Overheating and getting frustrated

I read in a recent post that your mopars are running in the 180 to 200 degree range. My car is running hotter than that and I don't like it. :mad: :mad: :mad:

I have recently installed a three core radiator, a 2100 cfm electric fan and a Mezeire 100 series electric water pump. It is now running close to the boiling point! A lot hotter than I want. What have I done wrong, what do I need to do or change.

Please help any advice will be greatly appreciated!!!

You need a fan shroud. The area of radiator that is not being ducted through the fan is being wasted. The installation of the shroud causes the "venturi-effect", just like your carb.

Yeah you need a fan shroud :)
3 other thoughts,you said you just added the fan,is it a pusher or puller fan???
Also if you don't already have one get an adjustable fan switch so you can set what temp you want the fan to kick in at.
What temp T-stat are you using?
You could make a card board and duck tape fan shroud to see if it helps before you go out spending $$$ if it helps buy a shroud.

Thanks for the input, but as you can see, I have only an inch or so between the fan and the water pump. I purchased a shroud to go with the fan, but it moved the fan back too far. i even looked into a low profile fan, but still not enough room. The fan is a puller style. The theroswitch for the fan is on at 185 and off at 170 and I have a manual over ride switch to turn the fan on early if needed. Still overheats. I had a Milidon high volume 160 degree thermostat in, but took it out as it heats up quickly.

The radiator is a Champion Radiator that good decent reviews. Any thoughts on this or other suggestions??? Should I start searching for an ultra low profile fan/shroud combo???

I see at Summit Racing they have dual fan/shroud combo kits that would decrease the depth directly in front of the water pump. Any thoughts on this working???

How many cfm is that set up? That looks like a very good set up,it will give you the extra clearance for your water pump and pull air through the entire rad surface

2100 cfm is not enough

17502

17502

That's an awesome set up. Where did you find that?

How's your ignition timing?

How's your ignition timing?

Can that cause overheating??? I believe that its set at 12 initial.

I hate to burst your bubble about all of the money you have spend on new cooling system items but here is something I have posted many many times before.

Don't try to re-invent the wheel. The auto manufacturers hired engines to build their cars and sub assemblies and the cooling system was one of them. All of them had test tracks in the Arizona desert to test them in extreme conditions.

The best thing you can do is keep things original. Over the years people remove/replace these things with no shrouds, flex fans, electric fans, and aftermarket radiators.

The factory type radiator with original thickness and fin count is the best system you can have. The fan shroud should be sealed so that all of the air behind the rad. is forced to be sucked THROUGH the rad. rather than around it. You are creating a vortex behind the rad. The placement of the fan is also important. It should be 1/2 in and 1/2 out of the rear edge opening of the shroud. Viscous clutch fans are good for engine power saving since they cut out at higher RPMs when the speed of the car helps with the air flow through the rad. but a standard fan is fine too.

Electric fans block the rad. simple by their presences weather they are front or rear mounted. People think that because they are mounted closely that they do a better job and think that a center mounted one is good. In order to duplicate the shrouded rear set engine fan that pulls air from the entire surface area of the rad. the electric fan(s) would have to be mounted over the entire surface area of the rad. and it is still a blocking problem.

Aftermarket rads. are very often built WRONG. Thinking that the larger thikness and higher fin count is better it is actually worse as in 10 pounds of crap in a 5 pound bag. It "crowds" the fin count and limits the heat dispersing characteristics it is suppose to be creating. It needs room to get rid of the heat.

I think I have read you post this before and i agree with you about the stock setup.

Some of the change was trying to compete in the car show circuit with the others who have gone to aluminum as well. It seems the judges , other car owners, seem to be attracted to shiny things. (i don't place well partly because I have kept the outside looking original with the factory wheels and have resisted the "shiny" chrome wheels.)

I have kept the original mechanical pump as well as the viscous fan so I may have to put that back on with a stock style shroud if I can't figure the heating problem out.

Is the timing comment true? Can an incorrect setting effect heat produced?

Found this as one possible explanation. I will have to double check the timing

Retarded will over heat it most quickly. The burn occurs over about 80 degrees of crank rotation, when started late, there isn't time for the the flame temps to be reduced by work against the crank. This combined with the reaction still occurring when the exhaust valve opens conspires to dump really hot gases into the exhaust passages. This greatly increases the valve temp and the amount of heat picked up by the cooling system thru the structure of the head and exhaust port. The exhaust manifold/headers also become very hot, enough to glow. With retarded timing, the temps come up very quickly.Too much advance will eventually result in overheating but it's much slower to build compared to retarded timing. Usually before anything bad happens one usually notices that the engine is hard to start, tends to explode thru the carb, and if it runs at all it's with no power and tends to detonate from the extreme pressures formed before TDC. So you usually head this problem off before the temps get very high.

