Thermostat went out...should I replace the entire cooling system?
 

Hi everyone,

My themostat is stuck open on my 2006 X5 3.0. i have about 75K miles on the clock and I am considering doing some preventative maintenance.

I was thinking that I should also replace the water pump, expansion tank and the hoses?

My mechanic is recommending that I just wait till I need to have them replaced. I would prefer not to be stranded since I know that the cooling system on these cars is less than ideal...

Thoughts?

Just a thought .....If it ain't broke don't fix it

Agreed for most items, but if the aforementioned things break (waterpump, hoses, belts), it will leave you stranded. If you're comfortable with that, then go ahead and drive it until it let goes.

I don't think anyone is a prophet regarding part failures, i.e.
waterpump, hoses, belts unless there something about a part
that leads one to believe failure may be eminent. In that case
part replacement falls under the heading of preventive
maintenance. That being said I've had more parts brake during the
warranty period than afterward. For me at least getting stranded
is not an issue. That's what AAA is for.

BMW cooling systems are notoriously weak on almost all models. They should be considered wear items and should be replaced before a failure. The alternative is that the water pump fails while wifey is driving and she overheats it. Now you have a complete engine failure and a cost of $3k minimum. Since you are already into the cooling system, at a minimum do the water pump. Obviously all new fluids. You could think about the radiator as well.

I would replace just the thermostat, and the hoses related to it.

I replaced my tstat, coolant temp sens, fan sensor, all hoses, and expansion tank. Only because tank and Tstat went at the same time. I figured a bunch of hoses coming off, won't hurt to do the rest. The big ticket items like pump, and radiator, I left for later.

I would do hoses, thermostat, and coolant. I would check the rest of the components to see if there were any signs of weeping (expansion tank, water pump). Hoses go soft, coolant loses additives, and thermostat has failed. Water pump and radiator can go much longer if you have kept the proper coolant in the system. And failure of those items is not strictly related to mileage.

As an aside, my wife knows just as well as I do that it isn't a good idea to keep driving a vehicle that has a red light on the dash. Might be worth reminding other drivers of the vehicle if they are not aware of what red warning lights mean.

i would do .....thermostat,waterpump and hoses realted to it.......how is your radiator..have you replace that and expansion tank..

The cooling system components are 100Kmi maintenance. I'd do the tstat now and others later around then

I just replaced my thermostat, water pump and expansion tank all at the same time since I was going to have it all apart anyway.