Do I stick with this vehicle or not...?

[LarryTheLX]

This video suggested all the aforementioned symptoms on a 290k miles 4.7 ie misfires, slight cooling loss, possible air trapped in cooling system, low heat, and yet no milky oil.
First the block tests found combustion gas in the coolant, justifying a borescope subsequently confirmed coolant dipping into the cylinder under system pressure check. Ultimately that’s what you want to confirm before disassemble the engine.

Thanks for the video(s), great info.. I'll forward to my mechanic. Mine does not have any fluctuations in the temp gauge at all, even when it has been low on coolant it's always gone from cold to the same operating temp level and stayed there. I didn't realize the all or nothing setting on the heat could be related to the main issue, I assumed the heater core was just showing age. Happy New Year to you also!

 

[41togo]

I know the feeling just last month I had a sunroof leak and I was looking for another LC as appears it always one thing or another. But in the end of the day, the 100 still the best and they all require same among of work including low mileage as they aged.
The 4.7 is the jewel of the truck so few will agree with any additives for the leak. In my college days I had used them with limited success, one memorable repair was an Opel GT with a 1.9 engine. Milky oil and I used numerous type without success finally removed the head gasket as it turned out to be a very small pin hole in the water pump timing cover. From the event, I kind of got discouraged on these products and a career in Pratt & Whitney reinforced that there’s few short cut.
Having saids, if you have to used it since you have a good mechanic and shop to rely on and you’ve researched the product with good reviews. I would at a minimum to change the oil and send a sample to Blackstone. It serves as a baseline whether coolant in the oil or not as well as other engine health perimeters at 290k so money well spend. If they found coolant in the oil, which they should then once you put in the stop leak K seal HD and driven her a bit and drain enough oil for a second sample. If there no more coolants in oil sample then you brought yourself some time. But if the test is positive, then the head gasket job is inevitable in additional should flush the cooling system as well without further delay. Good luck and let us know your progress and findings.

 

[LarryTheLX]

I know the feeling just last month I had a sunroof leak and I was looking for another LC as appears it always one thing or another. But in the end of the day, the 100 still the best and they all require same among of work including low mileage as they aged.
The 4.7 is the jewel of the truck so few will agree with any additives for the leak. In my college days I had used them with limited success, one memorable repair was an Opel GT with a 1.9 engine. Milky oil and I used numerous type without success finally removed the head gasket as it turned out to be a very small pin hole in the water pump timing cover. From the event, I kind of got discouraged on these products and a career in Pratt & Whitney reinforced that there’s few short cut.
Having saids, if you have to used it since you have a good mechanic and shop to rely on and you’ve researched the product with good reviews. I would at a minimum to change the oil and send a sample to Blackstone. It serves as a baseline whether coolant in the oil or not as well as other engine health perimeters at 290k so money well spend. If they found coolant in the oil, which they should then once you put in the stop leak K seal HD and driven her a bit and drain enough oil for a second sample. If there no more coolants in oil sample then you brought yourself some time. But if the test is positive, then the head gasket job is inevitable in additional should flush the cooling system as well without further delay. Good luck and let us know your progress and findings.

Yeah, I'm not dead set on the pourable fix, just trying to get my brain around the options / process. After more research on the heater core replacement I would definitely choose to bypass and just fake it with space heaters as alabama winters aren't that long or extremely cold. My original question about putting a replacement in the engine bay and rerouting hoses etc. is pretty funny now that I understand how all that works better LOL. Mine doesn't leak and the temp thing might improve with a flush of the whole system. Definitely will consider manifolds / starter replacement as intelligent maintenance if we end up tearing the motor down. Thanks again for the input!

 

[41togo]

Yeah, I'm not dead set on the pourable fix, just trying to get my brain around the options / process. After more research on the heater core replacement I would definitely choose to bypass and just fake it with space heaters as alabama winters aren't that long or extremely cold. My original question about putting a replacement in the engine bay and rerouting hoses etc. is pretty funny now that I understand how all that works better LOL. Mine doesn't leak and the temp thing might improve with a flush of the whole system. Definitely will consider manifolds / starter replacement as intelligent maintenance if we end up tearing the motor down. Thanks again for the input!

A Block test kit for combustion in the coolant would also be helpful in pre and pro stop leak additive.

 

[Bisho]

The issue with putting anything into your coolant system that is designed to seal leaks - now that stuff is still in your coolant system, potentially clogging your heater core and radiator. If it works, you may temporarily fix your head gasket leak (very dubious it would be a permanent fix), but create other cooling system issues.

 

[LarryTheLX]

The issue with putting anything into your coolant system that is designed to seal leaks - now that stuff is still in your coolant system, potentially clogging your heater core and radiator. If it works, you may temporarily fix your head gasket leak (very dubious it would be a permanent fix), but create other cooling system issues.

Yes that seems to be the historical concern with these type products. I did a lot of online research and had a lengthy, thorough conversation with the support folks at K Seal and felt comfortable giving this a shot for $30. I don't expect any issues with the radiator or heater core whether it resolves the actual head gasket problem or not but as minor as my symptoms are I think I have a better than average chance of it fixing the issue even if it's not a permanent fix. This is a spare / recreational vehicle so if a daily gets 2 years out of the fix I might get 4, who knows LOL? I'll see how it does as it has to circulate for up to a week and update on this later.