Yes, timing difinately effects engine temp.

Did you check the thermostat operation before fitting it? even new ones can be faulty.

Your photo is basically a "poster child" for overheating culprits. In no particular order I will address them.

1. Aluminum does not conduct heat as well as Brass, so your Aluminum radiator will not be as efficient as a stock 3 row. --- This would not be a problem if everything else was designed to work with it, but it's not.

2. Without a factory (any brands factory) designed shroud, you will almost certainly overheat, as the manufacturers spent Millions to design an efficient fan/shroud/pump volume-speed setup. --- The mid thread photo of a "suggested" dual fan/ flat aftermarket shroud will only contribute to your problems, as they act as an air dam as speed increases.

3. You have an electric water pump. They will flow about what a stocker will at low RPM; but can't flow enough to keep a performance big block cool at anything but idle (that’s if you had an effective fan/shroud set-up), They are generally sold as race set-ups, and really aren't any good for even that.

4. You have a non-vacuum advance distributor. These can work fine if the engine/car is designed for them, but if I remember correctly, you said it was set up for 12 degrees initial. That would work for idle (if everything else was set up for that), but will be extremely retarded at anything over completely stopped with no throttle opening. --- Retarded timing will contribute substantially to overheating (as well as poor performance) even with a workable fan/radiator/shroud/water pump situation.

5+. Even if you had a workable system, the radiator is not sealed to the support, Your "rated" fan CFM is marginal at best, and probably only half that, It appears as though you are using either a chromed, or polished stock alternator, which simply can't produce enough power to run a good fan, Those "lever-vent" radiator caps are not a good choice due to there variances in "actual" pressure, and basic inability to retrieve coolant from the overflow tank.

6. Unless you are running a coolant that has a high silicone content, and you have made certain that you have no residual voltage grounding through the aluminum radiator, your cooling will very quickly degrade in as little as a matter of months, and your aluminum radiator will be useful only as a paperweight.


I can't offer you any solutions unless you are willing to start from scratch, and sell off 90% of the stuff pictured in your photo.

You can change to the stock system, which will be an improvement, but you can produce stellar improvements over stock (just like changing to disk brakes from drums), if you are willing to change over your alternator in order to run it.

Lastly, I only point all this out as a guy that was born, raised, and (for decades) live in the desert, so I had to learn what makes a cooling system work, with A/C, in as high as 126 degree temperatures, while maintaining as much performance as possible.


Your environment is infinitely more forgiving than mine, so you can solve all your cooling problems by simply going back to basics, and improve upon them if you want, but like I said in the beginning of this post, your current system is not functional as it stands.

That seems to be a common thread, that I have gone too far away from stock and everything effects everything else whcich causes the problem. I thank each and every one of yuo for your valued input and I am taking each of your comments to heart, I am planning to go step by step back towards the factory setup. Starting at the water pump and then the shroud. Luckily I still have everything to put back on.

Keep it simple People,

I have a Factory 3-row 26" radiator, w/the factory shroud,and an original Chrysler 7 blade clutch fan, I also have a stock a/c water pump (8 blade),on my 440 powered '69 Coronet,in traffic on the "Las Vegas Strip",110 degree day,the hottest it got was 200 degrees!

I've seen people with "multi electric fan set-ups" overheating in 80 degree temps!
you might as well put a piece of cardboard in front of the radiator!

I have a radiator out of a "C" body with the tight recore adding coolant capacity.With 5 lbs of boost{13%} underdriven there is about 750 HP to the wheels.The only time my water temp goes over 200* is when I am stuck in bumper to bumper traffic.I have seen 210:grin:

Keep it simple People,

I have a Factory 3-row 26" radiator, w/the factory shroud,and an original Chrysler 7 blade clutch fan, I also have a stock a/c water pump (8 blade),on my 440 powered '69 Coronet,in traffic on the "Las Vegas Strip",110 degree day,the hottest it got was 200 degrees!

I've seen people with "multi electric fan set-ups" overheating in 80 degree temps!
you might as well put a piece of cardboard in front of the radiator!


Though I don't disagree with the point of your post, I have to correct a couple points so others don't get confused.

First of all, the 8 blade is a NON A/C pump. The 6 blade was for A/C cars, and was driven at 30% over-speed.

