Engine Coolant flow problems

AbhorrentSpecies

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Okay, so my 89 gt is doing something strange. When I first bought the car two years ago, I noticed the lower radiator hose was swollen and the car was overheating. Not crazy. But just a little. Since then, I've replaced the thermostat to a 180, replaced all the hoses and of course flushed and refilled the radiator which is an aftermarket aluminum one. Not sure of the brand, it was on the car when I bought it. It has a really small overflow as well that is incredibly insufficient and won't bleed any pressure. If I close the cap on the overflow all the way, the lower hose will collapse. So here's the other thing I just noticed last night. After buying a infrared heat gun. I was messing around in the engine bay. I noticed my lower radiator hose is starting to become swollen again, all the others are fine. So I ran the car and waited till it reached temp. The entire time the lower hose was much hotter until the thermostat opened and the upper hose began to heat up. Even after the upper hose warmed up, the lower hose was always hotter by about 15 degrees. The lower is also becoming so pressurized I noticed it's squeezing coolant out of the small spaces around the clamp and dripping down the bottom of the radiator. So anyway. After that long ass story, what gives? What needs fixing or replacing now lol
 
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Mustang5L5

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do you have standard accessories spinning the water pump in the correct direction?

The pump output should be on the upper hose, so once coolant is circulating, the upper hose should see higher pressure and higher temps.

Not closing the cap all the way could create some issues. You should really address the overflow issue so you can tighten the cap properly. If the car correct for the radiator? Is it the cap which doesn’t allow fluid to draw back from the overflow when the system cools?
 

AbhorrentSpecies

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Original engine?
Spinning the water pump the correct rotation?
Is the water pump the correct one (reverse rotation)?
It is the original engine. Not sure if it's the correct water pump. I didn't put that on. So long as the water pump is correct then my belt is running properly. I have it running the same way as if I still had all the stock accessories. How can I figure out if the water pump is a reverse rotation one?
 

AbhorrentSpecies

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do you have standard accessories spinning the water pump in the correct direction?

The pump output should be on the upper hose, so once coolant is circulating, the upper hose should see higher pressure and higher temps.

Not closing the cap all the way could create some issues. You should really address the overflow issue so you can tighten the cap properly. If the car correct for the radiator? Is it the cap which doesn’t allow fluid to draw back from the overflow when the system cools?
The radiator cap is new. Hadn't noticed an issue with it but I could try another one. The one time the hose collapsed it was because the overflow cap was tightened all the way, and as soon as I loosened it, the hose went back to normal. I don't have stock accessories but the belt still runs the same direction as if it were stock. No AC, power steering relocation and no smog pump. But the way my belt is routed is still the same as stock.
 

General karthief

wonder how much it would cost to ship you a pair
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Good question!!!
You'll need a friend, take the upper hose off, tell your friend hold onto it, start the car, if your friend screams like a girl and appears to have pissed himself, your pump is likely turning the right direction.
Wait, maybe that's why I don't have any friends?
 
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AbhorrentSpecies

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Good question!!!
You'll need a friend, take the upper hose off, tell your friend hold onto it, start the car, if your friend screams like a girl and appears to have pissed himself, your pump is likely turning the right direction.
Wait, maybe that's why I don't have any friends?
Hahaha, so could I just put some water in the thermostat housing? Then if it throws it out it's the correct direction, but if it sucks it in something is wrong?
 

Mustang5L5

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I don’t think it will work quite the way you would expect it to there.

Does the bottoms hose swell immediately even when cold?

If you open the cap (while cold) with the engine running, does it look like fluid is trying to push up?
 

AbhorrentSpecies

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I don’t think it will work quite the way you would expect it to there.

Does the bottoms hose swell immediately even when cold?

If you open the cap (while cold) with the engine running, does it look like fluid is trying to push up?
I'm not sure about all that. I'll check a few things tonight after work.
 

General karthief

wonder how much it would cost to ship you a pair
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with the engine running and hot enough for the thermostat to open, the coolant should be seen flowing from the tubes, you have to lower the level enough to expose the tubes, the radiator should flow from the passenger side to the drivers side.
 
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AbhorrentSpecies

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with the engine running and hot enough for the thermostat to open, the coolant should be seen flowing from the tubes, you have to lower the level enough to expose the tubes, the radiator should flow from the passenger side to the drivers side.
Okay, I'm going to check a few things tonight after work. I'll post again if I figure out anything.
 

Mustang5L5

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Even if the water pump is incorrect (standard rotation vs reverse rotation) I’m not sure it would really work well driving the impeller in the wrong direction so I’m not sure it would flow the coolant in reverese. So I wouldn’t fixate too much on this.


Still, considering you didn’t install the pump, should at least verify. Inwould think if the cap were removed and you started the engine, if it was incorrect you would see coolant dancing around inside the radiator. On my car, until the tstat opens, the coolant just sits there not flowing at all.
 
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Dan02gt

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Ok you said when you close the cap on the OVERFLOW the lower hose collapsed. The factory overflow just has a basic plastic cap and a turn down vent that is always open. If you have some kind of aftermarket overflow that is sealed air tight that’s one of your issues.
 
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AbhorrentSpecies

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Even if the water pump is incorrect (standard rotation vs reverse rotation) I’m not sure it would really work well driving the impeller in the wrong direction so I’m not sure it would flow the coolant in reverese. So I wouldn’t fixate too much on this.


Still, considering you didn’t install the pump, should at least verify. Inwould think if the cap were removed and you started the engine, if it was incorrect you would see coolant dancing around inside the radiator. On my car, until the tstat opens, the coolant just sits there not flowing at all.

Make sure the lower hose is good and not soft too.
It's a brand new hose.
 
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manicmechanic007

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I do not like the swollen bottom hose regardless of which way the pump is spinning
However that is the first thing I would check (rotation direction)the angle of the water pump fins)
Hope like hell the block is not cracked
 

7991LXnSHO

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I do not like the swollen bottom hose regardless of which way the pump is spinning
However that is the first thing I would check (rotation direction)the angle of the water pump fins)
Hope like hell the block is not cracked
I agree.
Lower hoses usually have springs to prevent collapsing. That it is both bulging and collapsing is a real warning sign. Gates, Goodyear (and one other G brand I am not remembering) should be up to the job. Avoid Dayco and store brands.
Also, it’s time for new Ideal brand hose clamps.
 
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90sickfox

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Sounds to me like the aftermarket overflow completely seals so it doesn't let pressure out or pull coolant back into the system during cool down. This is why it doesn't do it when the cap is removed.

The radiator cap should be around 16 - 18psi before it starts bleeding off pressure to the overflow. If the system sees more pressure than that it'll cause the hoses to swell and the cooling system won't circulate properly. When the car is cooling down it pulls the fluid that was pushed out when over 16psi back into the radiator. If your car has a bigger radiator it could push out more fluid into the overflow than a stock car would. I've seen a few people chase overheating issues based on the overflow overflowing....only to find out that the system just needed a bigger overflow tank because of the size of radiator. Bigger radiator = more fluid.
 
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Mustang5L5

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As a test, get a coke bottle and a peice of 1/4" coolant hose and drill a hole in the cap so the hose can pass into the coke bottle. Put 2-3" of coolant in the bottle and put the hose below the level. Instant recirculation bottle.

See if that has any bearing as to what is going on provide you can tighten the cap down all the way.

If you still can't tighten the cap down because it won't draw back, get a new cap. That is not normal operation. If shouyld be able to pull coolant back in otherwise you will have a vaccum inside as the coolant cools
 
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2000xp8

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I'd start by buying and installing a stock overflow tank.
 
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