M3 expansion tank - Is this normal?

[Mintsopoulos]

A nice welded piece to match a CSF intercooler wouldnt be a bad option

[swagon]

Originally Posted by G35POPPEDMYCHERRY

Ill try to "bend over" and take a look; I'm more legs than torso.


This post was questionable so I will say it...no homo.

Too late, my long-legged beast.

[swagon]

The charge cooler seems to be doing fine.

BUT, I have added too much coolant in the main expansion tank since September for my liking - half a liter. No other symptoms.

And the tank itself seems to be separating in the seams at the back end, as I measured it... even though I don't see any dried up coolant anywhere.

I just need to convince the dealer to stop denying my goddamn CPO warranty cos it's valid till June all over Europe and I ain't paying for this shit AND my cracked seat badges.

[///BMW Junkie]

I am in a slightly different situation, but please bear with me.

1) I got code that my charge cooler pump is running dry. Checked charge cooler expansion tank and it was very low so I topped it off

2) Checked after a few days, and it was low again. This time also checked the main expansion tank and it was low as well

3) Took the car to the dealer, it's passed the pressure test and was told there is a very small leak within the charge cooler (l did my research before going in and lots of leaking coolers came up. I mentioned this to the dealer since I was not seeing any coolant on the floor or engine bay)

4) Here's where it gets interesting. It's been about a month and a few hundred miles since I took the car home. I ordered a CSF cooler which I haven't installed yet. Reason being is during this time, the charge cooler tank has remained at the same level, and the main expansion tank is still continuously dropping.

If my charge cooler is leaking, would it have an effect on the main expansion tank? I thought they are separate systems.

[jmciver]

They are two separate systems. Check the seems of your engine coolant expansion tank for any white residue. My expansion tank was slowly leaking at the seems with the tell tale sign being white residue (dried coolant) along the seem of the expansion tank. If that is not the source of the leak, then it is elsewhere.

It sounds like your charge cooling system is fine based on what you described.

[Alpine_F82]

So I replaced my expansion tank today because it was leaking. So I replaced it, and today after the first drive, it is leaking out the same spots again so all that for nothing does anybody have any input. I also thought this may be why my car is hotter than usual, it stays around 235 which when I bought the car it stays at 210-220 in efficient now it’s 230-240. So does any one know what my problem may be. It’s blow out of the side of the tank within the first drive as it got the same temp 230-240

[jmciver]

Originally Posted by M4BimmerChris

So I replaced my expansion tank today because it was leaking. So I replaced it, and today after the first drive, it is leaking out the same spots again so all that for nothing does anybody have any input. I also thought this may be why my car is hotter than usual, it stays around 235 which when I bought the car it stays at 210-220 in efficient now it's 230-240. So does any one know what my problem may be. It's blow out of the side of the tank within the first drive as it got the same temp 230-240

If you installed a new engine coolant expansion tank and it is visibly leaking at the seems right after the installation, you unfortunately got a faulty new part. Sucks, but it can happen. Hopefully you can return it for a replacement. Of course, make sure to check your installation to ensure all fittings/hose attachments are tight (including the cap). The other thing to check for is not over filling the tank. If you do, there is an overflow vent that will vent coolant into the engine bay. Lastly, since the genuine BMW expansion tanks seem to have issues, I would definitely stay away from an aftermarket part as a replacement expansion tank.

[Alpine_F82]

Originally Posted by jmciver

If you installed a new engine coolant expansion tank and it is visibly leaking at the seems right after the installation, you unfortunately got a faulty new part. Sucks, but it can happen. Hopefully you can return it for a replacement. Of course, make sure to check your installation to ensure all fittings/hose attachments are tight (including the cap). The other thing to check for is not over filling the tank. If you do, there is an overflow vent that will vent coolant into the engine bay. Lastly, since the genuine BMW expansion tanks seem to have issues, I would definitely stay away from an aftermarket part as a replacement expansion tank.

Yes the tank last did the same thing because I got coolant flush at bmw and they overfilled the tank and it blew. So I replaced it and put to the correct line cold and drove around till temp was up and checked the tank and coming out the plastic weld put the sides. It’s sad I did all of that and it’s another faulty part. Do you think this would cause the extra 20 degrees I have been running in my engine or do you think it would be something else.

[jmciver]

Originally Posted by M4BimmerChris

Yes the tank last did the same thing because I got coolant flush at bmw and they overfilled the tank and it blew. So I replaced it and put to the correct line cold and drove around till temp was up and checked the tank and coming out the plastic weld put the sides. It’s sad I did all of that and it’s another faulty part. Do you think this would cause the extra 20 degrees I have been running in my engine or do you think it would be something else.

