$1000 jeep xj cherokee with 4.0L overheating in soft sand

[ian cj10]

Hi Moses

the current exchange rate puts the cost of this xj at$670 us 

as for the over heating ive worked out it has no thermostat but from the research ive been doing the right hand drive versions have the tranny cooler in the wrong side of the rad so my first move is going to be to reroute it to external tranny coolers as i have 2 in my shed that will bypass the rad & reduce heat getting to the cooling system

sounds good in theory we'll see how it goes in practice

also when it overheated it shut down ive been told that the crank pos sensor gets heat sensitive with age so ill need to replace that it fired up once it cooled for 15 or 20 minutes & ran fine so i just made sure it didnt get that hot again

cheers  ian

[Moses Ludel]

Oh, boy, a real bargain at $670 U.S.D.!  Ian, I like your focus on the trans cooler, as the sand would be a clear load on the transmission (lots of torque converter action!).  Isolating heat from the radiator coolant will help—as long as the bypass coolers are sufficient cooling for the AW4 transmission.  Two oil-to-air coolers in tandem would seem sufficient.  You might want to consider a transmission temp gauge or at least a transmission spot check with an infrared temp gun.

I always run a thermostat, a 190-degree F is usually adequate, maybe even a 180-degree F if not too cool.  (Too cool, the EFI system will stay in the enrichment/warm up mode.)  The thermostat doubles as a restrictor to prevent rapid flow of coolant through the radiator, which can result in inadequate heat dissipation as the coolant passes through the core.  Factory is a 195-degree F thermostat.  If all is working well, the coolant with a stock thermostat should run in the 195-210 range, even with A/C operating.

Moses