Cooling Problems

[ChargingZach]

Hello All,
I have a '68 Charger 318 stock & base model; It has the 22" radiator without the shroud and a 4 blade fan. Lately, when I am driving the car tends to get very hot at red lights or slow traffic and cools down (needle nearly in the center of the temp gauge) when I drive long and fast. So need some input on things...

1. When I used to live overseas we used to remove the thermostats off the vehicles as the weather never got colder than 20 degrees and the summers were about 50+ degrees; hence the cars ran slightly cooler. However, when I mentioned this to some friends - only two agreed with my idea of totally getting rid of my car's thermostat. Most others stated it will run hotter... not true from experience.
Now, today I went to my friend's garage and he told me this and it kinda makes sense but need your input guys. He stated that if the thermostat is removed it will quicken the flow in front of the block bypassing the rear flow; hence, making it seem that the car is running cooler when the rear part of the block will get hotter as the temp sensor is at the front of the block so it will tend to give a cooler false reading....

Any truth to this?

2. If I get a 22" radiator shroud will that make a difference?

3. Can I use a clutch system with the 4 blade fan?

4. How do I measure the fan to see if its 18" or more?

Thanks, please help.

 

[PP1RT]

Are you low on antifreeze? Wrong blend? Straight water?=rust?

I would leave the thermostat in there. It is there for a reason. The engine is designed to run a certain temp. Newer vehicles run even hotter.

 

[moes]

if your car over heats in traffic your fan is not pulling enough air through the rad at slow speeds or your rad could be plugged. That four blade fan is not cutting it. Don't run your engine without thermostat. Yes a fan shroud will make a big difference helping with cooling your engine. Make sure your fan is half in the shroud and half out .

 

[multimopes]

I never heard that one before. It could be tested I suppose with a digital temperature gun. I would believe it would even out after a while as long as the water passages aren't full of crud.
Yes, a shroud always helps. There most likely was one on your vehicle at one time but I could be wrong there also. There is a certain distance that a fan should extend into the shroud, I think it's one third of the way in. I don't see why you couldn't use a clutch fan. To measure a fan just draw some lines on paper at several distances apart, 17, 18, etc. an lay the fan on it. This may not be accurate but you'll have a good guesstimate. You could use a tape measure also. It sounds like you have had the car for some time now. Did the problem start gradually or suddenly. I would be looking for a collapsed return hose when up to temperature, especially when you look at it while operating the throttle on the carburetor. I would suspect that your thermostat is possibly failing also. Remove it and put it in a pot of water on the stove and heat it up. Put a thermometer in the water while doing this and observe when (if ever) it opens and see that it opens al the way. I have had 3 bad stats out of 4 in the recent past. There also is the possibility that your water pump impellor is slipping. Way back when had that happen on a non A/C car. The impellor was nothing more than a disc with holes drilled in it and it was pressed on the shaft. I installed the higher capacity A/C pump that actually had an impellor with blades. One other thing comes to mind; the timing could be off. Make sure your distributor is tight and check the timing. Over time a timing chain can stretch. One other thing is your coolant which should be 50/50 with water. I understand that an engine can run hot when running 100% coolant without water. I also remember discussions here about when running with no thermostat, that the coolant runs through the radiator too fast to exchange it's heat! Check the section on heating and cooling on this site for even more fun and games. I think I gave you a few things to ponder and I hope that you get to the bottom of it. I just also remembered the possibility your radiator is getting plugged up! Whew, that's enough! Good Luck.....

 

[66Satellite47]

Thermostats can go bad. If coolant level is good with fairly fresh antifreeze should be in "normal range", newer vehicles middle range is perfect. A 160 stat will be lower, 1/3 or so. Weak radiator cap will also raise temps. A 22" radiator will work fine, a shroud and/or the clutch fan will improve. But it seems like you have a basic problem that needs a fix. In the old days I used a coolant system flush chemical every couple years. That definitely helped the heater output in the cold Minnesota winters. Good T stat, good 16 - 17# cap, fresh coolant, is the place to start. This is all based on street driving.

