[Bayo]

Hey guys.
Yes I have searched, extensively... I have a 2015 x3 28i, 60,000 miles on the clock. It is losing far more coolant than it should. I have owned it for 3 years. It started slow but is getting worse. Now the warning comes on and I add about 1 to 2 cups of fluid every 2000 ish miles. Nearly all my driving is city, and it never gets hot (it has been below freezing for the last 6 months up here), but I do have a heated garage that it is parked in every night.

I have looked everywhere I can think in the engine bay, with a flashlight and mirror in hand (I washed out the engine bay really well a couple months ago to help find it after a fruitless search at that time as well) No sign of leaks anywhere. The bottom of the expansion tank is spotless, same with every fitting I can get to. No marks on the garage floor....

I just changed the oil and no milkyness there. Exhaust is normal, no sweet smell or excess white "smoke".

I'm stumped.

Do I just start swapping parts??

I know the expansion tank is the usual culprit, and that is where I will likely start, but there are no signs of a leak at all. That much fluid loss should show, shouldn't it??

Thoughts?

Thanks in advance.
James

[Marty in NY]

Originally Posted by Bayo

Hey guys.
Yes I have searched, extensively... I have a 2015 x3 28i, 60,000 miles on the clock. It is losing far more coolant than it should. I have owned it for 3 years. It started slow but is getting worse. Now the warning comes on and I add about 1 to 2 cups of fluid every 2000 ish miles. Nearly all my driving is city, and it never gets hot (it has been below freezing for the last 6 months up here), but I do have a heated garage that it is parked in every night.

I have looked everywhere I can think in the engine bay, with a flashlight and mirror in hand (I washed out the engine bay really well a couple months ago to help find it after a fruitless search at that time as well) No sign of leaks anywhere. The bottom of the expansion tank is spotless, same with every fitting I can get to. No marks on the garage floor....

I just changed the oil and no milkyness there. Exhaust is normal, no sweet smell or excess white "smoke".

I'm stumped.

Do I just start swapping parts??

I know the expansion tank is the usual culprit, and that is where I will likely start, but there are no signs of a leak at all. That much fluid loss should show, shouldn't it??

Thoughts?

Thanks in advance.
James

Hmmmm, how long now have you been adding a couple of cups per 2K miles. Just trying to figure out how much you've added total. and you're saying that you cannot see any fluid on the floor of your garage, your driveway or anywhere else, like in a parking spot where ever you end up going? and no sign of leaks around any hose ends, clamps, etc, etc, right?

[Wgosma]

Get the cooling system checked with a pressurized leak tester. Shop can do or you can buy one and DIY...better route than swapping parts at random.

[Bayo]

Originally Posted by Marty in NY

Hmmmm, how long now have you been adding a couple of cups per 2K miles. Just trying to figure out how much you've added total. and you're saying that you cannot see any fluid on the floor of your garage, your driveway or anywhere else, like in a parking spot where ever you end up going? and no sign of leaks around any hose ends, clamps, etc, etc, right?

Last time it was 2k. time before that, 3. time before that 5.... etc. In 2 years I have gone through approx. 1/2 to 2/3s of a jug. It obviously has a leak that is getting worse, but you are right, I can't see any sign of a leak anywhere. I spent a good half hour with a flashlight and a mirror this morning, and another 20 minutes after a 45 minute drive so it was good and hot.

It is always parked in the same place in the garage, nothing on the floor. Granted I haven't removed the belly pan and left it off, so maybe it is collecting there and then evaporating. Once the roads are dry up here I may do that (probably another 2 to 3 weeks before the snow is gone).

Thanks!

[Bayo]

Originally Posted by Wgosma

Get the cooling system checked with a pressurized leak tester. Shop can do or you can buy one and DIY...better route than swapping parts at random.

Ya that's probably a good plan. Although I should have seen something after a 45 minute drive if it was there to be seen.

Maybe pressure it up and leave it pressured for an hour to see if it leaks....

Hmmm have to look into those. One of few tools I don't already own.

Thanks for the reply

[Marty in NY]

Originally Posted by Bayo

Last time it was 2k. time before that, 3. time before that 5.... etc. In 2 years I have gone through approx. 1/2 to 2/3s of a jug. It obviously has a leak that is getting worse, but you are right, I can't see any sign of a leak anywhere. I spent a good half hour with a flashlight and a mirror this morning, and another 20 minutes after a 45 minute drive so it was good and hot.

It is always parked in the same place in the garage, nothing on the floor. Granted I haven't removed the belly pan and left it off, so maybe it is collecting there and then evaporating. Once the roads are dry up here I may do that (probably another 2 to 3 weeks before the snow is gone).

Thanks!

If I remember, the inside of the belly pan has squares added for stiffness and those can hold a fair amount of fluid before it overflows and you see it on your garage floor - but don't hold me to it cause I may be getting that mixed up with my wife's GTI. I know one of them does. I think the pressure check Wgosma recommended is a good idea and its simple to have done. They pressurize the system and then check for leaks and they can do it on a lift.

[Wgosma]

Originally Posted by Bayo

Ya that's probably a good plan. Although I should have seen something after a 45 minute drive if it was there to be seen.

Maybe pressure it up and leave it pressured for an hour to see if it leaks....

Hmmm have to look into those. One of few tools I don't already own.

Thanks for the reply

Look here https://www.newtis.info/tisv2/a/en/f...check/EPq9F23Z

note the comment about the expansion tank cap.

