I"ll try and make this quick.
I bought a 2001 jeep TJ Sahara, the heater core was leaking. It started out as small leak, pretty soon it go bad enough to install a heater core bypass. Before installing the bypass I checked the heater to see if it was working and it was not blowing hot air, however it was leaking. I just assumed the heater core was also clogged.
A short time after installing a bypass for the heater core, I was driving at highway speed when I noticed my temp gauge was pegged deep in the red at 260 degrees. I shut off the motor and pulled over. I found that the heater core bypass had failed, I assumed this was the cause of the overheating so I installed a brass fitting in place of the plastic fitting from the auto parts store. This was on June 12th. I also changed the oil and coolant this same day.
I have been continually having overheating problems since then.
Several days after replacing the coolant I checked my coolant levels and pulled the radiator cap, I noticed that the coolant looked terrible. It looked like it was full of dirt and rust. Like it hadn't been changed in several years. The overflow bottle looked like it had dirt in the bottom of it. I checked my oil, no signs of coolant, none.
Today I changed the thermostat, still overheating.
I'm thinking cracked/warped head, or a blown head gasket. I'm thinking the cause of the bypass failure was not due to a faulty part, but do a problem with the head.
My other theory is the bypass failure was due to a bad part. The rode-side fix resulted in low coolant and running hot; this built up pressure, causing my radiator to boil, shooting steam and coolant out of where the aluminium meets the plastic tanks on the the top of the radiator. When I flushed my coolant I had the heater core back in line, so whatever was clogging it made its way into the system. Basically I think I need a new radiator.
So my options are;
1: Replace radiator
2: Swap in a non 0331 head
Any bets on what the problem is? This jeep has been a mall crawler all its life, so off road abuse is not a cause, nor does it lead me to believe the head is the weak link here. Being that its a 0331 head, I suppose anything is possible.