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2004 BMW 325i overheated, why?


It all started with a SERVICE ENGINE light. i took it to the shop they told me

It needed a vacuum hose replaced. A week later the light turned on again. The car temperature rose but the car didn?t seem to be overheatingon the outside. Immediately after as I was trying to pull over safetly I heard a crack and white smoke coming out from the engine and the water burst out through the bottom of the car. Took it to the shop again and the mechanic just called me and said there is a radiator crack, needs a new reservoir, belt and hose $900 for the job including labor. The car had just been serviced $3,000 miles ago. I want my car fixed but my real concern is why did this happen? Looking for some feedback.

Just a guess … could be a bad water pump.

It was just serviced $3000 ago?

I see nothing here that causes me to second guess the mechanic. A cracked radiator lower tank is not outside of the bounds of reality.

Why it happened is impossible to guess from here. A look at the tank might provide a clue.

Replace the thermostat too. It could be sticking causing overheating and pressure to build up, which could have caused the burst part.

The description you give sounds more like a blown freeze-out plug or a head gasket. Most likely the former. If I were you I’d try to remember where the fluid was pouring from, the middle of the engine or from the front of the engine.

I think your shop is at best unreliable. Ask around or look online for a better local shop.

This car has a plastic and aluminum radiator. The plastic gets old and cracks eventually. This is just a little early, but not completely unreasonable. My wife’s '97 BMW lost its first radiator when it was 7 years old.

If you use non-BMW coolant, your cooling system will give you more problems.

By the way, if you are just a little handy and have basic tools, you can buy the radiator on-line for $140 and put it in yourself. Throw in a few dollars for a gallon of coolant, and maybe some hoses, and you are back on the road for about $200. It is a little early for the reservoir, but the mechanic probably wants to replace it while he has it out anyway. A new reservoir and cap is another $55 in parts.

I tell people that 6 cyl BMWs are great cars up to about a quarter-million miles, but if you don’t do most of your own work, they are expensive to maintain.

I bet a thermostat for this car cost every bit of $100.00, these are not a Stant unit. Thermostat has a data feedback feature, comming soon to other cars.