If you are running a non A/C pump with non A/C pulleys, all is fine, but if you are running a non A/C pump with A/C pulleys, you will get into overheating possibilities at higher (highway) RPM's as the water pump will start to cavitate, and flow less water due to the radiators inability to accept more water.

Conversely, a 6 blade A/C pump, driven by non A/C pulleys, can overheat at low speeds due to a lack of flow regardless of the radiator.

When you introduce the "mix and match" approach that many take, such as C body engines (which most all had A/C and A/C pulleys w/Larger capacity radiators), or the B body equivalent into a non thought out fabrication, people will swear by (or swear at) their combo.

The factories spent money, time, and testing, designing systems that worked. Enthusiasts usually just "guess", and love or hate the results.

That's one of the reasons that all the forums are rife with overheating threads, not just the Mopar ones.

Once you introduce all the factory, and aftermarket pumps, pulleys, radiators, fans, etc; It's quite a tribute to the original stock systems, that any of these cars still function, when combined with non ideal parts.

As you state, many people that use multiple electric fans still overheat in relatively low temperatures. This is due to not understanding the fundamentals of a cooling system, not because a modern electric fan system is not as good as stock.

Quite the opposite, as a well designed electric fan system can be worth over 30+ HP over a mix-matched stock system. In fact I can't think of any area that has as much potential for a HP increase for as little investment.

This does require a switch to a modern high output alternator, and amp Gage modification in old cars, but the cost is very minimal.


Though I agree with the point of your post, I certainly don't agree that a stock system can even come close to a modernized system if done right, plus you pick up a bunch of HP and torque in the process.

Though I don't disagree with the point of your post, I have to correct a couple points so others don't get confused.

First of all, the 8 blade is a NON A/C pump. The 6 blade was for A/C cars, and was driven at 30% over-speed.

If you are running a non A/C pump with non A/C pulleys, all is fine, but if you are running a non A/C pump with A/C pulleys, you will get into overheating possibilities at higher (highway) RPM's as the water pump will start to cavitate, and flow less water due to the radiators inability to accept more water.

Conversely, a 6 blade A/C pump, driven by non A/C pulleys, can overheat at low speeds due to a lack of flow regardless of the radiator.

When you introduce the "mix and match" approach that many take, such as C body engines (which most all had A/C and A/C pulleys w/Larger capacity radiators), or the B body equivalent into a non thought out fabrication, people will swear by (or swear at) their combo.

The factories spent money, time, and testing, designing systems that worked. Enthusiasts usually just "guess", and love or hate the results.

That's one of the reasons that all the forums are rife with overheating threads, not just the Mopar ones.

Once you introduce all the factory, and aftermarket pumps, pulleys, radiators, fans, etc; It's quite a tribute to the original stock systems, that any of these cars still function, when combined with non ideal parts.

As you state, many people that use multiple electric fans still overheat in relatively low temperatures. This is due to not understanding the fundamentals of a cooling system, not because a modern electric fan system is not as good as stock.

Quite the opposite, as a well designed electric fan system can be worth over 30+ HP over a mix-matched stock system. In fact I can't think of any area that has as much potential for a HP increase for as little investment.

This does require a switch to a modern high output alternator, and amp Gage modification in old cars, but the cost is very minimal.


Though I agree with the point of your post, I certainly don't agree that a stock system can even come close to a modernized system if done right, plus you pick up a bunch of HP and torque in the process.

Thank you for the correction, then basically I'm running everything as designed by the factory, my car is originally an air car,but I changed everything (both pulleys) to a non air set-up,that's probably why it works!

again, Thank You for the info.

I might have understood about 1/2 of that :-) I saw a really good article in a mag about MOPAR cooling systems from the 60's but for the life of me I can't find it. So before I start to understand everything that was posted, can we define 'over heating'? My future need will be for my 65 Coronet w/440. My immediate need is for my '02 Dakota R/T w/408. I have a 180degree thermostat and my inclination is to think anything over about 190 is over heating but based on previous posts that appears to be wrong. So 'how hot is too hot' for an aluminum block with aluminum heads? It routinely gets to 200 - 210 during the summer.
Thanks, Bill

By the way "Hemi-Itis", that is one sweet looking ride.

What brand of aluminum water pump housing are you using? I have heard that pump housings from 440 source can be a problem.

At this point the Coronet (i.e. 440 engine) has the original water pump. Not quite ready to begin restoration yet. Unsure what the Dakota has, it is the aluminum wonder that's causing me so many problems right now.