Radiator Temperature On High Side

[kolamp]

Hi to all BMWCM members & guests,Recently my car N52B25 started showing radiator temperature on high side sometimes up to 106C and maintain above 90C....sometimes it drops down to 85C (suppose to be normal at 85C) but then shoots up again until 105-108C then goes down again....my engine temp have been constant >105C & I know it is not normal....What cause of this issue? clogged radiator? early signs of water pump failure? Any advise coz I don't want to get stranded in the middle of the road with broken water pump or radiator...Appreciate your kind input bro & sis.TQVM

 

[anaksarawak]

3 things to check, pressure for leaks, expansion tank n cap, heat exchangers and if all r ok it might be your water pump.

 

[maxxsp]

Hi to all BMWCM members & guests,

Recently my car N52B25 started showing radiator temperature on high side sometimes up to 106C and maintain above 90C....sometimes it drops down to 85C (suppose to be normal at 85C) but then shoots up again until 105-108C then goes down again....my engine temp have been constant >105C & I know it is not normal....What cause of this issue? clogged radiator? early signs of water pump failure? Any advise coz I don't want to get stranded in the middle of the road with broken water pump or radiator...

Appreciate your kind input bro & sis.

TQVM

I had this exact problem on my car. Solved the problem by changing both the radiator & water pump. Can't say for sure which part was causing the problem as I changed both at the same time but I THINK the main culprit was the water pump. It no longer turned smoothly and had play in the shaft.

Here is a video showing the amount of play on my water pump.
[video=youtube;-5MEeww7uM0]http://www.youtube.com/watch?v=-5MEeww7uM0[/video]

Again but with the new water pump
[video=youtube;aU6X2glK63U]http://www.youtube.com/watch?v=aU6X2glK63U[/video]

 

[e34_lover]

Hi to all BMWCM members & guests,

Recently my car N52B25 started showing radiator temperature on high side sometimes up to 106C and maintain above 90C....sometimes it drops down to 85C (suppose to be normal at 85C) but then shoots up again until 105-108C then goes down again....my engine temp have been constant >105C & I know it is not normal....What cause of this issue? clogged radiator? early signs of water pump failure? Any advise coz I don't want to get stranded in the middle of the road with broken water pump or radiator...

Appreciate your kind input bro & sis.

TQVM

Firstly, I need to say I don't know much about the N52B25 but I do have some ideas as to why this is happening.

If I am not mistaken the N52B25 has an electrical waterpump unlike the old crankshaft driven pumps. I believe the thermostat is also now electrical. If your temperatures are going up and down sporadically, it could be the thermostat that is getting wrong information about the current water temperature and not opening to cool the coolant. Unsure if the coolant temperature sensor is built into the thermostat or if theres a seperate sensor. Also, I don't know if the waterpump can be driven at different speeds dependant on temperature or if it is fixed. If it is dependant on temperature, it could also be receiving wrong information and not pumping at the required speed.

Does the temperature go up and down while driving normally or stopped at traffic? If this happens only while you are stopped, your high speed fan relay may be faulty or your fan may not be working at all. You will need to check this yourself.

Whats the mileage on your car? The waterpump IS a service item and should be replaced during the life of the car. I believe that spending some money here and preventing a major failure is more than worth it.

Your radiator shouldn't get clogged unless there is either a headgasket leak causing oil to gunk up your cooling system or if there has been tap water used in the cooling system, depositing minerals and rusting internals.

Hope this helps!

 

[kolamp]

Thank you very much for your kind reply bro anaksawarak, maxxsp & e34_lover...

Ive checked the reservoir tank, hoses & radiator but there's no leak or oil residue....water in reservoir still at max level....the temp rises on both driving and idle...sometimes I've to switch on the heater to bring down d temp to 90C....it usually happens a day after spirited drive and a week after that everything back to normal....but during that week of high temp really scared me as the radiator temp can go as high as 110-115C.....sounds like water pump but need more input as I don't want to waste replacing things that are not broken...

on another note, I only topup the coolant with tap water & never pour any additives....could it be rust accumulate & blocking the path?

Again thanks for your kind input...appreciate it very much!

 

[jarance]

thermostat and possibility temperature sensor.

might consider the electric fan.

