Cooling question

[mustangman1974]

Alright, here goes a can of worms. Last summer I finally replaced my tired 5.0 (over 300k) with a ford replacement (First mistake). I choose to purchase custom auto air's perfect fit (Second Mistake) A/C system (Horrible customer service, Nobody ever answers the phone going on 3 months on missing parts). The Car is a daily driver, currently 550 miles a week.

This is my issue. I noticed that in traffic the temp guage climbs to around 200-210. I know this is not an issue, but its winter and the A/c isn't even charged. I have done a search and most people solved the problem with a large crossflow radiator. For me this is not an option. The A/C system bolts directly to radiator. I did some measurement and when I cut out for a large radiator it will push the condensor to the hood latch.

I used to run a 14in push and never had a problem. in stop in go traffic and 110 degrees it never went over 210. Well I have 1.5 in between the condensor and the closest obstruction. Either valance or latch.

I have research three possible solutions, but being a teacher now my funds are severly limited so the trial an error is not an option. First, replace the new copper radiator with the summit replacement. This gives me 1/4 in thicker core. Second, install an oil cooler 8in x 10in is the biggest. Third, replace mechanical fan (OEM flex the big steel ones) and shroud with a SPAL 16in extreme electric.

Suggestions are welcome.

Cutting to core or fabing brackets for the condensor is something I am not willing to do at this point. I struggled to get that damn A/C to fit and I really don;t want to mess with making more A/C lines.

Has anyone solved the cooling issue w/o cutting the core?

 

[jbuening]

How many cores are in your radiator currently? Upgrading to a 4 row will help some. IMO, the greatest help will be using a fan shroud with a high cfm electric fan. Couple that with a high volume aluminum water pump and you should be fine. Also, what temp thermostat are you running? Just a few things to think about.

 

[iskwezm]

i tried the "4 core" thing, all it does is transfer heat from one core to the next and next etc. I have noticed more cooling problems with electric fans (mine included) as oppesed to using a belt driven fan(not flex). i personally would go to you local junkyard and get a 3.8L Taurus fan or 94-95 mustang fan(with shroud) and use that.They can be had for about 20-30 bucks and have a 2 speed resistor,on high is 3000 CFM+, but they do draw about 40-50 amps on start up and about 10 running. replace the radiator with a 2 core aluminum,remount the condesor by using "custom" brakets made from strap stock(takes 1/2 hour).

 

[baskin]

I’m not sure what you mean by OEM flex fan. All of the reasonably modern OEM fans are either plastic or steal, with a fan clutch, but I’m not particularly familiar with the car that you own. If it does have a clutch, that’s the first thing to check. When the car warms up, rev the motor. I should produce a substantial mount of noise and airflow.

If it’s cooling at speed, a radiator may help, but it’s not the main problem. At speed your producing far more heat than at idle, but with a higher amount of airflow. What this indicates is that your radiator is rejecting the heat adequately. If you do decide to go with a new radiator, you can get similar performance to a high core count radiator by choosing one with a high fin density. You also get what you pay for in a radiator. A competent designer optimizes for impingement flow in lieu of laminar flow and does so byway of designed in turbulence. An oil cooler may help, providing that your oil is excessively hot, but if the oil pressure doesn't drop dramatically as the car heats up, it probably won't help much.

An electric fan that is of high quality will always outperform a mechanical fan at idle. The Taurus fan mentioned is one of the better choices and is actually about 3800 cfm. What’s more important is that the blade to open area is near the optimum 50% and the motor has a high peak to average current. The average current being approximately 35A and the peak current 110A. Both the high blade density and high peak to average motor allow the fan to move a large amount of air under actual flow-restricted conditions. Also, the Taurus fan uses a particular Seimens motor that uses a dual commutator in lieu of a dropping resistor. The significance of this is that you can’t power both circuits simultaneously without damaging the motor. An even better choice, if it will fit, is the 18” Lincoln Mark VIII fan, which has the same characteristics, but flows approximately 4500 cfm. I can post the dims if you need them.

 

[baskin]

If you want to be more accurate in the analyses, get hold of a thermal couple. Measure the water temperature, the ambient temperature, and the radiator air outlet temperature. This will give you a good estimation on cooling improvement with changes to either the fan or radiator. As an example, if your coolant temperature is 210, and your outlet temperature is 160 with an ambient temperature of 60. The heat rise from the atmosphere to the radiator outlet air is 100 degrees, the heat rise from the radiator outlet air to the coolant is 50 degrees The total heat rise is 150 degrees

Doubling the efficiency of the radiator will drop the rise to 100 + 25 degrees, and the car will run at about 185 degrees. Doubling the cfm of the fan will drop the heat rise to 50 + 50 degrees and the car will run at a theoretical (no thermostat) 160. If possible, check also the heat rise (thermostat open) from the top fins to the bottom fins of the radiator, 12 degrees is typical. If it’s substantially higher and you’re confident that you have the correct rotation water pump installed, then check and make sure the ignition timing is correct

 

[Hack]

How old is your current radiator? Possibly just replacing it could take care of the problem.

Another thing to consider is that a new, tight engine will run hotter than an old, worn one. Just the way it is. That is especially true the first few weeks or months.

9 or 10 years ago when I rebuilt my straight six it ran hot. It ran hot for the first few months. I bought a new radiator. Well it turns out I didn't need it. By the time I made the decision to buy the radiator and received it, the car was fine. Now I'm still running the old radiator.

Something to think about.

