[lowrydr310]

I posted about a month ago how I discovered my relatively new coolant tank doesn't make a nice tight fit with the cap despite swapping caps with my 330i (which does have a tight seal.) I may take advantage of the lifetime warranty and try my luck with another Rein tank.

I also have a small leak from the relatively new Gates upper radiator hose:


I get a faint smell of hot coolant outside the car from the drivers side wheel well, or from the area of the raditor by that hose when I open the hood, but not much of a smell from the passenger side.

Could these leaks be enough to cause the slow loss of coolant every few months? I last topped off about 3 months ago and just got the low coolant light this morning.

I had the under tray off the car and even removed the intercooler to see the bottom of the radiator, and there's no evidence of any leaks anywhere else. Water pump and thermostat area are dry and clean too.

I'm thinking of cutting that clamp off and replacing it with a t-bolt hose clamp before replacing the entire hose.

[3PedalJake]

`I would cut the crimp clamp off and inspect the plastic for cracks or mfgrg defects. Seems unlikely it would be the hose especially if it's new, and the clamp looks tight, doesn't look like it should be leaking on that account.

[lowrydr310]

Originally Posted by 3PedalJake

`I would cut the crimp clamp off and inspect the plastic for cracks or mfgrg defects. Seems unlikely it would be the hose especially if it's new, and the clamp looks tight, doesn't look like it should be leaking on that account.

If you look closely, the clamp is a bit crooked. It wasn't perpendicular to the hose/fitting when it was attached. I didn't think this would leak, but clearly there's some coolant seeping out at the end of the hose. I'll try cutting that off first before I consider replacing with a whole new hose assembly.

I'm still wondering if this leak and the cap could be responsible for the coolant loss. Like I mentioned above, I can really smell it near the drivers side wheel well after driving. My radiator cracked a while ago and sprayed a mess of coolant; I replaced it and rinsed the engine bay thoroughly. I assumed I was smelling residual coolant from that old leak, but it's still present. The engine compartment is clean and dry with no signs of coolant leaks other than the two I mentioned.

[mainbearing]

I have a Gates upper hose for a few years and it is completely dry. Maybe the quality has gone downhill with the latest. Get a warranty claim there, it should be dry. Now it makes me want to go with a Rein hose next time

As far as coolant loss, if you still have the loose fitting cap and reservoir tank, that may be where the loss happens. Not to mention the system may not reach proper pressure.

I would swap the Rein tank out with a Behr (Mahle) tank and cap, or go OE BMW.

[StradaRedlands]

Gates has always been a go-to manufacturer. Hopefully their quality isn't slipping!

[lowrydr310]

Originally Posted by mainbearing

I would swap the Rein tank out with a Behr (Mahle) tank and cap, or go OE BMW.

My current 335i Rein tank was purchased in July 2024 (side note: it's now $17 cheaper than it was back in July!) When I installed it, I used a new Febi-Bilstein cap.

My 330i has a BMW tank and cap, and after swapping the BMW cap over to my 335i it still doesn't seal tightly on the Rein tank, so the problem is definitely the tank and not the cap.

I wonder if I can do a warranty replacements for a different brand? I'm definitely not taking the chance with another Rein tank, going BMW branded tank this time even at 2x price. FCP doesn't even offer a Mahle/Behr tank for sale any more. The product page says Not Available and indicates it's made in the same country as all the other aftermarket tanks (not Germany.)