[bacardi198]

Hey everyone,

I've been getting the low coolant message for the past week or so...I checked the expansion tank, it was low, added some and it went away for a few minutes then popped back up. Checked again, added a little more to be on the safe side, and the message stayed. I also noticed the coolant in the expansion tank is light brown, so it needs to be flushed, which I'm going to do this weekend.

After adding in coolant the second time, the expansion tank is beyond max level (going to suction some out). In any case, I'm wondering how the car determines the coolant level?

On the E9X, there's a coolant level sensor on the expansion tank, but looking at the parts diagram for the expansion tank on the F30, I don't see one. I've searched RealOEM for "sensor" and went through what came up, but I don't see anything that would be a coolant level sensor .

Which leads me to my next question, if there isn't, how does the car know when the coolant is low?

Thanks!

[BashShah]

ok, 2 things

1) you have a Coolant leak somewhere.
2) Coolant Low means that after pouring in Coolant first time you should have Purged the coolant system. (Bleed it) Electronically in our cars ....look it up.

brown coolant is a sign of corrosion or Oil Mixing with Coolant somewhere.

Possible and most likely culprit (OFHG)

here read this Thread
https://www.e90post.com/forums/showthread.php?t=727609

[bacardi198]

Originally Posted by BashShah

ok, 2 things

1) you have a Coolant leak somewhere.
2) Coolant Low means that after pouring in Coolant first time you should have Purged the coolant system. (Bleed it) Electronically in our cars ....look it up.

brown coolant is a sign of corrosion or Oil Mixing with Coolant somewhere.

Possible and most likely culprit (OFHG)

here read this Thread
https://www.e90post.com/forums/showthread.php?t=727609

I've pulled the belly plan and looked upward into the engine bay with the car off and with the car running, and can't find any hint of wetness from a coolant leak. I may dye it in the morning and see if I can find a leak before doing the coolant flush this weekend.

I did run the bleeding procedure after adding into the expansion tank, but it was only at the "min" level when the message popped up. After adding to the "max" level, the car still said the coolant was low. This is why I'm wondering if there is a coolant level sensor similar to the E90 that may be faulty. If not, does anyone know how the F30 measures coolant level?

I was thinking it may be the OFHG so I preemptively ordered both the OFHG and oil cooler gaskets yesterday, but there is no seepage or leakage anywhere on the oil filter housing. I know when the OFHG on my E92 went out, the housing itself was leaking badly -- is it possible for the gasket to be bad and only allow oil to cross into the coolant, without an external leak? I can't find any cases of the OFHG going bad in this fashion (no external leak), but with the car only having 37k miles in 5 years, I'm not sure where else the oil may be crossing over into the coolant system.

Since the gaskets will be here tomorrow, I'm going to flush the coolant, change the oil, and replace both gaskets on Saturday morning.

[F32Fleet]

There are min-max lines on the outside of the expansion tank. Check right side facing the engine. They can be hard to see.

[bavarianride]

To OP, F30 coolant level sensor is embedded inside the expansion tank, so the whole tank needs to be replaced if sensor is busted.

https://www.newtis.info/tisv2/a/en/f...ensor/HHchhD0w
(328i and 335i same instructions)

How many miles are on the car? The coolant is supposed to be lifetime/100k miles, but a brown color means it should be flushed.

Do note the TIS procedure is only drain and fill, so do ask dealer/indy to connect to flush machine to get rid of rust and stuff.

BTW, F30 OFHG needs intake manifold removal, so my preference would be not to touch OFHG if no leak.

[bacardi198]

Originally Posted by bavarianride

To OP, F30 coolant level sensor is embedded inside the expansion tank, so the whole tank needs to be replaced if sensor is busted.

https://www.newtis.info/tisv2/a/en/f...ensor/HHchhD0w
(328i and 335i same instructions)

How many miles are on the car? The coolant is supposed to be lifetime/100k miles, but a brown color means it should be flushed.

