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Overheat Closed System with Cap


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I've been reading post after post but still have not found which path forward I should take. My truck is a 1987 4.0 renix ba/10. Yesterday I went a few miles into town and idled probably five minutes at my stop. I started To head home and started smelling something burning. Truck was running around 230 when it usually hangs around 160 on my gauge. I got almost home and I killed it running about 250 degrees. I Let it cool off to about 180, then headed to the house. Previous owner replaced thermostat 5 or so years ago and added in a filler neck mid line. I replaced the water pump maybe 3 years ago. It Still has the original pressure bottle and cap. Should I start with a Napa cap, replace my entire bottle, or go after the thermostat? I did have some coolant coming out of my upper hose and steam also. I have had multiple cooling issues with the truck over the years, but it has been sitting and being driven a couple times a month now. I know the radiator probably is needing a replacement also due to is age. Just want to start in the right place and then go ahead and do some other upgrades. Any help would be appreciated.

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I would at least start with the Volvo bottle cap.

 

If the tank is cracked, you should replace it.  Throw away the cap that comes with the bottle and use the Volvo cap.

 

(See Cruiser's rant about getting rid of the plastic pressure bottle.)

 

You said the coolant was coming out of the upper hose.  Where? At the bottle connection?  Somewhere along the hose?

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I know the radiator probably is needing a replacement also. Just want to start in the right place and then go ahead and do some other upgrades. Any help would be appreciated.

IMHO the radiator is the place to start. My '88 XJ is currently on its third radiator. They don't last forever.

 

This is my current setup. Bottle is vented off to the side. Assuming this makes it an overflow bottle.

I don't see a vent. It looks to me like it's plumbed the way it came from the factory, which means it's still functioning as a pressure bottle.

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The hose off of the top right of the bottle goes to nothing. I'm guessing vent/ overflow. Just wanting to make sure all I need is a new cap for it, radiator, hoses and thermostat. That's what I'm leaning toward and just want to be sure I'm after the right thing. The open/closed and closed with cap like this one has me confused

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The hose off of the top right of the bottle goes to nothing. I'm guessing vent/ overflow. Just wanting to make sure all I need is a new cap for it, radiator, hoses and thermostat. That's what I'm leaning toward and just want to be sure I'm after the right thing. The open/closed and closed with cap like this one has me confused

But you still have the bottom hose leading into the tank, so what you have is a bastardized system that can't possibly hold pressure.

 

Either put the closed system back to the original configuration so it has a chance of possibly working, or convert to an "open" system. In an open system, the overflow tank is fed by a tube that comes off the radiator filler neck, with the orifice above the gasket that seals the cap to the neck.

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I've been reading post after post but still have not found which path forward I should take. My truck is a 1987 4.0 renix ba/10. Yesterday I went a few miles into town and idled probably five minutes at my stop. I started To head home and started smelling something burning. Truck was running around 230 when it usually hangs around 160 on my gauge. I got almost home and I killed it running about 250 degrees. I Let it cool off to about 180, then headed to the house. Previous owner replaced thermostat 5 or so years ago and added in a filler neck mid line. I replaced the water pump maybe 3 years ago. It Still has the original pressure bottle and cap. Should I start with a Napa cap, replace my entire bottle, or go after the thermostat? I did have some coolant coming out of my upper hose and steam also. I have had multiple cooling issues with the truck over the years, but it has been sitting and being driven a couple times a month now. I know the radiator probably is needing a replacement also due to is age. Just want to start in the right place and then go ahead and do some other upgrades. Any help would be appreciated.

I replaced almost everything in my cooling system and it still over heated until I got a aluminum bottle with a really tight cap. Never gotten more then 180 since then.

 

This is what I would get and is what I have:

http://macsradiatorshop.com/surge-overflow-tanks/replacment-jeep-radiator-fill-tanks-366.html

 

Edit:

I had a brand new radiator and it still got up to 230 until o got that

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This is the setup I bought it with. What should the line off the top go to to not act as a vent? Plug it? The filler neck vent runs to the bottom of the tank.

Ah. I couldn't see that from the photos. Now that you tell us that, I can sort of make it out. Yes, if the filler neck overflow tube goes into the bottom of the tank, then it is acting as an overflow bottle.

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Ok good. So it is acting as an open system? I thought about replacing the radiator and thermostat and probably the hoses. Then if I put a new bottle or maybe just a new cap on my old one, then I should be able to continue to use the system the way it sits? I may get a radiator with a cap instead of the fill neck mid hose if that seems the better way to go. Also with this system, do I still need to burp down a hill with thermostat plug pulled or burp at cap?

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Ok good. So it is acting as an open system? I thought about replacing the radiator and thermostat and probably the hoses. Then if I put a new bottle or maybe just a new cap on my old one, then I should be able to continue to use the system the way it sits? I may get a radiator with a cap instead of the fill neck mid hose if that seems the better way to go. Also with this system, do I still need to burp down a hill with thermostat plug pulled or burp at cap?

Shouldn't need to burp it. 

 

Why don't you convert to 97 and later heater hoses while you're at it and ditch that heater control valve?

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Ok good. So it is acting as an open system? I thought about replacing the radiator and thermostat and probably the hoses. Then if I put a new bottle or maybe just a new cap on my old one, then I should be able to continue to use the system the way it sits? I may get a radiator with a cap instead of the fill neck mid hose if that seems the better way to go. Also with this system, do I still need to burp down a hill with thermostat plug pulled or burp at cap?

Shouldn't need to burp it.

 

Why don't you convert to 97 and later heater hoses while you're at it and ditch that heater control valve?

What would I need to get to do that? Can I buy the hoses new? How will that affect the truck? Thanks!
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Ok good. So it is acting as an open system?

 

Seems to be.

 

 

 

Then if I put a new bottle or maybe just a new cap on my old one, then I should be able to continue to use the system the way it sits?

 

The way it's now plumbed, the bottle isn't under any pressure. Unless it leaks, there's no reason to replace the bottle or the cap.

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