tbrumm
Full Access Member
Over the last six months, I have noticed that I have had to add a little coolant to the overflow reservoir every once in a while as the level has very slowly dropped. I replaced the reservoir (Thanks, Brian!) as mine was cracked on top. I have kept my eyes open for residue, drips, stains, puddles, etc. but haven't really found anything. The coolant system has been properly maintained by me and I have a newer Champion radiator. I happened to notice a few drips of something on the front drive shaft about 1 foot aft of the yoke. I smelled it and it did not have an antifreeze (Fleetcharge)smell. I took a flashlight and made a good inspection of the rear of the driver's side head. I noticed a couple of drips on the weld seam on the cab behind the head. Again I smelled this "moisture" but it had no odor. There is a little bit of white residue up behind the head though and the coolant has to be going somewhere. It isn't being burned (no smell in exhaust), no coolant in oil or vice versa. Anyway, to get to the bottom of this I purchased a pressure tester. I should note that I run a Motorcraft 7lb. radiator cap and not the standard 13 or 16lb. cap. I hooked up the pressure tester and pressurized the system to 15 lbs. I left that set pressured for a couple of hours. The pressure on the gauge had fallen to 13lbs in that amount of time. The only leak I found was the packing nut on one the coolant filter shut of valves (passenger side by fuel filter) was leaking. I tightened down the nut a bit as it was a little loose and that took care of that drip. Now, this valve "could" have been leaking all along, even with the 7lb cap, and I may not have noticed that. A slight drip would have just dropped onto the crappy fender sound insulation. That does not explain the drips on the driveshaft and cab seam (which didn't smell like coolant to me but maybe my sniffer isn't to good anymore). One thing is for sure: there was no coolant leak at the back of the driver's head while the system was at 15lbs. This was with the truck stone cold, so maybe the headgasket is only leaking a bit when the the truck is up to operating temp. Anybody experience anything similar or have any suggestions for additional testing? Thanks for reading! Todd