Maytime

First off, thanks for having me on your forum. I've been a lurker here for a while and have gotten loads of great info.

A little background: I've had this nagging issue with my 87 XJ in that it was running hot even without towing my boat, and would typically overheat on a hot day going up a grade. I noticed a lot of other folks here have had the same issue, so I thought I would share how I solved mine.

I had replaced a cracked flushing T, broken reservoir bottle cap, the bottle itself, installed a new radiator, and still this thing was running hot. The only things left were the thermostat and water pump to check, the latter of which was fine. The t-stat was very old, so I replaced that. Still hot. Finally pressure tested it while cold, and it turns out that there was a leaky heater control valve that prevented the system to build up adequate pressure. Once that was replaced, I can tow my 2800lbf boat and trailer on a hot day up a 6% grade and it won't even get above ~180 degrees F (gage temp).

I hope this helps some of you, I appreciate all the good info!

waltermitty

Did you use the recommended 195 T-stat?

djb383

Something ain't right.....I'd suspect your gauge, sending unit or something electrical. Bet actual coolant temp is substantially higher under those conditions regardless of whatever temp t-stat.

Maytime

Yeah that was the only one they had at the store.

It could be reading low, but it sure does seem like it is running 100% better than it was. I didn't touch anything electrical, just the mechanical components.