jeff spahn

I had a strange thing show up at the Sharks on the Mississippi.

When I parked my car after driving down I popped the hood and had it pointed out to me that as my car cooled down the upper hose was collapsing.

Here's what I do know:

Brand new Behr Radiator
New expansion Tank
New Radiator cap
New heater check valve

I lose no coolant.

Why would the upper hose be sucking partway closed?

Let's put the collective minds together and give me some ideas.

Jeff

the flyin' scotsman

how old is the hose/hoses?

GlenL

Maybe the air inlet at radiator cap isn't opening. Or doesn't have one.

Mrmerlin

try swapping in another cap

jeff spahn

I have a new cap coming from Roger so we will see what happens there. I haven't gone to the waterless cooling yet or this wouldn't be an issue.

extanker

as the coolant heats up it expands and flows into the expansion tank [hot level] as it cools it pulls the coolant back into the engine [cool level]. that the hose is flattening seems to point that it is trying to pull the coolant back. the hose maybe suspect,the cap may not let the coolant flow back and i would rebleed the system too.

depami

Don't be so sure about that.



Sounds like your cap isn't venting properly.

dr bob

Jeff--

Curious if your existing reservoir cap is the OEM Behr cap. Also you'd like to know if there are any leaks in the system when it's hot, to the point where it won't hold enough pressure. Lack of pressure capability means there are steam bubbles in the system, bubbles that collapse when no heat is being added. A properly-sealing system shouldn't have much if any bubbles, so the change in in volume shouldn't be so severe as to start collapsing hoses. (grabs the water properties book...) The difference in specific volume of water between 70ºF ambient and 190ºF internal engine temp is about 3%, a change that's typically accommodated by the flex available in the hoses.

If you have access to a system pressure tester, it would be good to confirm that the system really does hold 1 bar (~~14.5 PSIG) pressure. Proper pressure capability is absolutely essential to keeping the engine cool, and also spoils a bunch of mechanical erosion in the cooling jackets caused by those little atomic explosions (steam bubbles) rattling around in the water jackets.

Most chain parts places will loan/'free rent' the tester, and it takes just minutes to confirm the health of the system AFA leakage.

PHIL928

I have heard of this happening when running a 1.5bar cap

jeff spahn

Dr. Bob-
I have a new system pretty much. Car runs cool on very hot days even with the air on. I'll grab a tester from Advance Auto on Friday. Car is getting HD radio and Sirus put in today so I can't test today.

Has a factory radiator cap, got it from Roger. Try to use factory parts whenever possible. Didn't go with any different pressure cap unless wrong one was shipped.

Let you know when the new cap arrives if this solves it or if it was a pressure issue seen by the pressure tester.

ammonman

Did the cap fix the problem? I'm having the same issue on the return hose from the radiator to the T-stat housing.

Mike

Mrmerlin

Mike sounds like a new cap would fix things.
Really the only thing it could be is the cap not venting

ammonman

That was my first thought. Guess the caps don't last long as this one is only a couple of years old. I think I'll start replacing the cap when ever I change out the heater valve and short hose as that's and easy way for me to remember.

Mike

Mrmerlin

yep sounds like a plan,
I hope it works for you