[Egrunt]

I have a question about the fabrication of a coolant tank in stainless steel or aluminum. Do you think there would be an issue with stainless steel / aluminum getting hotter than current plastic coolant tank? If the aforementioned tanks did get hotter, would it raise the temperature of the coolant inside the coolant tank?
Looking at the other two vehicles (VW and Toyota) in our household both coolant tanks are constructed out of plastic. But the engine compartment in those vehicles do not get as hot as the M5. My other concern would be, having an aftermarket coolant tank installed would present a problem if a warranty related concern came about.

[AHall]

I think the warranty concern is valid. Also the repair information posted here indicates additional effects of whatever is causing this issue such as damaged charge coolers. So replacing the tank with an aluminum tank may prevent a leaking tank and the associated collateral damage to injectors, coils, etc. It may allow the additional affects of the true cause to progress to a more severe level.

[Aronis]

Now we can get into thermodynamics.

Q. Which material conducts heat better? Plastic or Stainless Steel?

A. I vote Metal will conduct heat better, but I could be wrong.

Q. Is the Tank a Source of Heat?

A. No, hell no. The hot coolant is but because the engine is creating that heat due to combustion. The stored fluid in that tank is not a new source of heat. It does not create any more heat. Yes, heat will radiate off the tank to the surrounding structures which are likely already HOT.

Thus no additional Heat "Created" and the metal tank would likely release more heat to the atmosphere than the plastic. I really REALLY doubt it would be a measurable difference. If you touch that new Metal Tank you may get a burn quicker than touching the plastic, more insulating, surface.

There are hotter surfaces adjacent to that plastic tank which are radiating more heat than it does.

my 2 cents, a Metal Tank would be better.

Mike

[vanmpower]

My 2018 came out of warranty at the end of June 2022. Up to that point I had brought in the car three times for low coolant warning and the third time, they replaced the tank (May 2022).

Fast forward to July 2022. My first, ~$2k, out-of warranty maintenance which included replacement of all spark plugs. Pick the car up; overtake another car on the highway; car runs rough and goes into limp mode.

The car has been at the dealership for two weeks now. So far one new coil and four new injectors...and on a test drive this afternoon...still running rough. The foreman has taken over the job. I am stressed out.

EDIT: ~69,000km.

[AHall]

Originally Posted by vanmpower

My 2018 came out of warranty at the end of June 2022. Up to that point I had brought in the car three times for low coolant warning and the third time, they replaced the tank (May 2022).

Fast forward to July 2022. My first, ~$2k, out-of warranty maintenance which included replacement of all spark plugs. Pick the car up; overtake another car on the highway; car runs rough and goes into limp mode.

The car has been at the dealership for two weeks now. So far one new coil and four new injectors...and on a test drive this afternoon...still running rough. The foreman has taken over the job. I am stressed out.

EDIT: ~69,000km.

Do you by chance know the color of the coolant

[hunter8793]

Originally Posted by vanmpower

My 2018 came out of warranty at the end of June 2022. Up to that point I had brought in the car three times for low coolant warning and the third time, they replaced the tank (May 2022).

Fast forward to July 2022. My first, ~$2k, out-of warranty maintenance which included replacement of all spark plugs. Pick the car up; overtake another car on the highway; car runs rough and goes into limp mode.

The car has been at the dealership for two weeks now. So far one new coil and four new injectors...and on a test drive this afternoon...still running rough. The foreman has taken over the job. I am stressed out.

EDIT: ~69,000km.

Let us know what they figure out.

[vanmpower]

Originally Posted by AHall

Do you by chance know the color of the coolant

They gave me a bottle of the blue stuff previously, to top up.

[M5Neededi]

Originally Posted by vanmpower

My 2018 came out of warranty at the end of June 2022. Up to that point I had brought in the car three times for low coolant warning and the third time, they replaced the tank (May 2022).

Fast forward to July 2022. My first, ~$2k, out-of warranty maintenance which included replacement of all spark plugs. Pick the car up; overtake another car on the highway; car runs rough and goes into limp mode.

The car has been at the dealership for two weeks now. So far one new coil and four new injectors...and on a test drive this afternoon...still running rough. The foreman has taken over the job. I am stressed out.

EDIT: ~69,000km.

Can you elaborate on engine running rough? And did you get a CEL or other warnings? My car appears to be in limp mode as well we were suspecting the fuel pump. No CEL or or warning messages. I have not had any issues with coolant (just bought the car with 26k miles). So probably not the same issue but I will not know until next week when I take it to BMW service.

[ResIpsaLoquitur]

Originally Posted by M5Neededi

Can you elaborate on engine running rough? And did you get a CEL or other warnings? My car appears to be in limp mode as well we were suspecting the fuel pump. No CEL or or warning messages. I have not had any issues with coolant (just bought the car with 26k miles). So probably not the same issue but I will not know until next week when I take it to BMW service.

Ugh, been through limp mode due to HPFP with no warnings as we were discussing on another thread in the past few days. Hope that it gets sorted out for you and that OP's issue is resolved as well.

[vanmpower]

Originally Posted by M5Neededi

Can you elaborate on engine running rough? And did you get a CEL or other warnings? My car appears to be in limp mode as well we were suspecting the fuel pump. No CEL or or warning messages. I have not had any issues with coolant (just bought the car with 26k miles). So probably not the same issue but I will not know until next week when I take it to BMW service.

The problem was first revealed when driving home from the dealership after a scheduled maintenance. I kicked down to pass someone and the car stumbled. The image below showed up on the screen and the CEL light went on too. Car was running quite rough but no nasty noises. I pulled over, restarted, rough idle gone. Screen said the car was drivable so I went home.

