Water level

[TMarsh]

Maybe I am just paranoid. I drive my car almost daily. I put my coupe together myself and it has a good radiator and clean block. It has a 165 degree thermostat and a temperature gauge in the car. The temperature probe is in the neck on the engine below the thermostat. It also has a moto meter temperature gauge on the radiator cap. Watching the temperature gauge indicates about 180-200 while the moto meter shows high end of normal operating temperature. An infared temperature gauge measures 175 at top of radiator and 20 to 30 degrees lower at the bottom. This is with timing retarded at idle at shutdown.
I know these monsters reach their on water level and I start out with the level just covering the fins. After a couple of weeks of daily driving I top it back off with 5 to 6 CUPS of water, no more, again, just covering the fins.
Ya'll think this is the level it likes.
No smoke, no driveway water leaks, runs good.
Thoughts are appreciated.

[Kurt in NJ]

I have a 160 degree thermostat, always antifreeze.on a 95 degree day I have similar temperatures after idling for 40 minutes, on the road the motometer usually runs close to “cold motor use radiator cover”
My radiator has a baffle that prevents seeing the tops of the tubes, yours should have one too, my level stays about the bottom of the baffle, only adding a cup or 2 a year
At 195 out the top neck it is 160 going back into the block , last radiator cleaning 40 years ago, most likely original radiator.
The temperature at the back of the engine runs within a couple degrees of the front, with #2 warmer than #4 sometimes

[Dino's A]

I don't run a thermostat because in California, you don't really
need one. Try filling it up more. My level is higher than just
covering the tubes. Probably 2" more. Try that and monitor from
there. Question: Does It ever drop below the tubes if allowed?

[TMarsh]

Radiator has baffle, I can look at a angle with a flashlight and see the tops of the tubes. I just fill it back up to cover the tubes. Have roofing nail in overflow tube and tube has been bent back as per service bulletin.

[nkaminar]

The thermostat sold for the Model A is designed for modern cars. When mounted in the radiator hose, put a clamp on it so that it stays at the bottom. Drill the hole larger and even add a second hole. The reason is that the thermostat does not sense the coolant temperature accurately without more flow through the system.

I have two thermostats, one for winter driving and one for summer driving. The one for winter driving has a 1/4 inch hole in the flange. The one for summer driving has 4 holes of 1/4 inch diameter.

[1crosscut]

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I'll echo Dino's question. Does it drop below the tops of the tubes in the radiator. If it does how long / many miles does it take to do so?

[nkaminar]

I carry a gallon of 50/50 water/antifreeze but never have to add any coolant. I have a new radiator, no leaks, and a leak proof water pump. If everything is set up properly, one should not have to add coolant. My concern is the mention of water level. I highly recommend 50/50 water/antifreeze rather than 100% water. Even distilled or DI water will pick up ions that will attack the iron.

[JayJay]

My 165 thermostat is in a Vintage Precision thermostat housing right on top of the water pump and it works great, temperature rises rapidly and holds well. I fill my radiator to just over the baffle at idle and it invariably burps out a bit of coolant at elevated rpm. Can't see where it ends up due to the baffle but it seems stable. I add about a quart every several hundred miles just because it seems better to add and let it find its own level. I use 50/50 antifreeze. I also carry 50/50 with me when driving.

JayJay

[Joe K]

I run a bit higher than the tube-tops. I have the overflow tube bent per the Service Bulletins, but IN ADDITION I have a rubber tube with a small clamp extending the tube up into the screw on cap (28-29) So I have perhaps another inch and a half of "swell space" which in turn translates into an equivalent additional level of water.



Joe K

[Synchro909]

If your car is losing water, try Bill Williamson's (RIP, Bill) trick of a roofing nail in the top of the overflow pipe.

[katy]

Originally Posted by TMarsh

Maybe I am just paranoid. I drive my car almost daily. I put my coupe together myself and it has a good radiator and clean block. It has a 165 degree thermostat and a temperature gauge in the car. The temperature probe is in the neck on the engine below the thermostat. It also has a moto meter temperature gauge on the radiator cap. Watching the temperature gauge indicates about 180-200 while the moto meter shows high end of normal operating temperature. An infared temperature gauge measures 175 at top of radiator and 20 to 30 degrees lower at the bottom. This is with timing retarded at idle at shutdown.
I know these monsters reach their on water level and I start out with the level just covering the fins. After a couple of weeks of daily driving I top it back off with 5 to 6 CUPS of water, no more, again, just covering the fins.
Ya'll think this is the level it likes.
No smoke, no driveway water leaks, runs good.
Thoughts are appreciated.

The amount of water that you're adding is just replacing the water that has evaporated since the last top up.

[old31]

I agree with Katy!

All of your temps are good. Stick a nail in it and maybe next time all you need to add is 2-3 cups.

I think you are chasing something that isn't there.

[jb-ob]

TMarsh,

Very common for original the over flow tube to rub against the inside baffle, wearing a hole in the tube. The result will be lowering the water level in the radiator. Something to check.

[Gene F]

My experience is a bit different. 5 or 6 cups in lets say running errands over about 4 weeks is too much. My guess is that when you put a bit of a load on the motor the head gasket is blowing a few bubbles in your radiator. Therefore, water is seeping into the combustion cycle, and then vaporizing out the tailpipe. Try retorquing the head. Be sure to back off a nut before going forward. Just warm the engine up about 1 minute (from cold) before doing this. It may fix it, but it also may make it lose a lot less water. This is just my experience, which may be diff. from others... Just sayin' TMarsh.