Can't figure out my overheating issue

[cdn66satellite]

I don't want to wade in with a seemingly silly comment but I do have to ask: Do you have an anti collapse spring installed in your lower radiator hose? Seeing as you have a new rad and at speeds should have enough air to cool the fluid, I cannot help but wonder if the hose is collapsing...

yeah it has the spring in it and no issues with it.

 

[Car Nut]

How's your water pump?

My car is a non a/c car too, but the parts place wanted to sell me a a/c car pump that's totally different.

 

[bigmanjbmopar]

I'm with Rebel, an electric fan and aluminum shroud should work fine you just need to make some holes in that box, think about it? All the air that hit's the radiator at highway speeds and it's trying to take away the heat from the tubes but is just bouncing back to the tubes re heating them and if your fan can't pull in 2500 or more CFM then is too weak and being overpowered by the highway wind kind of counteracting it. That looks like a 16" puller fan probably 1400 cfm. A cross flow radiator should work very well. Puts some holes in that shroud and call it a day. Maybe switch to a dual fan setup. Don't put a pusher in front you will just be blocking free air.

That with a timing check for sure. wrong timing can definitely cause overheating.

 

[mopar 3 B]

Fans are of no value at highway speed and your electrics are againts the radiator. They will only pull air that is in front of then. Ditch the shroud or go back to the factory setup.

 

[Cyty Slykers]

At idle my car runs fine but when I drove it for the 1st time (appx 20 miles) last week it ran hot. Freshly rebuilt 383 4 barrel, original 22" rad, new fan & clutch, new scan shroud,180 t stat..... I have new everything and have no idea what the issue could be.

 

[440beep]

What's your timing set at? And is it still there from when originally set? Too retarded and it will run hot. Define "hot" please.

At idle my car runs fine but when I drove it for the 1st time (appx 20 miles) last week it ran hot. Freshly rebuilt 383 4 barrel, original 22" rad, new fan & clutch, new scan shroud,180 t stat..... I have new everything and have no idea what the issue could be.

 

[slepr1]

Please post your fix on this issue. Overheating seems to be a common issue and you received allot of good advice. This will help others.

 

[62MAX]

I can't get over why everyone has to have electric fans,every car i have ever owned (and that is a lot) had all their original cooling system components and I've "never" had a cooling issue.I guess what it all boils down to,if something works,change it !!:icon_scratch:

 

[furyus]

Most of the time, when I see a question about over heating, the car has an electric fan. The fans don't have enough cfm, and the shroud blocks the flow. You can check all the other suggestions, but you won't get a 30 *temperature drop without a drastic change. Put a Summit 18" stainless flex fan with the correct spacer, plus a shroud. Even if you have to make it. Fan should be 1/2 way in the shroud.

 

[bigmanjbmopar]

Timing is a big factor in overheating, clogged or gunked up radiator due to not using good mix is another and a bad pump as well and last the stat is either wrong or broken. It just takes going down the list to find the culprit. For the rest of us certain mods make it necessary to make a change in the radiator and fan setup altering it from factory. Once you made a mod you find most of the time you now have an overheating issue that either you have to give up your mod and go back to all stock or go all out with the mods to make it work. it's a choice of the individual.

A new shiny aluminum rad looks a lot better than stock and different pulleys sometimes take more room and fans don't fit any more so electric fans are a great alternative also some of us want to take the load of a mechanical fan off the engine for more power. My fans which are advertised @ 1400 cfm each total would be 2800 cfm actually do more than that.

I'm pretty good about details and evidence so here is my video of my fans actual CFM using a meter.

https://youtu.be/jBamlNKtcXc

 

[WileE]

I can't get over why everyone has to have electric fans,every car i have ever owned (and that is a lot) had all their original cooling system components and I've "never" had a cooling issue.I guess what it all boils down to,if something works,change it !!:icon_scratch:

I ditto your statement EXACTLY.

