[wonglk9090]

Hi all,

My E90 330i (2006) 70k miles recently got a engine overheating problem.
The overheat signal came on when I drove it for about 1.5-2 hours.
When I open the hood it looks like the coolant leaks out at the pics shown.
There is also coolant on the hood but I did not take the photo of it.
Any ideas and help? I don't really know much about cars and I don't want to get overpaid for the mechanics store.

Thanks!!!

[Bartman619]

Looks like the coolant boiled out of the reservoir. It may be time to invest on a new water pump and thermostat...about $1000 or so fom an Indy mechanic.

[wonglk9090]

I used to think of water pump and thermostat problem but I guess if it really is the case, the engine would be overheated very shortly and I won't be able to drive for like 2 hours?

Am I right?

[BKV122]

This was just happening to me this weekend. Was on my way home friday and got the overheat icon, pulled over and had coolant all over the reservoir, like it boiled out. Had to get it towed home. That night i topped it off with distilled water and ran the bleeding procedure to see where it was leaking from, no leaks and i drove it about 30 miles saturday with no problems. I pulled the code p0128 (coolant temp below t-stat regulating temp) figured it was bc of the water I put in.
Then this morning I drained and put the 50/50 coolant water mix in and took it for a 4 min test drive and got the overheating icon and coolant was all over the reservoir again. So it was weird how the following day i had no issues with just the water and today after i drain and refiled with coolant it what looks like it boiled out the reservoir again.

I was just hoping for a pressure test tomorrow and see a bad reservoir and just replace that. Could it be just a bad reservoir cap/o-ring? or would it be the water pump and t-stat? why else isnt the coolant keeping cool?

I too have a '06 E90 ~88k and see all the recent post with water pumps being replaced so this might be it.

[Brad from the OC]

I have a 2006 325i with 47K miles and so far have not had overheating problems. I have been reading the various posts regarding water pump failures with the electric water pumps and I'm very concerned about replacing my pump before a failure. Murphy's Law says the pump failure will occur at the worse possible time in the worse possible conditions.

I'm delaying a pump replacement at this time as it seems the earliest pump failures are happening right around 50K miles plus or minus and some of the latest failures are occuring around 150K miles. So if I replace mine now, I can still have a pump failure at around 100K miles, or if I don't replace now, I can also have my first pump failure at 100K miles.

I believe that some E90 OPs are seeing overheating and then after either adding or changing coolant, see the problem go away. I'm not sure if the coolant is the root cause of the overheating or if the electric pump is experiencing early signs of a long term failure and revealing itself on an intermittant basis. Many electronic components fail on an intermittant basis and some components fail completely and without warning.

[wonglk9090]

BKV122 just keep updating you for what is going on with your car. I noticed my car only get the overheat warning when I drove it afternoon with the temperature read on the screen about 100F (California sunshine...). I had no problem with it when I drive at night or morning will cool weather.

[BKV122]

Originally Posted by wonglk9090

BKV122 just keep updating you for what is going on with your car. I noticed my car only get the overheat warning when I drove it afternoon with the temperature read on the screen about 100F (California sunshine...). I had no problem with it when I drive at night or morning will cool weather.

Its in the shop getting both pump and tstat replaced today, was doin it myself on monday but the xi has a different setup on the front end with more suspension compenents and front diff more difficult to do laying in my garahe and was carless for the work week. Ill let ua know how it runs after i get it back.

[Whit]

06' 325i 85K
OK guy's guess I am in the same boat. Blew off out the radiator cap after coming up a steep incline at 65mph and 105 out. Let it sit, nursed her home and refilled the system to determine leaks ect. Next day drove around for HOURS in 105 degree temps with NO issue...until I drove back up that same incline at 105 degrees and blew again. Got towed home, and still had about 50% of the fluid in the system.
Fan works. Heater works. System is tight, no leaks. Anything else I have ever had an issue like this it was either the cap or thermostat.
So I am going from the top down. I am replacing the cap today first then will run it through the motions. If still having issues I will proceed to the thermostat. After that I guess it will be the pump. So....

My pump works for the bleeding procedure. I can hear it cycling. Do they go out slowly or all at once?
I heard it should throw a code if it either the thermostat or pump fails but I have no code. Is this true?
Have the reservoir caps been known to fail?
There was no warning of impending doom...just strait to red warning lamp....

I will post as I eliminate possibilities. Good luck to those with the same issues.

[GoRomeo]

Keep us posted. Good luck!

I remember last year I had to add coolant to mine since the low coolant warning light came on. Just added a cup of cooant and no issues ever since. It was in July last summer I remember. I am sure we will start to see more and more water pumps going bad because the heat. (knock on wood of course)...

[Brad from the OC]

Originally Posted by GoRomeo

Keep us posted. Good luck!

I remember last year I had to add coolant to mine since the low coolant warning light came on. Just added a cup of cooant and no issues ever since. It was in July last summer I remember. I am sure we will start to see more and more water pumps going bad because the heat. (knock on wood of course)...

I believe that the heat isn't the cause of the water pump failure. I think that most of the pumps prior to failure have lower pump RPMs thus a lower coolant flow. In cooler weather the low RPM probably doesn't make much of a difference unless your stuck in stopped traffic or going up a steep incline. I've seen posts where OPs are scanning codes and looking for low water pump RPMs to help them decide if they should replace the pump prior to a complete failure.

[BKV122]

Got my car back today with a new pump and tstat installed worked fine for he ride back home. Tmrw will be the real test with my drive to and from work.

Originally Posted by Whit

So I am going from the top down. I am replacing the cap today first then will run it through the motions. If still having issues I will proceed to the thermostat. After that I guess it will be the pump. So....

If you replace the tstat u mind as well go for the pump aswell at the same time since both are located/attached to each other.

[Whit]

Update.
I replaced the water pump and thermostat in the 06' 325i(88K). The water pump was truly on it's last legs. After I installed the new parts and ran it through it's first vent cycle the difference in pump noise and water flow was immediately apparent. Looks to have been the electrics that finally gave out...the inside of the pump looks fine.
Side note....the DIY off of this forum was FANTASTIC! Very well organized step by step and I had no questions following the directions. Big thanks to the original author and others who contribute to the DIY.
Now what to do with the $700 in labor charges I saved

[SMOKE EM IF U GOT EM!!]

Originally Posted by Whit

Update.
I replaced the water pump and thermostat in the 06' 325i(88K). The water pump was truly on it's last legs. After I installed the new parts and ran it through it's first vent cycle the difference in pump noise and water flow was immediately apparent. Looks to have been the electrics that finally gave out...the inside of the pump looks fine.
Side note....the DIY off of this forum was FANTASTIC! Very well organized step by step and I had no questions following the directions. Big thanks to the original author and others who contribute to the DIY.
Now what to do with the $700 in labor charges I saved