Check Coolant Level warning, perhaps a leak?

[bmwgirl740]

I have a 1998 740I. My Check Coolant Level warning light comes on every so often. When it does, I check the level of coolant in my radiator and it is always low. This must mean there is a slow leak maybe? I have had it in the shop numerous times and they cannot find anything wrong with it. I find this odd. It never ever overheats or even gets hotter than it is supposed to. Does anyone have any ideas on what could be causing this or what this is? Thanks for your help!

[Trnsprtr]

If you have more than 50k miles, replace your radiator and expansion tank - NOW. If they can't find any leak around the radiator, your valley pan gasket is probably where its at, pretty common.

[bmwgirl740]

replace your radiator and expansion tank - NOW

Is that pretty expensive to replace the radiator and expansion tank? The car has 82k on it.

[Trnsprtr]

Not if you do it yourself - radiator is about 150 and the expansion tank another 50. You might be looking at a couple hundred in labor if somebody does it. Best time to get a coolant flush as well. 740's just have a real bad problem of having unexpected failures of the radiator once you get up in miles, even if thtis isn't the real problem, it's a problem.

If you can't see any evidence of chalky looking stuff around the radiator neck or seams of the expansion tank, my bet is on the valley pan - the v area under the intake manifolds. It will pool there and if small enough burn off, its a PITA to look around down there but worth a check.

[bmwgirl740]

That doesn't sound too bad. I just can't believe with all the many times I have had it in the shops that they cannot figure this out, lol. I will definately check into it, thanks!!