Does a 1999 XJ (4.0L) radiator have a drain plug. If so, where? If not, is removing the lower radiator hose the only way to drain coolant? Also, any help on changing this thermostat is welcome. I've done it on many other vehicles, but never on an XJ. Thanks

 

There easy just pull the top rad. hose off pop the rad cap then loosen the thermostat housing and pull the old one out put the new one in the same way the old one came out buy a gasket at the store for the housing and bolt the housing back on DONT over tighten it it will crack just make it snug so it doesnt leak fill with coolant and run with rad capo off to burp the system

 

I'm not certain on a 99 XJ but the radiator pepcock on my 91 XJ is on the inside lower left corner.

 

Remove the grill and you'll have access to it on the bottom left side of the radiator.

 

Use caution removing the plastic drain plug....they easily break. We found it really easy to drain coolant by 1st removing the air filter box (3 bolts) then removing the bottom rad hose from the water pump.