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E39 1996 540i Sport - Check Coolant Level

4.3K views 2 replies 3 participants last post by  Ronnie  
#1 ·
Hi Guys,

Happy Christmas to you all. Just bought myself a new 1996 540i, which has 128k on the clock and in prestine condition. When i took it home the OBC said "check coolant level". I checked and brought it to a local mechanic for a level check. The car was warm when i pulled in and with the car still running he opened the Rad cover slowly and the water/coolant bubbled out like a kettle boiling. In total it spewed about 2 litres out of it through the expansion tank onto the ground. The mechanic replied "i don't like the look of what you have bought mate, that should not do that, it should settle very quickly and not be spewing the water out continuously - i think you have bought someone elses problem, and the head gasket is about to go on this vehicle" As you can imagine on Christmas eve i was not a very happy camper hearing this. I know he doesn't work on BMW's as such but thought i would run it past you professionals as to your opinion on this. WE put back in over 2 litres of coolant and hey presto light went out but only to return back on 10 mins later as i was heading home. Temp hand sits perfectly in middle, don't see any drips on ground, and it just had a new radiator, water pump, fan belt, and tensioners installed abotu 1 week ago.... Could it be that it needs a new expansion tank, or new coolant sensor ? I at my wits end thinking its the head gasket - so it you can find some time to put me at ease please do !! However i got to be realistic and accept bad news if it comes my way and do what is necessary to fix this problem. Thanks folks. Merry Christmas to you all.

Peter.
 
#2 ·
Mmm It's all too easy to jump to conclusions and point at the head gasket:frown

Firstly i'd advise you bleed the cooling system

1.Jack the front of the vehicle up onto stands as high as possible,
2.Turn the ignition on,engine off,heater on fan setting 1 and temperature fully hot,
3.Remove the rad cap/expansion cap,remove the bleed screw from the rad and IF you have them the bleed screw(s) from the thermostat housing/top hose, return pipe or EGR thermostat.
4.Fill the radiator up and keep pouring till there are no more air bubbles coming out from the bleeds, when good then install bleeds and tighten down(don't snap them),ensure the rubber O-rings/seals are still on the screws/on the bleed holes.
5.Suck some water out so it's not full to the brim, replace the cap and then start the car. Run her up and check for heat from the vents when warm and check if over heating still persists.
6.If good then check the water level again in the morning when cool.

If the car has had a new radiator fitted then chances are the system was not bled correctly:frown

A new sensor may also be advisable :thumbsup

In future take your car to a reputable independent specialist.