351C Operating Temps
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351C Operating Temps
Hey! I have a question for ya.
I was driving my 73 Stang and I noticed the temp gauge creeping towards the 'H'. I only drive it 45 to 50 mph, with a occasional blast of high speed. It'll idle all day long and not over heat. This has been going on for a while. Everything works good and all looks good. Also, it has factory a/c, but it ain't hooked up yet due to the fact that I've not put a belt on.
What's going on? Is the thermostat junk or is it too hot for my 351C? Or are the head gaskets shot? It has 115k original miles and the engine doesn't look like it has ever been apart. Is the radiator too small?
Thanks!
I was driving my 73 Stang and I noticed the temp gauge creeping towards the 'H'. I only drive it 45 to 50 mph, with a occasional blast of high speed. It'll idle all day long and not over heat. This has been going on for a while. Everything works good and all looks good. Also, it has factory a/c, but it ain't hooked up yet due to the fact that I've not put a belt on.
What's going on? Is the thermostat junk or is it too hot for my 351C? Or are the head gaskets shot? It has 115k original miles and the engine doesn't look like it has ever been apart. Is the radiator too small?
Thanks!
Posting Legend
Joined: Sep 2001
Posts: 30,255
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Missing air dam?
Missing air flaps around radiator support?
Clogged radiator?
Collapsed hoses?
Improper type thermostat?
Your thermostat must be one for a 335 series engine with an internal bypass circuit. It should be an approx 195°F thermostat.
Missing air flaps around radiator support?
Clogged radiator?
Collapsed hoses?
Improper type thermostat?
Your thermostat must be one for a 335 series engine with an internal bypass circuit. It should be an approx 195°F thermostat.
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The radiator hoses are original to the car and no, they re not collapsed. If the radiator was clogged, I would have seen things floating around inside. But no, the antifreeze is bright green and clean.
It doesn't have an air dam (aka spoiler) on the front. It was gone when I got it. The air deflector that covers the top of the radiator is gone also.
I'll have to take the thermostat out and have a look at it. Should I do a radiator and block flush just to be safe?
Why would a Cleveland need an internal bypass circuit? Isn't 195 degrees a bit warm? Can I get away with a 180-185 degree thermostat?
Thanks
It doesn't have an air dam (aka spoiler) on the front. It was gone when I got it. The air deflector that covers the top of the radiator is gone also.
I'll have to take the thermostat out and have a look at it. Should I do a radiator and block flush just to be safe?
Why would a Cleveland need an internal bypass circuit? Isn't 195 degrees a bit warm? Can I get away with a 180-185 degree thermostat?
Thanks
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From: chicago burbs
Originally Posted by BlueOvalfan85
Why would a Cleveland need an internal bypass circuit? Isn't 195 degrees a bit warm? Can I get away with a 180-185 degree thermostat?
unlike the 351M/400, the Cleveland has a separate brass bypass restrictor that is pressed into the block casting under the Tstat.(the 351M/400 block has the restrictor cast in) these bypass restrictors get removed at machine shops and tossed out. without the bypass restrictor in place, too much coolant bypasses the radiator and the engine runs hot. here's a page that describes it well,
http://www.are.com.au/feat/techt/thermostat.htm
here's a recent auction for a bypass restrictor,
http://cgi.ebay.com/ebaymotors/1970-...QQcmdZViewItem
notice what it sold for! they are obsolete and out of stock. there ain't no more... but there's a guy that may start producing them, and new improved Cleveland blocks!
if yours is missing and you can't find one, i have a fix for ya.
Posting Legend
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A 195°F stat is what they are designed for.
The air dam and air deflectors are what channel air thru the radiator at road speeds. Without them there is no low pressure zone under the vehicle and the air up front bypasses the radiator. Many times they are torn out like the restrictor ring in the cooling circuit by people ignorant of their function. Remember Ford did not put a single part on they did not have to.
The air dam and air deflectors are what channel air thru the radiator at road speeds. Without them there is no low pressure zone under the vehicle and the air up front bypasses the radiator. Many times they are torn out like the restrictor ring in the cooling circuit by people ignorant of their function. Remember Ford did not put a single part on they did not have to.
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All right, thanks for alerting me to the restrictor ring. Like I said, the motor doesn't look like it has ever been apart. But first chance I get, I'll tear into it and check it out.
I never knew anything about this. I sure learn something new everyday from you guys. Anything else I need to know??
How difficult is this part to install and can I do it myself????
Thanks
I never knew anything about this. I sure learn something new everyday from you guys. Anything else I need to know??
How difficult is this part to install and can I do it myself????
Thanks
Posting Guru
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From: chicago burbs
Originally Posted by BlueOvalfan85
The radiator hoses are original to the car and no, they re not collapsed.
the lower hose is on the suction side of the pump and needs the spring inside it to maintain rigidity. you might be able to see it collapse by holding the throttle open some in the driveway, maybe not, it's hard to tell what's going on down there while you're driving.
Originally Posted by BlueOvalfan85
If the radiator was clogged, I would have seen things floating around inside.
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I'll have to check the lower hose again and see what it does.
Will a radiator and block flush help get rid of all the scale and lime?
Thanks
Will a radiator and block flush help get rid of all the scale and lime?
Thanks
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Posting Legend
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~~~~Maybe, kinda, sometimes, but not all the time. How is that for an answer.
The best thing to do with a radiator is to pull it and have it checked for flow and pressure at a shop. If it is a fairly new radiator it can often be rodded out and cleaned. If it is old then most likely the radiator will be "rotten". Old radiators lose the zinc in the brass which leaves a soft copper sponge metal behind held together with paint. Replacement is the only option at that point.
The best thing to do with a radiator is to pull it and have it checked for flow and pressure at a shop. If it is a fairly new radiator it can often be rodded out and cleaned. If it is old then most likely the radiator will be "rotten". Old radiators lose the zinc in the brass which leaves a soft copper sponge metal behind held together with paint. Replacement is the only option at that point.
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From: Longwood, Fl
Thermostat
Lots of good things to check, but let me throw in one more that has really bitten me in the hind quarters and cost time.
A brand new Robert Shaw 180 deg thermostat that wasnt opening out of the box. Did all the hose,radiator, fan clutch, stuff and even looked at timing advance. If you have the thermostat out, suspend it in a pot full of water that you can heat on the stove with a thermometer and heat to it rated temp. Sometimes they dont, or simply quit opening after while. Also check with a reliable guage before doing a lot of work, the sending unit or even the guage itself can go bad. Sometimes you can spend a lot of time "chasing your tail"----or am I the only one who does that?
A brand new Robert Shaw 180 deg thermostat that wasnt opening out of the box. Did all the hose,radiator, fan clutch, stuff and even looked at timing advance. If you have the thermostat out, suspend it in a pot full of water that you can heat on the stove with a thermometer and heat to it rated temp. Sometimes they dont, or simply quit opening after while. Also check with a reliable guage before doing a lot of work, the sending unit or even the guage itself can go bad. Sometimes you can spend a lot of time "chasing your tail"----or am I the only one who does that?
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