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Discussion Starter · #1 ·
When my engine is cold (for example before i crank it in the morning), the top coolant hose coming from the radiator going to the thermostat is soft and there isn't any pressure on it. If i open the radiator cap, the coolant level is right up there and full. When i start my car and let it idle a little, the top hose gets hard and there's pressure on it. It's not at the point whre it seems like it'll blow something but it still has a lot of pressure inside. The car doesn't overheat and there isn't any air in the system. I bled the system on a steep hill.
Is this normal behavior or is it something i should worry about?
A friend of mine has an 89 and his hose is always soft and he doesn't have any cooling issues neither.

My car is missing the fan shroud, so i have one on the way in case the radiator is running too hot, and my friend does have the shroud. My two little fan by the battery come on often even though the A/C is never on, and his never come on. His engine bay seems to be generally cooler than mine. I am 900miles into a new rebuild (new bearings, rings, and other stuff) in case it matters.

What do you guys think? Thanx
 

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Think you will find that normal. Pressure builds up when the system is working (water pump etc.). Fan shroud can be real important in the summer in a hot climate. If you live in Fl, Tex or somewhere like that you need to invest in a shroud.
 
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Discussion Starter · #3 ·
If your electric fans are turning on, then you're reaching about 212F.

What you describe with the hose sounds fairly normal. When you first start the car, with the radiator cap removed, is there any air bubbles coming out? If not, and you're not puking coolant out of the overflow bottle, I wouldn't worry about it.

But if I were you, I'd change the thermostat (and test the new one), just to make sure it's working fine.

Once you have the shroud, your little electric fans shouldn't be turning on, unless it's really hot during summer.
 
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Discussion Starter · #4 ·
When i open the radiator cap no bubbles come out at all. No air escapes or anything, The coolant is right up to flush with the cap.

The thermostat is a brand new toyota one. Initially the car had a smaller radiator than i'm currently running and the coolant would basically boil in the overflow bottle, and spill. I replaced the radiator, and actually drilled two very small holes in the side of the thermostat to allow coolant to go back in the engine to reduce the amount of coolant that was coming to the overflow. That didn't help so i changed the radiator and now the coolant doesn't boil anymore, the overflow is stable and the car doesn't overheat.
I was just worried about the pressure in that top hose once the car was running. It's always done that though.
I'm hoping the shroud will fix some of the problems. Thanx
 
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