leak/lbs/pressure.
 

II have a 02 dakota 3.9 an I'm noticing my coolant level getting low frequently and am not seeing a leak anywhere .Where do I need to start looking ,maybe at water pump or from cap?
Temp hardly reaches middle on gauge also when running.

Oil looks fine an radiator fluid looks fine an no codes or smoke.Truck runs fine also.

I also wanted to know what temperature rating the thermostat needs to be.160,180,190?.and the cap pressure also 20 or 16?
Thanks

Cap should be 16PSI, Stat should be 195.

Mystery coolant loss is always fun. If it isn't dripping when the engine is hot, I would check the by-pass hose from the water pump, to the intake. Unfortunately, that's under the bracket for the a/c, and alternator...... it will leak, and the coolant will basically boil off on the flat surface the timing cover provides right under it, so, you never see it hit the ground.

Freeze plugs like to leak too, but, those *should* show some evidence on the ground.

Might also test the coolant for combustion products. Parts store should have test kits for that for relatively cheap.

Wow Thanks!
I been running a 20 on cap!
Not sure but I think a 185 on stat!

anything over 180 on the stat is fine. If you want, you can drill 3 small holes in it (no bigger than 1/8") to help with getting steam pockets out of the system. Having the split top hose, you are on borrowed time at 20 pounds. Go to a 15 or 16. Alot of people have had the hose blow apart at the cap, myself included.