2011 E350 upper Radiator Hose
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Joined: Dec 2020
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From: Texas
E350 Base
2011 E350 upper Radiator Hose
I need help. Apologies if this is the wrong place. I was having a overheat issue, changed thermostat, water pump, resovoir tank and cap, and upper and lower hoses, and radiator. Overheating issue fixed, now the upper hose going into thermostat keeps popping off after about 10 to 15 minutes of driving.......not sure why. When putting hose back on it locks in place and I cannot pull it off. Please help. Thanks so much.
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'11 E350, '11 E550, '98 M3, '95 E320
Besides the obvious... not locking into place, something wrong with the hose and/or thermostat housing. Does the hose get very hard after you start and warm up the engine? Careful, don't burn yourself if it pops off.
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'11 E350, '11 E550, '98 M3, '95 E320
I meant with the engine running is the hose hard? Where I’m going is if the overheat was significant enough to damage the head gasket or warp head... you could be getting excessive pressure in the coolant system and it’s blowing out at the weakest spot.
I’d be 100% sure the hose was locking and then I’d probably grab a coolant pressure tester and verify the system pressure leading up to it blowing off. You can also pressurize the system with the tester and see if the hose holds. I don’t know the cap rating, minimum the system should hold, but at least 20psi it should hold.
I’d be 100% sure the hose was locking and then I’d probably grab a coolant pressure tester and verify the system pressure leading up to it blowing off. You can also pressurize the system with the tester and see if the hose holds. I don’t know the cap rating, minimum the system should hold, but at least 20psi it should hold.
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2011 E-350 4Matic Sport
What brand of parts did you use? OEM or after market? I've fought after market parts before that fit but just didn't perform right.
Case in point - our rv is based on a chevy express 3500 chassis. Lower rad hose has the quick connect at the rad end. I used a decent brand - Gates - for all hoses. All except that one end were standard clamps. I could not get that quick connect to fit properly without needing to remove a couple thousands of material from inside the hose fitting. Replaced with OEM hose that fit perfectly. I know that Gates probably makes hoses for GM as original equipment but those would be first quality. Sometimes the after market mfg is considered second quality. I've also had OEM parts out of the box that were bad but very very seldom.
I'm assuming that coolant pressure at operating temp is ok. If either the hose fitting or the thermo housing is slightly out of spec, the internal pressure at operating temperature is causing the hose fitting to balloon just slightly enough to pop off. When you pull on the cold hose you are pulling straight out. When the engine is running the pressure is expanding the hose fitting outwards from inside. If the clip is barely in place you won't be able to pull it loose but the internal pressure can pop it loose.
So if the coolant pressure is ok - I said I assumed it was because you don't have an issue with coolant coming out the reservoir then the logical place to look is at the housing and/or the hose.
Case in point - our rv is based on a chevy express 3500 chassis. Lower rad hose has the quick connect at the rad end. I used a decent brand - Gates - for all hoses. All except that one end were standard clamps. I could not get that quick connect to fit properly without needing to remove a couple thousands of material from inside the hose fitting. Replaced with OEM hose that fit perfectly. I know that Gates probably makes hoses for GM as original equipment but those would be first quality. Sometimes the after market mfg is considered second quality. I've also had OEM parts out of the box that were bad but very very seldom.
I'm assuming that coolant pressure at operating temp is ok. If either the hose fitting or the thermo housing is slightly out of spec, the internal pressure at operating temperature is causing the hose fitting to balloon just slightly enough to pop off. When you pull on the cold hose you are pulling straight out. When the engine is running the pressure is expanding the hose fitting outwards from inside. If the clip is barely in place you won't be able to pull it loose but the internal pressure can pop it loose.
So if the coolant pressure is ok - I said I assumed it was because you don't have an issue with coolant coming out the reservoir then the logical place to look is at the housing and/or the hose.
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Joined: Jun 2020
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'11 E350, '11 E550, '98 M3, '95 E320
What brand of parts did you use? OEM or after market? I've fought after market parts before that fit but just didn't perform right.
Case in point - our rv is based on a chevy express 3500 chassis. Lower rad hose has the quick connect at the rad end. I used a decent brand - Gates - for all hoses. All except that one end were standard clamps. I could not get that quick connect to fit properly without needing to remove a couple thousands of material from inside the hose fitting. Replaced with OEM hose that fit perfectly. I know that Gates probably makes hoses for GM as original equipment but those would be first quality. Sometimes the after market mfg is considered second quality. I've also had OEM parts out of the box that were bad but very very seldom.
I'm assuming that coolant pressure at operating temp is ok. If either the hose fitting or the thermo housing is slightly out of spec, the internal pressure at operating temperature is causing the hose fitting to balloon just slightly enough to pop off. When you pull on the cold hose you are pulling straight out. When the engine is running the pressure is expanding the hose fitting outwards from inside. If the clip is barely in place you won't be able to pull it loose but the internal pressure can pop it loose.