Do note the TIS procedure is only drain and fill, so do ask dealer/indy to connect to flush machine to get rid of rust and stuff.

BTW, F30 OFHG needs intake manifold removal, so my preference would be not to touch OFHG if no leak.

I appreciate the response, bavarianride.

The car only has 37k miles, and after siphoning the expansion tank's contents, there was about a quart of oil floating at the top. Beneath the oil was clean greenish-blue coolant. Here's a picture of the oil floating on top of the coolant in a paint mixing cup:



I drained the oil to change it, and to minimize spillage when I pulled the oil cooler housing, and the oil had no coolant (wasn't milky/brown/frothy, was the color it should be with 3,000 miles of use).

I pulled off the oil cooler housing and the gasket looks brand new...I'm thinking it was replaced sometime before I purchased the car last year. It's pliable, not stiff, not flat, and has all of the extra tab-like things around the gasket that are on the improved part number. If that was replaced, I'm sure the OFHG was replaced as well.

Could it be oil that was left in the system from before when the gaskets were replaced? I have no idea where a quart of oil would cross over into the coolant system other than at the OFH/OCH. I suppose I should pull the OFH off and check the OFHG just to be safe, though .

[bavarianride]

Is the car still under new car warranty(4 years/50000 miles) or CPO?

Was the OFHG/OCH replaced at dealer? If there is paperwork those jobs will be covered 2 years/unlimited miles, and dealer needs to fix this.

[F32Fleet]

Originally Posted by bacardi198

I appreciate the response, bavarianride.

The car only has 37k miles, and after siphoning the expansion tank's contents, there was about a quart of oil floating at the top. Beneath the oil was clean greenish-blue coolant. Here's a picture of the oil floating on top of the coolant in a paint mixing cup:



I drained the oil to change it, and to minimize spillage when I pulled the oil cooler housing, and the oil had no coolant (wasn't milky/brown/frothy, was the color it should be with 3,000 miles of use).

I pulled off the oil cooler housing and the gasket looks brand new...I'm thinking it was replaced sometime before I purchased the car last year. It's pliable, not stiff, not flat, and has all of the extra tab-like things around the gasket that are on the improved part number. If that was replaced, I'm sure the OFHG was replaced as well.

Could it be oil that was left in the system from before when the gaskets were replaced? I have no idea where a quart of oil would cross over into the coolant system other than at the OFH/OCH. I suppose I should pull the OFH off and check the OFHG just to be safe, though .

You have a serious issue. Please tell us how you acquired this vehicle and it's age/warranty status.

[BashShah]

Originally Posted by F32Fleet

You have a serious issue. Please tell us how you acquired this vehicle and it's age/warranty status.

1+

[jimk]

Seems to me that someone "topped off" the oil via the coolant expansion tank. Take it to the dealer and have the cooling system completely flushed.

[bacardi198]

Originally Posted by F32Fleet

You have a serious issue. Please tell us how you acquired this vehicle and it's age/warranty status.

I purchased the vehicle preowned at a dealer last October; it's a 2013 that was originally sold in October 2013, but only has 37k miles, so it's out of warranty only due to age.

I called the dealer and confirmed the OFHG was replaced in February 2017, but there is no 2 year / unlimited mile warranty on repairs that are done under warranty...which I think is really asinine.

Anyways, I pulled off the housing and both gaskets still look brand new. Not sure where this oil came from, I'm almost ready to believe it was accidentally topped off in the expansion tank like jimk mentioned. I've only driven it 800 miles since purchasing a year ago, and I didn't look at the coolant when I bought it as I assumed the dealer did due diligence.

Other things: the oil level has been perfect since purchase; the oil I drained over the weekend was a good color, no frothy/milky/coffee-like color; the coolant under the oil was a very clean greenish-blue color; car has never overheated or thrown any check engine codes.