 

[PurpleBeeper]

I agree with 90% of what all the guys above me have said. I suggest you first flush out the radiator/cooling system (Prestone flush or similar), add a fan shroud & see if you can find a 7-blade, stock OEM fan with a fan clutch, maybe of a newer 360??? Also, for sure, check the lower radiator hose for softness and/or lack of a "spring" inside (spring helps keep lower suction radiator hose from collapsing) & wash off the outside of the radiator with engine degreaser & a car wash power washer. If all that doesn't work, then check the water pump for the impeller being bad.

I'm betting you just have dirt on the outside of the radiator, the radiator is a little clogged or the lack of a fan shroud is hurting your low-speed cooling.

Oh yeah, removing the thermostat on old Mopars normally makes them run cooler....it's Chevies mainly that need "flow restrictors" when the thermostat is removed, not old Mopars. In general, it's good to have one in there though.

The front half/back half idea of Mopar cooling without a thermostat is ridiculous.

 

[ChargingZach]

Hi Guys,
Thank you all for the prompt replies. So heres the update(s).

1. It may be the rad as I did have it fixed (it was leaking from the bottom). I was told that sometimes they coat them paint too much. That remains to be checked. Coolant fluid is fresh in the rad and is 50/50.

2. The water pump is next on my list to check.

3. I checked the return hose and the spring is in there hence theres no way its collapsing I gave it my best shot to squeeze it and felt the spring inside.

4. I took out the Thermostat today... it was hot outside today. The old thermo was a 180. I installed one hi-flo Mr Gasket 160 thermo instead. I started the car and let it idle for a good while. The outside temp was about 30 degrees though felt much higher. Anyways, for 20 minutes of idle, the needle moved only 25% towards the center from cold. I then did a 30-40 minute drive through traffic slow (average speed 20mph) stopping at many lights and the needle moved over to the 75% mark from cold toward hot. It didn't go much higher. I kept driving till I came over to highway and drove the car at 65mph for about 1.5 miles getting off at the next exit. The needle dropped down to the center and then from there remained kinda centered till I got home 15 minutes later driving slow. Here are the pics as I took them in order. I hope that my car is not running hot still. I am going to purchase a Radiator Shroud (steel one is expensive but thats the one I am going to get).

 

[PP1RT]

Did they just have to solder the bottom tank seam or did they pinch off a bunch of tubes and solder them. After saying the radiator was repaired i would suspect something was not done right or a bunch of crud came loose after draining and refilling. Run it with the radiator cap (start cold)off and see how well the water flows when it gets warmed up to operating temp. Should see a surge of flow as the thermostat opens.

It sounds like this is a recent development so adding shrouds and stuff may just be masking the problem. A good clutch fan and shroud would be a nice improvement but the 318 doesn't create the heat that a stroker big block will. The car made it 49 years with the current set up.

 

[ChargingZach]

Did they just have to solder the bottom tank seam or did they pinch off a bunch of tubes and solder them. After saying the radiator was repaired i would suspect something was not done right or a bunch of crud came loose after draining and refilling. Run it with the radiator cap (start cold)off and see how well the water flows when it gets warmed up to operating temp. Should see a surge of flow as the thermostat opens.

It sounds like this is a recent development so adding shrouds and stuff may just be masking the problem. A good clutch fan and shroud would be a nice improvement but the 318 doesn't create the heat that a stroker big block will. The car made it 49 years with the current set up.

They soldered the bottom tank seam no pinched tubes.
Thanks, good idea I am going to try tomorrow and post results.

 

[Dennis H]

Shroud. Mine is plastic or molded composite. About $100 for a repop. Get a laser temp gun to be sure of actual temperature.

 

[oldbee]

Radiator or sender/gauge problem is my guess. That's too warm with a 160 t-stat, city or hiway driving; you oughta be looking at 170 or so or just the left side middle mark.

 

[ChargingZach]

Shroud. Mine is plastic or molded composite. About $100 for a repop. Get a laser temp gun to be sure of actual temperature.

I have been looking for a plastic repop online, I can't find one for a 22" rad for B B Body... Please advise where you got yours. Thanks.

 

[Dennis H]

I have been looking for a plastic repop online, I can't find one for a 22" rad for B B Body... Please advise where you got yours. Thanks.

Not sure, 26".