So if the coolant pressure is ok - I said I assumed it was because you don't have an issue with coolant coming out the reservoir then the logical place to look is at the housing and/or the hose.
Case in point - our rv is based on a chevy express 3500 chassis. Lower rad hose has the quick connect at the rad end. I used a decent brand - Gates - for all hoses. All except that one end were standard clamps. I could not get that quick connect to fit properly without needing to remove a couple thousands of material from inside the hose fitting. Replaced with OEM hose that fit perfectly. I know that Gates probably makes hoses for GM as original equipment but those would be first quality. Sometimes the after market mfg is considered second quality. I've also had OEM parts out of the box that were bad but very very seldom.
I'm assuming that coolant pressure at operating temp is ok. If either the hose fitting or the thermo housing is slightly out of spec, the internal pressure at operating temperature is causing the hose fitting to balloon just slightly enough to pop off. When you pull on the cold hose you are pulling straight out. When the engine is running the pressure is expanding the hose fitting outwards from inside. If the clip is barely in place you won't be able to pull it loose but the internal pressure can pop it loose.
So if the coolant pressure is ok - I said I assumed it was because you don't have an issue with coolant coming out the reservoir then the logical place to look is at the housing and/or the hose.
Lets verify the parts first. I didn't want to rabbit hole, sometimes I think and post as myself, using only OE/OEM parts, checking the basics and now your stuck looking for more.
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Joined: Dec 2020
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From: Texas
E350 Base
Yes with the engine running hose is not real hard. I have used some aftermarket parts. I will replace with OE, and see where it goes from there. When the car overheated it was for less than a minute, as I was pulling back in driveway. I did have coolant coming out resovoir first then replaced cap again, solved that problem. This has been the most frustrating experience with cooling issue I have ever had.
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2011 E-350 4Matic Sport
Some things to check:
- is the cooling fan operating correctly? At normal operating temp or with a.c. on it should be on low speed as commanded by ECU. At critical high temp it should switch to high speed.
- what does the oil look like? Should be clean with no chocolate milkshake appearance.
- any exhaust smell at the reservoir or any persistent white smoke out the tailpipe?
Not sure about the root cause of the overheat issue. From your description it seems that the hose has popped off before you've driven it long enough to verify overheat has been fixed?
Don't want to create a bigger scare but it's worth verifying both head gaskets are ok. Sometimes continued overheating is caused by exhaust leak into the coolant. Hopefully it's just a parts fitment issue.
- is the cooling fan operating correctly? At normal operating temp or with a.c. on it should be on low speed as commanded by ECU. At critical high temp it should switch to high speed.
- what does the oil look like? Should be clean with no chocolate milkshake appearance.
- any exhaust smell at the reservoir or any persistent white smoke out the tailpipe?
Not sure about the root cause of the overheat issue. From your description it seems that the hose has popped off before you've driven it long enough to verify overheat has been fixed?
Don't want to create a bigger scare but it's worth verifying both head gaskets are ok. Sometimes continued overheating is caused by exhaust leak into the coolant. Hopefully it's just a parts fitment issue.
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Thread Starter
Newbie
Joined: Dec 2020
Posts: 6
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From: Texas
E350 Base
Cooling fan is operating correctly, oil is good just changed, no exhaust smell in reservoir. The hose popping off only started after thermostat change. I have changed it again thinking that could be problem. Even when hose popped off car did not show it was overheating by the gauge and my obdII diag tool, temp remained at about 100c. Thanks so much for the help with this.
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Joined: Jun 2020
Posts: 1,363
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'11 E350, '11 E550, '98 M3, '95 E320
Aftermarket is a broad term... what were the brands of the components you bought for the cooling system and where did you get them from? I would have no issue with OEM brands like: Nissens, Behr, Continental, Gates, Wahler, Borg Warner, etc.. or Genuine Mercedes parts.
Reading back through your posts, I'm a bit confused because it sounds like you replaced certain components twice already... like the expansion tank cap and thermostat. Maybe consider reusing the original upper hose... if it stays on, the replacement hose could be the issue and if it pops off, the thermostat housing could be the issue. Assuming the original hose didn't pop off. Both our 2011 E350 and E550 have original coolant systems (100k miles +) and I wouldn't replace the hoses as they are still pliable, unless they started leaking.
Reading back through your posts, I'm a bit confused because it sounds like you replaced certain components twice already... like the expansion tank cap and thermostat. Maybe consider reusing the original upper hose... if it stays on, the replacement hose could be the issue and if it pops off, the thermostat housing could be the issue. Assuming the original hose didn't pop off. Both our 2011 E350 and E550 have original coolant systems (100k miles +) and I wouldn't replace the hoses as they are still pliable, unless they started leaking.
