• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

6.5l no pressure on cooling system

Trucker2k16

Trucker2k16

Well-Known Member
Messages
306
Reaction score
396
Location
Charleston south Carolina
Hey fellas im back with yet again another 6.5l question...
Ok so i just picked up another one and it runs normal temp 186-188 new dual t stats no leaks what so ever new hoses run truck for few miles and back home i notice upper hose has no pressure on it wth???? Cooling system is designed to build pressure. Could a bad Reservoir or cap cause this issue I replaced the cap and same thing. No coolant lost not in oil or ground i can pressurize the system to 15 pounds and in 30-45 mins it only drop 3-4 psi. Should i just run it? Or replace the Reservoir I hear that they will leak around the neck of filler where radiator cap goes?
 
If you tested it with a radiator pressure tester and found no leaks and it doesn't build pressure the cap is the only thing left, it takes more than a few minutes for the system to build pressure.. drive it and see and keep bleeding the system...
 
Twisted Steel Performance said:
If you tested it with a radiator pressure tester and found no leaks and it doesn't build pressure the cap is the only thing left, it takes more than a few minutes for the system to build pressure.. drive it and see and keep bleeding the system...
Click to expand...
Absolutely no air even filled up upper hose i figured in a 4 mile around trip it would of pressurized but i have found that the resouvour is leaking aroumd filler neck by spraying soapy water on it the cap is new ish maybe few months old but is a pos red tab one by stant
 
Not that crazy it just depends. Expanding on what Chris said it takes heat to build pressure. It only builds pressure because it is air tight and the thermal expansion of fluid and warmed air in the reservoir of underhood temps. It doesn't really circulate to the expansion tank much. It is not like a pump pumping air into the system. Now if it started boiling the coolant because without pressure raising the boiling point it would cause problems. But light load coolant won't get to > than ~ 220-230 F for coolant to boil/steam. So depending if you stats are 180F that leaves a some degrees variation for local hot spots to remix and keep from continuing superheating.

I had a Mitsubishi truck with hair line crack at the radiator metal filler neck I drove it a long time with crack normally and could add just a bit of coolant it was only when it was really hot that it would loose enough vapor/weep coolant that wanted to expand to the overflow to get low. The engine did not have bad hot spots like the 6.5.
 
schiker said:
Not that crazy it just depends. Expanding on what Chris said it takes heat to build pressure. It only builds pressure because it is air tight and the thermal expansion of fluid and warmed air in the reservoir of underhood temps. It doesn't really circulate to the expansion tank much. It is not like a pump pumping air into the system. Now if it started boiling the coolant because without pressure raising the boiling point it would cause problems. But light load coolant won't get to > than ~ 220-230 F for coolant to boil/steam. So depending if you stats are 180F that leaves a some degrees variation for local hot spots to remix and keep from continuing superheating.

I had a Mitsubishi truck with hair line crack at the radiator metal filler neck I drove it a long time with crack normally and could add just a bit of coolant it was only when it was really hot that it would loose enough vapor/weep coolant that wanted to expand to the overflow to get low. The engine did not have bad hot spots like the 6.5.
Click to expand...
Dual 190's i dont tow with it and the temp never gets over 186-188 my other 6.5 is the same way but takes at lease a hr or so of driving to build i bought the expensive coolant reservoir. I dont hear the coolant boiling and isnt blistering hot but warm enough that i can hold it for 3-4 secs
 
You must log in or register to reply here.
Back
Top