[Bayo]

Thanks guys. I will give it a shot as soon as I can get my hands on a pressure tester.

[Wrangler]

I had the same issue last year. Mine is a 2011 X3 35i. The floor and engine bay was clean as the coolant leaked only while driving/engine was running. The culprit was a fine hairline crack in the water pump. This was detected while doing multi point inspection during an oil change service.

[Marty in NY]

Originally Posted by Wrangler

I had the same issue last year. Mine is a 2011 X3 35i. The floor and engine bay was clean as the coolant leaked only while driving/engine was running. The culprit was a fine hairline crack in the water pump. This was detected while doing multi point inspection during an oil change service.

Wrangler,
How many miles were on your X3 when you noticed the water pump crack?

[Wrangler]

About 95000 Kilometers, just under 60K miles. $1500 to replace it by the dealer.

[Wgosma]

Originally Posted by Wrangler

About 95000 Kilometers, just under 60K miles. $1500 to replace it by the dealer.

It's a bear of a job to get to those pumps- I've read numerous posts here of them failing right at the mileage range you've indicated on cars with the turbo 6 motors.

I believe BMW has somewhat recently moved back to using mechanical pumps on newer motors.

[383vett]

The inside of the belly pan is smooth. There is a drain hole about 1/2 way back. Take the pan off and drive around until the car gets warm. Put the car up on jackstands and start the motor. The waterpump and thermostat are hidden in a cubbyhole and there are numerous hoses and connections where seepage can occur. I replaced mine last year. It was a bear of a job.

[Marty in NY]

Originally Posted by Bayo

Thanks guys. I will give it a shot as soon as I can get my hands on a pressure tester.

"IF" it turns out you need to replace your water pump, there are a few videos on YouTube you can watch but just to give you an idea, here is one that is somewhat generic on an N engine. This one is by BAV Autosport and as you will see its just a lot of labor but I just priced a water pump, T-stat and a gallon of coolant from Turner Motorsport for $450 total. Anyway, have a look, this is a two part video, here's part 1.

https://www.youtube.com/watch?v=o-BpUzAemyQ

[pungo]

Use a UV light (black light) in the dark to look for a leak anywhere there's coolant flow (hoses/water pump/radiator/etc...)

[kevink1]

I had the problem on my diesel 2015 for a few years. Had to add a little coolant every few months. (I tried not to wait until the warning). Dealers acted like it was normal. In my case, it seems to have stopped when I had my EGR recall done. It apparently was leaking and burning coolant.

But you have the gas engine. I can understand your frustration. The worry that maybe it will suddenly get worse on a road trip.

[Wgosma]

Originally Posted by Marty in NY

"IF" it turns out you need to replace your water pump, there are a few videos on YouTube you can watch but just to give you an idea, here is one that is somewhat generic on an N engine. This one is by BAV Autosport and as you will see its just a lot of labor but I just priced a water pump, T-stat and a gallon of coolant from Turner Motorsport for $450 total. Anyway, have a look, this is a two part video, here's part 1.

https://www.youtube.com/watch?v=o-BpUzAemyQ

Take a very close look at the location of the pump and thermostat- you'll then realize why this is a labor intensive job. I'm a pretty proficient DIY type but I will pay Mr Mechanic the big bucks when this work comes due!

[Bayo]

thanks everyone. Some good ideas and tips here. Never thought of the black light... that's a good one.

You guys are probably right, water pump is a good bet. Hopefully I can get under there this weekend and have a closer look.

[Bayo]

Anyone know how different the 6cyl is from the 4 for the water pump? most of the guides (like the Bavarian one posted here) are for a 6cyl or they don't specify.

[FranzX3M]

Check the level sensor under the expansion tank as its prone to leaking there. Mine did. Also check around the cap for any dried up coolant as the cap could be passing steam. Do you smell coolant after you park it? Sort of a sweet, slightly burnt smell. I believe you need to add a die to the coolant for the black light to work. If you remove the under pan and run the engine until the pump is running, turn off engine, then you should be able to reach up around the water pump and thermostat on passenger side to feel any weeping/wetness and if there is, smell it for coolant. Careful as it can be hot! While you are under the car, check all coolant hoses and pipes, joints, for leakage.

[FranzX3M]

The 4cyl and 6 cyl water pumps are different. the 4cyl pump I believe has a metal head while the 6 cyl has a black plastic head (where you connect the hoses. Carefull of Chinese knock off pumps on ebay and Amazon. VDO/Continental are reliable and make the OEM pump. Also it is super highly recommended to replace the thermostat at the same time.

[Marty in NY]

Originally Posted by Bayo

Anyone know how different the 6cyl is from the 4 for the water pump? most of the guides (like the Bavarian one posted here) are for a 6cyl or they don't specify.

Are you saying you have the 28i X3 4 cyl? If so, the part numbers are different than for the 35i and I agree that most, if not all of the info I found is on the 35i...maybe this means good news for the 28i folks in that their water pumps last longer...dunno but here are a few pix from Realoem that show the difference in what the water pump and T-stat look like between the two models.

It appears though that on either model X3, the water pump and T-stat are in the same location, that is the passenger side of the engine at the bottom, all access is via the bottom of the car. So, you get to lay down and be comfortable when changing them out while of course getting coolant dripping on your face, in your eyes, nose and mouth :-)

Its either a PITA to do yourself, not impossible by any means, but just a pain or expensive to have a shop do it. If you end up replacing your water pump, be sure to also replace the T-stat too. Hopefully for you, its just a hose leakage instead.

.