bmw 523i se problem

[craigwba]

hi all a bit new to this but thought i would see if anyone can help as i am losing my patience....
ok bought a 1998 R plate 523i se 2 weeks ago. It has 112k and is an excellent car to drive but..... last week the temperature gauge went into the red, i put the heating on but to my surprise no hot air.I called the RAC who spent over an hour trying to rectify the problem, the nice man released the so called air lock in the car,which when done it gave me hot air in the car and the temperature gauge went back to half way,which is normal.I have driven this car for about a week now with no problems but today i have no hot air, and the temperature gauge went to the red then dropped down to half, but still no hot air in the car.
My question is could this be a head gasket problem or is it a sticky valve?
The car has lost a bit of water and when the engine is hot and running i can see a small amount of water dripping from a pipe, but when the car is stood still after a run with the engine turned off there is no water on the floor!!!!!
Just needed some advice really if anyone can help that would be great........

[Mustard]

My guess would be the plastic water pump impellar imploding (basically it works its self loose on the water pump drive shaft and bits break off it causing poor water flow), I'd be expecting to replace the pump, thermostate and housing circa £150-£200 at a good independent as long as nothing else has been damaged

Edited by Mustard on Monday 24th March 15:33

[craigwba]

hi thanks for your reply, just to add to the post i have driven the car again and i have hot air again....would this be right with your diagnosis.it just feels as though i have developed an air lock,and i did think of draining all the water out and starting again to se if that rectifys it.

[Mustard]

What circumstances did it 'overheat'?

ie speed, amount of load on the engine

[craigwba]

just normal driving,not thrashing it at all, but got worse when i was on the carpark with the engine running i checked the engine while it was running and the top pipe that feeds the radiator was very hard and hot but the bottom pipe from the water bottle was cold hence thats why i am thinking another air lock? but i had left it for half an hour and drove it around the block where i have hot air again inside the car.
when the car was overheating the fan never cut in either which so i am told will only cut in if hot water is passing by to operate the fan, again possible air lock?
i am no mechanic but it is baffling me in what it could be, i have no water getting into the oil, and the oil cap is clean as a bell with no nasty gunk showing on the cap.

[Mustard]

If it was just 'normal' light load cruising then that sounds like classic water pump failure, as does having a blockage (I'm no expert, but sounds very similar to what happened with our E34 520i) as being driven hard helps the circulation

regards the fan, not sure if early E39's are Viscous couplings (if it is worth replacing it to just for good measure) or same as later E39 that have an electric fan IIRC

Edited by Mustard on Monday 24th March 17:48

[craigwba]

thats what i think as well,water pump failure.spoke to my mechanic tonight but he seems to think head gasket? or is he taking the easy option.....
i will let you no tomorrow the verdict.

[[TW]Fox]

First thing anyone ever says when you say 'I have a problem with the cooling sys... HEAD GASKET MATE' so dont panic just yet.

If there is no heat it sounds like there is no water in the heater matrix - this can happen when your coolant level is dangerously low, and this would also lead to fluctuating temperature. Check the level in the header tank. If its well down, this is your problem.

It sounds to be like you've got a leak in your coolant system which slowly drains all the coolant out, resulting in no hot air and then an engine which begins to overheat.

[craigwba]

thanks for that,my mechanic arrived yesterday and when he checked the water pipes there was no water in the pipes although the header tank had water.we have put in down to another air lock due to when we released the pressure the pipes filled up with water again and i developed hot air and a normal temp gauge.
my mechanic checked the oil(no sludge or water) checked the exhaust for any leaking water(none apparent) checked the water pump(working properly) so we could not understand where the water had been going.
I drove the car some 50 miles yesterday and no problems at all, i will just monitor the water level,if it persists i may take it to my bmw dealers and see what they say.
lets hope its ok now due to i love the car....
but this post may help others if they have the same problem....

[Mustard]

I still suspect your water pump intermitantly 'loosing drive' on its shaft, as mention previously our 520i E34 suffered similar symptoms.

Think I'd have it replaced to eliminate it (when our old one was removed it was plain to see what was happening)

[8Tech]

Yep!

Water pump, and if you keep leaving it you will be spending £1000 on a headgasket soon.

[Mustard]

8Tech said:

Yep!

Water pump, and if you keep leaving it you will be spending £1000 on a headgasket soon.

Do I get a gold star?

[jonrarit]

HI Craig, did you ever get to the bottom of your problem? I have a 2001 525i E39 and am experiencing temperature guage flucuations similar to yours. Under no particular load, temp guage creeps up to just short of the red then returns back to mid way all over the space of about 1 minute and repeats at random normally when in traffic.

thanks in advance

JR

[Fox-]

jonrarit said:

HI Craig, did you ever get to the bottom of your problem? I have a 2001 525i E39 and am experiencing temperature guage flucuations similar to yours. Under no particular load, temp guage creeps up to just short of the red then returns back to mid way all over the space of about 1 minute and repeats at random normally when in traffic.

thanks in advance

JR

I bet your radiator has started to leak. Thats how I noticed mine had gone.