It all seemed so simple. Add an under dash gauge to accurately read the temperature in the tri-power 389 engine. Bonney came with a light in the dash to indicate a heating problem with the engine. No accuracy whatsoever! As a result, my car buddy installed a temperature gauge under the dash and it seemed to be working, then it stopped. On a short cruise my neighbour noticed the gauge wasn’t moving. No big deal as I can mention it to my car buddy when he comes over to work on the tilt steering column installation.

My buddy checked the wiring to the gauge then that wire from the temperature sender in the manifold which came with the tri-power when purchased. It was pooched. He sent me to purchase another GM temperature sending unit which I installed and changed the wire connector to the sending unit. Yup it worked! After a few trips the gauge was reading over 200F. What now? The next step would be to change the thermostat. My buddy ordered in a racing thermostat 160F but it would take awhile to get here.

When the thermostat and gasket arrived, I drained the rad sufficiently to unbolt the thermostat cap, remove the thermostat, gasket and gasket maker. Once cleaned the new thermostat with new gasket and gasket maker, I was ready to bolt on the cap with the two original bolts. For what ever reason, the bolt on the passenger side was longer with exposed threads the full length past the nut head. I could not line up those bolts at all. My neighbour was watching also tried but no luck. Finally my buddy stopped working on the steering column and asked for a bolt to match the one on the driver side of cap. He was able to attach the cap. He suggested that the longer bolt might be used for the A/C unit which Bonney does not have.

I waited until the next day as recommended on the gasket maker package to reattach rad hose and refill the rad. I started up Bonney, backed it partway out the garage and let it heat up but no luck. The thermostat cap was leaking so back into the garage went Bonney. I drained enough anti-freeze to access the thermostat cap again. I removed the rad hose, unbolted the cap and removed the gasket and new thermostat. The gasket was gunked up so I left it aside and scrapped off the gasket maker from car and cap.

On the work bench, I took the cleaned cap and put a piece of thin white paper over it and did an old fashioned rubbing. I used one of my punches to cut out the bolt holes then scissored out the centre hole and cut out the pattern. With pattern in pocket I headed over to CTC with hope of getting another gasket or at least gasket material so I could cut out my own pattern.

No offence ladies but walking up to the auto parts counter and meeting all female clerks was not a great start. I apologized for my chauvinistic attitude in asking for a male clerk. The female clerk had no problem but let her try to solve my problem. Soon she found out that the computer showed no thermostat gaskets for 1965 Bonneville 389. However, the clerk was able to locate a package of various types of gasket materials. A few minutes later the clerk I have dealt with numerous times came out from the back. He looked at my gasket cut out, went to the back and reappeared with a number of gaskets We agreed on one which was close enough. I thanked them both, paid and went home.

After putting on gasket maker, I installed the thermostat, gunked up gasket then cap. It was no problem bolting in the cap. As before I waited until the next day to clamp down the rad hose, refill the rad with anti-freeze, turn on the battery, start Bonney and back it out to warm up. The highest reading on the gauge was 180F and no leaks.

As soon as the weather cooperates, I will take Bonney out for a run to see how the temperature gauge reads.