bigredstrokerace

Currently I am having overheating issues on a 1992 Jeep Cherokee Sport with the 4.0 inline 6 with AC, a mechanical fan on the passenger side, and an electrical fan on the driver side. Its sitting just over 206,000 miles.

It blew a head gasket prior to this work starting. I removed everything above the block. I sent the head off to a machine shop to have it resurfaced. I installed new rocker arms and bridges, being that the old ones were bent and worn, and I used all new bolts on the head. I torqued to the exact specifications given in the Haynes Manual (same as Mitchell On Demand and OE spec). All surfaces applicable on the intake, valve cover, exhaust, and t-stat housing were resurfaced as well. We put a new "fail-open" thermostat (OEM spec) in as well as replacing the entire t-stat housing with a new one. I put in a new water pump. I did a full oil change (10W30 and added Lucas as well). I replaced the radiator with an a new one (also OEM spec). I replaced all the heater hoses and the heater/vacuum control. I replaced all of the vacuum tubes visible in the engine bay. I replaced the air filter and the spark plugs. I replaced the coolant temp sensor at the rear driver side of the block (the one that connects to the temp light on the dash). I filled the cooling system with 50/50. I burped it by first squeezing the upper radiator hose repeatedly until no more air came out of the radiator cap opening. Then I parked the jeep in a downhill facing fashion (with the passenger side facing slightly more downhill). I sealed a funnel into the top radiator opening so that I could create a temporary reservoir that is higher than the entire engine compartment. I filled up the funnel and the unscrewed the coolant temp sensor at the rear of the head to allow for air to escape. After reinstalling the sensor, I attempted to burp the upper radiator hose again (nothing came out). At this point I closed the hood and started the engine. Within 5 minutes the warning light comes on at the dash while idling, whether the heater is turned on in the vehicle or not. (The vehicle had been off for over 24 hours.) The local temperature is approximately 80 degrees Fahrenheit. Furthermore, when the jeep is shut off, I grabbed one of the blades on the mechanical fan and gave it a hard spin. It freely spun less than one revolution. While the vehicle is running, both fans are on and blowing in the proper direction. These tests were done with the grill removed (to maximize airflow). The upper and lower radiator hoses are both hot as well as the radiator itself. It is maintaining pressure as well when I squeeze the upper radiator hose. The coolant is also crystal clear. There is no coolant in the oil either.

Does anybody have any ideas as to what could be the problem. I've quite literally just emptied every pocket and need to get this thing running. lol Any help would be much appreciated.

Austin Leonardis

Did you ever figure out what the issue was ?

jordan96xj

The original thread is 9 years old. Probably won't get a response.

Interesting that it never got a single reply until today.