here is the story, two months ago i was travelling on a highway speeding around 180KM and all of a sudden, the oil temp goes above the middle and then the water temp goes high too.... and mind you, the outside temp was around 45-47C and the A/C was on. So the first thing i did is i slowed down and the water temp goes back to the middle but the oil temp stayed at the same level. the trip was around 3 hours so i thought to my self, it was oil issue since S62s burn oil so i added oil and did not notice the water temp going up anymore. However, the oil temp keeps hitting the middle and even little bit more.
Yesterday, i was driving 140Km and there we go again, the oil and the water pegged but the water little bit to the middle right. so i freaked out and i slowed down again and turned the A/C off and the temp went back in the middle.
I took it to the dealer and the dealer said that he has the same problem with another M5 in the shop and he had already changed the water pump, Aux Fan and the Tstat. and still it is heating......
so i said let me see what could be causing the overheat. so today morning under a temp of almost 50C i was parking the car and all of a sudden, the oil and water temp are up again but the thing is the water temp never reached the redzone but the oil temp is almost to the middle right.
My question is, what is causing all this ? is it the Aux Fan or the water pump or or or !!!!!! my guess is that the dealer does not have any clue and i am not that expert in cooling systems
I think you can rule out the auxilaury fan since when you are driving at 140-180km/hr that fan will have no effect and is not needed. If this only happened while standing still, then the aux fan may be the problem. When you have the AC on, and the car is standing still, do you hear and see it running?
Since it sounds like it's a random event, it's possible that it is the water pump. I don't know the design of the S62 waterpump offhand, but I know that with some BMW engines, the impeller sometimes gets loose from the shaft, causing erratic cooling issues.
It could also be the thermostat which doesn't open/close freely anymore.
Some other inexpensive things to check:
- make sure the cooling system is properly bled. If not, air bubbles can cause the pump to cavitate. BMW has a very strict bleeding procedure for the engine which must be followed exactly. It may also help to massage the main radiator hoses while performing bleeding to promote any air bubbles to move.
- ensure that your radiator is clean. They can easily get plugged up by dirt/bugs/grass, etc while driving. A powerful water hose, sprayed at an angle and the use of a hard brisstle brush should clean it out properly.
I'd do the last two items first, and if they don't work, I'd replace the pump, thermostat, and coolant.
Last edited by verhagke; 25th August 2006 at 18:11.
It sounds like air bubbles, with the sudden jumps up and down. Or it could be bad sending units that are the culprit. Either way, you should be cleaning out your radiator frequently as dust/sand buildup is bad in the middle east.
then what i am going to do is clean the radiator and see what happens! cuz honestly it has been a while since my last clean-up.
the second thing i might do if this still happens, i am going to order the cooling solution from Zionsville for M5s and i guess this would help me with this kind of weather ! do you know anyone who installed that and are happy with it ?
I think you can rule out the auxilaury fan since when you are driving at 140-180km/hr that fan will have no effect and is not needed. If this only happened while standing still, then the aux fan may be the problem. When you have the AC on, and the car is standing still, do you hear and see it running?
Since it sounds like it's a random event, it's possible that it is the water pump. I don't know the design of the S62 waterpump offhand, but I know that with some BMW engines, the impeller sometimes gets loose from the shaft, causing erratic cooling issues.
It could also be the thermostat which doesn't open/close freely anymore.
Some other inexpensive things to check:
- make sure the cooling system is properly bled. If not, air bubbles can cause the pump to cavitate. BMW has a very strict bleeding procedure for the engine which must be followed exactly. It may also help to massage the main radiator hoses while performing bleeding to promote any air bubbles to move.
- ensure that your radiator is clean. They can easily get plugged up by dirt/bugs/grass, etc while driving. A powerful water hose, sprayed at an angle and the use of a hard brisstle brush should clean it out properly.
I'd do the last two items first, and if they don't work, I'd replace the pump, thermostat, and coolant.
thanks for the reply V, and yes i hear the fan on when idle. and most probably the cleaning of the Radiator might solve everything....
then what i am going to do is clean the radiator and see what happens! cuz honestly it has been a while since my last clean-up.
the second thing i might do if this still happens, i am going to order the cooling solution from Zionsville for M5s and i guess this would help me with this kind of weather ! do you know anyone who installed that and are happy with it ?
You also realise that running in desert temps (110+F) will make your oil temp rise beyond the center mark, and your water temp to run a little high. The spikes you are seeing are what's abnormal. The best thing to do is have the sending units checked, it's not uncommon for those to die out.
You also realise that running in desert temps (110+F) will make your oil temp rise beyond the center mark, and your water temp to run a little high. The spikes you are seeing are what's abnormal. The best thing to do is have the sending units checked, it's not uncommon for those to die out.
Thanks E55AMG2
but where would this sending unit be located ?
i forgot to mention that when the dealer hocked the computer in, there was no message saying that the car was overheating or any error message !
could this be another problem
i forgot to mention that when the dealer hocked the computer in, there was no message saying that the car was overheating or any error message !
could this be another problem
cheers
It's probably close to the radiator somewhere....tell the techs, they will know
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