[Shawnalston10]

My 2011 335i had a low coolant light singe I got it from the dealership. After checking my coolant level it was filled exactly where it was supposed to be but I continuously was having a low coolant message pop up on my car so I thought it was the sensor in the bottom of the coolant tank but after replacing the coolant sensor it still remained so I went ahead and decided to buy factory blue bmw coolant with 3 gallons of distilled water. I did a 50/50 mix (one gallon of coolant and one gallon of distilled water in a 5 gallon bucket and then mixed it together. After getting that mixed I lifted the front of my car on a Jack and removed my front innercooler (extremely easy to do) and then unscrewed the screw on the bottom of the radiator which drained about 70% of the coolant so then I disconnected a hose near the radiator plug (forgot the name of it) which got the other 30% of coolant out. After doing this I filled up my coolant tank with 2 gallons of distilled water only to flush out the system just to be careful which got a lot more blue coolant out of the system and once I drained that I installed the 50/50 mix and drove around till my car was hot and then I let the car cool off for a few hours and I opened the bleeder screw and a lot of air came out so I filled the coolant up to the line again where it's supposed to be and now I have no more low coolant light. Moral of story is you probably have trapped air bubbles and by draining the system you can fix your problem for under $30

[An20Olives]

Originally Posted by Shawnalston10

My 2011 335i had a low coolant light singe I got it from the dealership. After checking my coolant level it was filled exactly where it was supposed to be but I continuously was having a low coolant message pop up on my car so I thought it was the sensor in the bottom of the coolant tank but after replacing the coolant sensor it still remained so I went ahead and decided to buy factory blue bmw coolant with 3 gallons of distilled water. I did a 50/50 mix (one gallon of coolant and one gallon of distilled water in a 5 gallon bucket and then mixed it together. After getting that mixed I lifted the front of my car on a Jack and removed my front innercooler (extremely easy to do) and then unscrewed the screw on the bottom of the radiator which drained about 70% of the coolant so then I disconnected a hose near the radiator plug (forgot the name of it) which got the other 30% of coolant out. After doing this I filled up my coolant tank with 2 gallons of distilled water only to flush out the system just to be careful which got a lot more blue coolant out of the system and once I drained that I installed the 50/50 mix and drove around till my car was hot and then I let the car cool off for a few hours and I opened the bleeder screw and a lot of air came out so I filled the coolant up to the line again where it's supposed to be and now I have no more low coolant light. Moral of story is you probably have trapped air bubbles and by draining the system you can fix your problem for under $30

Wouldn't running the water pumps bleed procedure solve trapped air pockets as well? Or do we have to completely drain it all?

[Shawnalston10]

Originally Posted by An20Olives

Wouldn't running the water pumps bleed procedure solve trapped air pockets as well? Or do we have to completely drain it all?

I thought the same thing so I did the bleeding procedure and absolutely nothing changed.

[Yourtoastm8]

Im completely new on this site. So im probably in the wrong section but, can anyone help me? My car looses coolant slowly while im not driving it. Looses it quicker when i am driving it. Has slight oil in tail pipe and on start up slight blue smoke from tail pipe. It also has smoke coming from front radiator area after driving for a while. Bmw 335d 2010 e90 it has ben remapped also. Not by me. Thanks

[feuer]

Originally Posted by Shawnalston10

I thought the same thing so I did the bleeding procedure and absolutely nothing changed.

Often is the reservoir itself, not the sensor or air pocket or bleeding procedure.

[Shawnalston10]

Originally Posted by feuer

Often is the reservoir itself, not the sensor or air pocket or bleeding procedure.

Originally Posted by feuer

Often is the reservoir itself, not the sensor or air pocket or bleeding procedure.

My low coolant light is back on. Should I replace the reservoir

[feuer]

Originally Posted by Shawnalston10

My low coolant light is back on. Should I replace the reservoir

Yes.

[Welcome to NBA Jam]

Originally Posted by Shawnalston10

My low coolant light is back on. Should I replace the reservoir

Look around the coolant reservoir and on the frame. You'll see dried coolant on the side of the tank and turbo intake, and possibly pooled coolant on the frame and subframe.

Use a mirror and look under the seam. Clean the side of the tank and go for a drive. Come back and look the next day. If you see white marks and see coolant, you'll have your answer. Mine is leaking decently from the seam and corner.

At first I was nervous that my turbo coolant lines were leaking since I saw significant pooling on the subframe below the turbo. I poured some water from the side of the tank and watched it flow right to that very spot. Phew!

[feuer]

Originally Posted by Welcome to NBA Jam

Look around the coolant reservoir and on the frame. You'll see dried coolant on the side of the tank and turbo intake, and possibly pooled coolant on the frame and subframe.

Use a mirror and look under the seam. Clean the side of the tank and go for a drive. Come back and look the next day. If you see white marks and see coolant, you'll have your answer. Mine is leaking decently from the seam and corner.

