Coolant leak - expansion tank

[aNoodle]

Uggggh....I have a crack in my expansion tank!!!! Being six years old this month has not been a happy birthday. It's only a hair line fracture, but that was enough for me to loose all my coolant. What a mess. Luckily I was able to find the crack and I got the tank out. I'll hit the parts department tomorrow. But I need help with two questions....

(1) I don't know whether I should replace the coolant sensor on the bottom of the tank. The light went on five minutes before I had problems, indicating there was low coolant. Then it just went out. About five minutes later I had steam coming from the engine compartment and the temp guage went through the roof. Does the sensor only determine when it's low, then it goes off when there is no fluid at all? Or do I have a faulty sensor since it went off and obviously the coolant was not at operating levels.

(2) Do I have to replace the o-rings in each hose connector?

Any advice you guys have would be greatly appreciated. (Any other tricks you'd recommend I do while I have everything out? Should I preventatively replace some hoses?) Thanks everyone.

 

[Kirby]

Can't help with the sensor, don't know. I would suggest changing the hoses - cheap insurance. I'm doing exactly that this week on my Suburban.

 

[gizzy]

o-rings will degrade over time and since you will be in a good position to change them, you might as well do it. They don't cost much, and I think that it would be just a good piece of mind task to do. I don't know anything about the coolant sensor for the BMW, but for my beretta that I used to have, it only determined if there was water in the tank. Once the water went below the sensor, a residue was left on the sensor so that it would not indicate that I had put water back into the tank (I did not use distilled water). It worked fine, once I cleaned the contacts on the sensor. If a new sensor is a reasonable price, I would probably just replace it for peace of mind as well.

 

[aNoodle]

Thanks for your help Kirby and gizzy. I went ahead and replaced a couple hoses which come with the connectors containing the o-rings. I think I got it all back together again okay. No leaks so far. While I was in there, I decided to go ahead and swap out the belts (I made the mistake of letting a cousin put Goodyear belts in there in Vegas...I think they sat in a desert warehouse for several years before going on my car because they were just aweful...I'm back to BMW belts now).

Gizzy, you were totally right. I cleaned the sensor, it had a bunch of junk on it. Seems to work right now, the light came on.

I'm just wondering...I got it flushed today. I refilled the system and drove it around to get it all warm. There is a general smell of burnt rubber. Is that just the old coolant burning off since it was sprayed all over the engine compartment?

 

[gizzy]

The burnt rubber smell is probably from the heat being applied to the new hoses and will go away after a few days.

 

[aNoodle]

Damn. Actually it was the radiator cap...or in this case the cap is on the expansion tank. It decided to bite the dust at the same time...how wierd. So further fluid was heading up out of there even after I put the new tank on. $11.83 later, I'm back in business. No smell, no leaks, rock-n-roll.

Now, does anyone know how I add windshield wiper fluid to my resevoir?