New radiator, still overheating

paddyrk

Member
Jun 7, 2018
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Dublin, OH
Hello, I have a 1991 LX with a rebuilt 347 stroker, and it keeps overheating. I run straight water with royal purple, (water wetter) but when I am sitting and idling, even even park the temperature keeps increasing. I run the hp efi system so I know the temperature is accurate, but it will stay cool enough if I keep moving, 40+ mph. I replaced the radiator since the old one was somewhat damaged, and it keeps it a little cooler, but not enough for me to feel comfortable. I am using an electronic fan since the radiator support was dented upwards and there’s no room for an engine driven fan. Is there something I’m missing? Is it just because it’s a high displacement v8? Anything helps, thanks.
 
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paddyrk

Member
Jun 7, 2018
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Dublin, OH
Underdrive pullies?
whats your timing set at?
thermostat?
The thermostat is a new OEM one and every time I fill the radiator I can easily tell it is open, I have stock pullies except for the crankshaft pulley, and the timing is computer controlled but is set at 10 degrees
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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Thats all good, things to do:
Change back to the stock lower pulley
with the engine cold, jack up the front end as high as you can with the radiator cap off, squeeze the lower radiator hose many times, this will force the trapped air from the system.
get a cheap mechanical temp gauge and zip tie it to the wiper or mount one permanently, the stock gauges are a best guess.
BTW, where on the gauge is it hitting when hot?
will your hp efi show you a/f ratio?
 

paddyrk

Member
Jun 7, 2018
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Dublin, OH
Thats all good, things to do:
Change back to the stock lower pulley
with the engine cold, jack up the front end as high as you can with the radiator cap off, squeeze the lower radiator hose many times, this will force the trapped air from the system.
get a cheap mechanical temp gauge and zip tie it to the wiper or mount one permanently, the stock gauges are a best guess.
BTW, where on the gauge is it hitting when hot?
will your hp efi show you a/f ratio?
Okay thank you for the advice, it reads about 210 or more if I drive it to or from work which is about 7 miles. The efi has a handheld device where I can see everything including the temp and afr, and it’s usually rather rich, in the 13s and low 14s. At 220 degrees the gauge on the screen turns yellow to signal a warning, and will shut itself off around 235 degrees.
 
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billison

I like tinted tail
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Feb 27, 2006
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Make sure you have a shroud on your E fan and that it is pulling air into the engine bay through the rad.

Swap out that under drive pulley. Nothing good about slowing down your water pump and alternator to gain a horse.
 

paddyrk

Member
Jun 7, 2018
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Dublin, OH
Make sure you have a shroud on your E fan and that it is pulling air into the engine bay through the rad.

Swap out that under drive pulley. Nothing good about slowing down your water pump and alternator to gain a horse.
Ok, I will most likely try that soon
 

RangerJoe

I leave the horn on while driving
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Apr 26, 2010
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That fan is a pusher, which side of the radiator do you have it mounted to? Like stated above, way too small. Would need two at the cm that thing pulls. Really need to be somewhere around 2500cfm to cool it well.
My 331 has a stock style replacement radiator with dual fans from a contour. Even with the small radiator it cools fine.

Joe
 

wiseguyk

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Sep 23, 2016
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It might be more work than you're looking to do, but I recently upgraded my SVE dual fans to a single Lincoln MK VIII fan and it keeps my car SO much cooler even in 90+ degree FL summer weather.

Like @RangerJoe said, Contour fans are also an option and will fit nicely on the Fox radiator. It just depends on how comfortable you are with minor fabrication for the brackets and figuring out what you want to use for a fan controller.

I think if you're trying to keep the original shroud, you probably won't find an electric fan that'll fit and pull enough CFM to keep things cool...
 

Steel1

Mustang Master
Aug 18, 2017
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You could also use a dual fan set-up out of a 2000 Intrepid, fits the width of the radiator almost perfect.
That combined with a Flexalite vsc 33054 works well.
 

Boostedpimp

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May 8, 2003
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You could also use a dual fan set-up out of a 2000 Intrepid, fits the width of the radiator almost perfect.
That combined with a Flexalite vsc 33054 works well.

I've had this setup in two of my foxes for many years and one is daily driven every day without zero issues.
 
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afso

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Okay thank you for the advice, it reads about 210 or more if I drive it to or from work which is about 7 miles. The efi has a handheld device where I can see everything including the temp and afr, and it’s usually rather rich, in the 13s and low 14s. At 220 degrees the gauge on the screen turns yellow to signal a warning, and will shut itself off around 235 degrees.
try running no thermostat