While a leaking expansion tank does not help, I think the primary cause for the higher engine coolant temps is possible air in the system. The proper way to refill and bleed the system (according to BMW technical documents), even a partial fill, is to use a vacuum fill tool AND then perform the bleed procedure here:

https://www.newtis.info/tisv2/a/en/f...eck/1VnXqfU9E9

That said, most people have good luck with just following the bleed procedure 2-3 times after filling up since the vacuum fill tool is not a common one to have (although I have one and it makes the coolant fill process very clean and easy). Good luck....

[chatoyer]

Just adding another data point. 2018 F82 with 10K miles. Pointed it out to tech and SA and they immediately started making arrangements for a replacement.

[THEROK]

I'll post this pic on the charge cooler thread, but I think my charge cooler expansion tank is leaking at the seam as well?

[robertg]

Questions:

1. How much are dealers charging typically to do this out of warranty?

2. If you do it yourself a. How hard is it? b. Do you need to purchase coolant?
c. How much is the tank itself?

[Eldaes]

Originally Posted by robertg

Questions:

1. How much are dealers charging typically to do this out of warranty?

2. If you do it yourself a. How hard is it? b. Do you need to purchase coolant?
c. How much is the tank itself?

Off of FCPEuro, the tank in question is $165 in time of writing. It looks fairly easy to replace so I'd give it a shot. Plus since you're buying from FCP, its lifetime warranty so if it does go bad again, just replace it free of charge.

[icebiker]

I think I've answered my own question but would like some confirmation. While checking my charge coolant level (ok so far) I noticed the engine coolant expansion tank had some faint residue (see wavy lines circled in the pic). I assume this means it should be replaced? If so, should be covered by CPO, yes? Car is a 2016, 20k miles, CPO till November 2020. Thanks in advance for any input.

[jmciver]

It can be sometimes difficult to tell from a picture (typical engine bay dirt/dust vs dried, pale blue/white coolant), but if it is a dried, pale blue/white residue along most or all of the plastic weld seem, then you have a "weeper" that should be covered under warranty (including a CPO warranty). Another thing that you can do, and what I did, is to wipe the seem clean and see if it comes back.

[icebiker]

Originally Posted by jmciver

It can be sometimes difficult to tell from a picture (typical engine bay dirt/dust vs dried, pale blue/white coolant), but if it is a dried, pale blue/white residue along most or all of the plastic weld seem, then you have a "weeper" that should be covered under warranty (including a CPO warranty). Another thing that you can do, and what I did, is to wipe the seem clean and see if it comes back.

Thanks and good suggestion!

[bensf82]

Originally Posted by icebiker

I think I've answered my own question but would like some confirmation. While checking my charge coolant level (ok so far) I noticed the engine coolant expansion tank had some faint residue (see wavy lines circled in the pic). I assume this means it should be replaced? If so, should be covered by CPO, yes? Car is a 2016, 20k miles, CPO till November 2020. Thanks in advance for any input.

Hey, sorry to bug you but I'm having a similar issue atm with my 16 CPO M4. Were you able to get it resolved without issue? No low coolant warning but clearly looks like the tank is leaking on mine.

[G35POPPEDMYCHERRY]

Thoughts on this

[icebiker]

Originally Posted by bensf82

Hey, sorry to bug you but I'm having a similar issue atm with my 16 CPO M4. Were you able to get it resolved without issue? No low coolant warning but clearly looks like the tank is leaking on mine.

Hi, I topped it off about a month ago and so far so good. However I will be taking the car in for service next month and will have them check it to be sure.

[jmciver]

Originally Posted by G35POPPEDMYCHERRY

Thoughts on this

Looks like your expansion tank cap may be venting due to being overfilled based on the pattern of coolant spots located around the expansion tank. Take a look at your expansion tank level when the engine is at cold iron. It should be just above the low level mark on the yellow tank level indicator inside the expansion tank - thus allowing maximum room for the coolant to expand.

If your expansion tank level is ok, then it could be a leaking/malfunctioning cap or possibly a small hole/leak in the small expansion tank hose. Regardless, clean the area and monitor it closely after every drive to help you see where it could be coming from.

[bensf82]

Originally Posted by icebiker

Hi, I topped it off about a month ago and so far so good. However I will be taking the car in for service next month and will have them check it to be sure.

Thanks for the info!

[m4nual2016]

Is this too low for a cold engine?