Moroso Aluminum Expansion Tank

[Obioban]

The original bmw coolant overflow tank. After almost 200k hard miles I would take the chance on another one over the moroso.

I don’t think I’d try to repair it 😜

[Mspir3d]

Which tank split?

The original bmw coolant overflow tank. After almost 200k hard miles I would take the chance on another one over the moroso.

[Anri]

Seems like a downgrade to me. Heavier, loses the sensor. I could see it in a car with a failure prone stock tank, but that’s not us.

Ian,

Not only its a downgrade what your pointing but there is another more critical downgrade.. !!!!

Keep the OEM.

Regards,
Anri

[Obioban]

Mine split. I just replaced it with another unit off ebay and kept the old one in case I wanted to fix it.

Which tank split?

[STAATS]

Okay second test completed. The sight glass thread DOES NOT match the coolant level switch thread. The sight glass thread appears to be straight cut and the sight glass has a seal of sorts for it to work whereas the coolant level switch appears to have a tapered thread of sorts... the coolant level switch goes in the first few threads and then starts going on weird angles (hard to capture in photos). so the install will 100% require the use of the weld-in bung that comes in the kit.

I took some photos of the bits that came, testing of the switch open/shut and trying to test the sight glass in the supplied weld-in bung and the switch in the sight glass bung etc to show how they dont match up. Please see gallery:

https://photos.app.goo.gl/ZymxiXvSRgXZsQpW6

So final step is to install the weld-in bung provided... this won't be happening for some time... I need to remove the tank and the bracket as i will also need to weld on an attachment to the bracket for the Chase Bays Windscreen Wiper tank i am using... so that is a project for when i get time and go and see the welder... I will update on status and with photos once complete.

[Mspir3d]

Mine split. I just replaced it with another unit off ebay and kept the old one in case I wanted to fix it.

[STAATS]

Well just completed the first test - so the sensor reacts as expected. When the float opens the switch the dash displays the coolant level warning light. When the float closes the switch the dash coolant level warning light clears. There is a ~15sec delay between changing from open/close status to the dash reacting with the appropriate warning light or clearing of warning light.

So I can confirm this switch will successfully integrate with the stock wiring and dash system. Good start.

[George Hill]

We've run the Moroso tanks on racecars without issue and I would do it again for them, but I don't think it's the right solution for a street car.

[Feffman]

Okay finally just took delivery of the Moroso level sensor... First thing I will do is try and test the wiring and the switch mechanism to make sure it does indeed turn our coolant level light on/off on our dash as I would expect it too... then next I will look at if the thread of it matches up the the boss they already have in place for the coolant sight glass (as this would take any of the effort of an install out of the equation for others) and then finally I will look at doing my desired install which is to have the sensor in parallel with the sight glass so that as soon as the coolant is no longer visible in the sight glass the coolant level sensor is at its trigger point and sets the light off on the dash. this way you would still use the sight glass for check before runs / top ups etc but as soon as you cant see it in the coolant sight glass and it becomes an unknown you will get a warning on the dash. this will actually give a more advanced warning than the stock setup I believe and If you are monitoring you car and know you can see it in the sight glass then any situation where you have lost that ~200ml that would drop it below the sight glass level would be cause enough for me too pull off.

When i get a chance to start playing I will feedback any findings as well as photos where I can...

I await with baited breath.

[sapote]

Anyone here have experience with the Moroso Expansion Tank? I've heard the moshimoto ET for the non-m is terrible and that plastic is better, is this the same for the Moroso one? It costs a bit more than the OE, so I'm curious if its worth the switch.

It's a waste of money; stay with the stock BMW tank.

[STAATS]

Okay finally just took delivery of the Moroso level sensor... First thing I will do is try and test the wiring and the switch mechanism to make sure it does indeed turn our coolant level light on/off on our dash as I would expect it too... then next I will look at if the thread of it matches up the the boss they already have in place for the coolant sight glass (as this would take any of the effort of an install out of the equation for others) and then finally I will look at doing my desired install which is to have the sensor in parallel with the sight glass so that as soon as the coolant is no longer visible in the sight glass the coolant level sensor is at its trigger point and sets the light off on the dash. this way you would still use the sight glass for check before runs / top ups etc but as soon as you cant see it in the coolant sight glass and it becomes an unknown you will get a warning on the dash. this will actually give a more advanced warning than the stock setup I believe and If you are monitoring you car and know you can see it in the sight glass then any situation where you have lost that ~200ml that would drop it below the sight glass level would be cause enough for me too pull off.

When i get a chance to start playing I will feedback any findings as well as photos where I can...

[STAATS]

Also coincidentally stumbled across a very similar conversation over on M3Cutters: https://forums.m3cutters.co.uk/threa...-a-diy.228776/

They use some other kind of aftermarket level sensor and doesnt look like it uses an Aluminium boss so I dont like it as much as a potentially solution vs the Moroso sensor but still looks like it does the trick.

[STAATS]

Ugh COVID-19 has delayed the Moroso shipment again so looking like end of this month of early next to get the level sensor... not the worst as I am in the final stages of a CF Roof install and my regular welder who will weld on the tank is busy for the next few weeks but still annoying and delays the testing...

[STAATS]

I'm not on board with the opposite of good being better. The stock tank on our car is very reliable-- pretty much bulletproof if you replace it at 100,000 mile intervals, with the rest of the cooling system. The Moroso loses the coolant temp sensor, probably makes for less accurate coolant level setting, is heavier, unproven, more expensive, and heavier.

I don't think me or Feff are running around trying to convince people the Moroso tank is the way to go... just given our build goals and the risks we want to take / money we want to spend we have decided that running the tank is a better option for us... for me it was after years of building FSAE cars and just enjoying how bulletproof well fabricated Ally tanks are vs anything plastic. Sure our stock tanks aren't exactly failure prone but whoever it was that suggested carrying a spare tank that seems stupid... when you could just have one that wont break so you dont have to be off track at all and wouldn't have the chance of not pulling off after a failure fast enough... in any case its a choice and if I can get this level sensor to work as Feff is also trying then really the only concession we have made aside from cost is some weight... which considering my category has a minimum weight anyway and I have stripped weight in so many other places, I am totally cool with...

[Feffman]

I'm not on board with the opposite of good being better. The stock tank on our car is very reliable-- pretty much bulletproof if you replace it at 100,000 mile intervals, with the rest of the cooling system. The Moroso loses the coolant temp sensor, probably makes for less accurate coolant level setting, is heavier, unproven, more expensive, and heavier.

The Moroso tank loses the coolant level sensor (part 17137553919) which is why I've reached out to Moroso to see if they can install their coolant level sensor and bung (https://www.moroso.com/catalog/produ...num-bung63950/) to the bottom of their coolant tank in the same place as on the plastic stock tank. This is what STAATS is looking at doing on his own.

Fortunately, I've never had a coolant tank failure on my M3 but I've seen two fail, one at Road Atlanta and one at Gateway, both on what appeared to be very well maintained cars.

Feff