should it be of "concern"?? What do the experts say

[rockfla]

On my "Stock" flathead," Most " of the time when I have been driving it, the temperature, as it comes up to operating temp, goes all the way to "H" and will stay there approximately 30 seconds to maybe a minute, then drop to the mark between "N" and "H" and pretty much stay right there (and a few times it never makes "H" before it drops back to normal), maybe creep up to between the middle notch and "H" "occasionally" at a long stop or light, should I be concerned with that???? Yesterday when I drove it, it did just as I described BUT once I got it out on the road running it stayed below the center mark the whole time, 76 degree's and overcast here yesterday!!!

[51504bat]

I'd start with a known good mechanical or electric gauge so you know exactly what temps are not just H or N. Once you have exact numbers you can investigate further if necessary.

[38bill]

The rising and falling is probably the thermostat opening and closing. Like 51504bat said you cant really know what temps it is running at without checking it with a good gauge. Also check the thermostats to make sure they are working correctly.

[51 MERC-CT]

What would I do?
Tape over the gauge so I could not see it.
If at any time it boiled over, then I would be "concerned"

[rockfla]

Originally Posted by 51 MERC-CT

What would I do?
Tape over the gauge so I could not see it.
If at any time it boiled over, then I would be "concerned"

That has been what I have been thinking as it doesn't puke any coolant or loose any and it always drops to a "comfortable" level so I figure the the thermostats ARE working as within a minute it drops SO......AND its runs out beautifully thanks to Hoop & CharlieNY.

[deuce_roadster]

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Could be the sender is near the end of its service life if the thermostats are fine and all the electrical connections are clean and tight.

[solidaxle]

Go on line and order an infrared thermometer, Lowe's even sells them $39.00. You know you need more tools anyways.

[drolston]

The temperature sender is down in the head. The thermostat bi-metal coils that open the thremostat are up in the neck. It has to get to H in the head before the temp in the neck gets up enough to open the thermostats and start the coolant flow.

I drill two 3/16 holes in the flat edges of the thermostats. That allows some water to flow by the bi-metal strips when the thermostat is closed. That will slow your warm-up a tiny bit, but you will cure that initial swing to H.

That behavior is of no real consequence, but I just hated seeing that thing go to Hot every time. It causes unpleasant remembrances of sitting at the side of the road with boiling flatheads.

[rockfla]

Originally Posted by drolston

The temperature sender is down in the head. The thermostat bi-metal coils that open the thremostat are up in the neck. It has to get to H in the head before the temp in the neck gets up enough to open the thermostats and start the coolant flow.

I drill two 3/16 holes in the flat edges of the thermostats. That allows some water to flow by the bi-metal strips when the thermostat is closed. That will slow your warm-up a tiny bit, but you will cure that initial swing to H.

That behavior is of no real consequence, but I just hated seeing that thing go to Hot every time. It causes unpleasant remembrances of sitting at the side of the road with boiling flatheads.

Hence the "post" Like you it always makes the posterior bull frog tight (and that's water tight) when it swings to "H" and the subsequent "please, please, please" (with copious beads of perspiration on forehead) that ensues till it starts to fall!!!!