Wierd Cooling Issues- never seen this before- help?

GNN60GT500

Founding Member
Ive been around old Mustangs- never seen anything like this before-

looking for help-

I picked up a little 65 coupe to mess with because I got it cheap-

Its a 289- 10:1 compression, mild cam, head work, roller rockers, 5 speed car

Cooling system-

Im running a 180 thermostat, stock radiator, just added replaced old coolant with new coolant, running 100% antifreeze

The problem-

OK, if it overheats while standing still- needs more fan

If it overheats on the freeway, fluid needs to slow right?

My car-

It runs at 180 for 30-35 minutes of driving the creeps up to 210-

Once at 210, it stays at 210- regardless of whether Im on the freeway, in traffic, where ever-

Can anyone tell me any possible good reason it would go up to 210 after driving that long? I know its not really bad for it, but I dont understand :bang:
 
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iskwezm

10 Year Member
May 24, 2005
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mine used to always do that, once it got hot,forget it.check the lower hose, see if it isnt collapsing, or the radiator might be plugged and only under a load(driving) gets hotter.
 
Jan 17, 2004
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100% anti freeze will hold heat try lowering it to 50/50. But then again I don;t think there is one solution for hot runing mustangs.
 

yeloxr7

Member
Apr 18, 2005
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Is there a fan shroud on the car, with the fan about halfway into the shroud? This made a BIG difference in the cooling on my car.
 

GNN60GT500

Founding Member
Im sorry, I should have included that information as well, there is a shroud, and the fan is about halfway into the shroud-

just wierd- Ive had Mustangs that got hot right away when at idle, hot right away on the freeway- but never one like this-

what is really wierd is the fact it stops at 210- I would think it would keep getting hotter if there was a real issue- oh well-
 

reenmachine

Active Member
Jun 27, 2004
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Why are you running 100% antifreeze? Do you live above the arctic circle? Drain half of that antifreeze and replace with distilled water and toss in some Redline Water Wetter while you're at it.

I assume that since you know the actual temperature there's some sort of aftermarket gauge on there. Is it any good?
 

GNN60GT500

Founding Member
I am running an AutoMeter temperature guage on it-

I will admit, I am running 100% antifreeze because I was working on the cooling system/ rebuilt the carb/doing a general tune up, thought I had more distilled water, but only had antifreeze, and I didnt want to get cleaned up so I could run out and get some, start my car, find a leak or find something needed tweaking and get dirty again-

Basically I was being impatient and lazy- and I didnt want to drive any of my other cars while I was dirty- but hey at least I guess I can admit it- LOL

I would have just cleaned up and finished it the next day, but just had a daughter a month ago, promised the wife I would only wrench one day a week at most, and I didnt want to wait another week either-

I am going to replace half the antifreeze with distilled water tomorrow so Ill let you guys know what the effect was-

This is the first time I have ever ran 100% antifreeze in a car in my life, so Im starting to think that is the problem-
 

Tim65GT

Active Member
Feb 24, 2004
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Drain half of that antifreeze and replace with distilled water and toss in some Redline Water Wetter while you're at it.
I read recently that distilled water isn't what you want to put in your cooling system. Something about ions or lack of ions causing corrosion.

The article said bottled water would be better than tap water, but doen't use distilled water.

I think it was a cooling system article in Car Craft last month.
 

ratio411

Founding Member
Apr 21, 2002
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The article said bottled water would be better than tap water...
Bottled water is straight out of the tap at the bottling plant.

Sounds like the rad is struggling.
If the 50-50 doesn't do it, flush the rad, or look at a 3 row.
Also, put a spring in the lower hose.
I have had that hose suck shut many times. Gotta put a spring.
Wouldn't hurt to use a 160 stat. Your car won't run that low, just start cooling sooner.
Check the rad cap. You need to hold pressure to cool. If the cap is weak, you won't keep enough pressure. More pressure the better, but if you boost the PSI of the rad cap, you could possibly expose a weak part of the remaining system... so be warned not to go higher than you feel safe with or at least pressure test the system.
 

rbohm

SN Certified Technician
Apr 12, 2002
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first if you dont have a shroud get one. second if you still have the stock type 2 row radiator, dump it for a 3 row radiator. the 2 row rad struggles to keep a stock 289 cool in the winter(ok the southern AZ winter). third make sure your ignitino timing is in the 10-14 degree range, and that you are not getting detonation, audible or otherwise(yes there is such a thing as inaudible detonation). one more thing, put a decent exhaust system on that car. you need hipo exhaust manifolds and dual exhaust at least. tri-y or a good 4-1 header is better. i prfer the tri-y's. run 2 1/4" pipe out the back with a proper muffler, i thin flowmasters are too loud, i prefer a good turbo muffler.
 

jlangholzj

Mustang Master
Oct 23, 2006
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first of all, many people have the misconception that the more antifreze, the better it heats and cools. WRONG! there's a chemical reaction that takes place between the water and coolant. probally has to do with the whole distilled water thing(pure water no ions) although a 60-40 may handle more exteme conditions, you HAVE to have water in order for it to be effective.

my 289 heats up tto about 1/2 way on the temp gauge right away then stops.
 

Tim65GT

Active Member
Feb 24, 2004
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I re-read the Car Craft article (July issue). They say the distilled water has a lack of ions, so when the process pulls ions from the aluminum causing electrolysis. (An issue if you have aluminum heads or radiator) They did say bottled water or tap water has the ions, but with a 50/50 mix of distilled water/coolant, the ions would be provided by the coolant.

100% water is best for heat transfer, but coolant provides anti-corrosive additives, raises the boiling point and lowers the freezing level.
 

2nd Mustang

Founding Member
Feb 24, 2002
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How many rows in the present radiator? If it is a one row or two row, I can understand the higher temperatures. Many newer cars only had one row radiators and ran hotter. My old Camaro with a V6 had a one row and constantly ran 210 to 240 degrees with no ill effects.
 

ratio411

Founding Member
Apr 21, 2002
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How many rows in the present radiator? If it is a one row or two row, I can understand the higher temperatures. Many newer cars only had one row radiators and ran hotter. My old Camaro with a V6 had a one row and constantly ran 210 to 240 degrees with no ill effects.
New cars are designed to run hotter though.
EPA thing to burn off more emissions.

Our older engines are not supposed to be that hot.
Not good for longevity or performance.

I know 240 won't necessarily hurt an engine, but it ain't good for the nerves either.
 
New cars are designed to run hotter though.
EPA thing to burn off more emissions.

Our older engines are not supposed to be that hot.
Not good for longevity or performance.

I know 240 won't necessarily hurt an engine, but it ain't good for the nerves either.
A good rule of thumb on water and oil temp.

If below 240 degrees you are OK, Above 240 for extended period of times, she is in trouble.

HistoricMustang
 

rbohm

SN Certified Technician
Apr 12, 2002
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A good rule of thumb on water and oil temp.

If below 240 degrees you are OK, Above 240 for extended period of times, she is in trouble.

HistoricMustang
i would add one thing to that, if you are running 240 for some time, and the temp suddenly starts dropping, shut that motor down as you have just run out of coolant and are ready to burn up that motor.
 

HookandLadder

Founding Member
Feb 17, 2001
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St Louis
Something simple............is the thermostat facing the correct way? Don't laugh...I've seen more of these then I care to remember. The bullet part goes into the engine with the point pointing up or at the radiator.