Join Date: Oct 2007
Thanked 3 Times in 3 Posts
iTrader Score: 0 reviews
my '97 did that after the jokers at the dealer replaced the short block and left the radiator cap loose. I didn't think to check for that, or the vacuum lines left disconnected, and drove it for a couple weeks in the summer, towing and everything. Luckly, the 5.9 is a tough motor, and does not overheat easily, even when the coolant system is not pressurized. The cap was partway on, so it would build a little pressure, but let the coolant out to the reservoir bottle, and then leak air when it cooled, instead of pulling the coolant back in the motor. After a few cycles, the reservoir was full and the top of the radiator core was visible. I just put the fluid levels back to the right places and made sure the cap was back on right, and never had it happen again. you might have a bad cap or an air leak on the hose to the reservoir.
New: 2008 black MegaCab, 6.7, 4x4, auto, stnd gears, no performance mods, only 18k miles so far
Old: 1997 extended 5.9, 4x4, 5sp, 150k miles, mostly stock but added edelbrock shocks