Upper Radiator Hose Collapsed ?

[Greekman]

Today after driving my '79 for its monthly startup during the winter months, I noticed that my upper radiator hose was colapsed! Yes, flat as a pancake?

What has happened? Is this normal? Should I be concerned?

Maybe a stuck thermostat? I did have the heater on for about 30 minutes.

Please help as I have never seen or heard of this happening before.

Thanks,


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Did you check for low coolant level?Might be time for a replacement, I would do the lower hose also,did the hose feel spongy? if so replace.if you haven't replaced thermostat in awhile I would do this also.

[Greekman]

Pappy, engine was too hot to remove radiator cap that I thought if removed would also vent the system and return the upper hose to its normal state. I did smell some coolant, but I had noticed before a small pin hole in the radiator and had added some radiator stop leak.

Haven't replaced the upper or lower hoses as dealershiip said looked fine when they replaced all the heater hoses last Fall.

I replaced the Thermostat last summer when car was running a bit hotter than normal.

Once the motor cools down I will look again at the coolant levels in the radiator and overflow tank.

I have had the car for less than one year so still looking everthing over mechanically.

Thanks for you thoughts and maybe still someone out there has seen this before.




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[Vanity Plate Bob]

Years ago a hose would weaken and collapse.
Then some had a spiraled wire in them. I'm sure they are better material now but if its orig, that's a long time.
May be a good idea to replace it.

[78SilvAnniv]

If it has collapsed once, it will again, with less effort.
Heidi

[Jack]

I'd take a look at the cap, overflow hose & overflow tank. Maybe it got hot enough to puke a bit into the OF tank, but maybe the OF hose has a kink in it or there's goop in the OF tank that prevents the system from sucking it back into the rad ... as it cools it makes negative pressure ... collapsing upper hose?

Bottom rad hoses are most prone to collapse ... 'cause the wp sucks from that hose ... bottom hose is the one that needs a wire core/spiral. A chevy can suck even a NEW lower hose shut if it don't have some kinda support in it
JACK

Today after driving my '79 for its monthly startup during the winter months, I noticed that my upper radiator hose was colapsed! Yes, flat as a pancake?

The exact same thing happend to my "78"
Mine still had the original radiator cap, so i replaced it & now
the upper hose do'es not colapse anymore!

Get a new cap with the correct pressure rating, and all
will be well!

[Stallion]

Originally posted by gary b.
The exact same thing happend to my "78"
Mine still had the original radiator cap, so i replaced it & now
the upper hose do'es not colapse anymore!

Get a new cap with the correct pressure rating, and all
will be well!

If by changing the cap (which works off of pressure and has a spring on it?) do you think that it worked because the spring in the cap for the pressure was shot and done?

It's possible that the radiator, when filled last year, was filled up but not enough to fill the engine compartment and heater. If this happened and let's say your coolant level was low in the radiator, the water pump would be circulating air instead of coolant through your engine causing the upper return hose to collapse or get squeezed out. The fix, turn on engine, turn on the heater, remove the cap, observe level after engine warms, add coolant, replace the cap and feel the upper radiator hose, feeling for pressure (coolant) of the coolant traveling back into the radiator. If you feel no pressure at the hose and the hose collapse again, your thermstat is definately stuck.

[Greekman]

First of all thanks to all of you who responded and helped me out with this unusual situatiion.

Once engine cooled enough to open the radiator cap, I noticed the following:

The radiator was full.
The overflow tank was at normal max level.
The upper radiator still after venting the system would not go back to its normal shape. After a closer inspection of the upper radiator hose it did feel somewhat spongy and weak.

I did the following:
Ordered from Chevrolet a new upper radiator hose.
(Was going to replace the radiator cap, but Chevrolet has replaced the original stainless steel cap with a new black plastic type so I decided to give mine a try first).

I'll let everyone know if after the installation of the new hose if I still encounter the flatting of the upper hose.



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[Vanity Plate Bob]

I am almost certain there is a gauge unit that can ck press of a cap. The gauge is attached and a hand pump supplies pressure.
It is the size of an oversized aniti freeze tester. This is performed with the cap removed from the radiator.
Ck a radiator shop, repair shop, dealer etc.

[Greekman]

Yes, I have a Zant Tester as you described and will test the pressure on the cap before completing the upper radiator hose installation.

A good idea. I can also pressure test the whole cooling system while I'm at it.

Thanks,


.

If it was me I would spend the 50 bucks and replace all the hoses, rad cap,therm, coolant etc. Why take the chance of something that might be 20+ years old and can leave you stranded on the side of the road at night.

Those are all inexpensive items which should be replaced BEFORE they go bad, not after. You have just gotten your first warning with the top hose.

Roy

[Greekman]

Roy, thanks for your reply.....

I have had the car less than a year and have had to deal with the more immediate troubles like leaky brake calibers and steering linkage.

I did have the car into the Chevy dealer and they replaced all the hoses they thought looked like they should be replaced. They replaced all the hoses except the upper and lower radiator hoses.

It would sure be nice if we could predict ahead of time what items on a 24 year old car had been and or will need replacing before it fails.

I do intend to have this car Flight Judged and do not want to replace items on an original car just because its old. The car is not a daily or even weekly driver and when its on the road it is often with other old Corvettes.

Thanks,



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[KOPBET]

Originally posted by Greekman
The upper radiator still after venting the system would not go back to its normal shape. After a closer inspection of the upper radiator hose it did feel somewhat spongy and weak
.

Jack is right IMHO.

This is a bad hose regardless of anything else going on in your engine. Replace it and the lower as well if it is as old. Keep the spring from the old lower hose unless the new one has one in it!

The upper hose should be pressurized by the water pump and should not collapse from suction. If the stat doesn't open then there is no place for the pump to push the water, hence no suction on the lower hose. Therefore I doubt this is the problem.

The hose material just gets soft and weak over time and this one just does not have the structural strength to support itself.