[_TB_]

325d 11/2007

After driving at about 110km/h for close to 60 km - the coolant temperature still was not higher than ~63 degrees C. I have an error on the aux waterpump, can that be the culprit of the low coolant temps? Or am I looking at a new thermostat?

I ordered a DPF regen before leaving home - but according to the pre-DPF temperature it never happened. I supposeit is because of the low coolant temperature.

[Dazza335iC]

I found a broken thermostat in mine when I got that warning. Unfortunately I don't believe US cars came with the aux water pump, so I'm unsure about that,

[Mik325tds]

Yes, definitely new thermostat. A defective waterpump would more like cause too high temps. DPF regens are inhibited if the coolant temp is too low.

[Hoooper]

The aux pump circulates through the heater in the cabin I believe. It is possible for that to contribute to low coolant temps if it malfunctions but I would think you would notice as it would have to have a tradeoff of uncontrollably warm temps in the cabin.

[335dlci]

Originally Posted by Dazza335iC

I found a broken thermostat in mine when I got that warning. Unfortunately I don't believe US cars came with the aux water pump, so I'm unsure about that,

Early production had them in us.

[Owen81]

Apparently, the "additional water pump" circulates the coolant through the heater core after the car is shut off. So you can hit the REST button, and it circulates coolant so you still have heat with the car off while you are out of the car briefly.

I have the Aux pump error code as well, but its not related to your low coolant temps, your T-stat is definitely bad.

[Greck]

What is the normal working temperature for our diesel engines?

[335dsleeper]

Originally Posted by Greck

What is the normal working temperature for our diesel engines?

Please use the search function. Coolant temp has been discussed numerous times.

[ninja_zx11]

Originally Posted by Greck

What is the normal working temperature for our diesel engines?

With a brand new thermostat,you should get 85ºC~89ºC under normal driving conditions.Thats what i noticed right after replacing thermostat on my X5-35D.Before i was getting 72~75.And i noticed rise in fuel economy right after that.
88ºC is what stamped on a thermostat.

[JuiceQuadre]

Found out about bad stats thanks to this forum, having them replaced asap. Interested in how the economy will be after the replacement. These are already great cars economy-wise but the more the better, right?:P

Anyway will make a thread about my new 335D soon just need my acc to be verified=) This forum is awesome for gathering info btw. Been reading it every day for last week.

[caiken]

Originally Posted by JuiceQuadre

Found out about bad stats thanks to this forum, having them replaced asap. Interested in how the economy will be after the replacement. These are already great cars economy-wise but the more the better, right?:P

Anyway will make a thread about my new 335D soon just need my acc to be verified=) This forum is awesome for gathering info btw. Been reading it every day for last week.

Lucky you are able to get someone to replace your stat.

First Indy I brought it to wouldn't do it because check engine was not on.

Second Indy wanted $990 to do it and recommended to take to the dealer instead because they were not diesel certified.

Sigh.....

[Torqu3]

Originally Posted by caiken

Lucky you are able to get someone to replace your stat.

First Indy I brought it to wouldn't do it because check engine was not on.

Second Indy wanted $990 to do it and recommended to take to the dealer instead because they were not diesel certified.

Sigh.....

That's ridiculous. The part is really cheap, and from what I have heard, replacement isn't really that difficult to do. Perhaps someone with better searching abilities than me could link a DIY and you could give it a go. Pretty much any time you take these cars into a shop, the final cost will be about $1000.

[JuiceQuadre]

Ouch, sounds harsh.

Well i have a friend who has a friend who works for small company that prepares sport cars for amateur sport drivers so no problems there.. We will see about the prices but they promised to be reasonable.

[ingenieur]

Many discussions on the E70 site:
http://www.bimmerfest.com/forums/sho...9&postcount=15

[caiken]

Originally Posted by Torqu3

That's ridiculous. The part is really cheap, and from what I have heard, replacement isn't really that difficult to do. Perhaps someone with better searching abilities than me could link a DIY and you could give it a go. Pretty much any time you take these cars into a shop, the final cost will be about $1000.

Actually looks kinda hard from the top, but easier if you have a lift.

[335dlci]

It can all be done up top. Remove the egr cooler and it's right there.

[BB_cuda]

Originally Posted by 335dlci

It can all be done up top. Remove the egr cooler and it's right there.

+1, with cooler out the way, job was fairly simple. I did loosen the mount points of the plastic water pipe as it winds it way around drivers side of engine. This was to give for flexibility of line that connects to thermostat. I did job from top except for the catch pan below for coolant spilling.

[335dlci]

Originally Posted by BB_cuda

+1, with cooler out the way, job was fairly simple. I did loosen the mount points of the plastic water pipe as it winds it way around drivers side of engine. This was to give for flexibility of line that connects to thermostat. I did job from top except for the catch pan below for coolant spilling.

Forgot the plastic water pipe. +1

[remlemasi]

Careful with that plastic water pipe. Easy to crack when you're putting things back together and you're frustrated that things aren't slipping in too easily.

[daytonadave]

Originally Posted by Mik325tds

Yes, definitely new thermostat. A defective waterpump would more like cause too high temps. DPF regens are inhibited if the coolant temp is too low.

The stat in my 335d failed in the open position, giving me low coolant temps.

[_TB_]

Still haven't had the time to change it yet - but yesterday I spent quite some time in stop'n'go traffic. The temperature came above 80 - and then it started the high temp regen. (600-650) I had to keep driving for it to finish, while it generated temps rose to 92. Pressure before the DPF was @ 22mbar before and ~14mbar after.

..Next step - to replace the thermostat tomorrow along airfilter and cabin filter. It got a new oil filter and new oil today

[335dsleeper]

Originally Posted by _TB_

Still haven't had the time to change it yet - but yesterday I spent quite some time in stop'n'go traffic. The temperature came above 80 - and then it started the high temp regen. (600-650) I had to keep driving for it to finish, while it generated temps rose to 92. Pressure before the DPF was @ 22mbar before and ~14mbar after.

..Next step - to replace the thermostat tomorrow along airfilter and cabin filter. It got a new oil filter and new oil today

Good luck. Just be very gentle with the EGR coolant lines.