Rehabilitated Thermostat Housing
by Bob Jeffers

First he said:

Hi All, This was just an exercise to see if it could be done.
I purchased a TD type thermostat housing on ebay. It was unusable as purchased ($5.00). The upper part that goes into the radiator hose was so badly corroded, that big chunks were missing. Both gasket surfaces so badly corroded that no gasket would be able to stop leaks. No thermostat. That's where I started.

First step was to get rid of the cross piece that supported the original thermostat. Then grip the lower flange in the lathe chuck and open up the housing body to 1.780 - 1.800" for a new thermostat. Then remove what was left of the collar that went into the radiator hose.

Then remachine the gasket surfaces for the bypass hose fitting and the elbow at the bottom.

Obtain a 3/8" thick piece of steel heavy wall tubing to replace the collar. This was roughed out oversize so that for welding it did not have to be precisely jigged.
This was then brazed to the the casting. When cooled it was chucked into the lathe and the outside and inside turned to match the casting. Then the length was turned to match the original overall length (approx.).

The new thermostat was held to the rim inside the housing by two 4-40 screws. Also two 1/8" holes were added to allow air to escape when filling the system.

Then he said:

The unit was now usable but an addition was added to permit the temperature sensing bulb to be placed below the thermostat. A 3/4" steel rod was found in the scrap box and drilled out to 37/64" and tapped 3/8" BSPP (3/8 pipe - 19 TPI). This piece was made 1/2" long. Then the housing was placed in the milling machine and a 3/4" end mill used to put a hole in the side opposite to the bypass elbow fitting. The threaded sleeve was brazed to the housing. We are now all done except for paint.

Was this a worthwhile exercise? From a dollar standpoint no. From a learning perspective very much so. I turned a piece of junk into a very useable part for our beloved XPAG engines. Even added a place to put the temp sensor so you can watch the engine warm up instead of waiting for the thermostat to open to see what the temp of the engine is.

Comments and questions greatfully received. I'll do my best to answer the questions.

Here's what it looks like: