472 hemi running to hot?

[STEVESBAD69]

I have just finished the restoration on my 69 roadrunner and have started driving it to work out the bugs.

I am a bodyman and my mech skills are short to say the least. I am running a 180 thermostat,4 core alum rad,2 12" elec fans, March serpentine belt sys,13 lb rad cap. I have added water wetter to apox 20% coolant to water mix. The eng runs at just over 180 untill i stop at the first stop light and then the temp starts to climb. After going on from the light the eng will not recover to the 180 and i have not let it get over 210. What should this eng temp run at with this eng? and what to do if i need to get that temp down. Thanks for any help.

 

[benno440]

my 505 also does the exact same thing, if running the thermo fans until back to 180 does not work then i imagine you need bigger cfm fans. that would be my first guess. when driving i sit on 180, when i stop it climbs very fast, i switch the fans on at 210 then within 20 seconds its back at 180

 

[STEVESBAD69]

benno440

Thanks for your reply. I guess that and additional pusher fan is in my future.I am rumming a/c on the car and should be able to squeze a fan between the grille and condenser. Just a side note: I sold a 55 chev pick up street rod to a guy in Vincentia NSW about 2 years ago. again Thanks for the help.

 

[benno440]

ahh nice,
yeh i run a pusher fan the puller wont fit as i also have a march serpentine kit, i run be cool radiator and there dual 12" fans i think they are.

 

[snakeoil24]

1. Get rid of electric fans, switch to a clutch fan, make sure your shroud covers the entire radiator.
2. Are the Belts tight on water pump pulley.
3. Initial timing 8-12 degrees Idle at break in with vacuum advanced disconnected and plugged.
4. Check centrifugal weights and springs on distributor are mounted to posts.
4. Check your thermostat, boil it in water and see when it opens.
5. Lift he front of car and bleed air from the top of the heads.
6. Check that your not loosing water in radiator or over flow is spitting while running.
7. Expect excess heat at break in.
8. Buy a Co2 checker make sure you have good head gasket seal.
9. Idle Mixture is it too lean?
10. Detonation? Listen with a piece of wood against valve Cover.
11. Get an infrared thermometer and check exhaust tempratures at each exhaust port. Temp should be 600F +/- 20f

 

[Hemirunner]

X2, especially on the fans. Those electric fans really don't move much are and you can tell on yours since it only heats up when you slow down and air flow through the radiator goes to near nothing. I run a high compression 572 hemi and I cool it with a stock clutch fan setup and a stock 1970 956 radiator. No issues. Also, make sure that aftermarket pulley setup isn't an underdrive setup on the water pump. That just adds to the problem. And check to see that it has enough initial timing in it at low rpm.

 

[bigmanjbmopar]

Is the motor newly rebuilt? If so It would run hot until broken in. Can you fit a flex fan and run the pushers outside on a temp relay? My 493 works great this way with a 3 row.

 

[Meep-Meep]

I take it this is a new engine? When you shut it down does it stop abruptly? I have seen this result with new engines but the problem goes away after a few hundred miles. Just don't let it get too hot and it seems you are aware of that.

 

[george68hemirr]

1. Get rid of electric fans, switch to a clutch fan, make sure your shroud covers the entire radiator.
2. Are the Belts tight on water pump pulley.
3. Initial timing 8-12 degrees Idle at break in with vacuum advanced disconnected and plugged.
4. Check centrifugal weights and springs on distributor are mounted to posts.
4. Check your thermostat, boil it in water and see when it opens.
5. Lift he front of car and bleed air from the top of the heads.
6. Check that your not loosing water in radiator or over flow is spitting while running.
7. Expect excess heat at break in.
8. Buy a Co2 checker make sure you have good head gasket seal.
9. Idle Mixture is it too lean?
10. Detonation? Listen with a piece of wood against valve Cover.
11. Get an infrared thermometer and check exhaust tempratures at each exhaust port. Temp should be 600F +/- 20f

i agree.....had spal electric fans and electric water pump and same problem......threw it out and went back to stone age...full shroud/flex fan/mechanical water pump.....runs all day at 180degrees

 

[kb67mopar]

my 5.7 hemi right now has a clutch fan from a 4.7 with no shroud and won't overheat at idle....the mechanical fans move SOOO much more air and cheaper too.

 

[super-bee_ski]

PS:
For a HEMI, is 210 degrees truly a "critical temp" ?
I know many 440s etc that run 200+ degrees.
Ideally, yes, 190 is an ideal temp but, hot summer days in Tuscon AZ your temps are 95 to 100 degrees from May through September.

I live in Edward, CA (daily temps are 100+)
Las Vegas, Phoenix, etc all have temps over 100 degrees.

 

[Hemirunner]

Most new cars run at 210 or so. It's not an issue and engine wear is actually reduced at that temp. Unfortunately, todays fuels do not like the those temps when being used with a carb. With EFI, you pressurize the fuel which raises its boiling point so it doesn't vapor lock like a carb.

 

[kb67mopar]

yeah pretty sure my 5.7 hemi in my truck runs a 203 F thermostat. The Hemi in the Coronet is running a 195.

 

[cordoba-rick]

My 1999 Dakota 318 came from the factory with an 8 blade fan. Do not know if this will fit but if it does, with a good fan clutch, your car should never overheat again unless your timing is off or your radiator is small/restricted.

 

[HEMI-ITIS]

A lot of good advise here.What compression is this engine?? What is the timg set at??

I have NO room for a mechanical fan,have 2 pushers in fron of the rad:tongue7:

 

[super-bee_ski]

I think my point is:
"We" all read lost of info from various scources.

Some individuals say their engines run at 180 degrees etc.
My point is: Many "Factory" cars have (had) thermostats that opened at 195 degrees. (per the book)

So, I say, a healthy "factory" system under pressure is operating "as designed" at 200/205 degrees.

Some guys will fret at 195+ and they will stress while watching their gage and yet, that IS what the factory designed them to operate at.

Just my 2 cents worth.

 

[Dennis H]

180 Napa Superstat. Green coolant. Shroud. Copper 26" radiator. Clutch fan. Ma knew. Stay with the formula. No electric. No aluminum. Like Volare Roadrunners are not better than 69 1/2 Beasts, newer is not always better. Just sometimes.

 

[383man]

I use the stock waterpump on my 493 and a flex type fan. I also have an aluminum rad and a shroud. It cools fine but if I sit in traffic very long on real hot days it will creep up to 200. So I added a pusher fan you can see here and I have it on a toggle switch. That way I only turn it on when I need it for assistance. If I turn it on when it creeps up to 200 to 205 on real hot days sitting at the lite and then it brings it back to 180. It works very good for me. Ron