Help. Driving son to indoor baseball practice this evening and high engine temp warning indicator comes up on screen. I am close enough to practice when warning comes up that I am not concerned. I let car cool (easy 26 degrees F) and I check coolant level (which is full). Driving home same problem happens, and I notice that I have no heat in the car. I stop 2x turn the car off and turn on the residual heater (or whatever its called) and still no heat, just cold air. I limp home and now car is in garage with hood up (no evidence of fluid outside of radiator or overflow. Electric fan was on for 5 minutes and is now off.

Car has 94K and has been really trouble free.

My nickel diagnosis, my thermostat needs replaced. I hope and pray nothing else serious is wrong. Won't be able to take it some place to check it out until AM.

EDIT: I just did some digging on the forums. It seems I am not alone. Hadn't figured on the water pump being an issue, but that makes sense.

Thoughts / opinions?

 

You got it. Thermostat/water pump replacement time. Dealer will run you about a grand...Indy $700 or so and $500ish if you DIY (so I'm told anyway).

 

I agree - most likely the water pump or thermostat (frozen closed). Assume you have listened under the hood for noise coming from the pump (failing bearings) and have felt the hoses to see if water is flowing from the pump and if so if water is flowing through the thermostat after operating temperature is reached.

I would caution you to not operate the vehicle, even with cool down intervals as you run the risk of warping the head or destroying gasket integrity, which will be far more expensive than towing the car (if you are not going to do the work yourself). Aluminum engines have no tolerance for overheating.

 

OP, keep your fingers crossed that you haven't caused the damage noted by BimmerFan52. Considering you continued driving when the overheat warning came up, I wouldn't be surprised.

 

sounds like water pump failure. avoid driving it when hit gets hot.

 

At these prices even for a DIY better you know for sure what needs replacing. A friend of mine had the overheat on his 530 mainly in traffic and he changed a sensor on the side of the radiator and told me it was all good now. That was until two days later and the problem repeated. He took it to a indy shop and they determined it was another sensor that was up near the fire wall windshield area. It was replaced and it's now been almost a year with no over heats. Maybe se if there are any stored codes first unless you just have a lot of money and time to throw at your car. But on the other hand, your mileage is getting to that point where the pump and thermostat is probably gonna need changing. If mine doesn't go by 100,000 I will be changing it anyway.

 

Following up, it was the water pump and I had the thermostat replaced on an abundance of caution. Knock on wood, all seems to be going swimmingly.

 

Glad it worked out for you, hope all is well now. You shouldn't have to worry about other "damage" since the car didn't actually overheat (steam pouring from under the hood, engine stops running, etc). I hope you got the replacement for ECS Tuning, I will be using theirs when it's my turn. I like that they use a metal impeller instead of the OEM plastic one. Plus theirs is about $350 as opposed to the dealer or other source.
From your first description it sounded like a water pump, if you ever run a high temp and the coolant is full and it's not overheating it's pretty safe to assume the water pump is no longer pumping water.

 

Guys,
First time posting on here. I have a 2004 545i with 100K miles. The low coolant light came on the other day, and I took it to BMW dealership. This is what they said was wrong:
secondary y-pipes ($105)
coolant center pipe unit ($1600)
valley pan ($125)
intake gaskets
water pump ($400)

for a total repair of 4200 with labor. car is running fine and I was surprised to see this costing this much. does this sound accurate? Any help would be much appreciated.

 

Sounds accurate at dealer prices, but remember, they will rape you if given the chance. I'd look for the parts online (ecstuning.com and getbmwparts.com are 2 good options). Then either research the DIYs here and tackle it yourself, or find a trusted indy shop in your area and get the work done for about half the dealer labor rates.