New upper radiator hose collapsed ?

[2006Tahoe2WD]

Hello,
Day before yesterday I replaced the upper and lower rad. hoses and heater hoses and fittings. Of course drained the coolant and replaced with DexCool. This morning I went to check the work after a drive yesterday and I noticed the new upper hose was flat as if things cooled down and the vent cap didn't allow air back in. I loosend the cap and sure enough I heard air going back in so I figure there is something wrong with the cap. Is this a common failure? Seems odd because it must be a very simple check valve in the cap. Thanks for any ideas.

 

[MassHoe04]

I had an issue on my Jeep last year. New cooling system top to bottom. I was having a problem venting. Instead of gently filling the overflow tank as things expanded, it built pressure in the radiator and engine and pushed out in a gush. I replaced the brand new cap with the 20 year old cap and never had the problem after that.

In my case the spring-loaded stopper was allowing too much pressure to build and it would burst out to the overflow when the cap finally reached the maximum pressure it was designed to hold back.

On yours, you may want to inspect the cap. But you may want to inspect the overflow reservoir too.

As fluid expands, excess coolant is supposed to flow from the radiator to the overflow reservoir.
When the system cools, coolant is supposed to get pulled back into the radiator to make up volume.

If the tube that is supposed to allow the system to draw coolant from the reservoir back into the system is blocked, I could see how the engine and radiator cooling would cause the hoses to collapse in on themselves.

So, check your cap. But, I might be more willing to bet you have dirt or debris blocking the little passage tube/opening on the overflow reservoir...

If systems were neglected or in harsh environments, it is easy for stuff to get in there and block the tube. Doesn't take much!

Let us know.

 

[swathdiver]

@Doubeleive

Hey Wes, is that cooling system restrictor on the 800s in the hoses or the radiator?

 

[Doubeleive]

@Doubeleive

Hey Wes, is that cooling system restrictor on the 800s in the hoses or the radiator?

it's on the radiator, small outlet, has a small hose that goes from the right hand upper side of radiator to the reservoir tank

 

[2006Tahoe2WD]

I had an issue on my Jeep last year. New cooling system top to bottom. I was having a problem venting. Instead of gently filling the overflow tank as things expanded, it built pressure in the radiator and engine and pushed out in a gush. I replaced the brand new cap with the 20 year old cap and never had the problem after that.

In my case the spring-loaded stopper was allowing too much pressure to build and it would burst out to the overflow when the cap finally reached the maximum pressure it was designed to hold back.

On yours, you may want to inspect the cap. But you may want to inspect the overflow reservoir too.

As fluid expands, excess coolant is supposed to flow from the radiator to the overflow reservoir.
When the system cools, coolant is supposed to get pulled back into the radiator to make up volume.

If the tube that is supposed to allow the system to draw coolant from the reservoir back into the system is blocked, I could see how the engine and radiator cooling would cause the hoses to collapse in on themselves.

So, check your cap. But, I might be more willing to bet you have dirt or debris blocking the little passage tube/opening on the overflow reservoir...

If systems were neglected or in harsh environments, it is easy for stuff to get in there and block the tube. Doesn't take much!

Let us know.

Thanks for the comments. I sucked on the cap and couldn't get any flow. Searching online indicates the cap is likely to go bad in this way. Could also be as you say - I'll look again. I don't think the "overflow" and "vacuum" line is kinked or clogged but it could be. I had it out the other day and didn't see anything odd. Thanks again.

 

[swathdiver]

it's on the radiator, small outlet, has a small hose that goes from the right hand upper side of radiator to the reservoir tank

Thanks, was wondering if his problem could have stemmed from that, remembering those fellas from a couple years ago with radiator woes like Kevan.

 

[MassHoe04]

Maybe somebody used some Stop Leak to plug a leaky radiator or heater core. If left running through the system a long time, that stuff can eventually block small openings, tubes and vent holes.

 

[afpj]

when I changed out my rad hoses, I bought dayco brand and the upper hose collapsed like you describe. Swapped it out for gates, fixed that issue. I’m pretty sure I burped the system the same both times. The dayco physically felt thinner , softer than the gates hose. sometimes name brand matters.

 

[2006Tahoe2WD]

Update - this morning I checked and the upper hose was not collapsed. I unscrewed the cap and didn't hear any hissing. I think whatever hung up the suction check valve let go. Could have been 100% coolant that dried out in there while I was filling things back up. I don't know. I'm tempted to just order a new cap. Issues that go away by themselves often come back by themselves.

 

[2006Tahoe2WD]

BTW - my new hoses are AC Delco from RockAuto.

 

[MassHoe04]

Update - this morning I checked and the upper hose was not collapsed. I unscrewed the cap and didn't hear any hissing. I think whatever hung up the suction check valve let go. Could have been 100% coolant that dried out in there while I was filling things back up. I don't know. I'm tempted to just order a new cap. Issues that go away by themselves often come back by themselves.

Could have been a chunk of rust from inside the block passing through... Maybe it got caught, then pressure from coolant flow could have broken it up, allowing it to pass like a kidney stone.

 

[Joseph Garcia]

Let us know in a few weeks, if your issue is still gone (hopefully).

 

[2006Tahoe2WD]

I replaced the overflow tank and cap. The new tank looks great.
Take a look. Old dirty 16 year old tank and the new OEM one.

 

[2006Tahoe2WD]

I was asked to report on the working of the original cap. It started working again - no collapsed hoses - but I replaced it anyway.

 

[Jerome Nelson]

I had this issue as well. I replaced the original cap with a new one from Advanced Auto Parts ($16) and it went away.
Later, I cleaned the old cap with a degreaser, soaked it in hot water, and replaced the new cap with the old one to test it out. The upper hose collapsed again while cooling. :/
Finally, I swapped the old one for the new one again - and haven't had any issues with it since.

 

[2006Tahoe2WD]

Yes, not worth messing around with trying to revive the old cap. Just get a new OEM cap and be done with it.