I ran some coolant flushing stuff for 3 hours, drained it, filled up and drained 3 more times but there was still residual oily grime from the system floating up to the top. I think the best bet is to have it flushed at the dealer, although I don't know if they do a power flush or if it's just a drain and fill. Can't get an answer from the service department because the guy doesn't know off the top of his head and can't check because he was "the only one working today" .

[bavarianride]

Originally Posted by bacardi198

I purchased the vehicle preowned at a dealer last October; it's a 2013 that was originally sold in October 2013, but only has 37k miles, so it's out of warranty only due to age.

I called the dealer and confirmed the OFHG was replaced in February 2017, but there is no 2 year / unlimited mile warranty on repairs that are done under warranty...which I think is really asinine.

Anyways, I pulled off the housing and both gaskets still look brand new. Not sure where this oil came from, I'm almost ready to believe it was accidentally topped off in the expansion tank like jimk mentioned. I've only driven it 800 miles since purchasing a year ago, and I didn't look at the coolant when I bought it as I assumed the dealer did due diligence.

Other things: the oil level has been perfect since purchase; the oil I drained over the weekend was a good color, no frothy/milky/coffee-like color; the coolant under the oil was a very clean greenish-blue color; car has never overheated or thrown any check engine codes.

I ran some coolant flushing stuff for 3 hours, drained it, filled up and drained 3 more times but there was still residual oily grime from the system floating up to the top. I think the best bet is to have it flushed at the dealer, although I don't know if they do a power flush or if it's just a drain and fill. Can't get an answer from the service department because the guy doesn't know off the top of his head and can't check because he was "the only one working today" .

One option is to flush coolant and refill, then check if oil shows up again. If it is accidental filling of oil to expansion tank, then the flush should hopefully take care of it.

[F32Fleet]

Originally Posted by bacardi198

I purchased the vehicle preowned at a dealer last October; it's a 2013 that was originally sold in October 2013, but only has 37k miles, so it's out of warranty only due to age.

I called the dealer and confirmed the OFHG was replaced in February 2017, but there is no 2 year / unlimited mile warranty on repairs that are done under warranty...which I think is really asinine.

Anyways, I pulled off the housing and both gaskets still look brand new. Not sure where this oil came from, I'm almost ready to believe it was accidentally topped off in the expansion tank like jimk mentioned. I've only driven it 800 miles since purchasing a year ago, and I didn't look at the coolant when I bought it as I assumed the dealer did due diligence.

Other things: the oil level has been perfect since purchase; the oil I drained over the weekend was a good color, no frothy/milky/coffee-like color; the coolant under the oil was a very clean greenish-blue color; car has never overheated or thrown any check engine codes.

I ran some coolant flushing stuff for 3 hours, drained it, filled up and drained 3 more times but there was still residual oily grime from the system floating up to the top. I think the best bet is to have it flushed at the dealer, although I don't know if they do a power flush or if it's just a drain and fill. Can't get an answer from the service department because the guy doesn't know off the top of his head and can't check because he was "the only one working today" .

Mercedes has a citric acid flush product. Youay want to take a look at that.

[F32Fleet]

Originally Posted by bacardi198

I purchased the vehicle preowned at a dealer last October; it's a 2013 that was originally sold in October 2013, but only has 37k miles, so it's out of warranty only due to age.

I called the dealer and confirmed the OFHG was replaced in February 2017, but there is no 2 year / unlimited mile warranty on repairs that are done under warranty...which I think is really asinine.

Anyways, I pulled off the housing and both gaskets still look brand new. Not sure where this oil came from, I'm almost ready to believe it was accidentally topped off in the expansion tank like jimk mentioned. I've only driven it 800 miles since purchasing a year ago, and I didn't look at the coolant when I bought it as I assumed the dealer did due diligence.

Other things: the oil level has been perfect since purchase; the oil I drained over the weekend was a good color, no frothy/milky/coffee-like color; the coolant under the oil was a very clean greenish-blue color; car has never overheated or thrown any check engine codes.

