Overheating problems 2003 BMW 325i

[jovanni]

I have a 2003 BMW 325i and i just started to have overheating problems. I took my car out and it warmed up just fine but then the indicator was saying my car was over heating and it was in the red side of the indicator. Im not sure why it could be indicating this i have some ideas but im not sure. i might need a new cooling sonsor, a new thermostat, or a new Auxiliary fan for the car. i say the fan because i turned on the car on when warming it up and it would turn on and off i have no idea if this fan is suppose to be running constantly or on and off. please help me solve this my car has been unable to be driven due to this problem.

[02Pilot]

Regardless of mileage, at 14 years old the entire cooling system should be replaced; it's generally considered to have a 100k mile lifespan. There are any number of things that may have failed. The larger problem you may face is that, if the engine sat in the red zone for more than a few seconds, it's very possible you have compromised the head gasket, the head, or indeed the head bolt threads in the block.

Warming up the car for any length of time more than a minute or so is not necessary or even a good idea, and if you insist on doing so, you should not leave it unattended.

[jclausen]

Before you replace anything find out what happened, also the front part of the cooling system is more prone to failure water pump, expansion tank & mounting plate, thermostat, fan clutch, radiator, hoses to radiator and expansion tank. Plus once you find out what happened, you could fix just that and run the engine to see if there is any engine damage from the overheating, before dumping a bunch of money in a complete coolant system replacement.

[bmwdirtracer]

Yeah, um, there's not enough information here. I agree completely with O2Pilot: the entire cooling system needs to be replaced, except for the heater core. jclausen's an excellent pro, and I agree with his statement, too.....we're talking about a difference of maybe 2 water pipes and a couple of heater hoses, so the two are not far apart.

In order to determine just how much is destroyed, you need to make the cooling system intact, and I think maybe that's the point jclausen is making. When the system is intact, and holds pressure and vacuum, and is vacuum-bled....THEN you can determine whether the cylinder head and head bolt threads in the engine block are compromised, via a leak down test, engine hot.

If the engine gets hot after replacing the water oump, thermostat, any component that's leaking....and IF the fan(s) are correctly working, well, there's a good chance you need an engine, or extensive rebuilding work.

You absolutely MUST have the car at a BMW specialist professional. If you take the car to a generic shop, YOU LOSE..

Um, we do need to know whether the car is manual or automatic, by the way. One has a fan clutch, one doesn't.