temperature readings on.....

[derek costello]

So I have installed a overflow capture tank on my 53 mercury flathead and have filled with antifreeze to the top of the rad..
Now after bringing up to full warmup I again shot the engine with the infrared
temp gun ...................top at rad 177degrees, bottom of rad 189degrees,
centre of heads 200degrees.....no thermostats with electric cooling fan.

Again I am still getting temperature readings that seem "backwards" !

I have tried to look in the rad opening to see if the coolant is flowing in the correct direction, but cannot see the flow.

I am beginning to think that my water pump impellers are reversed ?
I have never had the pumps off of the engine????

[paul2748]

Ever had the radiator serviced? Could be a clog somewhere

[WABOOM]

Calling @G.M.

[Tinker]

Look at how the block water flow is designed. Pump in the front of the block. Outlet in the front of the block. So to see different temps at different points along the system is completely normal. I'd just be concerned about temps at the back of the block. All temps you mentioned seem fine. But everything might need a cleaning. Block to rad. Not really expensive or horrible.



If the temp is higher in the inlet and not the outlet. The rad might be clogged. Making for hot water to pool. I'm not sure you can even buy reverse water pump propels. It would be a first anyways.

[1931 flamingo]

Remove the rad cap, start engine, there should be a lot of water coming thru the TOP hose(s) onto the top of the radiator core. You might try a diff temp gun or change the batteries??
Paul in CT

[WABOOM]

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^ He would need to remove both thermostats for that test to work.

Take out thermostats, and put the hoses back onto the T-stat necks.
Disconnect top hose from the radiator tank. Start engine. Water will flow if pumps are working.

[JSeery]

He is not running thermostats per his OP.

[WABOOM]

I didn't see that part. My apologies.

[derek costello]

OK, I had to run this engine steady for a video photo shoot for 2 1/2 hours in 50 degree weather, with the electric fan on all of the time the engine temp never got over 190 degrees,
speeds were Idling a lot, to 50mph, it performed flawlessly!

But again the wrong top to bottom temps with infrared! I can't figure it out..................

[WABOOM]

What happened when you disconnected the top hoses from the radiator?

[ford38v8]

Assuming all clean and functional, the temperature of a radiator will never be constant at all points, and it's overall efficiency depends on the placement of the fan. As yours is electric, you will have a generic shroud that may not be fitted to your radiator for maximum cooling.
The lower temperature at the top may also be attributed to a natural air pocket at the top, together with the failure of aerated water to provide heat transfer at the upper level.

[Paul Bennett]

The water flow pattern within the radiator may hold the answer as to why the temperature appears hotter at the bottom of the radiator than at the inlet. You didn't give a reading for the top tank.

FWIW, while I don't have possession of my car (at mechanics awaiting more work), I was able to drive it briefly after the new motor with electric fan, was installed. Interesting the fan came on after 5 minutes of high idle and shut down after about 2 minutes of run time. It was a new experience for me and I was pleased with the results. Dash gauge stayed below half reading.

Question - can you provide any details on the catch tank.
Suggestion - re the reverse water flow - foegitabodit, sounds like things are working well so consider your situation should you never have taken the IR readings.