Electrical fault

[sam95wise]

Hi, just purchased a 2001 4 pot z3 with hgf for £500. Previous owner has changed the radiator and water pump ... He's definitely done it himself as I see cable ties holding the rad in. My concern is the sensor cables attaching to the rad he's linked one of the live connections to I am assuming ground and twisted another live onto the connector and plugged in .... What does the rad connect to on terms of electricity? I am an electrician myself however not an automotive one sadly. I do have the fan permanently running maybe this could be it to combat the over heating ?

Sorry for long post I'm just curious to learn how to rectify

 

[Duncodin]

If you have an electric fan then there'd be a thermal switch on the radiator that controls/signals the power to the fan. ie fan runs when radiator is hot.

If your electric fan runs all the time even when cold and you think the wires have been tampered with then it might mean that thermal switch has been bypassed to supply power to the fan.

I don't have an electric fan so i can't look to see how it should be wired.

Assuming you're talking about engine cooling system and not aircon system.

 

[sam95wise]

Yeah talking about the engine cooling system... Definitely been messed with. Just curious as to why that's all ... I'll put back how it was and go from there. Again I am assuming it's been done this way as the heater matrix is blowing cold air into the cab and I have head gasket failure probably giving me the most cooling I could have under the circumstances.

 

[Duncodin]

Z3 often gets an air lock in the heater matrix. People draining and filling coolant but not bleeding. On top of the radiator is a bleed screw. The cold air might just be that. ie nothing to do with the radiator fan.

The reason for bypassing the thermal switch might be just a duff thermal switch.

You're sure there's a head gasket failure? You'd need to fix that first.

 

[sam95wise]

Yeah she goes 15 minutes before over heating... The coolant then starts to bubble at around 20 mins. Slightly milky oil in the rocker. No leaks I'm aware of. Rad has been changed water pump also. Only other option is... I've missed a leak, airlock, or thermostat. Bled the system when I got it. And she did about 15 minutes. Looks as though it's been caught early, engine sounds fine runs very well ( for around 13 minutes).

That's a good point ill check continuity on it.

But yeah I haven't turned the car on since I got it home, I'm just looking around the engine bay discovering bodged attempts at solving the over heating.

 

[Shelly]

 

[Mint]

Hi and to the forum from me too in Stafford. When you bleed the system try raising the front of the car up.