[GOTMH8N]

I have a question. The other day I was on the highway where I did some hard pulls and as I was coming up to my exit I noticed the water temp had dropped down to around 180. Then as I came to a stop at the street light it came back up to 210 like normal. Could this be a sign the water pump is on its way out? Since the early water pump codes say fan speed below normal, I always thought that would cause an increase in water temp though.

I have yet to see the water temp fluctuate like that, but I've done mostly city driving lately and this was the first time I've driven the car hard on the highway in a while.

[CUTigers]

Your profile says you have a 335i, mine only has gas and oil temp

[CHECKERED]

He's probably using JB4 gauge hack

The temp gauges is not accurate, don’t worry about it

[GOTMH8N]

Originally Posted by CHECKERED

He's probably using JB4 gauge hack

The temp gauges is not accurate, don’t worry about it

I am using my JB4 controls. So it's pointless to even have the water temp gauge on?

[CHECKERED]

Originally Posted by GOTMH8N

I am using my JB4 controls. So it's pointless to even have the water temp gauge on?

Correct, the scaling is all over the place, if you are still concerned you can do some logging and see what the actual temp is, or gauges by using the OBD II port, similar to this http://www.scangauge.com/

[BoostedE90]

Could try this on menu 07.00

http://e90.wetpaint.com/page/BC+hidden+menus?t=anon

[GOTMH8N]

Originally Posted by CHECKERED

Correct, the scaling is all over the place, if you are still concerned you can do some logging and see what the actual temp is, or gauges by using the OBD II port, similar to this http://www.scangauge.com/

Does the JB4 check for codes even if there is no CEL, since a failing water pump releases hidden codes before it fails?

Originally Posted by BoostedE90

Could try this on menu 07.00

http://e90.wetpaint.com/page/BC+hidden+menus?t=anon

This is interesting

[CHECKERED]

Originally Posted by GOTMH8N

Does the JB4 check for codes even if there is no CEL, since a failing water pump releases hidden codes before it fails?

the JB4 itself does not check for codes,
it will not auto clear important codes like the water pump only 'annoying' codes such as O2 sensor due to catless downpipes, misfire, lean conditions

[GOTMH8N]

Originally Posted by CHECKERED

the JB4 itself does not check for codes,
it will not auto clear important codes like the water pump only 'annoying' codes such as O2 sensor due to catless downpipes, misfire, lean conditions

Hmm ok

I might look into the vent gauge attachment and hook up a water temp gauge. Just so I can keep a close eye on the water temp.

That's the one thing I hate about this car; that MFing electric water pump! It drives me crazy that it can just fail at any time.

[enrita]

easiest way to diagnose is to actuate the water pump with either BT cable or INPA and see if it can hold the requested % . If the pump misses the % by a lot like you request 95% and it only spins 80-85% than you know its gonna fail very soon.

[BMWM.D.]

Originally Posted by GOTMH8N

I have a question. The other day I was on the highway where I did some hard pulls and as I was coming up to my exit I noticed the water temp had dropped down to around 180. Then as I came to a stop at the street light it came back up to 210 like normal. Could this be a sign the water pump is on its way out? Since the early water pump codes say fan speed below normal, I always thought that would cause an increase in water temp though.

I have yet to see the water temp fluctuate like that, but I've done mostly city driving lately and this was the first time I've driven the car hard on the highway in a while.

Yes, it is very normal for the coolant temp to drop after making a full throttle burst. One of the great things about the N54 platform is that the DME has a lot of control over coolant temps in the cylinder head. Between the electric water pump, the MAP thermostat (controlled by a heated wax core) and electric fan.

There are several operating modes the DME will choose for cooling strategy. When you got WOT, it will open the thermostat and crank up the water pump speed. Normal coolant temp for the N54 is targeted around 104 C. It runs warmer when cruising for better fuel economy, reduced friction, etc. , but when putting a heavy load on the engine, it will try to reduce temps to 90 C (which is about 194 degrees).

This is actually how the MAP thermostats have worked for years, even on the E46. Now with the electric water pump, BMW has made it that much more effective. Hope that helps.

[GOTMH8N]

Originally Posted by BMWM.D.

Yes, it is very normal for the coolant temp to drop after making a full throttle burst. One of the great things about the N54 platform is that the DME has a lot of control over coolant temps in the cylinder head. Between the electric water pump, the MAP thermostat (controlled by a heated wax core) and electric fan.

There are several operating modes the DME will choose for cooling strategy. When you got WOT, it will open the thermostat and crank up the water pump speed. Normal coolant temp for the N54 is targeted around 104 C. It runs warmer when cruising for better fuel economy, reduced friction, etc. , but when putting a heavy load on the engine, it will try to reduce temps to 90 C (which is about 194 degrees).

This is actually how the MAP thermostats have worked for years, even on the E46. Now with the electric water pump, BMW has made it that much more effective. Hope that helps.

Good to know! Thank you. I assumed it was the thermostat opening but I wasn't sure and this car makes me too paranoid sometimes so I had to ask.

[DanielGonz]

Originally Posted by BMWM.D.

Yes, it is very normal for the coolant temp to drop after making a full throttle burst. One of the great things about the N54 platform is that the DME has a lot of control over coolant temps in the cylinder head. Between the electric water pump, the MAP thermostat (controlled by a heated wax core) and electric fan.

There are several operating modes the DME will choose for cooling strategy. When you got WOT, it will open the thermostat and crank up the water pump speed. Normal coolant temp for the N54 is targeted around 104 C. It runs warmer when cruising for better fuel economy, reduced friction, etc. , but when putting a heavy load on the engine, it will try to reduce temps to 90 C (which is about 194 degrees).

This is actually how the MAP thermostats have worked for years, even on the E46. Now with the electric water pump, BMW has made it that much more effective. Hope that helps.