View Full Version : Flathead and thermos

12-29-2005, 11:46 AM
This is a duplicate posting from the newsgroup. Wanted to see if I could get as much help as possible with this issue.

Moved from the very high temps of Texas in June with a '60 Lark. Did
fine with the 160 degree thermo until it started getting cold here in
Pennsylvania. About three weeks back I installed a standard issue 180
degree version. Noticed it was about half the depth of the older

Needless to say - did not work too well. After install, temp went to
just over 3/4 and then the thermo finally opened. Drove it gingerly
around and it would bounce back and forth between just above and just
below 3/4.

Shop manual shows original application with heat sensor just above the
top of the head in the thermo housing. New thermo is way up inside and
is obviously not getting the heat it needs to work properly.

Here is what I might try next. Throw away (store in box to be found
years later) metal spacer and find a piece of radiator hose that fits
perfect into housing. Cut in two and put new thermo in the middle.
Want to space the new thermo's heat sensor just above head as shown in
shop manual.

Anyone done the same? Anyone see any potential problems? Other
suggestions (other than getting rid of the 170 for a V8)?

Thanks ahead.

My 7E7 - Restored by my Uncle in 1995

12-29-2005, 09:21 PM
It's been a long time since I've driven a 170 but I drove a couple for many years in Pennsylvania with no thermostat problems.

If memory serves me, the spacer fits in the gooseneck and holds the thermostat down against the head. The thermostat should not be "up inside" the housing.

12-31-2005, 04:22 PM

Thanks for the reply. Maybe not enough little sixes around to get anymore replies.

Actually, I think the reason that the housing itself is as tall as it is because the thermo needs to be some distance from the block. With the thermo down in the bottom, it would only be less than an inch from the top of the combustion chamber. It would open pretty quickly and not allow the coolant to reach its optimum temperature.

I think at this point I am going to try placing the thermo a lot closer to the bottom of the housing and see what I get. Maybe I will luck out and hit it right the first time.

Anyone else like to chime in?

My brother's 7E7 - Restored by my Uncle in 1995

12-31-2005, 06:52 PM
Just to add my 2 cents, you really do need the spacer as Rockne said.
I'd also go back to the 160 degree thermostat. That's what I run with my '59 Lark VI. The car runs well and no overheating. I even drive it in the Winter as long as there isn't any salt on the roads. By the way, I live on Long Island about 50 miles east of NYC.
Just as aside, if you have the original temp. sending unit on your block, you may wish to replace it with a new one. I thought that my car was overheating last Spring. I replaced the thermostat and the temp gauge still indicated way up to HOT. When I replaced the sending unit, all returned to normal.

'59 Lark Regal Hardtop