I ran some coolant flushing stuff for 3 hours, drained it, filled up and drained 3 more times but there was still residual oily grime from the system floating up to the top. I think the best bet is to have it flushed at the dealer, although I don't know if they do a power flush or if it's just a drain and fill. Can't get an answer from the service department because the guy doesn't know off the top of his head and can't check because he was "the only one working today" .

Mercedes has a citric acid flush product. I've read some people use laundry detergent (IE Tide) but DO NOT use dishwasher detergent because it attacks aluminum. Of course there are OTC products.

[bacardi198]

Originally Posted by F32Fleet

Mercedes has a citric acid flush product. I've read some people use laundry detergent (IE Tide) but DO NOT use dishwasher detergent because it attacks aluminum. Of course there are OTC products.

I stopped by the dealer and spoke with the shop foreman who is also the service manager; he said he will flush and clean the cooling system for me, and keep it under $250 total.

I asked him what they would do, and he said he'd have a junior technician do the job and he'd keep an eye on him and help him along the way, letting the junior tech take his time to learn how to do it for in the future. He said it'd be a "good learning experience" for someone who hasn't done it before.

He actually said they'll use dish detergent to clean all the oil out, I'm assuming he knows what he's doing since he's worked for BMW since 1991 . He also mentioned pulling the hoses to the heater core and flushing through there to make sure it's good as well...seems like they're going to do a thorough job, and it'll be done at the dealer so I don't see them cutting corners or giving it back with oily residue (as opposed to say Firestone using their flushing machine).

Scheduled for drop off on Tuesday afternoon and he said I should be able to pick it up Wednesday late morning. I'm almost tempted to do it myself, but at the same time, spending $250 to not have to mess with the car, jack it up, fill, run it, drain it, fill, run it, drain it, etc. on the weekend seems like money well spent.

[BashShah]

Personally speaking, I think a Flush with a Machine is 10 times better than a Drain and Fill with detergent or any other oil breaking soap.

Also, I would add 1 step more just to be sure.
Machine Flash with a Laundry Liquid Detergent, small amount like 1/3 or 1/2 of a recommended amount in a FRONT LOAD Washing machine.
Front Load Washing machines use (he)=(High Efficiency) detergent, Basically LESS Bubbles, Less Air, and would be perfect for a Coolant flushing machine.

and once this was done, I would do one more flush with water, then drain and refill with BMW coolant+Distilled water equal parts.

1st to wash system
2nd to rince soap out
3rd to put regular coolant back in.

I am just trying to be 100% sure here for a peace of mind.

[F32Fleet]

Originally Posted by bacardi198

I stopped by the dealer and spoke with the shop foreman who is also the service manager; he said he will flush and clean the cooling system for me, and keep it under $250 total.

I asked him what they would do, and he said he'd have a junior technician do the job and he'd keep an eye on him and help him along the way, letting the junior tech take his time to learn how to do it for in the future. He said it'd be a "good learning experience" for someone who hasn't done it before.

He actually said they'll use dish detergent to clean all the oil out, I'm assuming he knows what he's doing since he's worked for BMW since 1991 . He also mentioned pulling the hoses to the heater core and flushing through there to make sure it's good as well...seems like they're going to do a thorough job, and it'll be done at the dealer so I don't see them cutting corners or giving it back with oily residue (as opposed to say Firestone using their flushing machine).

Scheduled for drop off on Tuesday afternoon and he said I should be able to pick it up Wednesday late morning. I'm almost tempted to do it myself, but at the same time, spending $250 to not have to mess with the car, jack it up, fill, run it, drain it, fill, run it, drain it, etc. on the weekend seems like money well spent.

ya that'll woek

[bacardi198]

Originally Posted by BashShah

Personally speaking, I think a Flush with a Machine is 10 times better than a Drain and Fill with detergent or any other oil breaking soap.

