Monday, February 28, 2022

Thermostat project - Day 2

 8:08 am - Monday - February 28th - Newell House, AZ - 52° F, 24% humidity, wind 2 mph out of the north by northeast....overcast today with a forecast high of 80° F.  On this date in 2016 we were having dinner at Prison Hill Brewing in Yuma, AZ......↴

Day 2 (Sunday) of the thermostat project dawned cold, but clear.  We had all three electric heaters running to bring the coach interior up to a livable temperature.  After taking our 1.25 mile fast walk I changed clothes and returned to the passenger side engine bay to resume work on installing the new thermostat.  First up I decided to clean the four 3/8" bolts, and find 4 new lock washers........

Cleaning the bolts

....and then turned my attention to cleaning up the top of the thermostat housing into which the thermostat is installed....

.....I didn't take any pictures of the process, but I removed the hose, and clamps, and cleaned them both, as well as the two hose fittings, then installed the new thermostat before heading back out to the coach to reinstall everything.  The installation went very smoothly, and within 40 minutes the the top of the thermostat housing was bolted into place, and the two hoses reattached.......


....all that remained was to torque down the four bolts.  I was told to torque them to 75 foot pounds, so I started with first torqueing them to 50 foot pounds, then proceeded to move them up the scale to the suggested 75 foot pounds, but that is where things when amiss....I got three of the bolts to 55 foot pounds, and as I was tightening the 4th bolt I heard a loud 'SNAP', and my worst fears were realized.  I had broken off the bolt in the thermostat housing.  Now I had to undo everything I had just done to get to what was left of the broken bolt.  I had visions of it being broken off flush with the lower housing, and having to drill it out, which is always a tricky proposition, especially in the tight confines of the space in which I was working.  I was imagining having to drive into Surprise (an hour round trip to Home Depot) to buy four new bolts, and all of that really put a crimp in the good feelings I had just felt a second before snapping off that bolt.

As I removed the top of the thermostat housing for the second time I was stunned to see that about 1/8" of the broken bolt was protruding above the thermostat housing base, meaning I might not have to drill it out.  I retrieved my Vise Grips, and clamped them on to that small stub, then turned it counter clockwise......much to my relief the stub turned fact extremely easily....I removed the Vise Grips, then gripped the stub with my fingers and found I could just unscrew it using my was that easy!

The broken bolt

.....with the broken bolt removed I only needed to acquire four new 3/8" bolts, and then reinstall the thermostat housing.  I was still not looking forward to the hour round trip drive into Home Depot, but I got in the VW and headed for town.  As I approached Highway 60 on Center Street I remembered seeing a little hardware store (Delgado's) about two blocks off Center Street, which is Wittmann's main street, so I decided to go there first to see if I could find what I needed.  What a surprise!  They had Grade 8 bolts, and plenty of the 3/8" ones with the length I needed.....$1.29 each!  I was out the door, and back home within 10 minutes with a big smile upon my face.....this was the absolute best outcome to a seemingly disastrous situation.  In the time it took me to reinstall everything I would have only been half way back from Home Depot.....

The new Grade 8 bolts are installed

.....sometimes things happen for a reason.....after reinstalling the thermostat housing I took time to examine the remaining 3 'good' bolts only to find that a couple of them had begun to stretch as I attempted to torque them to 75 foot pounds.  I had no idea until I broke some point in the future one of the stretched bolts might have broken, and who knows where that would have occurred.....on the side of an Interstate somewhere?.....who knows.....

You can see the stretched part right in the middle of the threads retrospect, breaking the bolt was a blessing in disguise.  The original bolts were not Grade 8 (I knew that), were 40 years old, and there is no way they could (in retrospect) withstand 75 foot pounds of torque, as I found out.  Instead of torqueing the new Grade 8 bolts I tightened them equally to a point with which I am comfortable.  I'll pour the coolant I removed (about 6 gallons) back into the radiator, and if I see any leaks I'll begin torqueing them, but only as far as it takes to stop the leaking.....that is, IF they leak.

With that I now have installed one of the two new thermostats.  I'm going to pour back in the coolant, then take the coach out for a test drive to see if I have improved coolant temps.  I'm inclined to install the second thermostat now, which is good practice, but if the temp comes down with just replacing the one thermostat I may defer the installation of the second one until a later date when my shoulders have recovered from the effort.  Now that I know what I'm doing it should take less than the two days it took me with the first one.

By the time I put everything away it was 5 pm, and I was filthy.  I needed a long, hot shower, and a

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  1. You better check the torque specs. I think you are about double what you should be.

    1. I agree Robert! Torqued then to 40 foot pounds.....put coolant back in, and no leaks! Thanks for your input!


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