Adventures With an old GMC motorhome.

 Adventures with an old GMC motorhome.

I bought the GMC RV 36’ Kingsley from a coworker and friend in Winnemucca. He loved it, but his wife hated it. She called it a “Twinkie” - thought it was ugly. I think I may have saved his marriage by buying the motor home. The year was 2003.

I bought it especially to carry my mother to Kansas City to visit her twin sister, whom she had not visited in about 12 years. She had a heart condition and couldn’t fly on planes, and trains took too long and didn’t go just where she needed to go. Our car was too little and cramped, so I figured the motor home would be the best bet. She could lie down for the trip, and a bathroom was just down the hall, as was the refrigerator.

I knew the GMC was getting old, and I was expecting some trouble mechanically, so I carried enough tools for an engine overhaul if necessary.

(That’s only a slight exaggeration.) 

After getting all luggage onboard, we left Winnemucca heading west. The motor home rode smooth as silk on the air bag suspension, and the 455 c.i.d. Oldsmobile engine had lots of power. I had to be careful of speed limits, as it wanted to cruise at about eighty if you didn’t pay attention. The cruise control wasn’t working when I left home, and I let it go, since I was in a hurry to get on the road.

The first night we parked in an RV park in Moab, UT. I plugged in the power and everything worked fine, lights and everything. Except the water had a leak when I hooked up a hose. Obviously freeze damage last winter, and I skipped the water hookup and advised that baths would be at the RV park bathing facility. The water was leaking from under the water inlet, so at least I knew where to look when I got a chance to fix it.

The next morning we stopped in Nucla, CO, where we had lived for nine years and visited with our friends there. 

While I was there, I unscrewed the water inlet pressure reducer and found the back of the device had split off, so I needed a new one. On a machine this old, it may be hard to find.

The first engine trouble was near the top of Monarch Pass at nearly 11,300 ft. Elevation. At first I thought it might be vapor lock, since the engine was stumbling and cutting out. It finally just quit, and I had to carefully back down to a wide pullout and park it. Since the vacuum assisted power brakes were marginal with the engine not running, I really had to stand on the pedal to keep it from rolling back too fast. When I got off the road, I put the selector in PARK, hauled back on the hand brake, and after I carefully left off the brake pedal and it didn’t move, I got out and found some big rocks and chocked the wheels.

When I opened the engine cover I was surprised to hear the gasoline boiling in the carburetor and see the vapor spewing out. It was scary dangerous for an explosion, and I didn’t think the little extinguisher by the driver’s seat would be adequate if it lit off. I’ve seen carburetors percolate before, but never like this. The only thing we could do is open the doors and windows and try to ventilate as much as we could. Then we waited for the engine to cool off and the carburetor to normalize again.

I noted on my mental list to check that the carb heat valve was working correctly when I got a chance. Little did I suspect that they didn’t design this engine to even have a carb heat valve. They must have totally depended on both exhausts balancing equally. One small leak or one small dent on an exhaust pipe and the channel under the carb becomes a path for hot exhaust gasses to pass through.

This was not engine overheating. No coolant was lost and no coolant was boiling. It was just the carburetor that got hot due to the steep climb and the high elevation, and the deficient design of the intake manifold. 

After about an hour, I decided to attempt a start. The engine started immediately, and I let off the hand brake, put the gear selector in low, and drove over the top of the pass, which was only a couple of hundred yards away.

I left the selector in low as we came down the east side of Monarch Pass toward the town of Salida. A few years earlier a school bus lost its brakes coming down that side and crashed and killed the whole football team. If you have lived in Colorado you soon learn how to safely drive over those mountains. 

We stayed overnight in Colorado Springs, and the next day we were having no more trouble with the engine. When we gassed up in Colorado Springs I calculated the mileage at 11.34 mpg, which is the highest of the trip. Of course, it was all downhill! Most of the trip it was 6, 7, or 8 mpg.

We were making good time when we stopped in Goodland, Kansas, for refreshments. I noticed the brake pedal dropped a notch as I pushed it down. I tried it again and felt the same thing - the pedal stopped where it was supposed to, but in a second or two of steady pressure, it dropped to a lower level. 

I stopped at a NAPA parts store and got out and looked for a leak on a wheel. There were none. I took the cover off the master brake cylinder, and as I suspected, the front reservoir was full and the back one was low. Bad master cylinder doing what it is made to do. Half the brakes still work when a fault occurs somewhere in the system.

 I went inside the store and asked for a master cylinder for a ’77 Oldsmobile. I knew they wouldn’t carry one for an old motor home, but I was hoping for one that fit. 

I was in luck! They had two of them, but different. So we studied the one on the RV, and I picked the one that looked to be a match. They sold it to me, along with a self bleeder kit and a can of brake fluid. It took me about a half an hour to change the cylinder and bleed the brakes. Soon we were back on the road to Kansas City to meet Mom’s sister.

