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69_GS_400
09-21-2007, 10:25 PM
The upper radiator hose almost sucks close when I punch the gas?

Anyone have this same problem?
Or a solution to the problem?

70aqua_custom
09-21-2007, 10:33 PM
The upper radiator hose almost sucks close when I punch the gas?

Anyone have this same problem?
Or a solution to the problem?

I want to hear the answer to this one. I thought the upper hose was under pressure and the lower hose, with the spring, was the suction side :Do No:

Sportlark64
09-21-2007, 11:23 PM
Overheating too?? Only thing I can think of there is a T-stat stuck closed , if not you gotta a heckuva water pump on that beast ! I've heard of the bottom hose collapsing if the spring rots out .Makes me think something upstream is blocked . Sounds like your water pump is pulling all of the water from the rad/hose and collapsing the top hose (since it doesn't have a spring).:idea2:
Steve

gymracer01
09-22-2007, 12:26 PM
Assuming you have not reversed the water pump in some way, the first thing you would think is that there is a restriction in the top of the radiator or top outlet. It is not uncommon to have a hose suck together when a vehicle is not running and is cooling off. this is caused by a bad radiator cap that does not let in air to allow of the cooling of the coolant and creates a vacuum in the system that sucks the hose together. But a problem running is another deal. Just for kicks, try it with the cap off.
JIm N..

Smartin
09-22-2007, 01:36 PM
If there is not enough flow through the thermostat, the water pump could be causing the hose to collapse due to starvation of water.

GRIMM
09-22-2007, 04:42 PM
and if youre radiator or cooling system is plugged and you run the engngine with the cap off, you will shot a nice amount of coolant all over everything.

nailheadina67
09-22-2007, 08:00 PM
My vote is to try removing the thermostat and see what happens. Perhaps it's not opening all the way? :idea2:

LARRY70GS
09-22-2007, 08:24 PM
Thermostat for sure.

Floydsbuick
09-23-2007, 08:09 AM
My wifes former 90 Estate Wagon, and our current BBB 4X4 both sucked the upper rad hoses shut. Both had functional thermostats and cooling system. Matter-of-fact, the 4X4 just sucked the hose down between the fan and distributor. Stopped the clutch fan cold! I think when the thermostat first opens, it'll suck a weak, older hose shut for a brief period. This has never caused overheating issues either. Well....the truck got a little warm (200) when the fan stopped.

BuickBuddy
09-23-2007, 09:02 AM
Floyd is correct. It's a weak hose. My Electra does it till the car gets warm and there is pressure in the system. :TU:

LARRY70GS
09-23-2007, 09:27 AM
Floyd is correct. It's a weak hose. My Electra does it till the car gets warm and there is pressure in the system. :TU:


Could be, but a hose that weak would also balloon from the pressure when up to temperature, a sure sign of impending failure.

paul c
09-23-2007, 09:47 AM
radiator cap.

GotTattooz
09-23-2007, 03:00 PM
As previously stated, and without a doubt, it's your radiator cap. It happens all the time on big rigs ( I'm a diesel mechanic). The radiator cap has 2 valves in it. The first one being the obvious spring on underside which seats the rubber gasket, which determines the pressure rating. But if you check the very bottom of your radiator cap, there's a brass or copper disc, which, if you can get your fingernail or a screwdriver under, actually pulls out a litle bit and allows coolant from the overflow to return to the radiator when the system cools. When the upper hose collapses, the bottom valve is not working correctly. For an easy check, next time the hose collapses, pop the radiator cap, and you should see the hose return to normal. Replace the cap.

-Josh

LARRY70GS
09-23-2007, 06:21 PM
With the engine running the radiator cap has nothing to do with a collapsing hose..the obvious thing to check is the thermostat.


I agree, if the water pump is sucking more coolant through the lower hose than the upper hose can supply, it will collapse. The thermostat is either sticking or stuck in one position and it cannot pass enough coolant. If the hose was collapsing after the engine was off, I might think the cap was at fault.

70aqua_custom
09-23-2007, 09:27 PM
the suspense is killing me...



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69_GS_400
09-23-2007, 11:17 PM
Ok well I will start with the thermostat..

