Temperature

[azan23uk]

Dear All,Need some advice here. My 528i temperature began crossing pass halfway mark yesterday. It did again this morning but never passed the 3/4 mark. As far as cooling system is concerned, expansion tank cap, plastic screws, radiator, all hoses, water pump have all been changed 2 months back as the engine was losing coolant previously. Still, i'm loosing coolant now and with regards to the high temperature above, my mech initially suspected the electric fan. Upon checking, he found that the thermostat/housing is not working well. What's this thermostat? Anyone facing this problem of loosing coolant but cannot find the source of the leakage? TQ

 

[selfmech]

Dear Azan,

The cooling system is a closed one hence the level of coolant is more of less stable. If you are losing it then it could be your air con system or you gasket is leaking give you have change everything else.
The thermostat housing can be visually inspected for leak. If you see green stains then it is leaking.
The thermostat itself is mechanical so I doubt you mech can tell it is not working well by external inspection.
It is not expensive so just change it and see. I changed mine two years ago and the old one is still lying around. I tested the springs and it seem fine so I believe the housing will give way before the thermostat.

Good Luck.

 

[azan23uk]

Thermostat

Thanks for the advice, Mech.

Googled the thermostat thingy and finally got some idea. My mech noticed a water leakage in the thermostat. Upon taking out the thermostat, one of the 3 small screws on the thermostat was broken, leaving the piece still inside the cyl head. It was alrdy rusted. Now trying get the broken piece out to make way for new thermostat set. I hope this is the last piece of the puzzel to solve the mystery of "disappearing coolant" of my e39.

 

[bimmer73]

Thanks for the advice, Mech.

Googled the thermostat thingy and finally got some idea. My mech noticed a water leakage in the thermostat. Upon taking out the thermostat, one of the 3 small screws on the thermostat was broken, leaving the piece still inside the cyl head. It was alrdy rusted. Now trying get the broken piece out to make way for new thermostat set. I hope this is the last piece of the puzzel to solve the mystery of "disappearing coolant" of my e39.

There is another piece of PVC piping under the Manifold it deteriorate at certain intervals with hairline cracks. Get that changed too. That was the cause of my cyl head going bust

 

[bimmerholic]

bimmer,

care to show the PVC pipe you're referring to? THanks man.

 

[IanDaddy]

Just discovered yesterday, similar leak near the thermostat housing on my M54. I have finally found the cause for the disappearing coolant, I had to add top up about 100ml every 1-2 weeks. However, I don't have an issue with the temperature, it is very stable at just before halfway mark. Also discovered that the serpentine belt is shot. Will have all these fixed up tomorrow with a flush of radiator too.
Will fix the set of Bilstein B4 I purchased last week too.

Bimmer73, what PVC piping are you referring to. Please share.

 

[bimmer73]

It called the heater inlet pipe. no 8 in the picture

 

[azan23uk]

Temperature

It called the heater inlet pipe. no 8 in the picture

On my car, that pipe under the manifold was changed together with the rest of the hoses last month. I was hoping the coolant loss would stop after that. Obviously it did not.
To update, after the new thermostat, my temperature is back to its old position, slightly below halfway. Now I'm just monitoring the coolant level. Fingers crossed.

 

[infinityKL]

seems to be common problem as the 39 ages... in my case its was a hairline crack, cylinder head..

same problem, only discovered when open engine, which was the last choice of coz...this is after changin the whole freakin cooling system$$$water pump,hoses,radiator,expansion tank,fans,belts etc etc and yet the problem persist.. it was quite a pain looking for the double vanos(528i) cyl head.. just the head cost 2800 for a used refurbished set.. did a top overhaul too since the engine is ald open.. in total spent about 12K, plus some wear and tear stuff.. the crack is so tiny, i could hardly see wt my naked eyes! but thats where the small quantity of water went missing slowly... now its a dream to drive this machine!!

 

[macgy]

experienced the same problem 2 months after i change the thermostat, which later lead to engine overhaul, problem still continue until my mechanic change another thermostat, fine for a month then overheat problem start again, to cut story short, found out the thermostat is of lousy quality, can't remember the brand but it start with "w" something, FYI after i change to behr brand, car is fine again.

 

[jaleeks23]

Last week, after doing vanos and while regular service, did pressure test, found water pump starting to leak, changed to ori water pump. After water pump, another pressure test was done and detected heater inlet pipe (item 8) leaking. Since had to remove manifold to change the pipe, changed the water pipe (item 6) too. All original pipe and water pump. Tomorrow need to go change my top water hose.

 

[azan23uk]

I think once in 2 years, e39 gotta make that cooling system 'pilgrimage'. Change everything. Forget the pressure test...sure got leakage one. My mechanic hardly uses the pressure test unless, according to him, the customers are aware of the circumstances i.e you may end up changing everything.

 

[jaleeks23]

True....For mine, the water pump and all hoses came brand new with the car back in 2003, not changed.
I had to change the radiator and expansion tank back in 2008 due to minor leak. So, the hoses and water pump lasted 7yrs! I was told that as long as the coolant level and mixture is maintained and regular checks, avoiding huge change in pressure in the system will help prolong lifespan.

 

[azan23uk]

Its quite common to find that parts that come from the factory i.e new cars tend to last more than 5 years. It is said that OE manaufacturers are subject to certain quality standards imposed by the car makers. But however, for replacement parts, OEM will supply lower quality more often than not, as these parts are usually changed after warranty period expires.

 

[infinityKL]

yes OEM tends to wear faster hence the cheaper price compared to factory...

 

[jaleeks23]

erm...are we saying even if I buy original from BMW, with BMW logo, it won't last as long? Not OEM....

 

[azan23uk]

While an OEM makes parts for BMW that carries BMW logo, they also make parts for BMW that do not carry BMW logo. Jurid, for example makes OEM pads for E39. At the same time, u can also buy e39 Jurid pads carrying Jurid logo only and no BMW logo. I had the chance to use both of them. The BMW logo Jurid pads are a lot better. I Paid RM350 for the ones with BMW logo...only RM160 for the Jurid logo. Same goes for absorbers (Sachs/ Boge), supension joints and arms Lemfoerders etc...