2014 GL450 coolant hose to thermostat assembly disconnects after 30 min!!
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2014 GL450 coolant hose to thermostat assembly disconnects after 30 min!!
When we replaced the thermostat assembly the rubber hose to the top of the radiator keeps disconnecting from the thermostat assembly after running the vehicle for 30 min. We made sure the catch spring was secure. What are we missing? Wondering if we are supposed to run the car with the cap off to release any air? The thermostat assembly was from fcpeuro and the hose is oem. Is there too much pressure? We also did not bleed the entire coolant system. Thank you!
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From: Fleriduh
W212 E63S Wagon - GSL580 - E63 - E350 - C300
I did the exact same thing three weeks ago. I did not have the hose fully clipped in. I asked around and was told to use silicone to assist in getting it to fully seat. I had none and used some coconut oil from the kitchen :-) (it was that or gee)
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@OldManAndHisCar thanks for the reply 
did you use an aftermarket thermostat assembly? We really jammed the hose in there and checked that the clip was secure….. even tried to yank the hose out again. Thought we had it connected really good this time but, a 14 mile drive to a gas station and back home, it started leaking again as I pulled into the driveway. Opened the hood and the hose was completely disconnected…..
did you use an aftermarket thermostat assembly? We really jammed the hose in there and checked that the clip was secure….. even tried to yank the hose out again. Thought we had it connected really good this time but, a 14 mile drive to a gas station and back home, it started leaking again as I pulled into the driveway. Opened the hood and the hose was completely disconnected…..
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From: Fleriduh
W212 E63S Wagon - GSL580 - E63 - E350 - C300
@OldManAndHisCar thanks for the reply
did you use an aftermarket thermostat assembly? We really jammed the hose in there and checked that the clip was secure….. even tried to yank the hose out again. Thought we had it connected really good this time but, a 14 mile drive to a gas station and back home, it started leaking again as I pulled into the driveway. Opened the hood and the hose was completely disconnected…..
did you use an aftermarket thermostat assembly? We really jammed the hose in there and checked that the clip was secure….. even tried to yank the hose out again. Thought we had it connected really good this time but, a 14 mile drive to a gas station and back home, it started leaking again as I pulled into the driveway. Opened the hood and the hose was completely disconnected…..
What I had to do was pull out the metal clip on the receiver side (there is a click for it). Seat it as well as I could - then push the spring clip thing down. I then pressure tested (to 25lbs).
For me, it did not pop off until the car was to temp and I hit the gas a bit.
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@OldManAndHisCar well I do have some coconut oil! For silicone, should I use 100% caulking silicone? I’m worried it would somehow get into the coolant and mess something else up……
I’m trying to avoid having to order and oem thermostat assembly……$400!!!
the aftermarket one was made by wahler, looks exactly the same as oem except the part number and mb symbol was sanded off….. surely it’s identical?
I’m trying to avoid having to order and oem thermostat assembly……$400!!!
the aftermarket one was made by wahler, looks exactly the same as oem except the part number and mb symbol was sanded off….. surely it’s identical?
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From: Fleriduh
W212 E63S Wagon - GSL580 - E63 - E350 - C300
Wahler is the OE...should fit. Mine is OE, from Mercedes..I did not have it on correctly.
As for the silicone, LUBRICANT not "caulk". The rubber seal needed to slide into the groove. I figured that the oil was better than some of the other things that were in the garage (or bedroom).
As for the silicone, LUBRICANT not "caulk". The rubber seal needed to slide into the groove. I figured that the oil was better than some of the other things that were in the garage (or bedroom).
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I have a new hose, clip and hexalobular screw on the way from MB…… hopefully with lubricant it will remain secure……I forgot to mention the screw was missing so maybe there was also some vibration as the thermostat assembly was not completely secured.
@OldManAndHisCar how did you pressure test? I suppose I could leave the car on, heater on high for 30 min and rev the engine? Also leave the cap off the coolant tank to release any air just in case?
@OldManAndHisCar how did you pressure test? I suppose I could leave the car on, heater on high for 30 min and rev the engine? Also leave the cap off the coolant tank to release any air just in case?
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From: New Orleans
2014 GL450, 1992 W140 300SD, 1993 W140 300SE, 1987 E30 Convertible
Two things you need to check. 1) install spring in place and take a look into thermostat housing if spring fully engaged in locking position. Then, when installing hose can use any lubricant, even engine oil, for rubber o-ring, and make sure it clicks on both sides
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From: Gresham, OR
GL450
I haven't had a problem with this specific connection, but for other coolant connections I've found that the new o-rings for other coolant hose connectors are VERY tight, and require what I feel is a surprisingly large force to insert even with a silicone lubricant. You'll be pushing harder than what you think is appropriate for a plastic fitting. What I had to do for at least once of the connections (and I did this using advice I read from others), is to remove the flattened o-ring from the old original connector (in my case the original plastic had cracked but the o-ring was ok) and swap it with the o-ring on the new connector. When you do this, you can see how much larger the new o-ring is, and how it could prevent the new male connector from seating all the way into the female connector. The downside to re-using the old o-ring is that the seal isn't perfect, I've seen a tiny bit of leakage around the connector, but it inserts fully and stays locked in place. So I would recommend using a lubricant and pushing very very hard, maybe even hold it for a few seconds to let the o-ring form from the original circular cross-section into the rectangular cross-section of the groove.
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E550 Coupe 2wd (2016)
I had trouble getting one end of my hose all they way in too. It seemed to go in and the clip went on, but didn't feel right. Pulling and wiggling the hose it popped out. You should always pull/wiggle hoses to check, but especially so with clip-in.
Some O-ring lube and a little force got it in slightly deeper, then the clip felt right when it went in place.
Also, if you can see in the slot on the radiator where the clip holds it, you can see the slot of the hose appear in there when the hose is deep enough.
Some O-ring lube and a little force got it in slightly deeper, then the clip felt right when it went in place.
Also, if you can see in the slot on the radiator where the clip holds it, you can see the slot of the hose appear in there when the hose is deep enough.
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From: Melbourne, Australia
2010 ML550 VIN WDC1641722A564750, 2010 B180
The proper procedure when reattaching the radiator hose to the thermostat is to put the clip in place FIRST and then insert the hose. You'll hear it click when the hose is properly seated. Your problem is a common one where people insert the hose first and then attach the clip and after a short drive the hose disconnects itself.
