Radiator hose flat?!

atalarico

atalarico

Senior Member
Well, here's a new one to me. I popped my hood randomly while tinkering in the driveway and saw my upper rad hose was sucked flat for some reason! I opened the overflow tank and heard some dripping. Popped the cap and heard a little suck too.

It started rounding back out again, but wtf was that all about? Did I not burp all of the air out when I replaced my rad hoses a while ago?

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So I wiggled the underside of the rad cap (brand new OEM one too) and pushed it up and it felt like it unstuck. Put the cap back on and popped the overflow cap and squeezed the upper hose. I could hear fluid moving through again.

Bad cap?
 
Probably bad cap not relieving vacuum properly as engine cools - it should suck the fluid from the overflow container. I suppose the small diameter hose going to the overflow container could be plugged but the obvious cause is the cap.

Buckaroo
 
Buckaroo said:
Probably bad cap not relieving vacuum properly as engine cools - it should suck the fluid from the overflow container. I suppose the small diameter hose going to the overflow container could be plugged but the obvious cause is the cap.

Buckaroo
Click to expand...

Yes, probably cap.
 
Probably not the cap. Have you cleaned the reservoir tank lid and the two hoses attached to it? Those get clogged too. Also, clean the plastic nozzle attached to the radiator by the cap.
 
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Thanks guys. Probably the cap because i would squeeze the upper rad hose and hear nothing going to overflow. Then I'd pull the cap and push on the inside part of the cap that moves up and down, and then try to squeeze the hose again and stuff would flow to the overflow tank.
 
An odd update; I popped my hood and saw that now coolant has leaked from the upper radiator hose where it connects to the engine. Wtf?

What am I missing here? Guessing I have to disconnect the hose and clean up the mating surface?

I still haven't replaced the radiator cap, but I haven't been driving it at all either. The hose is brand new and the clamp is the original clamp with 230k on it. It wasn't leaking before I noticed all of this flat hose thing and I was driving it a bit.
 
Last edited:
atalarico said:
An odd update; I popped my hood and saw that now coolant has leaked from the upper radiator hose where it connects to the engine. Wtf?

What am I missing here? Guessing I have to disconnect the hose and clean up the mating surface?

I still haven't replaced the radiator cap, but I haven't been driving it at all either. The hose is brand new and the clamp is the original clamp with 230k on it. It wasn't leaking before I noticed all of this flat hose thing and I was driving it a bit.
Click to expand...

Clean it up, fixed mine from leaking. I had lots of corrosion on mine. ALso a new compression style clamp would help.
 
The overflow line is clogged. Pressure is not getting relieved. Fix it before it blows out a hose or a weak point in a heater core or radiator.
 
Thanks for the info. If the overflow hose is getting clogged, then why did the following happen:

Pulled the overflow hose off of the overflow tank port. Attempted to blow through it toward the radiator cap but I couldn't. Pulled the radiator cap and jiggled the valve part of it back and forth a bit after feeling it was a little sticky. Put the cap back on and then was able to blow through the overflow hose.

To me that says bad rad cap (even though it's brand new OEM). I have plenty of silicone hose to re-cut a new overflow hose, but let me know if my cap theory sounds reasonable.
 
Under normal circumstances you should not be able to blow from the overflow tube into the rad with the rad cap on.

If you could, then that would defeat the purpose of having a pressure regulated cap. It would be like having a zero pound cap.
 
Well, Im making a fantastic mess today forgetting exactly how much coolant comes out when you go to pull the upper hose off.

I bought new OEM clamps for the upper hose. I pulled the hose off and scrubbed the connector quite a bit with steel wool since there was corrosion going on. Picture attached of after clean up.
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I also compared a new rad cap with my few month old rad cap and the spring feels the same, so I didn't replace that.

Checked the overflow hose and it's totally clear. The one thing I'm wondering is if the silicone tube was too short and maybe it's causing a kink? Picture here.
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I'm going to let it run for a bit and see how it all does. I really wanted to take it off-roading tomorrow on my way to a climb but not super confident now.
 
How much coolant in the reservoir? I had the same issue. Replaced rad cap, maxed out fluid to F line, so far so good. Long term will be doing replacement of radiator, thermostat, fan clutch, hoses and adding in series tranny cooler


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Frdmskr said:
How much coolant in the reservoir? I had the same issue. Replaced rad cap, maxed out fluid to F line, so far so good. Long term will be doing replacement of radiator, thermostat, fan clutch, hoses and adding in series tranny cooler
Click to expand...


Overflow res was just a little below F. Funny story on your long term plan...that's exactly everything I replaced over the summer (although I replaced the rad two summers ago I think).

When I put the new hose clamp on in the same spot as the old indents, I noticed that the bottom side of the clamp was crooked and not clamping the bottom of the hose.

Maybe that was it the whole time? I mean, wouldn't an improper seal on the hose clamp allow air in (suction to make the hose flat when turned off) and a coolant out when the system was put back under pressure?
 
Frdmskr said:
Yup. Hence all with a bad rad cap having same issue. Nights solved it


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Click to expand...



Sweet! Here's to hoping! My poor 4Runner would be fine if I just stopped screwing things up on it.

Sooo, coolant is not a big deal if it spills all over the belts and pulleys, right? I tried wiping up what I could, but yeah.
 
I'd imagine shit happens. I got some on a battery...rather the mechanic did and it still works.


Gotta love iPhone typonese


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