lpguy

Well after busting 3 hose clamps i gave up on my hose leak and came here... Found out it was just the weep hole telling me the water pump was bad So today i get to changing the water pump and i go ahead and swap thermostat, turns out PO wasnt running a thermostat
What would problems would this cause anyone? Also can anyone tell me what the threads are on the hardline that comes out of the water pump to the heater core? I seemed to have boogered them up trying to reuse the old line (which i also now need to replace).... Im hoping i can chase the threads with a tap, if not gonna have to buy another water pump. Also anyone know what that hardline is technically called so i can get it at the auto parts store?

djb383

FSM says "do not operate engine without t-stat". Thread is 3/8" NPT.

lpguy

Im gonna run with a thermostat but was just wondering what if any harm it would hve cause by not running a thermostat for an unknown amount of time... Would this have cause my pump to fail? Or my heat not to work? Thanks for tap info

tjwalker

Most likely no damage because of running without the stat. The water pump failing is most likely coincidental. Replace the pump, get a good quality 195 degree stat in there (From Jeep or a Stant SuperStat), a fresh 50-50 mix of coolant to distilled water, and you should be good to go.

wildbill1

Running without a thermostat probably didn't do any permanent damage. You will likely get better fuel economy once you install one. Use a 195* for best results.

As far as the hard line, it may be difficult to find. I've seen where some 4.0 owners replace it with a barbed hose fitting and use a longer heater hose. As far as size, I'm thinking it's 1/2" NPT thread in the water pump.

mike mike

The only damage was most likely to your wallet at the gas pump!!!

lpguy

I was only getting like 16mpg.. I just passed it off as what im stuck with... my jeep dealer down the street actually has the hardline in stock.. Gonna grab it with a thermostat on way home. Want to get it back on the road today

waltermitty

The "tube" may be a dealer only part. My '98 XJ required the $22.00 dealer purchased part as mine was beginning to deteriorate. The head has a recess for the t-stat to sit in before the gasket/housing is bolted on. If you've been running without one chances are there is corrosion there. Just carefully scrape it clean. While it's opened up flush the block, rad and heater core with water. change directions on the heater core flush.

Solomon7

Make SURE you get the right tube. there's 2 different tubes that look very similar from the dealer when I did mine.

freegdr

i use 3/8 galv pipe cut to length