At first I was nervous that my turbo coolant lines were leaking since I saw significant pooling on the subframe below the turbo. I poured some water from the side of the tank and watched it flow right to that very spot. Phew!

That isn't the problem. Re-read the 1st post. Coolant level is Ok. Low Coolant warning. Replace the sensor. Low coolant warning remained. Level inside the reservoir is two part system. One part is float bar that goes up and down to show level when you remove the cap, other part is float that give sensor reading because sensor doesn't get in direct contact with the coolant at all. This part often gets "stuck" and to me only known remedy is reservoir replacement.

[Xander Cruz]

Originally Posted by feuer

Often is the reservoir itself, not the sensor or air pocket or bleeding procedure.

My et tanks seals were all busted, and the cap wouldn't stay sealed. I just replaced the et with temp sensor. Drove to work this morning and got the same temp warning yellow>red limp mode. When I replaced the et I topped off fluid and let the engine run for 15 min with the cap off for the et to let any air escape. I'm thinking next might be the water pump itself? 110K miles

[Xander Cruz]

Originally Posted by An20Olives

Wouldn't running the water pumps bleed procedure solve trapped air pockets as well? Or do we have to completely drain it all?

You can run it cold with the reservoir tank uncapped for 10 min. or... press the start button with the fob inserted without your foot on the break, then crank your heat up and the pump should start moving coolant through the et.

[Welcome to NBA Jam]

Originally Posted by An20Olives

Wouldn't running the water pumps bleed procedure solve trapped air pockets as well? Or do we have to completely drain it all?

Yep. The bleed procedure will do the same procedure as mechanics have done for years and years and years, but with the electric pump. Plus some other optimizations. It's the easiest bleed procedure of any car I've had.

[S P A C E M A N]

Originally Posted by feuer

That isn't the problem. Re-read the 1st post. Coolant level is Ok. Low Coolant warning. Replace the sensor. Low coolant warning remained. Level inside the reservoir is two part system. One part is float bar that goes up and down to show level when you remove the cap, other part is float that give sensor reading because sensor doesn't get in direct contact with the coolant at all. This part often gets "stuck" and to me only known remedy is reservoir replacement.

I'm on my 3rd tank in one year, and I'm still getting this warning in error. What is wrong with these reservoirs, and is there a better version to replace with so this doesn't keep happening?

[feuer]

Originally Posted by S P A C E M A N

I'm on my 3rd tank in one year, and I'm still getting this warning in error. What is wrong with these reservoirs, and is there a better version to replace with so this doesn't keep happening?

Are you purchasing OEM or aftermarket? Often is installer error. If you jam funnel in there to pour coolant you could get the float stuck.

[S P A C E M A N]

Originally Posted by feuer

Are you purchasing OEM or aftermarket? Often is installer error. If you jam funnel in there to pour coolant you could get the float stuck.

I've replaced twice with Rein aftermarket tank. No funnel jamming. This time around it was fine for about two months, then the light came on. Then it went off for a couple days, and now it's back on.

[TunafishE93]

See if you can meter the low coolant sensor.. Coolant full should be pins connected.. If pins are connected you have issues else where.. You might have a shady wire..

[feuer]

Originally Posted by S P A C E M A N

I've replaced twice with Rein aftermarket tank. No funnel jamming. This time around it was fine for about two months, then the light came on. Then it went off for a couple days, and now it's back on.

Originally Posted by TunafishE93

See if you can meter the low coolant sensor.. Coolant full should be pins connected.. If pins are connected you have issues else where.. You might have a shady wire..

Get OEM, is less than $150 shipped, or try what TunafishE93 suggesting. Some Rein reviews show what you are experiencing https://www.fcpeuro.com/products/bmw...pt0131#reviews

[TheGoodTheBadTheUgly]

First and cheapest thing would be to get a Genuine BMW sensor and to throw the Rein one in the garbage.

[S P A C E M A N]

Originally Posted by feuer

Get OEM, is less than $150 shipped, or try what TunafishE93 suggesting. Some Rein reviews show what you are experiencing https://www.fcpeuro.com/products/bmw...pt0131#reviews

Originally Posted by TheGoodTheBadTheUgly

First and cheapest thing would be to get a Genuine BMW sensor and to throw the Rein one in the garbage.

Thanks for the suggestions! I jumped the pin before the second replacement, so no issues with the wiring. I'll get an OEM sensor to start and see how that goes.

[6ixSpd]

Say NEIN to Rein!

[S P A C E M A N]

Originally Posted by S P A C E M A N

Thanks for the suggestions! I jumped the pin before the second replacement, so no issues with the wiring. I'll get an OEM sensor to start and see how that goes.

I went ahead and got the whole OEM reservoir, which comes with the OEM sensor already. So far it's working perfectly.