2017 GLS550 Coolant Leak

[rpaoness]

I did for the over-the-master section. The middle looks more fixed but I’m doing this in 2-minute intervals among a whole bunch of other stuff. Hopefully Sunday I can be a lot more deliberate. I was just glad the pressure kit fit and I could see a drip at that firewall hose. It would not have been visible at all if I hadn’t already pulled the master cylinder cowl cover.

[kevm14]

I did say that was the likely culprit....

[rpaoness]

I can barely see just the hose part coming onto it from the firewall. Is there some complicated plastic multi hose thing in between the false firewall and the firewall? Is it likely cracked or just some hose clamp losing tension?

[kevm14]

Some plastic is probably cracked. I'll get the diagram.

[kevm14]

Something in the 10, 20, 30, 50 parts area I believe. Hopefully this is enough to figure it out.

[rpaoness]

Looks like piece 20 was cracked. The small line running down also snapped off when we tried to remove it. We were looking for the oil leak and think we have it tracked down to some like 1” diameter maybe push-in plug at the top outboard rear corner of the drivers side cylinder head. Had to cut away the zip ties on the wiring harness in that area. Are there any obvious plugs/o-rings in that area before I try prying it out?

[rpaoness]

A couple of minutes of googling and I think this might be it:
PN 000-998-65-90-M22

https://www.pelicanparts.com/More_Info/ ... ie3odL8PDr

https://www.mbpartsource.com/oem-parts/ ... dhcw%3D%3D

Actual PN 000-998-65-90?

[kevm14]

Yes that's it. It's really just one piece and you simply replace. If I recall it has an "o-ring" that's really just part of the molding. They snap off and snap on.

Other options:
https://www.mercedesbenzpartsshop.com/o ... c3VsdHM%3D

https://www.fcpeuro.com/products/merced ... 1895100950

https://www.fcpeuro.com/products/merced ... 0009985590

[rpaoness]

The plug/o-ring is in stock, but not the heater fitting.

New London has apparently just been bought by a new owner and no longer honoring the online ordering system through Mercedes that I placed an order through (but somehow still saw my order?). He said he's going to cancel the online order and do some conventional at-the-counter one. He's planning on overnighting the heater fitting, so they should have it by 11:00 AM tomorrow.

[kevm14]

FCP typically ships out of Milford, CT which would be very fast for you.