Coolant System Issues

bimmerXfive · #1 04-06-2012, 05:36 AM

I have just recently changed my expansion tank due to a split seam but now I cant get the hoses to seat properly and they all drip. They do seem loose when pushing them on. Does this mean the o-rings are shot and I need new hoses?

In the end I wound some teflon tape around the spigots on the expansion tank and then pushed the hoses on and it seems to work but I dont want to drive too far in-case my dodgey fix fails.

On another note what are the parameters for the coolant level sensor to come on? I believe that the sensor is a reed switch activated by a magnet on the float inside the tank? I have turned the ignition to on and held the float right down and no warnings come up. Does the car need to be running for the sensor to work and is there a test for it?

Cheers for your help.

PUREVIL · #2 04-06-2012, 07:33 PM

Did you get an OEM expansion tank? If it's not, there is a possiblilty that the new tank is not a good match for your OEM lines.

I swapped mine yesterday with an OEM part and the lines hooked up no problem with no leaks.

lowlows18 · #3 04-06-2012, 10:31 PM

the same problem happen to me and i did use a oem tank.. i ended up getting all new hoses that run to the tank and all was good

thunderX · #4 04-06-2012, 11:31 PM

Be sure to lube the o-rings and mating surfaces before installing so they don't kink.

I replaced mine also w/ OEM parts and hoses... no leaks.

bimmerXfive · #5 04-07-2012, 12:29 AM

Yeah it is an OEM tank.

Im going to order new hoses anyway.

Ive driven it a bit so far and the hoses dont seem to be leaking yet.

Anyone know about the coolant sensor as far as what it takes to make it come on?

bastereo · #6 04-07-2012, 01:48 AM

I think the float for the level sensor is a different piece than the float stick part you can see and hold down.
But I think you are about right with the magnet and float idea, just wrong float.

bimmerXfive · #7 04-07-2012, 03:12 AM

Ahh ok i thought the magnet was attached to the level float you can see.

Just wouldn't mind being able to test it.

PUREVIL · #8 04-07-2012, 10:22 AM

I think the "float" sensor is simply there to let you know the level inside the tank for filling purposes. The actual sensor clicks in the bottom of the tank has wires going to it. My new tank came with a new sensor so it was plug and play. I did save the old sensor and have it saved if you wind up needing one.

X5Ghost · #9 04-07-2012, 12:03 PM

I just did mine a couple days ago with an OEM tank and everything seem fine! I will be replacing the hoses soon. The odd part is my old tank had a very small drip from the seam mating upper/lower sections together at one of the corners but I don't see any cracks! This tank was already replaced 50k miles ago and practically looks new but I'm not sure I see a defect causing the leak! Just the residue along one of the corners! Weird!!!