operating temperture
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Fleet Mechanic
Joined: Oct 2004
Posts: 1,720
Likes: 507
From: clinton,tn
operating temperture
i have a stock 49f1 with the 239 flathead. the question i have is when it is at running temp it is between half and the third mark on the temp gage. is this normal for a flathead. i do have new water pump's and a shroud. have not changed the thermostst yet. thank's.
Senior User
Joined: Sep 2004
Posts: 279
Likes: 0
From: Appleton, Wisconsin
the most accurate way to check this is to put a thermometer in the radiator fill hole.
with the cover off and the truck parked, you can idle the truck with the choke up a little to bring it to operating temperature.
take the reading off of the thermostat when the gauge reaches the temperature
I just did this myself
a little past midway on my gauge was 160 , 180 was almost the 3/4 mark
Todd
with the cover off and the truck parked, you can idle the truck with the choke up a little to bring it to operating temperature.
take the reading off of the thermostat when the gauge reaches the temperature
I just did this myself
a little past midway on my gauge was 160 , 180 was almost the 3/4 mark
Todd
Fleet Owner
Joined: Dec 2000
Posts: 25,378
Likes: 5,387
From: Central PA
Had a similar problem with my '54 F-100. Under normal operating conditions the gauge showed between half and 3/4 hot. On hot days, slow traffic or long drives it got hotter. Last summer I replaced the thermostat and now it rarely goes over the 1/2 way mark. There was a long thread on this a while back. Do a search for the thread. There are many thoughts about thermstats. The parts store gave me a choice of 2 thermostats, I chose the lower temp one thinking my truck would run cooler. I guess it does, but now my heater does not give off the heat it used to on cold winter days.
One consensus from that long thread was this: do not run a vehicle with out a thermostat.
abe
One consensus from that long thread was this: do not run a vehicle with out a thermostat.
abe
Lead Driver
Joined: Oct 1999
Posts: 6,776
Likes: 553
From: Kalispell, MT
Here's a couple of thoughts...fwiw....stock gauges are pretty inaccurate and are only good for a benchmark. Once you determine where normal is for your engine you're set.
1. You can check your temp with a mechanical gauge threaded in where the stock sender goes.
2. OR, use one of those new infra-red digital guns to take temp readings on the heads and radiator tank.
The limitations of using a thermometer in the top tank is you have to open the system. Since your truck is designed to use a 7# cap your results might vary. Pressurized system raises the boiling point in the 8RT/8BA to around 220.
Flatheads (and OHV's) do better between 180 and 210. Oil flows best at those temps, crankcase vapors are reduced, sludge doesn't build up as fast, etc, etc. This is one case where cooler isn't necessarily better.
1. You can check your temp with a mechanical gauge threaded in where the stock sender goes.
2. OR, use one of those new infra-red digital guns to take temp readings on the heads and radiator tank.
The limitations of using a thermometer in the top tank is you have to open the system. Since your truck is designed to use a 7# cap your results might vary. Pressurized system raises the boiling point in the 8RT/8BA to around 220.
Flatheads (and OHV's) do better between 180 and 210. Oil flows best at those temps, crankcase vapors are reduced, sludge doesn't build up as fast, etc, etc. This is one case where cooler isn't necessarily better.