 

[Shorthorse]

The problem with electric fans and tight shrouds is that they flow at a constant speed. I don't know the real numbers but lets say a fan at 2800cfm passes the same volume of air equivalent to 40MPH. At 60, along with the restrictive shroud, it is actually restricting the 60MPH air. Like Bigal75 said, air flaps allow the road speed air to pass. Hemi Rebel has a good example of a shroud with flaps.

 

[mopar 3 B]

Just a note: I have driven the 68 Charger 383 and auto trans with no fan belt or shroud, solid fan and stock radiator at freeway 70 mph speeds and no heating issues until slowing down. You are running an aluminum radiator, shroud, electric fans and overheating at freeway speeds not to hard to figure this one out. In coming air flow is where it is at and has nothing to do with fans until you slow down. If you want air to flow open the door. By the way the 383 was not stock either.

 

[Dennis H]

No electric fan, no holes drilled in the thermostat, no springs in the hoses. No overheating issues. Just Ma Mopar copper, shroud, thermal.

 

[Cyty Slykers]

Test drove my car yesterday with a spring inside the lower rad hose and without the tstat to see if my overheating issues would reappear. Once again at idle no overheating issues but notice that my new Holley 750 dble pump needs adjusting...when I decided to drive it maybe 15 miles it ran hot like before and at that point I decided to checkout my rad and could see several flute clogged up so I'm thinking that's my problem.

 

[bigmanjbmopar]

I run the Evans stuff with no star and occasionally find iron chunks small but still just big enough to possibly clog a row or two. Sounds like you are close to solving it glad to hear hope all the advice has helped.

 

[Cyty Slykers]

I have my fingers cross lol..hopefully cleaning out the radiator will be the end of my headaches... since I have a mild build on my 383 should I convert my 2 row rad over to a 3 row?

 

[bigmanjbmopar]

Two rows of larger tubes is more efficient than 3 or 4 rows.

Read this sticky post in this section.

http://www.forbbodiesonly.com/mopar...02-Aluminum-Radiator-upgrade-Change-Read-this

 

[RJRENTON]

Gentlemen,
I also suggest the 7 blade fan with a thermostatically controlled fan clutch and shroud. It seems to me that Mopar engineering supplied that setup with a big block and A-C, the only difference was the water pump was OVERDRIVEN, at about 3x crankshaft RPMs to circulate coolant at a higher VELOCITY. Once again the issue of radiators is not the materials of construction, or the number of tubes from the hot tank to the cold tank, but the number of "fins per inch" on the air side. These fins are the heat exchange component. You should also consider a HIGHER temperature thermostat, as this determines the coolant temp. The design criteria is the LMTD or the logrithmic mean or temp difference between what is being cooled (coolant temp) and the temperature you are trying to cool it with (air inlet temp) and the greater the difference, the more heat is exchanged. Velocity thru the radiator (coolant side) usually expressed in feet/second or sometimes as gallons/minute is a calculatable quantity. A rule of thumb is approx 20 to 30 ft/second. Another aspect is the specific heat of the coolant, which is coolants ability to absorb heat and then release it to the cooling media (air stream) Ask the radiator supplier what his design factors are. He will likely say xxxHP. But this number must be converted to BTU/Hr to make a heat exchange calcuation (most suppliers don't know). Electric fans are OK, but their Cubic Feet Minute capacity must be known as well as their static pressure capability must be known. Propeller fans have low static pressure capabilities (either in front of the rad or the engine side of the rad) and they will only move air equal to their area presented. if the static pressure presented to the fan, exceeds their design, air flow will be low. This design point is called the fan curve, which graphically shows the fans capability. But....the above information is my opinion, based on many years of heat exchanger design.
Cheers,
RJ Renton

 

[62MAX]

You part about the water pump being overdriven to circulate water faster is the direct opposite from the recommendation in the old Chrysler Direct Connection performance manual which state the 6 blade A/C pump should be used as it circulates the coolant slower and keeps it in the radiator longer for better cooling.