No worries, My wife doesn't listen to me either !

 

I have a Snap-On coolant pressure tester and it's pretty cool for this stuff. I've tried dye with limited success, particularly if the leak is subject to fan wash and requires a hot drive to expose. I found a leak this past weekend when I did my degas bottle that I was unaware of. Top the system off, pump it up to 15psi and wait. Dye is effective, but if it's in a tricky spot, leaking at a steady drip and subject to the engine cooling fan air while driving (fan wash), it can cause splatter or spray that is hard to sort out, particularly if you already have the general area targeted. $.02.

 

I have been following this thread and reading everything I could. I looked everywhere and couldn’t see or smell anything, lights, mirrors, plywood under the truck on my gravel drive, stress, no sign of my leak.
Then I went to the parts store and borrowed an Ever Tough radiator & cap test kit along with an adapter set (ever tough parts #67085 and 67086). Within 1 min I found my degass cap is destroyed, won’t hold anything. Within 5 min I found my lower hose from my degass bottle to the radiator was leaking past the clamp.

Well worth the time gents and I’m kicking myself for not doing it sooner. Maybe this will help OP.

 

That's the ticket, right there...

 

Hopefully something shows up Pete. My bet is on the fitting as well if it was removed and then put back in. I guess we will find out!

 

Narrowed it down significantly!

Borescope didn't do anything for me except to reveal that I need to snug down my valve cover bolts.

Dye... lovely fluorescent dye!

ALL hoses and fittings, and the entire perimeter of the water pump, the degas bottle itself & cap, the radiator and cap, thermostat housing, block drain plug, and heater hose return fitting.... all are 100% clear with no presence of dye. There is no pinhole in the radiator or from anywhere else which is being blown about by the fan, and there is no evidence of dye anywhere on the fan blades.

The leak is somewhere behind the A/C bracket, underneath the compressor, and above the elevation of the block fitting where the heater return hose connects. With the engine off, after a good run down the road and back for 30 minutes to circulate the dye, I can see the drip. However, it's deep enough back to where I cannot see the true leak point.

I'm not sure how to proceed from here. Can the compressor be moved far enough out of the way to see what's going on... WITHOUT opening the system?

I've even searched for passenger side views of the engine to see if anything makes sense, but cannot find appropriate pictures. Everyone seems to favor shots from the DS.

Insights or suggestions, anyone?

 

I thought to go back to see if I had a picture which might help, and found one. The red outlined arrow points where I can see the drip falling. However, with the belt and fan shroud in place, I've not been able to get my scope camera in position to see anything useful.



The more I think about this, the more I believe I'm going to have to pull the tensioner pulley bracket and move the compressor out of the way just so I can see what's in there.

Am I looking at a potential freeze plug in that area?

 

I am 90% sure the AC compressor can be unbolted (belt removed) and moved to the side without breaking the seal in the system.

I have not done it myself, but I seem to remember seeing videos and pictures of the engine being removed with the AC compressor pushed to the side.

Of course movement is limited, but you might be able to get it out of the way enough to get to the leak location if that is your plan of attack.

If someone else doesn't chime in about the freeze plug question, I will see if I can find the answer in the FSM.

 

Thanks, Sous. I'm going to attempt the removal this afternoon after I get back home, and hopefully be able to see what's going on and at least get the repair plan together, if not get the final repair completed.

I'm currently back at the plant again today (following a two-day hiatus for oral surgery - extraction and bone graft), and the demands at work are growing rapidly. We're only 37 days late for the paper machine startup due to the impact of COVID on equipment deliveries and contractor availabilities. What makes this really bad is that because of a nice October 1 price increase for our product line (first increase in 10 years), this startup delay is costing us about $100,000/day in pure profit, and that doesn't account for the profit we would already be making on without the price increase - no small matter, and the pressure is really on for my entire group of five production service departments! That said, when I get home, I'm done and just don't have it in me for any more computer screen time.

 

Good! Nice to have it narrowed down. Your arrow appears to point to just below the area where the heater core supply port on the forward end of the passenger head is.

 

Pete, I had a good look through the FSM this morning and either missed it or there isn't a section on freeze plugs and their location. All sorts of information about the cooling system and it's components though. Like you, we are looking forward to you finding the source of the leak and fixing it, hopefully for "free dollars".

 

Ask and you should receive.

 

Reps sent Adam! Well done sir, once again. This will not only aid Pete in the discovery of his leak, but will be available for FTE'rs and visitors for years to come.

 

Thanks for that picture, Adam!

I may have it licked at this point.

Turns out that my leak was coming from between the front timing cover and the block at about the 10:00 position (looking at front of engine , towards the rear, from the front bumper). The "ooze" would only come out after running the truck, and amounted to a drip about every 2-3-4 seconds. The location of the oozing is immediately behind the A?C compressor bracket, and I could not locate it until I moved the bracket out o the way (breaking off the 18yo plastic handle from my oil dipstick in the process - I HATE old plastic!).

After texting with Sous for a bit, I decided to go ahead and use a "reputable" ELC-compatible coolant leak sealant fluid via the degas bottle (K-seal). The alternative is pulling the engine to remove and replace the front timing cover, and I really cannot do that myself, and am extremely hesitant to pay someone else the kind of money required for them to do it for me.

So, I've been running the stop leak additive since Saturday evening, knowing it takes multiple heat up and cool down cycles to pull the additive from the degas bottle and through the engine. I could have poured it into the upper hose, but did not want the concentrated additive package sitting on top of my thermostat at all. I idled for 30 minutes in the driveway Saturday evening, ran a couple of good 30 minute errands with my wife on Sunday, drove 30 minutes to work and back yesterday, and inspected the bottom engine area last night. It looks like the K-seal has thoroughly circulated at this point, and the oozing appears to be sealed up. I'll keep inspecting every evening after returning home from work, and if it holds through the rest of this week, I'm going to purge and flush the coolant again, refilling with fresh coolant, and then change my coolant filter twice over the coming month or two.

If the ooze comes back, then I'll choose to get the front cover replaced, and go ahead and proactively take care of a few other things at the same time - might as well, being at 325K miles with the engine is out (i.e. front main seal, LPOP, LPO pressure regulator, Moroso oil pan gasket, weld-in dipstick mount housing, etc.).

Pictures below show you both a close up of the ooze as well as a more distant view of the location, which is right behind the compressor bracket, and even right behind the Fuel Bowl Drain Line which I moved out of the way to see more clearly.
..

 

Been following this for a while. Glad you found it! That sounds almost like a worst case scenario leak. You know where it is, but it's not practically accessible... Keep us updated with the sealant.