Radiator cap pressure
#1
Radiator cap pressure
Ok i have a 1997 chevy express cutaway van with a 6.5 diesel. engine runs great doesnt overheat but when i drive down the highway and get off the ramp and slow down the expansion tank lets coolant out till it gets low. truck doesnt overheat or anything just looses coolant after driving on highway. there is a brand new 15 pound cap from chevrolet but a friend of mine said go to a higher pressure cap.. any ideas would be great
#4
Join Date: Oct 2012
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Might want to give this a read and see if the details match up:
6.5 blowing coolant everywhere (Total Rebuild) - Diesel Place : Chevrolet and GMC Diesel Truck Forums
6.5 blowing coolant everywhere (Total Rebuild) - Diesel Place : Chevrolet and GMC Diesel Truck Forums
#5
#7
Mine has done this ever since i had the injection pump replaced it has a new water pump new t-stats fan clutch and rad only thing in the system orig is the tank. coolant stays green and i lose about as much coolant as a can of pop. i have a welding system on the truck that works off the alt and i have had it running for 4 hrs and it doesnt lose coolant or overheat . ive added dye to the system and the only place i see coolant is from the tank. it blows no white smoke even at start up runs cool down the road what size is the rad cap supposed to be.. mine is a 15 pounder
#9
ill pressure test the system tomorrow and see what it does and go from there . this one has not only me stumped but my father who's a retired diesel mechanic of 40 years.
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update.... ok i put a pressure tester on it about 4 hrs ago pumped it up to 15 pounds and it hasnt moved at all. im letting it sit all day and part of the day tomorrow and go from there i used a pressure tester that blockes off the bottom of the tank so it doesnt let air out of the vent on the tank so theres 15 pounds of pressure in the system
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Update... i have gone back out and its still at 15 pounds. i have also cranked the engine over without it starting to let the valves open and for the pistons to move around and its still at 15 pounds. im going to let it sit another 2 hrs and go out and crank it over again and see if the pressure goes up or stays. i have unplugged the pdm so it wont start but build pressure in the cyclinders.
---AutoMerged DoublePost---
update.... ok i put a pressure tester on it about 4 hrs ago pumped it up to 15 pounds and it hasnt moved at all. im letting it sit all day and part of the day tomorrow and go from there i used a pressure tester that blockes off the bottom of the tank so it doesnt let air out of the vent on the tank so theres 15 pounds of pressure in the system
---AutoMerged DoublePost---
Update... i have gone back out and its still at 15 pounds. i have also cranked the engine over without it starting to let the valves open and for the pistons to move around and its still at 15 pounds. im going to let it sit another 2 hrs and go out and crank it over again and see if the pressure goes up or stays. i have unplugged the pdm so it wont start but build pressure in the cyclinders.
Last edited by Daves97express; 06-08-2013 at 03:46 PM. Reason: Automerged Doublepost