aux. pump buzzing

[Mike08]

Hello Members,Noticed a buzzing sound :eeps:coming from the aux. pump next to my fuse box,with all the hoses running to and from the engine.can anyone tell me whats wrong,im not gettin any error lights or coolant temp raising,all hoses are pressured wen engine is warm

[bimmer dot info]

The buzzing could be the water valves or a failing aux pump. The aux pump does do much for engine temp or cooling.
If you want to test the aux pump remove it and test it outside of the car. You just needs a 12V input to run the pump.

[Mike08]

when i unplugged it,i got kind of a hunting idle.but no check engine,so it seems that it is working.has any one else aux.pump went out

[bimmer dot info]

Mine caught on fire. I just removed it. I dont really understand why the idle started hunting.

[jamester_a]

Hi Mike,

Check out Bob HazelWood's description and fix for your problem here:

http://bimmer.roadfly.com/5series/messages/archive/msgsy1998w38/4551.html

- James
94 525ia

Hello Members,Noticed a buzzing sound :eeps:coming from the aux. pump next to my fuse box,with all the hoses running to and from the engine.can anyone tell me whats wrong,im not gettin any error lights or coolant temp raising,all hoses are pressured wen engine is warm

[mottati]

The aux pump does do much for engine temp or cooling.
.

do you mean the pump does NOT doe much for temp/cooling?
my recently purchased 91 m5 had a bad aux pump, so the previous owner bypassed it. I recently found one on ebay, from a guy parting an m5, so i bought it and will put it in one of these days, just because i want it 'correct', but my car seems ok without it functioning.
Mike

[Mike08]

oh ok.Im thinkin about removing it and connecting the hoses.i Heard it is just a extra pump to flow coolant faster

[mottati]

oh ok.Im thinkin about removing it and connecting the hoses.i Heard it is just a extra pump to flow coolant faster

thats what was done on my m5, works ok, but i assume the heater function would be better with it in place. I'm not totally clear on when it runs, perhaps it helps circulate coolant when the car is off? for parked car heating (if the e34 even does this).

[bimmer dot info]

The heat kinda drops when you are at idle without the pump. That is the only change I have noticed.
I dont think the e34 has parked heating.

[Mike08]

no parked ventilation is only on the 7 series and 8 series late model 5er

[bimmer dot info]

I've wired in parked vent. It only turns on the blower. Does not heat or cool (wish it did).

[jrmarshall]

When I had a leak in that area, my BMW tech fixed it and bypassed the pump without any ill effects. He said it helps circulate cooland in the heater core for faster warmup in winter, but where I live, it's not important.

[doctor mel]

aux. pump was leaking on mine, so i removed it and resealed the plastic vane assemblygasket with silicone, unfortunately, on reattaching the hose, the plastic nipple broke(its plastic was going to fail anyway). I went to the pick a part junk yard and bought two whole aux. pump and solenoid valve assemblies for 10 bucks each! the dealer would or could not sell the failed nipple housing by itself. btw the assemblies are easy to find since they were used in the 5 series, and 7 series and there is no shortage of 7 series in the junk yards..