I, and the dealership, immediately assumed it was one of the new spark plugs; but no.

The car has always been drivable during this issue unless you're hard on the throttle then things cut out into limp mode. I also think it's more susceptible to happen when I have an M-mode on.

[M5Neededi]

Thanks @vanmpower Interestingly the limp mode started after I picked my car from dealer to fix center console buttons and the gesture control. But you seem to have a different problem. I have not gotten any messages.

@ResIpsaLoquitur yeah I hope the dealer will figure it out quickly and take care of it. I will mention HPFP to them.

[Maverik259]

Originally Posted by Egrunt

I have a question about the fabrication of a coolant tank in stainless steel or aluminum. Do you think there would be an issue with stainless steel / aluminum getting hotter than current plastic coolant tank? If the aforementioned tanks did get hotter, would it raise the temperature of the coolant inside the coolant tank?
Looking at the other two vehicles (VW and Toyota) in our household both coolant tanks are constructed out of plastic. But the engine compartment in those vehicles do not get as hot as the M5. My other concern would be, having an aftermarket coolant tank installed would present a problem if a warranty related concern came about.

Agree with Aronis
1) I would do Aluminum over Stainless due to weight and its ability to dissipate heat quicker. Plus stainless will corrode in the right conditions. Not sure how coolant fluid would react with it.
2)Yes a hot tank would heat up the fluid inside although i would imagine it would be negligible. Those tanks are expansion tanks and i wouldn't expect that fluid to be pulled down to the system. with that said, i would not put a metal tank inside our hot engine bay without covering it in heat reflecting tape first.
3) as with all other aftermarket parts, they won't affect your warranty unless the fault can be linked to that part. ie. if you suddenly lost all your coolant because of a leak in the aftermarket tank, then yes expect it to not be covered under warranty.

[gblansten]

Near 21,000 miles on my 20 M5 and had to top off the coolant reservoirs yesterday for the first time. I've had to do this on my three prior M vehicles. Doubt there is a leak. The engine reservoir was the driest.

[Aronis]

Add one. 2018 M5, 46k miles (my dad's car). Coolant leak noted at routine service. (as well as bad battery internal switch).

I ordered a new coolant tank today. DIY.

Mike

[Aronis]

Reading up on DIY tank replacement. Interesting that the manual has one remove the DME unit on that side, but oddly it does not appear to be in the way of removing the tank? I have to take another look to survey they job. Why removing that if it's not in the way?

Mike

[916_M5]

Originally Posted by pbonsalb

Some reports were that the coolant damaged wiring that caused problems but I can’t recall what wiring—into spark plug holes?

This EXACT thing happened to me. I had a small crack on the reservoir on the driver's side. Leaked on to my ignition coils. Warranty swapped out tank, the coils it leaked on, and their corresponding plugs. No leaks since. I would also have them check all the wiring harnesses around the area to make sure they did not fry / expose wiring.

[916_M5]

Originally Posted by vanmpower

My 2018 came out of warranty at the end of June 2022. Up to that point I had brought in the car three times for low coolant warning and the third time, they replaced the tank (May 2022).

Fast forward to July 2022. My first, ~$2k, out-of warranty maintenance which included replacement of all spark plugs. Pick the car up; overtake another car on the highway; car runs rough and goes into limp mode.

The car has been at the dealership for two weeks now. So far one new coil and four new injectors...and on a test drive this afternoon...still running rough. The foreman has taken over the job. I am stressed out.

EDIT: ~69,000km.

Did you ever run low on fuel? Sound like a fuel system issue. I had a similar issue from running low on fuel. Fried my driver's side fuel pump. Needed new pump, injectors, and plugs on the driver's side. Can run's better than ever.

[Aronis]

Originally Posted by 916_M5

Did you ever run low on fuel? Sound like a fuel system issue. I had a similar issue from running low on fuel. Fried my driver's side fuel pump. Needed new pump, injectors, and plugs on the driver's side. Can run's better than ever.

67,000 computers in these cars and the thing lets you run the tank that low....LOL....

Mike

[Maverik259]

Originally Posted by Aronis

67,000 computers in these cars and the thing lets you run the tank that low....LOL....

Mike

im curious where the low coolant sensor even is if one exists at all. its clearly not in the resevoir tank...isn't there one in the wiper fluid tank? hmm

[pbonsalb]

What is the sensor in the tank?

[vanmpower]

Picking up the car this afternoon with crossed fingers. From the Foreman:

"Replaced #5,6,7,8 injectors and ignition coils. It was a connection issue due to the coolant leak in the past. the connectors had coolant residue build-up. we replaced all on this side (bank 2) of the engine. opposite side is dry no issues. The car was road tested with spirited driving and re-scanned after every road test. No more faults recurring. We are open until 5pm. Thank you for your patience on this repair."

Knock on wood but I am extremely pleased with the way my dealership has handled this.

[Maverik259]

Originally Posted by vanmpower

Picking up the car this afternoon with crossed fingers. From the Foreman:

"Replaced #5,6,7,8 injectors and ignition coils. It was a connection issue due to the coolant leak in the past. the connectors had coolant residue build-up. we replaced all on this side (bank 2) of the engine. opposite side is dry no issues. The car was road tested with spirited driving and re-scanned after every road test. No more faults recurring. We are open until 5pm. Thank you for your patience on this repair."

Knock on wood but I am extremely pleased with the way my dealership has handled this.

"with spirited driving" lmao