Frankly, if you are going to drive a 25 year old motor home across the country, you should carry lots of money, lots of insurance, or be a good mechanic. I was in the third category, but there were times I wished I was in the first category and could just hand the work to somebody else.

When we got to Kansas City, (actually Independence, Missouri) we stopped first at my cousin Jim Russell’s house, where they all were waiting for us. We had a great family reunion, and they all wanted a tour of the motor home. So we led them through from one end to the other, and they were very impressed at the lovely interior. Back then, even at 25 years old, it still looked pretty good. I didn’t go into the mechanical problems so far.

The plan was for Carolyn and I and Melissa, our granddaughter, to leave Mom to stay and visit her sister for a week or so and we would drive down to Oklahoma to visit Carolyn’s family. We stopped in Oklahoma City to visit her Aunt Laverna, then went on down to Durant, her hometown. 

Carolyn had a large family in Durant, and when they did family reunions, they had to rent a pavilion out at the county fairgrounds. 

At this point we had just over 2000 miles on the road, and no further troubles came up.

After a week visiting family in Oklahoma, we drove north to pick up my Mom. It was the Fourth of July weekend, and was pretty hot. We stopped in a really nice RV park in the town of Peculiar, Missouri, on the night of the Fourth. At sundown we were alarmed to hear explosions all around us. We went out side and it looked and sounded like a war. We found out that since we were near the border of Kansas and Missouri, the citizens of both states spent the night trying to outdo each other with fireworks displays. I don’t know how many thousands of dollars they blew up that night, but it was impressive!

After picking up my mother, we came back south to Gentry, Arkansas, where Aunt Mary Detweiler, my Dad’s sister was living on an Adventist school campus and still teaching in her eighties. We had a wonderful visit, reminiscing over the years right after WWII when all the Rogers kids (my Dad’s siblings) got out of the military and got married. 

We continued on back to Durant, where Mom got to meet Carolyn’s family, and then traveled on south to Keene, Texas, for a short visit with Darla, Carolyn’s cousin, who also taught at a school there. 

We started home again, the long way around, to visit our granddaughter Chandler in Arizona. We cruised through Monahans, Texas; Roswell, New Mexico; to Phoenix, Arizona. After a visit with Chandler’s mother Tonya, we picked up Chandler to stay with us for the summer. Then we drove north to Flagstaff to visit my brother John and his wife, Carolyn.

As we climbed the mountain into Flagstaff, we had some trouble with the engine overheating. We stopped a couple of times to let it cool off.  We were carrying water to replace the lost steam in the 35 gallon tank in the back. Since this just started, I was pretty sure it was related to the thermostat, but if I drove slower and didn’t push it up any hills, it was OK. I drove the rest of the trip through Las Vegas and Tonopah, Nevada at night to keep things cool.

When I got home at the end of the 5000 mile trip, I unscrewed the cover on the thermostat and found it stuck half open. Wouldn’t close, wouldn’t open more. That was strange - I’ve never seen that before or since. Usually they fail either open or closed. That was an easy five minute fix.

For the rest of July, 2003, I took off the carburetor, and then the intake manifold, looking for the source of the boiling carburetor. That’s when I realized the engineers who designed this engine skipped any provisions for stopping exhaust gasses from shooting through the manifold from one side to the other, roasting the paint and boiling the gas in the carburetor. I heard later from other GMC owners that sometimes the manifold actually cracked from the heat and had to be replaced. I’m sure some GMC’s burned to the ground from this design flaw.

When I removed the intake manifold, I found a huge ball of crispy carbonized oil hanging under the warped sheet metal cover over the valve train. It weighed several pounds, and I carefully lifted it out of the motor, trying not to break off and drop any pieces into the engine. I picked up any loose pieces I could see on top, then drained all the old oil out of the pan and flushed it with solvent from the top down. 

I took the intake manifold to work and in my spare time, clamped the manifold to the milling machine with the left side indicated level above the table, then I carefully machined a 1/8 “ step around the exhaust port on that side only. I made a rectangular block to put in the manifold to completely block all exhaust gasses from that side. I left the right side open so some hot gas could heat up the choke heat tube and keep the automatic choke working normally.

While I was fixing manifolds, I noticed that both exhaust manifolds were leaking, which may have been a factor in the unbalanced flow through the intake manifold. I took both of them off and using a carbide tool on a fly cutter, machined them .005’ at a time until they were flat again. There are not nearly enough screws holding them on, and they were bowed over .030” between screws. With new gaskets all leaks were gone and the engine was much quieter and cooler

I got everything back together and running fine within the month, and then we planned a trip to Oregon for Chandler’s birthday the next month, August.