VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 Teflon tape for sending unit adapter

When I redid the head on my '31 I installed an adapter (old original one) that allows the sending unit to come out the top and also to run a heater hose to the heater (plugged for now). I think I am losing some coolant around the adapter (not the sending unit). Is it common to use teflon tape for this adapter? I read in an instruction manual on a more recent engine (1971) not to use teflon tape on the adapter, but this may be a different situation.

Thanks,
Brandon

Using a Teflon tape could or will isolate the adapter and the sending unit will loose it's ground path.

Andy , 1931 models have an ether filled bulb and bourdon tube.

My concerns with a tee adapter for the heater hose is that the original bush fitting has a internal tapered seat which the bulb seats against and seals on. If the replacement does not have the taper , then it is relying only on the threads to seal the temp gauge bulb and nut.

The 1931 water temperature sending unit is mechanical and non-electrical so no ground is required.

i dont allow any teflon tape in my shop . just like other sealants i mean the sil. it ends up in the wrong places . there are many good sealants on the market that work . like leak lock aviable at most referigation supply stores . hope this helps

Teflon tape installed correctly shouldnt be a problem.The thread into the head is a pipe thread and the fitting on the bulb is a straight thread that relies on the tapered seat for sealing . Much like a brake fitting . Have a good look at the sealing surface of the bulb fitting it may need to be dressed up. you can us high spot blue to see the contact surface. High spot blue is used in machine shops to check contact surfaces on tapers/bearings and such . most automotive stores should have it . Make sure you never go near any part of the inside of your car . If you get it on your interior you wont get the stuff out. A little bit goes a long way.

OK, thanks guys. I'll check very closely again and make sure that the leak is coming from the fitting/block and not the fitting/sending unit. If it is in fact the block I'll try some teflon tape.


Brandon

IF you do use Teflon tape, be sure to get YELLOW tape. The white tape will dissolve in oil or other petroleum products, but YELLOW tape is specifically made for the gas industry. Costs something like 3X more but still not that expensive.