The cooling system for Hapy's new engine has been a journey. Looking back on multiple years of efforts to get Hapy to be genuinely water-cooled, today's post covers what may be the last thing I needed to do. I have lots of links referencing pretty much all of the things I've done, but I probably missed a few at the beginning of the project because many of those early posts covered multiple project aspects.
Initial Cooling System
Recall when I started this project, I sourced a radiator off craigslist for $30 (See TDI - Day 2). At the time, I was even offered the air-conditioning condenser, and it had the original fans. I passed on the air-conditioning condenser, which he subsequently sold, and I removed the fans. I added 2 flex-cool fans and wrapped the radiator with an aluminum frame (See bracketing the radiator and rad brackets continue) and put sides on it (See Radiator shrouded) to reduce the amount of air allowed to slip back around from the rad exhaust back into the rad intake. This sort of worked, though I always had my eye on the temperature. Along the way, I removed a bunch of extra wiring from the original harness that was part of the air conditioning circuit, and added a switch to the dash for turning the fans on.
Reality Strikes, for example). Ultimately, I learned that the plastic parts were designed to fail first, so more expensive parts didn't fail when the engine got too hot and the coolant expanded faster than the expansion tank could handle. Still, replacing that outlet flange and getting the coolant temperature sensor to seat properly are two of the most patience-testing things I've done on this conversion. Having these components by the fuel tank makes the reach and visibility particularly difficult.
Still, with the system seemingly in-tact, the engine temperature would still climb and not come back down easily. As the miles and years passed, the engine would heat up faster and cool down slower. We had a super-long return from 4Peaks in 2017 (See 4Peaks 2017 - Road Report), and had our first vagabonding experience when we were unable to make it to Frog Lake due to an overheat, and big coolant loss (See Almost Frog Lake Part 1 and Part 2). The whole time, Boo was incredibly supportive, and heroically kept my spirits up. My last, most tragic failure was when I added the wrong kind of coolant. That amplified the problems, and ultimately led to the troubled drive to Newberry this Summer (See Newberry 2019 - Getting There).
I promised Hapy that I would start fixing the cooling system when we were on the side of the US-26 outside Rhododendron, unable to make it to Frog Lake. So, that next Spring, I replaced the old Jetta radiator with a Mishimoto all-aluminum radiator (See Back to the Bus: Rad Swap Part 1 and Part 2). Things were not that much better on the way to 4Peaks in 2018 (See 4Peaks 2018 - Road Report), but with the ignition fire on the way home, it quickly moved to the back burner. I removed the wiring for the heater fan controls when I did the ignition replacement, believing it was causing large load spikes. While that didn't really change the cooling system, its a change worth documenting. By the time the ignition was done, festival season was over. But before I covered Hapy for the winter, I replacing the fans with a real dual-fan shroud (See Cowling the Hapy Radiator). I thought this was the final solve. The drive to 4Peaks seemed fairly good (See 4Peaks 2019 - Road Report), with temperature spiking at 196*, but the drive home was again spent watching the temperature gauge. We peaked at 205*, but the alternate route through the farm country allowed us to keep our speed (and therefore temperatures) down. The drive to Newberry, though, was enough for me to know that I had not solved the problem, and I really needed to fix it right if I was going to truly enjoy driving distances with Hapy.
Green Diesel isn't BioDiesel). That bad fuel held my speed so low, I didn't have temperature issues the rest of the way home. I knew they still lurked, so after the fuel system was drained, new filter system installed and new fuel added, I shifted back to my nemesis: the cooling system. I started with a basic drain and water-flush. Then, I removed the thermostat and filled with water, ran the engine, and drained. I did this a couple of times. Then, I went nuclear and did a chemical flush with Thoroflush. The Prestone radiator flush is weak tea compared to this stuff.
The directions are hard to find on the internet, but it's fairly clear:
Remove 1 gallon of coolant from your system
Mix one gallon of water with the right amount of Thoroflush mix for your application
Add mixture to cooling system
Get engine up to temperature (to open thermostat) and run for 10-15 minutes. DO NOT RUN LONGER THAN 15 MINUTES
Drain and flush with water until drainage is clear (no pink from chemicals)
Seems fairly straightforward. But, I pulled my thermostat, so how long do I need to run it? I was unable to find any direction for this case. I concluded that since my engine was fairly warm (upper 160's), if I added the mixture and ran it for less than 15 minutes, I would do no harm, but might not get maximum benefits. So, that's what I did. I used the water from the 2nd rinse-flush and added the mixture to that, ran the engine for just shy of 15 minutes, drained, flushed, and flushed again. After flushing everything out, I re-installed the thermostat with a new housing and O-ring. I determined that the old housing was slightly warped (possibly from the flushing efforts), and found that removing the hose from the thermostat housing makes re-install 100x easier. I filled with G40 and distilled water, clearing the bleeders so there were no air pockets trapped in the system.
Testing and Proving
|gmap image of 99W steep|
There is a hill climb on 99W between Newberg and Sherwood. Every time we take the back road alternate route, we drive up this hill as our last big pull. Accordingly, it is a consistent gauge for how Hapy is doing. When I drove this hill after Newberry, I barely kept the temperature under 203*F, driving with the flashers on in 2nd gear (25mph* tops). This time, Hapy's temp peaked at 194*F running at the speed of traffic (55mph*) in 4th. In both cases, this was at the end of a multi-hour daytime summer-heat drive. This feels like strong evidence the cooling issues have been solved.
That's it for today's saga. Sorry there weren't any real pictures, there really wasn't much to take a picture of, except, maybe, a picture of the cooling system map. That reminds me, I never did document system-by-system how the conversion was done. Hmm.. maybe I should dust off that documentation effort over the winter. Anyway, thanks, as always, for following along.