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Re: 2017 GLS550 Coolant Leak

Posted: Sat Dec 20, 2025 6:15 pm
by rpaoness

Re: 2017 GLS550 Coolant Leak

Posted: Sat Dec 20, 2025 6:20 pm
by rpaoness
I also think removal of the fitting may require me to pull the belly covers and I'm not sure about frame-horn-to-side of turbo clearance. Would be good if I can find a generic molded hose that I could cut out the 3/8-1/2 adapter I need from with the total 3" or so of hose.

Re: 2017 GLS550 Coolant Leak

Posted: Sat Dec 20, 2025 6:38 pm
by kevm14
viewtopic.php?p=23869#p23869

viewtopic.php?p=23911#p23911

Yes 3/8" heater hose. That is the thread where I replaced all of the plastic turbo cooling lines with rubber heater hose.

You'll probably have to remove the thermostat which may break in the water pump. And you may have to remove the oil filter adapter in which case you need a new gasket. But looking at my pics maybe not.

Re: 2017 GLS550 Coolant Leak

Posted: Sat Dec 20, 2025 9:18 pm
by rpaoness
I don’t see any plastic other than the tee fitting.

Re: 2017 GLS550 Coolant Leak

Posted: Sat Dec 20, 2025 9:29 pm
by rpaoness
Since I couldn’t find a 3/8-1/2” hose piece I replaced the tee with a plumbing fitting and hose barbs of the right sizes. Working for now and no leaks so far.

I’ll have to try to get pns if that one I found isn’t it. With just that hose in the link I guess I’d be all set until something else leaks

Re: 2017 GLS550 Coolant Leak

Posted: Sat Dec 20, 2025 9:47 pm
by rpaoness

Re: 2017 GLS550 Coolant Leak

Posted: Sat Dec 20, 2025 9:58 pm
by kevm14
Apparently those are different than mine.

Re: 2017 GLS550 Coolant Leak

Posted: Sat Dec 20, 2025 10:12 pm
by rpaoness
Since I'm probably going to use it for just the hose anyhow (and the tee fitting casting looks uncannily like the stock one), I ordered Dorman off Amazon for $40.

https://www.amazon.com/dp/B09JHRBSLT?re ... asin_title

Re: 2017 GLS550 Coolant Leak

Posted: Sat Dec 20, 2025 10:14 pm
by rpaoness
A pic I took mainly for pulleys, but the 1/2" NPT tee is visible.

Re: 2017 GLS550 Coolant Leak

Posted: Tue Dec 23, 2025 5:57 pm
by rpaoness
Managed to break off the vent line fitting from the center of the intake valley to the vent line on top of the engine.

PN 2782031217.

I put a short piece of hose a couple clamps for now, but I'd like to swap for the correct quick connect.

Found it on ECS for $17.45, claims OE supplier on the "image", but it's just Rein. Still about 1/2 Rockauto's price for the same.

https://www.ecstuning.com/b-rein-parts/ ... 31217~ren/