 

[zookeeper]

It's not clear to me what type of fan you're currently using, but you say you used to run a 14" pusher fan. If thta's what you're running now that is part of the problem. Unless space is a big problem (which it shouldn't be with a small block in an early Mustang) never run a pusher fan. They block the radiator and cause the overheating they are supposed to prevent. Look at any stock vehicle with an electric fan, you won't find one with a front mounted fan anywhere. The engineers that design cars know that you simply can't put anything in front of the radiator core, but we as a group have been a little slow to pick up on that principle. There are ways to make pushers work in space limiting applications, and that is to run a pair of small diameter fans as high on the radiator as you can.

 

[mustangman1974]

To start the fan is a 17in Steal OEM flex fam from summit. It was 1/2 bigger then the Stock Form 1965 Fan. I tested the CFM at idle with an HVAC guage. and the Summit OEM flex fan flowed about 600cfm more. Yes I am running a fan shroud. It is the factory with some modifications to address larger fan.

I am currently running a 160 degree thermostat.

its hitting 210 in 70 degree weather at an idle in traffic. With hood open it barely reaches 200 in 90 degree heat.

Radiatior is a 3 core Modine replacement. Brand new with motor.

Water Pump is brand new Bosch replacement for alumin. fron cover. No backing plate.

Engine just hit 8,000 miles today. Yeah I drive alot

Previously I had a more built motor, and I used a cheap pep boys alumin thin blad flex fan, and a Derale S curve blade flex electric pusher up front.

Currently as soon as I hit 25 miles an hour it cools down. at 50 ITs quick like 1/8 mile. to about 175-180.

Baskin you stated something about a heat couple. Is this just a fancy temp guage? I have access to all kinds of temp probes and guages. I am a bit of a coputer geek so I have temp probes for overclocking I could easly use. Where do you take measurements? Will tell me wheter a larger radiator or fan is needed?

I hope this infor helps some of you out. Summit actually has a direct replace ment thats is a 2 core alumin. 252 all welded. Not a bad price.

 

[baskin]

Yes, just hang it in the air behind the radiator or fan, I'm pretty well convinced that the radiator is fine, but you can at least make a valid decision once you have the numbers.

Your last post gave the best clue though, I would bet that the air is just circulating from the back to the front of the radiator with the hood closed. Try putting a towel across the top radiator support and see if you get the same 30 degree drop. I don't know if you have orchard supply hardware where you're at, but they sell a thick adhesive backed foam that I've tested to 212F

 

[jbuening]

If the motor is at normal temps when you are driving (25mph or over), then the radiator is doing its job. If it is overheating at idle, then either there is not enough air being pulled through the radiator from the fan or as said above you have hot air circulating back in front of the radiator either through the top of the support or through the radiator itself. What kind of cfm did you measure with the flex fan, just out of curiosity? My suggestion would be to get a SPAL fan and mount it with the stock shroud in place.

 

[mustangman1974]

what about installing an oil cooler? Or, should I concentrate on the air flow problem first?

 

[Rusty67]

The oil cooler is a good thing to have and you might want to install it anyways later but right now you should make sure that the cooling system is working properly. Try puting it in neutral and reving it when it starts to heat up and see if the temp falls back off. Are you running any under drive pullies on the water pump/crank ? If you are going to put a heat sensor in then put it as close to the inlet waterneck as possible.

 

[baskin]

The only car I’ve seen that really needed an oil cooler is my TR6, and what’s unique about it is that it has 11.5 to 1 compression, fairly small rod bearings, and a 488 gear ratio. The result was that the oil would get so hot that the oil pressure would drop to zero by time the car was at 190. I attribute the oil heating to both the small bearing surfaces and to the higher ring to cylinder friction caused by the compression. Although this did solve my cooling problems, the oil temperature was well over 300 degrees, so even with the relatively low surface area of the cooler, there was a lot of heat rejection. Heat rejection, given the same cfm of airflow per surface area, is proportional to a multiple of surface area and the difference in temperature between the liquid an the ambient air temperature. So if your oil temperature is reasonable, it probably won’t help.

If you take a look at some of the muscle cars, you’ll find the cars with similar characteristics were provided with oil coolers from the factory. The 428SCJ and Boss 302s, when equipped with a low gear ratio, for instance, were also equipped with the drag pack, which included an oil cooler. So unless your rod /crank crank/block side clearances are way off, you have very high compression, or a very low gear ratio, I doubt that you need an oil cooler. If you’re running conventional oil and your oil pressure isn’t dropping significantly, your oil temperature is probably under 250.

 

[BlueMonster65]

is your idle too lean? and what is your base timing set at? i also had this problem even after i switched to a mega humongass radiator and electric fan. turns out my electric fan was crap so i bought a permacool fingerchopper electric fan and my problem was solved. now it runs too cool. i would use a 180 deg highflow t-stat, i don' think you need a high volume water pump, the miloden one i have is actually worse than the oem pepboys special i had on the car. 210 is hot but not too bad, also check your coolant mix, try running just straight water and a corrosion restistance additive if your are not subjected to freezing temps. water is a better conductor of heat than ethelyne glycol.

 

[mustangman1974]

New Radiator

After weeks of messing I just stepped up to a Fluidyne drop in radiator. Its a 3 core alm. Looks cool and just barely fits. Befor I do the bolt up I did notice that there is no diverter plates in either tank. What keeps the coolant from short tracking in only the cores directly under the inlet???? Was this a wasit of 420 bucks?