Topless64-455
09-23-2007, 11:32 PM
So what is the problem whrn the hose gets sucked down when the car is cooled off. It runs fine but when I pop the hood a day later the hose is sucked flat?

It that a bad cap?

Thanks

gymracer01
09-24-2007, 01:50 PM
Topless, I can tell you for sure that is a radiator cap problem. Replace the cap with a quality unit of the correct kind and that will fix it.
Jim N.

Topless64-455
09-24-2007, 02:05 PM
Thanks Jim!:TU:

I will try another cap.

69_GS_400
09-24-2007, 02:23 PM
I just put in a new thermostat and radiator cap last week. But I may have put too much gasket maker and mabey it gunked it up.

the cap I bought was a 16 psi from advance auto. I have a factory 3 core radiator, nothing special.

I am today going to look at the thermostat, LARRY has always been right on with helping me with my troubles:TU: :TU:

nailheadina67
09-24-2007, 04:59 PM
I would think if it were your cap it would suck closed as it cools down. You'd be surprised how much air gets sucked back in as it cools.

I'm being serious here....we have an attached garage, and when we first moved in here one night I went through the garage to let the dog out. I kept hearing these "farting" sounds coming from under the hood of my car. :puzzled: Turned out it was the check valve under the "repro" radiator cap I had letting air in as it was cooling down. It used to do that for about 5 or 6 hours.......until I tried a better radiator cap, now it doesn't do it. :Dou: :laugh:

Tim
09-24-2007, 05:24 PM
Joe, I always blame it on the dog!:shock:

GotTattooz
09-24-2007, 06:47 PM
My sincere apologies. I skimmed over the part about "at full throttle." I guess I need to pay a little better attention. The problem I descibed it what "topless" Ed was talking about when the engine has cooled down.

-Josh

LARRY70GS
09-24-2007, 07:03 PM
I am today going to look at the thermostat, LARRY has always been right on with helping me with my troubles:TU: :TU:


I've been wrong before. It seems to me that with the engine running, there should be pressure in the system, and if the cap isn't relieving the pressure at its rating, than if anything the hose would be rock hard. With the engine off, as it cools down, coolant would be sucked back into the radiator, and if that wasn't happening, the hose might collapse.

djd35de
09-26-2007, 12:37 AM
Yes for sure its the radiator cap!!!!!

Replace it.

David

70aqua_custom
01-03-2008, 02:05 AM
ttt

Schurkey
01-03-2008, 02:32 PM
I just put in a new thermostat and radiator cap last week. But I may have put too much gasket maker and mabey it gunked it up.

the cap I bought was a 16 psi from advance auto. I have a factory 3 core radiator, nothing special.

I am today going to look at the thermostat, LARRY has always been right on with helping me with my troubles:TU: :TU:
So, what happened?

My money is on the rad cap being defective.
1. It's not holding pressure if the upper hose can collapse.
2. It may not be venting properly.
3. You can't pump water OUT of the upper hose unless you are pumping it INTO something else--and the engine is already full. The thermostat shouldn't make a bit of difference; you wouldn't see the upper hose suck closed when the engine is cool, but running--right? Yet the thermostat is closed then, too.

I'm betting that the rad cap doesn't hold pressure; when he whacks open the throttle, the fan speeds up and the coolant in the radiator gives up heat--so it contracts faster than the coolant in the block is expanding. There is an overall reduction in the volume of coolant. The cap doesn't vent properly--so the upper hose collapses because the lower hose has a metal coil inside, the heater hoses are too rigid, and everything else is metal.

Don Palumbo
01-03-2008, 06:40 PM
Have seen this a thousand times... radiator cap!!!

LARRY70GS
01-03-2008, 07:27 PM
Now that I think about it, the cap does make more sense. Had a bad cap on a friends car last year. It filled the overflow container, and then started puking out onto the engine.

BUICKRAT
01-03-2008, 07:44 PM
You guys are ALL right. A restricted therm OR a bad cap can cause it. The other thing that can cause it is if the car was meant to have an overflow tank and it is missing. Or there is unwanted air in the cooling system.

Schurkey
01-04-2008, 02:02 PM
You guys are ALL right. A restricted therm OR a bad cap can cause it.
How would a restricted thermostat cause an upper rad hose to suck closed if there's pressure in the system?