[DeVikingChef]

Wow, this really explains a lot.

4 weeks ago I came to my car in the parking garage after work and saw a huge puddle under the car. I already assumed it was coolant, this turned out to be the case when I got into the car. Immediately the coolant low message.

Lucky enough (or not), there is a BMW dealer 5 minutes from my work.

It took about an hour before they came to me and told me that it was only a tube and that they could repair it "quickly" before closing time.
After the fix, they also haven't hinted the slightest bit that this could be something that would play across multiple BMWs.

But with this knowledge I will definitely call them on Monday and get a story, perhaps demand a refund.

*Based in The Netherlands, BMW f31 2019 320i

[Mr.Smartepants]

This just happened to me last Friday on the way home from work. 5 miles from home the "low coolant" caution, then 1 minute later the "engine temp high" caution, immediately followed by the "engine overheated pull over right f'ing now" warning. Oil temp was still below normal operating temp so I limped home and shut it off. After an hour, I checked both expansion tanks and they were bone dry. I disconnected the hose from the expansion tank and the whole hose came out easily (missing the cylinder head connector). I called the BMW (UK) dealer 20 miles away and they said there was no recall on my car even though I quoted them the BMW service bulletin number. They refused to acknowledge that the USA/Canada recall even applied in the UK.
They wanted me to pay for a tow truck, their "diagnostic fee", and parts/labor. Screw that!
So I called their parts department and asked if they had part # 17129845173 in stock and the guy said "yeah, we always have a good supply of those on-hand", when I told him about the recall, he said "yeah, I'm not legally allowed to comment on that, but we go through a lot of that part #."
Replacing the part and refilling the system took me less than 2 hours.
So, do I NEED to pay BMW to do the cooling system vacuum treatment? Or am I safe to drive it as-is? The engine oil temp gauge reads exactly the same as before.

[acediac]

Originally Posted by Mr.Smartepants

This just happened to me last Friday on the way home from work. 5 miles from home the "low coolant" caution, then 1 minute later the "engine temp high" caution, immediately followed by the "engine overheated pull over right f'ing now" warning. Oil temp was still below normal operating temp so I limped home and shut it off. After an hour, I checked both expansion tanks and they were bone dry.

...

So, do I NEED to pay BMW to do the cooling system vacuum treatment? Or am I safe to drive it as-is? The engine oil temp gauge reads exactly the same as before.

I just had this exact problem, I was in the middle of the highway in the middle of a rainstorm 10 minutes from home, so I kept driving even though it fluctuated between the yellow and red warnings. The temp gauge showed normal about 100C the whole time! Got home quick as I could and the engine was hot and slightly smoking...

I already read about this a couple of months ago, and already bought the part but was too busy to change it! Now I may have a cooked engine

Mr Smartepants, how much coolant did you put in? Were you able to use the car after that or did you end up vacuum flushing the system?

[Mr.Smartepants]

Originally Posted by acediac

Mr Smartepants, how much coolant did you put in? Were you able to use the car after that or did you end up vacuum flushing the system?

That sucks. I hope your engine is OK. I only used maybe half a gallon (tops) of 50/50 mix (I still have half of the BMW bottle of concentrate).
I did not take it for a vacuum flush and I've had zero problems after the repair. Engine oil temps are back to their normal ranges.

I may have to vacuum flush the cooling system anyway since I plan on replacing the oil filter housing and upper radiator hose fitting BEFORE they fail.

[acediac]

Originally Posted by Mr.Smartepants

That sucks. I hope your engine is OK. I only used maybe half a gallon (tops) of 50/50 mix (I still have half of the BMW bottle of concentrate).
I did not take it for a vacuum flush and I've had zero problems after the repair. Engine oil temps are back to their normal ranges.

I may have to vacuum flush the cooling system anyway since I plan on replacing the oil filter housing and upper radiator hose fitting BEFORE they fail.

Ok, just an update, only the high temp circuit was depleted, and I had to top up with 3 litres of coolant but in the end I bought a vacuum kit and vacuum flushed it anyway because I was worried about further damage to the engine. It was not as difficult as I thought, once I took the bottom tray off and found the right hoses to drain it following the newtis guides (did both high temp and low temp circuits) and did both bleed procedures. I also replaced oil + filter because I'm sure the oil had a workout. Interestingly, the manual says the coolant system is about 9L but I only filled about 4.5-5L total for both circuits. I suppose I could never really drain a portion of the thing as the lowest hoses still sit above the radiator bottom.

I did a drive today with my brother following behind and remarkably there was no visible smoke, temps were normal and power was good. It remains to be seen if there is any warpage or long term damage but right now the oil and coolant don't seem to be mixing.

I also plan to replace the oil filter housing, and will buy one of the aluminium ones from Amazon (I just searched for 11428596283). There are a few people selling these but they all seem to be identical from the pictures. I think some chinese company must have made an aluminium mold for this and mass produced it because of the demand from all the failures as I think there are a lot of B48 engines in the chinese market. Anyway, I figure it could be no worse than another plastic one so I'll take a chance. I might buy original gaskets though just in case.

When you say "upper radiator hose fitting" are you talking about part number 11118511205 as that seems to be another common failure?

Also thinking of doing the water pump 11518638026 since I have to drain the coolant again anyway.

[acediac]

For anyone just doing the expansion tank to cylinder head hose replacement 17129845173 it is quite an easy job, I did it without removing the manifold or the ECU, just the bracket in front of the cylinder head side with the 3 bolts and 4 clips to hoses. Then just fish the hose around, starting perpendicular to the front of the engine from the left. You can reach around on the right side around the back. It actually took me longer to unclip some of those hose holder clips without damaging them, than to actually connect the actual hose up.

