rad hose sucking closed

[NOTAURIUS]

Does anyone know what would make my upper radiator hose suck togrther on my 92? iT DOES IT IN HOT AND COLD WEATHER.It contracts together until its like an inch wide or less. I tried a new rad cap already. It stays that way long after shutting the car off also. I am concerned that it may be restricting flow. The t stat is new also.

 

[Bizzy]

sounds like something might be blocking the overflow tank. When the engine cools it draws fluid back up out of the overflow tank if it is low. Perhaps the tank has a some crap in it blocking that tube

 

[sdpatt]

Does it do this while the engine is running or after the engine is shut off? While running, there is about 16 pounds of pressure inside the hose and it better be at full cross section. There should be no flow restrictions at that time. After shutting off the engine, the coolant loses heat and contracts, causing a slight vacuum in the system. That is when it draws fluid from the expansion tank if that radiator cap is working properly and the path is not restricted.

Since you have a new cap you should check to make sure that it has the spring loaded pressure seal and the correct pressure rating. It may just be that the upper radiator hose is so weak that it cannot handle the slight vacuum without collapsing. That would indicate that it is time for a new upper hose. Some brands of hoses for some cars have a metal coil placed inside the hose to prevent just what you are describing. If it only happens after the engine it shut down, it is not a cooling system limitation, but just a little physics at work.

 

[projectSHO89]

Does this occur only when the engine is hot, when the engine is cold, or does it matter? Notice I did not ask about the ambient temp.

If it does this while the engine is cold, I would suspect obstructed coolant channels in the heads or the block. During cold running, the pump should be drawing coolant from the block and pumping it back out the water tube on the top of the pump. The water outlet assembly distributes this coolant flow to both heads, the heater hoses, and the throttle body/miscellaneous loops, back through the water jacket in the block and back to the pump. Once the thermostat opens, a portion of the coolant bypasses the thermostat, is drawn through the radiator for cooling, and re-enters the pump via the long inlet tube that the lower radiator ose connects to.


It also might be that the hose is old and its sidewalls have weakened. That would allow the suction of the pump through the radiator to slightly collapse the hose.

Steve

 

[rangerj]

Matt,

You are right to be concerned about coolant flow restriction. A collapsed hose will indeed restrict coolant flow.

I can't add much to the advice above, but a few questions come to mind. Did you change your water pump pulley, and/or other pullies? Changing to "underdrive" pullies is a popular modification. When did this hose collapse problem begin?

Is your water pump original? Did you change your thermostat, and is it one with the little preasure relief "jiggle valve"? Did you change the radiator hose, and is it from a reputable auto parts supplier, e.g. NAPA, Certified, Car Quest, Auto Zone, O'Reily's etc?

You may have to do a reverse flush with a good chemical cleaner to correct the problem. Is the water in your are very "HARD" with chemicals like lime, iron, etc. When you put in fresh anti-freeze, use deionized, PH neutral, water to make your 50/50 mix. (from the drug store just down the isle from the snow tires)

By any chance did you mix the "New" pink anti-freeze with the old green stuff? From what I have read one drop of green anti-freeze will "gel" a whole gallon of the new stuff (slight exageration).

The two are not compatible, at all (period). I have seen this new stuff turn ito the consistency of tapioca when the owner added a little of the old green stuff to the system (new car).

Anti-freeze develops an electric charge over time that will deteriorate the rubber hoses from the inside. The hoses become soft and spongy. Have you changed your coolant at least every other year?

When you do find the problem, let us know what it is so that others can avoid it! shrug rangerj

P.S. Williamsport PA is the home of the "World Series of Little League Baseball" thumbs_u