Has two speed settings.

 

[HunterZ3]

Hi Synclare, yes the fan seems to be cutting in as normal

 

[t-tony]

Turning on the heat inside the car simply looses heat from the cooling system and lowers the temp.

Tony.

 

[Shelly]

 

[Keet]

I'd agree that the most likely cause will be the thermostat,and welcome to the forum

 

[Nodzed]

 

[Slam]

Hi and welcome from London

 

[Jack Ratt]

Hi Hunter welcome to the forum. I'd go for waterpump and thermostat too. Is your coolant level constant with no leaks? Chances are your water pump and thermostat are the ones the car was born with and are now approaching 20yrs old so they are due for changing. A low mileage car does not preclude it from normal age/wear and tear issues.

 

[PHILIP BAXTER]

Hi, and welcome from me in Cardiff.

 

[Mazza]

Hi and welcome to the forum from Bognor Regis

well worth changing both thermostat and water pump and ensure system is purged of air.

 

[andyglym]

to the forum from West Cumbria.

 

[Mint]

Hi @HunterZ3, to the forum from me too in Staffordshire. Yep I agree, sounds like a thermostat issue, but may as well change the water pump while you are there