intermittent overheat

[help me]

anyone had intermittent overheating problems
my car sometimes overheats only on freeway driving. I watch the temp gauge (through hidden menus) drop to around 80degrees before it climbs quickly and yellow warning appears on idrive screen, I can then turn engine off then back on while coasting and temp returns to normal. This can happen a couple of times on long drives then not happen for a week. At first i thought it was temp sender so i replaced (didnt fix) after speaking to bmw they suggested electronic thermostat so i replaced it and it still overheating. Now i know these water pumps are notorious for failing but when they fail they normally fail for good. Any input would be appreciated as this problem is quiet annoying

[Experimental]

How many miles on your car and what year? BMW coolant and BMW oil?

[b1aze]

How often does this happen? Do you see your oil temp rise at all?

[miro2296]

water pump going out?

[Dackelone]

Could be your water pump. But when you replaced the thermostat... did you bleed the cooling system properly? I think you can turn on the ignition(don't start the engine) put your foot to the floor on the gas pedal for ten secs... you should then hear the water pump start to cycle on and off. You might have some air in the system - so a "burp" might be in order!

The way you described the car over heating on the highway... it almost sounds like how the old e36/e46's would have the same issue when the water pump impeller would spin freely on the shaft. BMW has had a habit of using composite impellers that are simply not as reliable as a metal impeller.

Btw... Turner Motorsports has good deals on electric water pumps. So does Tischer and United for OE BMW parts.

G.L.
Dackel

[help me]

Car is 08 and has 72000kms has BMW coolant and oil and pretty sure I bled system completely oil temp doesn't go above 120degrees car gets driven everyday
And only happened twice since I changed thermostat two weeks ago think I going to have to bite the bullet And do waterpump and just pray it fixes it

[135i OREO]

Does your temp ever go into the red?
Does your radiator fan kick on? (You should be able to hear it if it overheats)
My waterpump just went out and the first sign I got was that the radiator fan turned on 30 seconds after I started the car. That was about 3 minutes before it comletely failed though. Since the water pump is electric, I think it just goes out quick, not slowly. I could be wrong though.

[RimasRS]

That is crazy BMW at least could give us water temp gauge.
Like in older e46 there is no overheating bulb/indicator you can not pay attention when temp goes to the top.

Its just looks a little scary when I see those posts

[135i OREO]

Originally Posted by RimasRS

That is crazy BMW at least could give us water temp gauge.
Like in older e46 there is no overheating bulb/indicator you can not pay attention when temp goes to the top.

Its just looks a little scary when I see those posts

Yup. There is no real warning. Car feels a tad bit weird and then 5 seconds later, yellow temp indicator, a few seconds later, red temp indicator. Its pretty fast since out turbo cars generate more heat.

[RimasRS]

Originally Posted by 135i OREO

Yup. There is no real warning. Car feels a tad bit weird and then 5 seconds later, yellow temp indicator, a few seconds later, red temp indicator. Its pretty fast since out turbo cars generate more heat.

I wonder how quick it can damage the engine or burn the head gasket

[135i OREO]

Originally Posted by RimasRS

I wonder how quick it can damage the engine or burn the head gasket

Thats a good question. When my waterpump went out, I was 2 miles from my house on the autobahn. I drove on the median as soon as it went yellow and then stopped completely and shut the car off when it went red. It took me 90 minutes to drive those 2 miles cause I kept stopping to let it cool off and then did it all over again. I think I had to stop about 10 times total. I know it is not the smartest thing to do but it doesnt seem like anything was damaged. Just make sure you dont drive it at all when it is RED.

The waterpump is now replaced and I have no codes and nothing is out of the ordinary so hopefully I did not damage anything.

[help me]

temp will go into red if you dont turn car off and on quick enough
i think were pretty lucky these engines are supposed to be hard to damage if you dont turn off and try to keep going you might be able to hurt something but that would be an effort in itself as the car wont let you drive anyway. Im going to check electrical signals to the water pump and thermostat over the next week just to make sure there is no problem with the computer side of things and i might even remove jb4 as well