coolant lit up on check panel help m3

Post Sat Oct 21, 2006 3:39 pm

hi guys just got back from 2 weks away and the "kuhlwasser" ceck light is on on the check panel . checked water levels and that and all seem okay and engine isnt overheating. just wondering whether it may be any of the sensors??? and where they are ?? also would i be able to tell by looking, at the sensor, if it has gone or not?

sorry for the questions fellas but as much as i love my m3 , im no mechanic.

any helpwould be great, toby

Post Sat Oct 21, 2006 4:24 pm

same problem occoured today, i reckon first try flush out the system tommorow morning and add new water and anti freeze,

thats what heynes says to do but i can't see how to flush the system

Post Sat Oct 21, 2006 4:39 pm

It maybe the sensor has just stuck, try unscrewing it and freeing it up.

Also, give the coolant a quick topup, and make sure it's bleed correctly, on the M3 it's self bleeding, coolant cap off, switch on engine until the water coming out of the return pipe near the fill up cap is continuous flow with no bubbles.

Post Sat Oct 21, 2006 4:49 pm

oh damn he got m3, i missed that
how do you bleed 325i?

Post Sat Oct 21, 2006 4:54 pm

Find a decent hill, park car facing uphill, run engine with heater control set to hot, leave engine get upto temp and unscrew the bleed screw on the thermostat housing until all the air escapes, leave engine to cool then top up coolant. This may take a couple of goes as the M20 is a right pain to bleed.

Post Sat Oct 21, 2006 5:09 pm

Post Sat Oct 21, 2006 5:33 pm

hi simon, where would i find sensor is it the one on header tank???

Post Sat Oct 21, 2006 8:08 pm

tobias wrote:hi simon, where would i find sensor is it the one on header tank???

Yes mate

Post Sun Oct 22, 2006 1:39 am

There's a miniature reed switch inside the stem of the coolant sensor. Water eventually works its way into the stem and corrodes through the very thin wires to this switch.
Pull off the coolant sensor plug and short together the two pins of the socket. If this keeps the light off, then fit a new sensor.
Make sure you get the right one. There are two versions which look very similar outwardly, bur work in a completely different way.

Post Mon Oct 23, 2006 6:02 pm

hi guys

bled the system but there were no bubbles coming from return pipe. so is it likley thyat its the sensor in the header tank or does anyone have any other suggestions??
regards toby

Post Mon Oct 23, 2006 7:13 pm

Brianmoooore wrote:There's a miniature reed switch inside the stem of the coolant sensor. Water eventually works its way into the stem and corrodes through the very thin wires to this switch.
Pull off the coolant sensor plug and short together the two pins of the socket. If this keeps the light off, then fit a new sensor.
Make sure you get the right one. There are two versions which look very similar outwardly, bur work in a completely different way.

Post Mon Oct 23, 2006 7:24 pm

sorry brian how do i short it. im useless with electrics

do i need to pull it apart or short the two pins

Post Mon Oct 23, 2006 7:46 pm

Pull the plug of the sensor and short the sockets in the connector together with a piece of wire.
Turn on ignition and light should not come on. Leave ignition on and pull out the shorting link.
Light should now be on.
Replace the shorting link. Light should still be on.
Switch ignition off, and back on. Light should be off.

Post Mon Oct 23, 2006 7:55 pm

thanks very much brian will give it a go in the morn and update tomorrow

Post Tue Oct 24, 2006 12:52 pm

hi brian your shorting the sensor worked

would i mbe best off ordering new from bmw or are the sensors the same in all e30's????

Post Tue Oct 24, 2006 9:31 pm

tobias wrote: are the sensors the same in all e30's????

No the sensors are not all the same, and the last time I bought one from GSF, it took three attempts to get the correct one!
Level sensors on cars with a seperate header tank are fitted with the terminals upwards, whereas those on the type of tank that is joined to the side of the radiator are fitted with the terminals downwards.
If you get the wrong one, the light will remain off when the coolant level is low, but will light when the coolant is at the correct level.
There is a small difference in the length of the stem of the two different versions.

Post Tue Oct 24, 2006 10:56 pm

so in your opinion should i go to bmw??

Post Tue Oct 24, 2006 11:10 pm

tobias wrote:so in your opinion should i go to bmw??

No, just make sure you get the correct one. I've no idea how GSF, ECP and BMW compare for price on this one.
Dealer could well be cheapest if carriage charges are involved.

Post Wed Oct 25, 2006 12:01 am

tnx for all the help brian