Overheating issue

[Whitaker717]

Hi guys, tonight I noticed my temperature guage climbing in the Comanche. I usually run around 180 degrees but the needle was at 210 and even a bit past. Usually there is just a bit of coolant in the tank but tonight it was bubbling back into the tank. Almost boiling. Lol. Why would this all the sudden do this? My e fan is not working and I am working on replacing it. I have replaced the radiator, water pump, thermostat, and clutch fan. Could the heater core be plugged. I’m still not sure how this system works, so if someone could explain it to me I would appreciate it. Thanks

[Whitaker717]

1 hour ago, saveevryjp1998 said:

What year and setup? Any pics of the current coolant system setup? Otherwise we are all just guessing. If I had to guess, you have a Renix 4.0 closed coolant still (87-90). This problem comes up often. Most guys struggle to properly purge the system of air and will tell you to switch to an open system. Include pics of all lines to heater core and bottle. Sometimes people bypass the bypass. Many things can cause your issue if indeed you have a closed system. Things like a bad core, an old hose with a leak, faulty cap, any faulty part in the coolant system. Basically anything allowing air in or not purging all the air completely out once a repair has been made will cause the same issues. During the original cash for clunkers thousands of them rolled through junkyards. People constantly scrapped them thinking it was engine problems and usually head gaskets. JP mag(yes mag for magazine I'm old) put an article out years ago to inform people how to purge a closed system. It seemed to be lost knowledge to many mechanics and continues to puzzle them to this day. Get the pics. If your wanting to learn a closed system(assuming it is), 1st step will be learning how to purge it. Then it will be tracking down where a leak or air is coming in if there is a faulty part or gasket.

 

P.S. I hungered for years waiting every month for my monthly JP porn mag in hopes of seeing a new article of Trasborg's MJ builds. They aren't laughing or making fun of his MJ builds now.

Here are a few pics. It’s an 87, 4.0, 4x4

[87MJTIM]

Looks like seeping around the cap.  Either get a Volvo cap (see Cruiser54) or change the bottle and cap.

[Whitaker717]

There is no liquid coming from cap or bottle anywhere. That must be old from someone or something.