radiator cap?

[suprastarr]

How would I know if my Radiator cap is bad? My Radiator hoses are collapsed after driving and I was told its the thermostat or it could be the radiator cap. Is there anyway to test a Radiator cap?

[IrishLt]

There is a contraption that basically looks like a bicycle hand pump that connects to the cap...lets you pressurize it. Check with advance/autozone/napa.....pick your poison...one oughta have a tester that they do the whole loan out deal with.

[johnegg]

collapsed hoses indicate that the system is trying to suck coolant back into the rad from the over flow bottle.

 

pull the hose out of the over flow bottl and make sure it is not clogged.

also make sure it is not stuck on the bottom of the bottle which can plug it up.

pull it up 1/2 inch off the bottom.

 

is there oil gunk in the over flow bottle?

does it smell like exhaust in the over flow bottle?

 

when the engine is COLD, check the coolant level in the radiator.

if it is forcing coolant out, but cannot suck it back in, it could be low.

 

i doubt it is the the cap.

they usually fail in differnt manner.

[suprastarr]

Truthfully I think its the head gasket but I'm just trying to cover all my bases I just have NEVER seen a Radiator hose collapse before.

[lunarx]

Apologies for reviving an old thread, but these posts have been very helpful to me.

 

My upper & lower radiator hoses were also collapsing on an 07 LGT.

When I finally noticed that the reservoir overflowed, following a top-off, I decided to search the forums.

 

Turns out I had (2) suction caps.

An aftermarket 16psi on the Surge Tank and a factory 108kpa on the radiator.

 

After much confusion (at Subaru Parts Counter) I found out;

Surge Tank should have a 108kpa [16psi] suction cap.

Radiator should have a 137kpa [20lb] pressure-only cap.

Not sure either cap was defective but having (2) identical caps was obviously bad.

 

Installed new factory caps of each and all is good.

Hoping this info is helpful to someone else.