New engine temperature
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From: Da UP, eh!
New engine temperature
I just completed the installation of my new 347 stroker motor into my old Bronco. I put in a brand new Autometer water temperature gauge that goes up to 240 degrees. I took the truck around the block a couple of times to feel everything out, and my temp got up to 220 by the time I got back home. What should be the running temp do you think for my engine, and at what temp am I risking engine damage?
Hotshot
Joined: May 2004
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From: The hills of No. Calif.
That's getting a bit warm. On a carbed engine I like to see about 180º, and EFI around 195º but 200º isn't really out of line on a hot day. By 220º I tend to get a bit alarmed and prefer not to see temps of 240º-250º as that's where things can start to go south.
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From: Da UP, eh!
Thanks for the reply. My first thoughts are:
1) bad thermostat, which was replaced a year ago on the old engine, so I put it in this new engine.
2) water pump, but I installed a brand new high flow
3) radiator, original one that came with the truck, but seemed to be fine for the old engine...probable upgrade in the future
4) I was only running at about 10 mph around the block on a hot day, so maybe I didn't get enough air across the radiator
1) bad thermostat, which was replaced a year ago on the old engine, so I put it in this new engine.
2) water pump, but I installed a brand new high flow
3) radiator, original one that came with the truck, but seemed to be fine for the old engine...probable upgrade in the future
4) I was only running at about 10 mph around the block on a hot day, so maybe I didn't get enough air across the radiator
Hotshot
Joined: May 2004
Posts: 12,170
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From: The hills of No. Calif.
Are you running a fan shroud? At lower RPMs it makes a big difference in the amount of air that gets pulled through the radiator.
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Joined: May 2006
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Check the gauge to make sure it's reading correctly. I literally just ended a 2-3 year off/on quest surrounding my Bronco's apparent overheating... found the Autometer mechanical gauge was reading 13 degrees high! Through-out the whole process I never doubted the guage's accuracy because of Autometer's excellent reputation. My lesson learned was check everything - too bad I checked the guage last, not first.... It's probably not your problem, but it's an easy check just to make sure you don't waste time and money like I did swaping everything else first... Best part is that a new autometer gauge is sitting in the dash and is reading properly. Good luck finding your problem.
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I tested the guage by removing it from the truck, then I set up a pan of 50/50 on the bench so that I could heat it with a mapp torch. I suspended the sensor bulb from the autometer gauge in the 50/50 so that it didn't touch the bottom or sides of the pan. Then I suspended 2 probe thermometers and a thermister from a fluke multimeter all in the same pan of 50/50. I heated the 50/50 and watched all 4 readings (2 probes, fluke and autometer) The 2 probes and the fluke all read the same temperature through the range and the autometer would consistantly read 10 - 13 degrees higher throughout the scale with a 13 degree difference in the operating range from 190-215 and the 10 degree toward the bottom of it's scale. Of course these numbers are approximate as the autometer gauge isn't calibrated right to the single degree.
I did check the replacement gauge before putting it in the engine and it read consistant with the other three thermometers in the same test.
In the past, I've had success with electric hot pots instead of the pan / map torch that I used this time - just like for testing a thermostat.
I did check the replacement gauge before putting it in the engine and it read consistant with the other three thermometers in the same test.
In the past, I've had success with electric hot pots instead of the pan / map torch that I used this time - just like for testing a thermostat.
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From: Troy,NY
Originally Posted by hunter1897
Thanks for the reply. My first thoughts are:
1) bad thermostat, which was replaced a year ago on the old engine, so I put it in this new engine.
2) water pump, but I installed a brand new high flow
3) radiator, original one that came with the truck, but seemed to be fine for the old engine...probable upgrade in the future
4) I was only running at about 10 mph around the block on a hot day, so maybe I didn't get enough air across the radiator
1) bad thermostat, which was replaced a year ago on the old engine, so I put it in this new engine.
2) water pump, but I installed a brand new high flow
3) radiator, original one that came with the truck, but seemed to be fine for the old engine...probable upgrade in the future
4) I was only running at about 10 mph around the block on a hot day, so maybe I didn't get enough air across the radiator
I'd take the radiator to a shop and have them flush it. You don't want 30 years of junk going in to a nice new motor.
Slow speeds like that are tough on old bronco's. The cooling wasn't the best to start with. On your next ride try to keep it over 20 mph and vary the speed. Get a good fitting shroud. When you bring your radiator in to get it flushed ask them about recoring if the radiator looks questionable.
It is going to run a little hotter while everythiing seats. Keep those rpm's up for a while to let them seat properly! A slow cruise around the block isn't the best way to to it. 220 isn't a good temp. but it's not a unheard offor a break-in either.
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From: Da UP, eh!
To answer a few questions and such, I do have a fan shroud, exactly the one for the early Bronco. I'm not sure if the gauge is reading exactly correct as was pointed out by Fordfan28, but I can truly appreciate his experiment for checking the bias of the gauge. I took her out again this morning, first on my own, then with the kids. We went around the neighbor hood a few more times, and this time going just a little faster, up around 20 or so, I watched the temp gauge climb as before, but right at about 220, I saw it drop real quickly, so I have to assume the thermostat opened up and a shot of cool fluid cooled it down nicely. But, having seen that, I might opt for a lower temp thermostat. I think I'm good for now...over the initial hee-bee-gee-bees of over-heating. Thanks all.
