It's been a few weeks since we fixed all 20 coolant leaks, the big one being the cracked cylinder head. Good news to report, not one drip on the ground in 2 weeks! The cylinder head crack braze repair was weeping, so I took a product called Blue Devil Block Sealer and poured it right into cylinder head through the temp sensor port and ran the engine for 45 minutes and drove it for an hour. I was skeptical and unsure of what this mysterious fluid would do. I took others advice and isolated all the auxiliary coolant stuff from the engine. This fluid flowing in the coolant in just the engine and radiator seemed to do the trick. Going to leave it just like that for a few months and then might flush the coolant and refill with all new coolant and plumb all the coolant lines back the way they are supposed to be.
On my quest to perfect the crazy auxiliary coolant setup, the system was having trouble with the old 3 way manual ball valve setup. That valve was just above the radiator cap, which caused air to get trapped there. I would have to cycle the valve every time I fired the Espar boiler up to bleed the air out. Interesting enough, this was not a problem when the engine was heating the coolant auxiliary loop. And the automatic air purge valve was hiding other issues, not cooperating with the radiator cap and stuff. So I ripped all that out and found this valve, which they call a heater core bypass valve.
This isn't technically a 3 way valve, but I made it into a 3 way valve. Fluid enters the valve through the "in" port from the Espar boiler. From there, the valve either directs flow left or right to "1" and "2". On the right, or "2" side, there is just an extra port that I just plugged. Port "1" goes the engine block for to heat the block on cold mornings. Port "2" goes to the auxiliary loop that works the cab heat, hot tub heat exchanger, rear air heater, and water heater, in that order. The old setup used to heat the water heater first, but that was really dumb, so I plumbed it the other way around while I had it all ripped apart. This winter I got tired of waiting an hour for the water in the water heater to get hot enough so I could finally get heat in the cab.
On the climate control panel there was an knob that used to work a damper that allowed you to choose inside or outside air. There are so many air gaps in the cab that it was really useless so that got ripped out when I first got the van and sealed the outside air inlet with duct tape. So I got some throttle cable from the auto store and hooked that up to that 3 way coolant valve. Now I can switch what the Espar boiler heats right from the driver seat! It's so simple and easy, I don't know why I didn't think about doing this before!
I hung this tank from the passenger side mirror when I was diagnosing the air lock problem in the coolant system. Wasn't planning on installing it, but during the diagnosing, I thought it would be really nice to have the tank so you can have a visual check to see if you had coolant flow. Also was going to need it since we separated the auxiliary coolant system from the engine and didn't have the radiator. So found a sweet spot next to the passenger footwell. So nice to just drill holes through the exterior body and through some bolts in. It was tight for the hoses under the floor because the wheel well was there.
The hose on the right only had about 2" of clearance so I got lucky and really needed these 90 degree hose adapters. The results are everything I wanted. Been driving around and it works great, every time! Only downside right now is that there is no heat when the engine is running. I have to fire up the Espar boiler to get heat. But hopefully that is temporary while we check to see if that cylinder head repair will hold up. At some point I'll post a schematic of the coolant system. It's kind of a mess without that, and there have been so many versions, I have chicken scratch notes everywhere.