The real issue is how soon it will break again. The hose connectors are brittle and the hose is rigid, and it connects between the engine that moves and the coolant tank that doesn't. Searching on Amazon, there seems to be a silicone hose version that might be worth considering. I'm thinking the connectors are still plastic but a silicone hose might have more give and put less stress on the connectors.

[Mr.Smartepants]

Yeah, I'm assembling a list of parts to change.
11517644809 is the part number that includes the alternator mount/gaskets.
11518638026 is the pump only.

[bimmerGT]

Just ordered the expansion tank to cylinder head hose (17129845173) to change it as preventive maintenance before it die (unfortunately in Europe it isnt a recall). I own a 2018 F34 320i with stage 1 with 70k kms.

To those who did this maintenance before I wanted to ask for some tips.

How much coolant I´m going to loose during this operation? Should I empty the expansion tank before remove the hose? Will be mandatory to bleed the air out after this operation?

Thanks in advance!

[Mr.Smartepants]

Originally Posted by bimmerGT

1. How much coolant I´m going to loose during this operation?
2. Should I empty the expansion tank before remove the hose?
3. Will be mandatory to bleed the air out after this operation?

1. If it doesn't burst when the engine is running, you'll probably lose maybe 100-200ml. Mine burst when the engine was running (I drove it home) and I lost less than 1L.

2. NO! No need for this unless you plan to do a full coolant flush.

3. Yes and no. There's a procedure to use the electric aux pump to "soft-bleed" the hot side of the cooling system which is explained below. But if you're changing the hose as a preventative measure, then very little air will get into the system so no need for a full vacuum purge.

Bleeding the high-temperature cooling system:

Remove vacuum filler device on coolant expansion tank for high temperature.
Open bleeder screw on coolant expansion tank for high temperature and shut again after approx. 10 s.
Adjust the coolant level in the coolant expansion tank for high temperature to maximum.
Shut the sealing cap on the coolant expansion tank for high temperature.
Connect battery charger.

Starting the high-temperature cooling system bleeding routine:

Switch the ignition on.
Secure vehicle against rolling away/driving off (apply parking brake and put in P in automatics).
Switch on low-beam headlights and hazard warning lights.
Check that driving experience switch is not set to ECO-PRO.
Set heating to maximum temperature and turn blower to lowest speed.
Press accelerator pedal for 10 seconds to floor.
Cooling system bleeding routine starts
Then start engine.
Increased idle speed of 1200 rpm is set.
After 1 minute, increased idle position (1200 rpm)

- Press on accelerator up to about 3000 rpm for 10 seconds.

- Idle for 10 s.

- Press on accelerator up to about 3000 rpm for 10 seconds.

- Idle for 10 s.

- Press on accelerator up to about 3000 rpm for 10 seconds.

- Idle for 10 s.

- Press on accelerator up to about 3000 rpm for 10 seconds.

- Idle position for 10 seconds.

- Press on accelerator up to about 3000 rpm for 10 seconds.

The high-temperature cooling system bleeding routine has finished approximately 11 minutes after having started the engine.
Engine speed drops to idle speed level.
Switch off engine.
Allow the engine to cool down.
Adjust the filling level in the high temperature coolant expansion tank to maximum.
Close the sealing cap of the coolant expansion tank for high temperature until it lines up with the arrows.

[bimmerGT]

Originally Posted by Mr.Smartepants

1. If it doesn't burst when the engine is running, you'll probably lose maybe 100-200ml. Mine burst when the engine was running (I drove it home) and I lost less than 1L.

2. NO! No need for this unless you plan to do a full coolant flush.

3. Yes and no. There's a procedure to use the electric aux pump to "soft-bleed" the hot side of the cooling system which is explained below. But if you're changing the hose as a preventative measure, then very little air will get into the system so no need for a full vacuum purge.

Thanks a lot for your detailed response! I will try to replace it this weekend

[bimmerGT]

Hose successfully changed this morning. It took about 45m and 0.5l (0.132 gallons if I’m not wrong) of coolant was enough to complete this operation. I ran the bleeding procedure as described in previous posts and everything looks fine after a few kms.

Does anyone know if the new hoses (with new reference) are still having the same problems after a few years/milleage?

Thanks everyone!

[quakerroatmeal]

I've heard they revised the part. Hope they used better quality plastics on the revised edition.

[Trossuk]

The drama of this continues….the pipe failed whilst on an 800 mile road trip to visit family over the new year. Recovery from top of Scotland back to Derbyshire took 13 days with the RAC! 32k on the clock. £500 repair bill from BMW. I had them do it as I didn’t know exactly what had failed and wanted them to check everything out. Pipe was £27. Gotta love the stealers. Moral of the story, change this pipe now…..

[1sickf30]

What hoses besides "Hose cylinder head expansion tank"
do you guys recommend doing at the same time?

[quakerroatmeal]

Originally Posted by Trossuk

The drama of this continues….the pipe failed whilst on an 800 mile road trip to visit family over the new year. Recovery from top of Scotland back to Derbyshire took 13 days with the RAC! 32k on the clock. £500 repair bill from BMW. I had them do it as I didn’t know exactly what had failed and wanted them to check everything out. Pipe was £27. Gotta love the stealers. Moral of the story, change this pipe now…..

You actually paid a decent price at £500