1986 Fiero with 3.4 PR all new. took it out for a ride the upper radiator hose "Collapsed". The only thing I can think of is low coolant. OGRE, What would cause this ? Thanks

Does it stay collapsed? Sometimes hoses fail that way, but usually it's because the cooling system is in a slight vacuum as the temperature cools. All that means is there is enough air in the system to create the vacuum. If it pops back into shape when you remove the thermostat cap, it's air. If it does not pop back into shape, it's the hose.

1. Upper on Left tank?
2. Engine running or Off?

Maybe Crush/blocked left cooling pipes
Could mean heater loop plumber is suspect. Very common in engine swaps.
Take out Tstat as a test...
See my cave, heater and Tstat

quote Originally posted by Gall757: Does it stay collapsed? Sometimes hoses fail that way, but usually it's because the cooling system is in a slight vacuum as the temperature cools. All that means is there is enough air in the system to create the vacuum. If it pops back into shape when you remove the thermostat cap, it's air. If it does not pop back into shape, it's the hose.

Air when cool means bad/wrong rad cap or hose to overflow tank is blocked...

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)

In addition to correcting the root cause of the collapse, you may also want to put a stainless wire coil in the hose. Just go to a parts store and buy any radiator hose that has the same diameter, pull the coil and put into your hose.

I'm "Guessing" the one from the thermostat housing, It's on the car I sold, the buyer contacted me & said thats what happened, can't be sure. I was hoping He would "Sign one here", and look at this thread. I gave him the "Link".

If an upper hose flattens like that it is from some vacuum. Plugged hose from overflow bottle or radiator cap not opening under vacuum. Under vacuum they are supposed to allow coolant back in from overflow bottle. Even if it empties the bottle.

sounds like I got another one of stants geat products. can't tell ya how many thermostats and caps I've had to bring back.

Wasn't there a "post" here awhile back about STANT having put the WRONG Part # "in all their Catalogs" at advanced, autozone ect ?? that the car "calls for" a totally different cap to work correctly ?

It's in the Ogre's Cave.

Powertrain-Cooling-Radiator caps.

[This message has been edited by Gall757 (edited 02-26-2013).]