overheating 735i

[harleywilma]

MY 1996P 735i 105K IS OVER HEATING,I HAVE TOPPED IT UP AND IT JUST BLOWS THE WATER OUT AGAIN,THE HEATER IS BLOWING OUT COLD AIR AND I CANT FEEL ANY WATER IN THE TOP HOSE ALTHOUGH THE HOSE IS VERY HOT AND NOT PRESSURISED,THERE IS NO SIGNS OF WATER IN THE ENGINE THE CAP AND DIPSTICK SHOW NO SIGNS OF EMULSIFICATION,COULD THIS BE A JAMMED THERMOSTAT OR THE HEAD JUST STARTING TO BLOW.

[silverback mike]

Knackered/blocked rad?
Doesn't sound like headgasket problems...

[thesilverfox]

it may be one of two problems the thermostats break and jam shut, also the impeller falls of the end of the water pump if left too long it will blow the head for sure done about DONT DRIVE IT TILL YOU FIX IT
go for the thermastat first changed about 20 so far, if its gone you cant miss it.
also its got the plastic housing also change it they crack with the heat
also you must bleed it correctly or you wont get all the air out

[silverback mike]

A very good point by silverfox. The 540's suffer from the impellors going on the water pump. I know this because the chap I bought my 540 from had the very same problem.....Can't believe I didn't remember that.

[harleywilma]

how will I tell if ive killed it,and is it possible to tow a steptronic,as it needs recovering

[Alistair H.]

You can tow it for up to 30 miles, but only at a max 30 mph!

I would go for a new radiator and water pump in that order. You can get then relatively cheap from german and swedish.

You have not said in which conditions it overheats..e.g is it at idle in traffic? - Have you checked the viscous fan is working properly?

[harleywilma]

THE CAR IS OVER HEATING IN TRAFFIC AT IDLE,HAVE NOT CHECKED THE FAN YET AS THE CAR IS WAITING TO BE RECOVERED FROM LONDON TO BEXHILL,IM JUST TRYING TO ASSESS THE BEST WAY OF DEALING WITH IT WHEN IT GETS HOME,AT PRESENT THE CAR GOT VERY HOT QUICKLEY THERE IS NO HEAT FROM THE HEATERS EITHER, TOP RIGHT HOSE NOT PRESSURISING BUT PLENTY OF STEAM AND PRESSURE COMING FROM RAD FILLER CAP,NOTHING OUT OF THE EXHAUST AND NO SIGNS OF EMULSIFICATION IN THE OIL.

[Alistair H.]

Sounds defo like water pump. I have just done mine on my 730i.

If you are tecnically minded, you can do it yourself. I paid £60 for a pump,£30 for two new belts, plus £10 for antifreeze from German & Swedish! - so it can be done cheap. You do have to take plently of bits and bobs out though to get to the pump.

I bet BM would charge the wrong side of £500 squids just to open the bonnet. If yoy tackle it yourself and get stuck, feel free to drop me a line.

[numbnuts]

Make sure you put the two coolant tubes from the back of the pump in correctly ie: dont pinch the seals otherwise its an inlet manifold of job.

[harleywilma]

ITS 22 22 HUNDRED HOURS,IVE GOT A CHAP BRINGING IT DOWN ON A RECOVERY LORRY FROM WIMBLEDON FOR £130 HE WILL BE HERE AT 11.30 TONIGHT IM SHITTING IT AND HOPING ALL YOU KNOWLEDGEABLE CHAPS HAVE GOT IT RIGHT,IVE GOT A GOOD MECH AND WILL GIVE HIM ALL THE GEN FROM THIS SITE ,HOPEFULLY HE WILL GO STRAIGHT TO THE PROBLEM FROM ALL YOUR DIAGNOSTIC HELP ON THIS BRILLIANT FORUM AND SOLVE THE PROBLEM,THANKS FOR ALL THE HELP AND IS MUCH APPRECIATED,ANY ADVICE DEEPLY APPRECIATED ALSO SO IF YOUVE MISSED ANY THING PLEASE ADVISE AS I DO NOT WISH TO BE AT THE MERCY OF BMW MAIN DEALERS

>> Edited by harleywilma on Friday 18th February 22:34

[harleywilma]

Car is back now,filled it up with water, smells like some exhaust fumes comming from rad,me thinks it may be shagged,any one want a cheap 735i v8.

[silverback mike]

Keep with it.....A new rad isn't the end of the world if that's what it is....Shame to get rid of an otherwise good car for that.

A new rad should be about £168 from euro car parts, fitting isn't really that bad.

B'stard cars

[harleywilma]

talked to ray morgan this morning who runs leader engineering and specialises BMW in st leanards hastings he still doubts that the head has gone so im still trying to stay positive he is aiming at the pump.

[silverback mike]

Harley, I will go as far as saying I will eat my pants if it is the head.



Keep smiling mate. I had to pay £200 for pranging some dozy mare's car....Not even a mere hint of a scratch on mine....BMW's are definately 'arder than Ford puma's.

[harleywilma]

Cheers mike,I hope you wont have to.Bad luck for your little prang,my missus got out of our workhorse xm 2.5 diesel to close the gate on our drive last sunday afternoon,she didnt push the handbrake hard enough with her foot and it came down the drive and hit my daughters vw polo caving in both the front wing on the xm and the rear quarter of the polo,not been a good week so far,roll on monday.

[silverback mike]

ouch.