390 temperature??

Just curious if anybody could tell me what the normal operating tempetature is for a 390 in my 61 Caddy. I test drove it for the first time yesterday in 98-100 degree weather and it looked like it was around 200-215 degrees. Is this too hot? It seemed steady and didnt rise anymore than that, but just curious of any advice or issues I might be having cause it seems pretty damn hot. Thanks

 

Your coolant is on the verge of boiling, get a new thermostat. They should open at 180*, leave the 160* ones alone.

 

If a new thermostat doesn't work, you might want to get a helper fan. Not traditional, but it'll save your motor from overheating in traffic. The 390FE in my old Galaxie would run really hot in the summer (I'd even throw a 160 thermo in it for the summer to get it to run under 200). I put an electric fan on a toggle switch in the car to help it stay cool in traffic in the summer.

I'm also assuming you have a fan shroud on the car. That makes a big difference, so if you don't have a full shroud, get or make one.

And back to your original question, you should be running around 180 degrees. If the coolant hits about 220 its going to boil over.

 

I would also check the Rad cap and possibly install a coolant recovery system , the crossflow radiators seem to push out more coolant than an upright style although they do seem to cool better ( the crossflow ) Your Temp isn't that severe , but I also like an engine to run under 200 --The shroud is possibly the best thing you can have on the car to help with the cooling . Does the car have a clutch fan? If so also check that it could easily be the culprit if it's heating mostly at low speed

 

On a full size mopar site a guy put an aluminum 96-98 Explorer V6 radiator in a 440 powered 68 Chrysler using the stock lower hose and an Explorer V8 upper hose.

I was having over heating issues with my 66 Chrysler (383 and AC) so I bought a $170 Explorer radiatior and used to hoses note above. It was a drop in job and only took 6 hours from opening the hood to driving off after burping the system! The over heating issues are gone!!!

I also have a 57 Cadillac that tends to run hot. From my measurements it looks like the Explorer radiator will fit in it as well.

The expolrer radiator has a lower hose outlet on the drivers side and the upper outlet on the passenger side. The upper outlet comes out at a funky angle but the Explorer hose snakes back to the center of the engine for a vertical thermostat housing.

If anyone is interested below is a link to the article on the Mopar web site.
http://www.cbodydrydock.com/content.php?article.7

Carmak
Riverside, Iowa

 

It does have a full shroud on it so that part is ok, I'm worried it's the clutch but how would I check to make sure it's working cause it is heating up at low speeds? (sorry, that might be a stupid question) I'm gonna replace the thermo and the cap and go from there. Any help on the clutch would be great. Also, what if I wanted to get rid of the clutch and fan all together, which electric fan would ya'll recommend?

 

You should be able to turn the fan with some resistance from the clutch , if you can just reach in and "give'er aspin " --then it's bad ---you can also crank it with the hood up , peek through the crack ( with the hood up of course) and see if the fan spins for a bit after you kill the engine --a little is ok , 5 or so rounds isn't good ---also --some are thermally operated and they have a bi-metal coil on the front side of the clutch feel to see if it is that type --. My opinion is that is the best as it will " cycle " and even in traffic doesn't put a " pull on the engine if it's not needed . As far as an electric ---well if this isn't a daily driver I wouldn't recommend that. You are only about 100 miles fom me and you know about the wasp that builds the mud nest --We call them dirt-daubbers here --they like to build on radiators of cars that sit a good bit especially if you just use a shed to store it under ( car-port ) and they wil build between the radiator and the electric fan and ruin the motor on it . You would think it would just break it up and go --those nests are a lot stronger than the fan motor. I recommend , if you want to change the typ fan to a non clutch version to a "flex" style . Myself I would just replace the clutch , and drive on ----

 

I'm hopin to drive this as much as possible so almost everyday would be ideal. From the sound of it and from what I can remember, I think the fan does like to turn a little too "freely". I might just look into a clutch but an electric fan sounds good too. Would I have to upgrade to a higher output alternator to run a electric fan considering I have the stock generator in it right now?

 

I really hate to say on th Generator part --I don't know the amperage rating of yours , the fans shouldn't pull much , but that will depend on how many you use, the size ---many factors . With the electric , you would need to install a relay so when you walk away they don't keep on running and you come back to a dead battery. It's not a complicated thing to do , but whether you use the temperature sensing controllers or just a toggle --I do recomend the relay that will turn off power to the fans when you turn off the ignition switch.

 

i have a 390 and had overheating problems, it was my bran new water pump, i opened it up and it had 6 fins instead of 12 like my old one, i threw my old one on there and all is well.

 

I'm always surprized when these post come up and people have water boiling at 212 degrees
with antifreeze, 17 lb. pressure cap and a coolant recovery system, you can run 220 all day long.

the pressure cap alone raises the boiling point 3 degrees for each lb. of pressure 17lb. cap and the water boils at 263 degrees. but make sure you run a recovery system when you shut down the pressure drops faster than the temperture and the sytem purges.