Upper radiator hose problem

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Jul 30, 2009 | 07:05 PM

JimT

Thread Starter

Burning Brakes

Joined: Nov 2006

Posts: 893

Likes: 7

From: Orange Park Florida

Upper radiator hose problem

Engine temp has been erratic lately. At high speed, temp runs up to 210+ degrees, but when I slow down for a few minutes, temp drops back to normal (mid 180s). After a ride yesterday, I found that the upper radiator hose had collapsed. The bottom hose has an internal spring to eliminate hose failure, does the upper need a spring? The hose in question is a Gates hose, and to me it feels a little too soft and pliable. Is this a weak hose problem, or does it sound like I have a cooling problem - air lock in engine/radiator. Possible thermostat failure?

I am using the Robert Shaw thermostat (vented), and have never noticed this collapsing hose problem before. Fluid is circulating freely. Any info/comment would be appreciated.

Jul 30, 2009 | 07:12 PM

bigvette1

Drifting

Joined: Jan 2002

Posts: 1,645

Likes: 11

From: Schaumburg IL

I would check for several things
- soft hose
- air pockets, take the cap off and run the engine till hot fill as needed
- what's the lower hose doing and is the spring in there ?

Do you have a high flow water pump?

Jul 30, 2009 | 07:58 PM

JimT

Thread Starter

Burning Brakes

Joined: Nov 2006

Posts: 893

Likes: 7

From: Orange Park Florida

I do not have a high flow water pump, however, I'm getting good flow.

The lower hose has the spring and is functioning properly.

I am thinking that the upper hose is "weak." I've replaced the radiator cap, and replaced the thermostat (drilled extra holes for venting) but I've never seen an upper hose collapse before. Strange.

Thanks for your input!

Jul 30, 2009 | 08:08 PM

1stC3Vette

Burning Brakes

Joined: Oct 2004

Posts: 920

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From: Shelby Township Michigan

Jim,

Did you replace the radiator cap and thermostat after you noticed the hose collapsing?

Dino

Jul 30, 2009 | 09:07 PM

PeteZO6

Drifting

Joined: Apr 2007

Posts: 1,970

Likes: 45

From: Cameron Park CA

Does the hose collapse while the engine is running, or does it happen after you park it and it cools off?

When pressure is reduced in the system due to cooling, the radiator cap is supposed to let air in to equalize the pressure. That's the theory anyway.

Jul 30, 2009 | 09:15 PM

72LS1Vette

Safety Car

Joined: Aug 2001

Posts: 4,883

Likes: 11

From: North Easton Mass

Is the hose old? If so, buy a new one from somewhere like Dewitt's so you can get a correctly formed replacement. The chain stores have part numbers but they aren't correct - I looked at every one and none of them were right.

Rick B.

Jul 30, 2009 | 09:19 PM

JimT

Thread Starter

Burning Brakes

Joined: Nov 2006

Posts: 893

Likes: 7

From: Orange Park Florida

Think I found it! The overflow tube to the expansion/overflow tank was closed. The tank I have has a lever type shut-off valve on the input from the radiator (don't ask me why - it was on the car when I purchased it). Therefore, no escape for expanding fluid. I must have bumped it and closed it during some recent work. I'll remove that fitting in the morning.

Thanks for all your comments.

Jul 31, 2009 | 08:22 AM

bigvette1

Drifting

Joined: Jan 2002

Posts: 1,645

Likes: 11

From: Schaumburg IL

Hey JT,

Would have to think that one through and hope that was your problem. Normally the upper hose is pressureized and "fat" not collapsing. Almost makes you think the flow is reversed. Anyway good luck and hope all is well.