Also, I would add 1 step more just to be sure.
Machine Flash with a Laundry Liquid Detergent, small amount like 1/3 or 1/2 of a recommended amount in a FRONT LOAD Washing machine.
Front Load Washing machines use (he)=(High Efficiency) detergent, Basically LESS Bubbles, Less Air, and would be perfect for a Coolant flushing machine.

and once this was done, I would do one more flush with water, then drain and refill with BMW coolant+Distilled water equal parts.

1st to wash system
2nd to rince soap out
3rd to put regular coolant back in.

I am just trying to be 100% sure here for a peace of mind.

Agreed with everything you said, that was going to be my plan of action if I did the final flushing myself. In the future, if this ever happens again (which I'm sure it inevitably will), I will take that course of action myself.

Update from the dealer:

They flushed it and ran detergent through the heater core and all of the cooling system, but they were still getting some oil floating to the top of the expansion tank.

The service manager spoke with a BMW Field Engineer about what could be causing it, the engineer said out of all of the cases he's seen in the field on the N55, oil in the coolant leads to the gaskets or the oil filter housing assembly itself being bad. With the gaskets being changed by BMW less than 7k miles ago, the engineer said the OFH assembly may have a crack that's allowing oil to pass through to the coolant.

Service manager wants to replace the OFH, and also the oil thermostat I believe (which sits in the housing as well), to the tune of $1,600. He said BMWNA agreed to good-will some of the cost and the parts will be in tomorrow, I should have the car back Friday. He doesn't believe it's the head gasket or anything with the head since the car runs great, idles great, and there are no codes (shadow or otherwise) that indicate any issues.

My question is: what if they complete the repair, and oil is still crossing over into the coolant? Do I have to pay even though they misdiagnosed? That would be insane to allow them to just keep changing everything they want hoping it's the fix, at that point it's essentially burning money. For now I'm going to stay optimistic that the OFH assembly is the cause, even though I didn't see anything wrong with it when I took it off last weekend.

[BashShah]

You dont have a choice but to let the dealer do it.
I say let them do it, and wait to hear back, they can not test the Head Gasket any other way.
if they were wrong, then they should be reimbursing full cost of a mis-diagnostic and repair.

[harmanonline85]

I have a 2013 328xi and i always get the low coolant warning in winters. I got it checked and there were no leaks and the coolant level was right upto the mark but still it shows low coolant warning on idrive. Sometimes it goes away after the car runs for a while but sometimes it stays there. Any suggestions/inputs?

[BashShah]

Originally Posted by harmanonline85

I have a 2013 328xi and i always get the low coolant warning in winters. I got it checked and there were no leaks and the coolant level was right upto the mark but still it shows low coolant warning on idrive. Sometimes it goes away after the car runs for a while but sometimes it stays there. Any suggestions/inputs?

You need to replace the Coolant Expansion bottle.
The Level is faulty.
unfortunately, the level and expansion bottle are one.

I had the same issue.
drove me nuts that it would say low coolant but there was more than enough.

Also, if you topped of coolant, did you run the bleed procedure electronically.
if the bleed procedure runs more than 15 min, then you have a alot of air in the system.
I had to do this like 3 times and had to put a charger on the battery terminals.

Good luck.

[harmanonline85]

Originally Posted by BashShah

You need to replace the Coolant Expansion bottle.
The Level is faulty.
unfortunately, the level and expansion bottle are one.

I had the same issue.
drove me nuts that it would say low coolant but there was more than enough.

Also, if you topped of coolant, did you run the bleed procedure electronically.
if the bleed procedure runs more than 15 min, then you have a alot of air in the system.
I had to do this like 3 times and had to put a charger on the battery terminals.

Good luck.

You were right....had to get my coolant expansion tank changed since the sensor was faulty...got it replaced and now no warnings😌😌 Thanks for all your help!!