 

[Ranger16]

I have been looking for a plastic repop online, I can't find one for a 22" rad for B B Body... Please advise where you got yours. Thanks.

http://www.megapartsusa.com/products.asp?cat=542
http://www.herbsparts.com/products.asp?cat=592

 

[ChargingZach]

Okay so heres the update... Gonna start off with the cheap stuff and work up to the expensive stuff. I went to the mechanic and sat there for a good three hours trying to logically cancel items off the list.
1. Changed the Thermo..
2. drove the car around and it runs cool; ran it slow and still ran alright though slightly hotter.
3. parked and let it idle and the needle worked up to hot.
4. at idle put a few papers in front of the rad and it sucked them up.
5. installed a electric fan in front of the rad and left it idling for 20 minutes; it slowly very very slowly started to cool but stayed mainly in the hot region.
6. Threw it in Drive and it heated up quicker.
7. went for a drive again and it cooled up.

Have ordered a 7 blade fan - after that will probably go to a hiflow powerful waterpump - after that will recore to a two or three core. I am hopeful most of the problem will be solved after the 7 blade fan even though I will loose about 30 hp in the process.

 

[PP1RT]

I would go after the radiator first. The 4 blade fan was good enough for the first 49 years....should still be plenty now.

 

[PurpleBeeper]

Okay so heres the update... Gonna start off with the cheap stuff and work up to the expensive stuff. I went to the mechanic and sat there for a good three hours trying to logically cancel items off the list.
1. Changed the Thermo..
2. drove the car around and it runs cool; ran it slow and still ran alright though slightly hotter.
3. parked and let it idle and the needle worked up to hot.
4. at idle put a few papers in front of the rad and it sucked them up.
5. installed a electric fan in front of the rad and left it idling for 20 minutes; it slowly very very slowly started to cool but stayed mainly in the hot region.
6. Threw it in Drive and it heated up quicker.
7. went for a drive again and it cooled up.

Have ordered a 7 blade fan - after that will probably go to a hiflow powerful waterpump - after that will recore to a two or three core. I am hopeful most of the problem will be solved after the 7 blade fan even though I will loose about 30 hp in the process.

I think you're on the right track. If it's mainly running hot at LOW speed, & not a HIGHWAY speed, that's an indication that you're not flowing enough air a low speed (fan/shroud). A better/cleaner/bigger radiator would help, but I'm betting it's the air flow that's 75% of your problem. Don't worry, a CLUTCHED 7-blade fan will disengage & not rob you of 30 hp.

Not likely, but on another possibility is that you're not flowing enough coolant at low speed....rare, but possible. That would be caused by under-drive aftermarket pulleys or eroded away water pump impellers. I can't remember if this is Chrysler or another brand, but "some" motors have different number of water pump impeller blades....say 5 impellers for non-AC cars & 7 impellers for AC cars or something like that....again, not sure if that's Chrylser or not.

As for using the "pusher" electric fan in front of the radiator.... that should help somewhat at LOW speed & IDLE, but hurt you at HIGHWAY speed since it's blocking some of the front of the radiator (blocking air flow on highway, but helping air flow at idle/low speed).

 

[PP1RT]

I think you're on the right track. If it's mainly running hot at LOW speed, & not a HIGHWAY speed, that's an indication that you're not flowing enough air a low speed (fan/shroud). A better/cleaner/bigger radiator would help, but I'm betting it's the air flow that's 75% of your problem. Don't worry, a CLUTCHED 7-blade fan will disengage & not rob you of 30 hp.

Not likely, but on another possibility is that you're not flowing enough coolant at low speed....rare, but possible. That would be caused by under-drive aftermarket pulleys or eroded away water pump impellers. I can't remember if this is Chrysler or another brand, but "some" motors have different number of water pump impeller blades....say 5 impellers for non-AC cars & 7 impellers for AC cars or something like that....again, not sure if that's Chrylser or not.

As for using the "pusher" electric fan in front of the radiator.... that should help somewhat at LOW speed & IDLE, but hurt you at HIGHWAY speed since it's blocking some of the front of the radiator (blocking air flow on highway, but helping air flow at idle/low speed).

I am just thinking it sounds like these issues showed up after the radiator was "fixed". Were there problems before the "fix"??

 

[oldbee]

Straight out of a 68 FSM, I tried to include BB's also in case one of those lurkers looked.

 

[oldbee]

In a nutshell an a/c car used smaller impeller(less fins),7 blade fan & higher ratio pulley for the belts; spun everything faster if I'm figuring right.