 

[kama]

Hi Kolamp, my engine same as urs N52B25. Replaced my water pump and thermostat mid last yr, pump failed during high speed driving, overheating sign came off. 2 weeks prior to this incident, there is a a humming sound from engine bay, especially during morning drive. After about 5 minutes, sound went off.
Went to mechanic next day and confirmed its water pump, I replaced both water pump and thermostat. Mechanic said before water pump totally failed, it might work intermittently, sometimes ok..sometimes not ok.
Its wear and tear. I use original bmw coolant, mix it with 505 water.

 

[kama]

Hi Kolamp, my engine same as urs N52B25. Replaced my water pump and thermostat mid last yr, pump failed during high speed driving, overheating sign came off. 2 weeks prior to this incident, there is a a humming sound from engine bay, especially during morning drive. After about 5 minutes, sound went off.
Went to mechanic next day and confirmed its water pump, I replaced both water pump and thermostat. Mechanic said before water pump totally failed, it might work intermittently, sometimes ok..sometimes not ok.
Its wear and tear. I use original bmw coolant, mix it with 505 water.

 

[huskar3399]

it's time to change the car bro. cabuttt! hehe

 

[e34_lover]

Thank you very much for your kind reply bro anaksawarak, maxxsp & e34_lover...

Ive checked the reservoir tank, hoses & radiator but there's no leak or oil residue....water in reservoir still at max level....the temp rises on both driving and idle...sometimes I've to switch on the heater to bring down d temp to 90C....it usually happens a day after spirited drive and a week after that everything back to normal....but during that week of high temp really scared me as the radiator temp can go as high as 110-115C.....sounds like water pump but need more input as I don't want to waste replacing things that are not broken...

on another note, I only topup the coolant with tap water & never pour any additives....could it be rust accumulate & blocking the path?

Again thanks for your kind input...appreciate it very much!

Definitely DO NOT use tap water. Only use distilled water mixed with original BMW coolant. Coolant has anti-rust, anti-corrosion properties and it is needed in the system. It should be flushed every 2 years or so as it can break down and become conductive.

Since the temp rises while driving as well as idling, it would probably rule out the fan as you get way more airflow while moving compared to the fan anyway. Can you confirm that your fan is working?

So you are left with 3 things. Waterpump, thermostat or coolant temperature sensor.

Just wondering where you are getting the coolant temperature readings? Does the car seem to warm up at faster or slower on different days? Trying to rule out the coolant temp sensor.

What I find strange is that it goes away a week after a spirited drive... This doesn't make sense to me at all.

Whats the mileage on your car?

 

[anaksarawak]

During my radiator test I run without coolant and I do notice its temp when up to 117 on highspeed up genting but after adding bmw coolant 50/50 or 2 bottles of coolant plus RO water it stable at 108 up genting.

May I suggest you to replace your expansion tank cap and do a proper change of coolant and remember to bleed it well.

 

[kolamp]

Thank you Jarance for your input...I'll send my car to check the thermostat & also the water pump by this weekend....electric fan still running as usual...

Hi Kolamp, my engine same as urs N52B25. Replaced my water pump and thermostat mid last yr, pump failed during high speed driving, overheating sign came off. 2 weeks prior to this incident, there is a a humming sound from engine bay, especially during morning drive. After about 5 minutes, sound went off.
Went to mechanic next day and confirmed its water pump, I replaced both water pump and thermostat. Mechanic said before water pump totally failed, it might work intermittently, sometimes ok..sometimes not ok.
Its wear and tear. I use original bmw coolant, mix it with 505 water.

Bro Kama, sounds like my problem more likely like yours...intermittent as sometimes OK & sometimes not....meaning my water pump need to be replaced soon...ouch!

Huskar3399, I wait for you to change 1st...ur car is older than mine LOL

e34_lover, Noted on tap water...I'll flush everything by this weekend, check the sensor & water pump and see what happen next....got my temp reading through my performance steering...lucky got the steering if not just wait for warning light to pop ups without any early sign & by that time you're already stranded on the roadside heheh....my current mileage is about 70K KM...

Anaksarawak, I'll check the expansion tank cap later to see whether it need to be replaced or not & mix with BMW coolant after flushing...thanks for your kind suggestion bro!

 

[kama]

Yeah..my mechanic did pressure test as well to detect other leakages during the new water pump installation. Try check other spare parts dealer like suan huat or stuttgart, u might save some cost saving on the parts, but probably labour might be higher. I changed at Quill, a bit costly for both parts.