Dammerung Posted Wednesday at 07:56 PM Share Posted Wednesday at 07:56 PM So, I’ve decided to finally tackle my coolant system because after 3 plastic bottles breaking, I’ve had enough. I bought an aluminum tank to replace the plastic one and it uses a radiator cap. What I want to know is, what is the pressure rating for the closed cooling system? P.S - I won’t switch to open cooling until I get a new radiator at the very least Sent from my iPhone using Tapatalk Quote Link to post Share on other sites
PIKE Posted Wednesday at 08:34 PM Share Posted Wednesday at 08:34 PM Once you install the aluminum tank with radiator cap you WILL have an open system. An expansion tank for a 2.5 engine works very well. It bolts right in. The holes for the screws are already there. It mounts on the drivers side towards the front of the engine bay. You will have to relocate a few things. Then just run a hose from the expansion tank to the fitting below the radiator cap. Fill the aluminum tank to the top and keep an eye on the level in the expansion tank. It has markings for cold and hot levels. I believe the OEM cap for a 4.0 is 13 psi. Hope this helps. Quote Link to post Share on other sites
Dammerung Posted Wednesday at 08:47 PM Author Share Posted Wednesday at 08:47 PM Once you install the aluminum tank with radiator cap you WILL have an open system. An expansion tank for a 2.5 engine works very well. It bolts right in. The holes for the screws are already there. It mounts on the drivers side towards the front of the engine bay. You will have to relocate a few things. Then just run a hose from the expansion tank to the fitting below the radiator cap. Fill the aluminum tank to the top and keep an eye on the level in the expansion tank. It has markings for cold and hot levels. I believe the OEM cap for a 4.0 is 13 psi. Hope this helps.Wouldn’t the tank be pressurized still? I thought that an open system would have an expansion tank that is not pressurized. Or could I plug off that valve under the cap?Sent from my iPhone using Tapatalk Quote Link to post Share on other sites
Pete M Posted Wednesday at 08:56 PM Share Posted Wednesday at 08:56 PM for what it's worth, I have a closed system but with a modern radiator (with cap) and the cap is rated 16lbs and has never popped. Quote Link to post Share on other sites
Dammerung Posted Wednesday at 08:59 PM Author Share Posted Wednesday at 08:59 PM for what it's worth, I have a closed system but with a modern radiator (with cap) and the cap is rated 16lbs and has never popped. Thank you Pete! I’ll look into getting one. This little tank is some universal eBay one that I’ll have to fix up to make it work.Sent from my iPhone using Tapatalk Quote Link to post Share on other sites
PIKE Posted Wednesday at 10:12 PM Share Posted Wednesday at 10:12 PM 1 hour ago, Dammerung said: Wouldn’t the tank be pressurized still? I thought that an open system would have an expansion tank that is not pressurized. Or could I plug off that valve under the cap? Sent from my iPhone using Tapatalk I assumed you had a Macs tank. If you filled the tank half way I guess it might work, maybe someone has tried it. You don't want to plug that fitting, that's where the pressure will escape. Quote Link to post Share on other sites
Dammerung Posted Thursday at 06:33 AM Author Share Posted Thursday at 06:33 AM What kind of hose clamps should I use?I don’t want to use the worm gears because they’re butt ugly and they’ve been letting me down recently.Sent from my iPhone using Tapatalk Quote Link to post Share on other sites
cruiser54 Posted Thursday at 12:11 PM Share Posted Thursday at 12:11 PM Isn't a new late-model radiator rather inexpensive? Kill 2 birds with one stone? Quote Link to post Share on other sites
Dammerung Posted Thursday at 06:00 PM Author Share Posted Thursday at 06:00 PM Yeah, but that’d take my truck out of commission for a while. I don’t have the time to replace a radiator with my school and everything.Sent from my iPhone using Tapatalk Quote Link to post Share on other sites
Eagle Posted Thursday at 09:15 PM Share Posted Thursday at 09:15 PM On 1/13/2021 at 3:47 PM, Dammerung said: Wouldn’t the tank be pressurized still? I thought that an open system would have an expansion tank that is not pressurized. Or could I plug off that valve under the cap? Sent from my iPhone using Tapatalk What tank did you get? The one I used takes a radiator cap (I used a 13-pound), and it also has a barb fitting for a tube that goes to an overflow (expansion) catch bottle. This makes it functionally an open system rather than closed. Mine's a Moroso, but the Mac's tank specifically for the XJ and MJ didn't exist when I did mine. Here's the link to the Mac's tank: https://macsradiatorshop.com/product/macs-1987-1990-jeep-cherokee-aluminum-coolant-tank/ See the smaller fitting that's ON the filler neck? A radiator with a filler neck has the same thing. That's for the hose to the overflow catch tank. Quote Link to post Share on other sites
velco Posted Thursday at 10:18 PM Share Posted Thursday at 10:18 PM Or you can plug the overflow and keep running a closed system. I am using a 16-lb cap. Quote Link to post Share on other sites
Dammerung Posted yesterday at 01:18 AM Author Share Posted yesterday at 01:18 AM What tank did you get? The one I used takes a radiator cap (I used a 13-pound), and it also has a barb fitting for a tube that goes to an overflow (expansion) catch bottle. This makes it functionally an open system rather than closed. Mine's a Moroso, but the Mac's tank specifically for the XJ and MJ didn't exist when I did mine. Here's the link to the Mac's tank: https://macsradiatorshop.com/product/macs-1987-1990-jeep-cherokee-aluminum-coolant-tank/ See the smaller fitting that's ON the filler neck? A radiator with a filler neck has the same thing. That's for the hose to the overflow catch tank.https://www.ebay.com/itm/153133492767That’s the tank I bought. I think I’ve worked it out now.Sent from my iPhone using Tapatalk Quote Link to post Share on other sites
Eagle Posted yesterday at 06:07 AM Share Posted yesterday at 06:07 AM Okay, so that barbed fitting on the filler neck is for the tube to an overflow catch bottle. Quote Link to post Share on other sites
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