BMW E90 coolant question

billymitchell

The low coolant warning light just came on in my car earlier on today, and I had a look and the level does seem pretty low.

I'm kind of afraid to do anything with it myself in case I f*** it up more. The warning light is gone off again, so I'm not sure what the craic is with it.

Can anybody offer me advice on what I should do??

Slidey

My opinion, top it up with a drop of water 'til it is between the min and max mark and keep an eye on it, if the level drops again then you will need to get it checked out.

Captain Slow IRL

There are 2 bleed screws (possibly only 1) that have to removed prior to filling the coolant system - 1 should be located on the expansion tank and the other 1 down near the black plastic housing on the front of the engine, although their location is dependant on the engine type. You may have to remove the large engine cover to see the second bleed screw.

With this done, turn ignition on, then turn the interior heater on (at lowest fan speed, without turning it off) and temp at max - turn off your stereo and a/c to lessen drain on your battery. Then top up coolant at expansion tank, as water starts coming out steadily from each bleed vent, replace the screw and fill expansion tank to the top. Then put the cap back on the tank and carefully drive it, making sure you've hot air coming out of the interior heater vents. After you've driven it, let it cool down and recheck the coolant level - repeat above process if necessary to get coolant back up to level.

PM or post up the last 7 digits of your vin no. and I'll try to post up a pic of the screws and their location.

voxpop

If you coolant is disappearing, you probably have a leak somewhere. Can you seen any coolant in the undertray or a chalky residue anywhere. Top up to "kalt" mark(you can get coolant from a dealer, its pretty cheap, or just use tap water if its only a small top up).Only do this when the engine is cold - a few(3-4) hours after driving or in the morning and keep a close eye on your temperature gauge. If you are not mechanically minded, probably best to take it to a mechanic - if the engine overheats from lack of coolant, its toast.

Not sure about the E90 but the E39 have a pretty rubbish cooling system - from waterpump and thermostat issues to cracked pipes and fractures in the expansion tank. Once coolant starts going, time to get the whole system looked at probably.

Captain Slow IRL

The E9x coolant system is far more reliable than the E39/E46 - don't think there's any common recurring fault with them. That's not to say there isn't a leak in the system, if coolant loss occured after topping up and bleeding the system, you'd have to have it checked out.

voxpop

Captain Slow IRL wrote: »

The E9x coolant system is far more reliable than the E39/E46 - don't think there's any common recurring fault with them.

Couldnt be any less reliable - just spend the weekend replacing waterpump/thermostat and housing due to coolant going missing in my E39. The parts I took off were in a real state. Seems to have fixed the leaking problem, then I go to bleed any left over air yesterday and the feckin bleed screw breaks - stupid plastic screw - queue coolant spraying out all over the engine until the pressure drops.

Im developing a real love hate relationship with the banger.

Captain Slow IRL

Haha, I know exactly how you feel!

billymitchell

I topped it up with water the other day once the warning light went on.

I have a fair idea how far up it was topped up to, so I'll check it again this evening to see what level its at. If its still around the same level, I'll check it again in a couple of weeks to make sure it still hasnt gone down.

If it has gone down,i'm down the garage straight away. If not, its due a service in about 2500km, so I'll just drop it in over the next few weeks anyway and get somebody to look at it.

If there is a leak, can it happen in may places and is it a bit expensive to fix?

voxpop

billymitchell wrote: »

If there is a leak, can it happen in may places and is it a bit expensive to fix?

It could leak in a few places - a garage will do a pressure test, which should highlight any leaks - if its a pipe leaking, fixing is cheap enough (although the pipes themselves are expensive,for a pipe, from bmw). If its something else then it could get relatively expensive - mind you not as expensive as an overheated engine - so worth getting it fixed. Just ask the garage to do a pressure test and then call you before doing any work.

billymitchell

Just checked my coolant there, and it seems to be at pretty much the same level for the last few weeks, so it may be ok until my next service(a few weeks away).
But when moving my car to have a look under the hood, I noticed some leakage on the ground underneath where the car was. It seemed to be water, but I'm not 100% certain on this. I'll move my car again in a bit, see if there is another leak underneath it. Hopefully not.
Anybody got any ideas what it might be??? Seemed to be underneath the centre of the car if that is any help!!

Slidey

Air-con condensation water perhaps?

billymitchell

Slidey wrote: »

Air-con condensation water perhaps?

Just read up on what you said and it could possibly be. I checked it there again, and it is defo just water. Is this simmit to worry about.

Slidey

Nope.

Leave it running for a bit with the air con off and see if it stops the leak

voxpop

Slidey wrote: »

Air-con condensation water perhaps?

+1

Coolant will smell different and will have a rainbow kind of shimmer in the light

billymitchell

Thanks lads, panic over for another little bit