COOLING PROBLEM

i take it your running hot at idle... a/c on or off (or over 200* nonetheless?)...
your fan clutch may be on the way out if it happens at idle.

i think a given 3 core vs a similar 2 core is better. for the money, it is tough to beat the 3 core HD units from AZ, Pep, etc (made by Modine and/or GDI)...like 130 bucks. that is the route i will go when the time comes.

BTW, if you are running hot on the highway, that suggests the rad is not doing its job....the 180 you run should be keepin you decently cool....i would really check the fan clutch (based on what you have said so far).
good luck.

Fluidyne and Griffin are 2 very good radiator companies. U/d pullies are not helping your water pump and probably is the reason you are running what you are. 210 btw is not too terribly bad, 220-230 you should start worrying for sure. If you got rid of the u/d for the water pump I bet you'de drop that extra 10 degress and run a healthy 200. Try first draining and thouroughly flushing out your radiator, you'de be surprised what builds up in there. Another route you can go is a high-flow pump that makes the velocity of the coolant move quicker to help disapate heat a little faster. 3 rows are in an equal stance, better than two. The thing you really want to pay attention to though is fins per square inch, the higher the count, the more heat the radiator can get rid of. If you make a jump to 3 row, just make sure it will fit as they tend to be thicker in size. One thing that is for sure however is make sure it is made of aluminum because it gets rid of heat much better than the stock brass/steel (I think that's the second material) does.

1991vert said:

well, i really dont care if the radiator is all bling blingy or what name it has on it...as long as it does it's job. do you think this radiator is any good?

Radiator,79/93 5.0l 3 Row
NOTE: Heavy Duty Mustangs Ford Racing
Heavy duty 3-row radiator with 14 fins per inch keeps your Mustang extra cool. Includes automatic transmission cooler on driver's side (1.75'' x 8'' size). Recommended for all modified vehicles. THIS RADIATOR IS A DIRECT BOLT-IN HIGH PERFORMANCE REPLACEMENT RADIATOR.

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We weren't really referring to it being all bling blingy as you said, but the fact is that not all radiators are created equal. I suggested aluminum not because of looks, but because that metal flat out works better against heat than most other metals. And what brand name you pick has part responsibilty as to it being good or not. Manufacturers implement their own specs into a radiator and those are the reason as to why it works better or worse than others. If you want a no-name brand so to speak but a good one, try one from summit - you defnitely can't beat the price.

1991vert said:

which "fix" would you attempt first? the fan clutch, the waterpump or the radiator?

i thought ford racing were usually good parts, only reason why i suggested that radiator. i need some opinions before i go and waste $$ on something that i might not even need lol

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87GT may have a better idea. i cant tell you; i think it is a judgement call that someone lookin at the car should make.

at idle, two factors really stand out (for me):
1) the pullies (good call, 87GT - i thought about that, and have read that they can compromise idle cooling system performance, but forgot to mention it).

2) the state of your fan clutch. there are tests to do to check one, however they are rather arbitrary. things like spinning the fan on a cold motor (CAR OFF). then warm it up and SHUT IT OFF. then spin it again. it should be a decent amount harder to spin.
some folks like to rev a hot motor to 2.5K RPM, and shut the motor off. watch the fan spin - it should stop spinning pretty darn quick.

if you have the clutch off, look at the thermo-spring on the back of the clutch. if you see silicone leaking around the spring, get a new one. clutches lose a few hundred (or more) rpm a year. just wear and tear.

also, make sure your fan has no cracks on it (for safety and efficiency).


im hoping 87GT has more insight for ya. all i can do is tell a little info i know and let you decide. BTW, first thing i would do is ditch the underdrive pulleys...i know they mess a lot of people's idleing temps up (unless you have done mods to the point where you are idleing at 1K or over, to help compensate).

you can take your rad to a shop and have them check it out for you, for not much money (i have read that, but never done it).
again, comes back to the little things you notice that would take forever to articulate on here.

BTW, if you are prepared to spend 400 beans on a rad alone, i would get the radiator that i or 87gt listed, along with a 3G upgrade and electric fan and controller or new HD clutch (and maybe new fan blade), and a good stat. you could do that for the money you save, and maybe come out ahead, gaining an elec fan and 3G in the process (if you piece it together right). just my thinking.
enough rambling; good luck.

Thanks hissin50. Yeah it really is a judgement call. When there's a cooling problem or any problem for that matter it can be so hard to tell what it really is over the internet. Do yourself a favor and try the cheapest manner, buy the $4 flush and/or a cleaner and see what you can get out of there. I currently have a cooling problem on mine right now. I have flushed about 10 gallons of some rusty as can be water out, have a cleaner in it right now, have replaced the t-stat, and have noticed that the vortex in the radiator with the engine running is very weak which leads me to believe that after 270k miles, the water pump has simply lost a lot of efficiency and/or there is still a blockage in coolant flow somewhere. You can take my problem for instance, a lot of times it can be much more than just one thing. All I can say is that on a given day, the car is starting to hang around 1/2 scale which tells me i'm slowly getting it down from where it ran about 240-260 at one time

I like the philosphy "keep it simple stupid". It's pretty straight forward, just check and do the easiest things first.

If the water pump isn't leaking, then there's probably no gain that will come from replacing it. They rarely simply become less efficient at moving water around.

If it's the original radiator - it's likely in pretty questionable shape on the inside - worth checking out.

Like Hissin - I suspect the problem has to do with a combination of your underdrives - which slow down both pump and fan - and an old radiator that's not as efficient as it once was.

Michael Yount said:

If the water pump isn't leaking, then there's probably no gain that will come from replacing it. They rarely simply become less efficient at moving water around.

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There is one except to that. I use to have one of those flex water hoses at the bottom of my radiator. Well when it got old the metal rings inside of it moved to my water pump and messed up the blades. I wasn't getting any leaks but my car would heat up at idle and cool back down when I drive. Beware of those hoses.

1991vert said:

-legendary, do they make a specific radiator for 87-93 mustangs or is it a universal radiator? if it's universal, what size is it?

i already have a 3g alternator, but a massive stereo system. i think it's time for that to go. out with the old, in with the electric fan. i hate spending money

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I don't think summit makes a radiator just for the stang. The one in the link (from the other thread) is the one I have. It's a 2 core.

I too have a massive sound system (1000 watts) and I run an electric fan on the 3g. It works just fine.

Legendary said:

I don't think summit makes a radiator just for the stang. The one in the link (from the other thread) is the one I have. It's a 2 core.

I too have a massive sound system (1000 watts) and I run an electric fan on the 3g. It works just fine.

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No they make a universal fit one, although summit does sell a direct replacement for about $250.

Your stock radiator is likely more than able to meet cooling demands if it's working correctly. Most local shops will do a cleaning/rodding for $50 or so. That would free up money to address the underdrives/fan issues. The only way to speed the pump back up is with different size pulley(s); however, the fan issue can be addressed with an electric fan -- properly sized it'll cool as well or better than a mechanical, and using MUCH less HP. However, your charging system has to be up to the task - and there's where your underdrives may get in the way again. Or if it's the stock 65A, you'll likely need an upgrade to power the fan. Lots of choices.

Most fan clutches work with a fluid inside that is temperature sensitive. Below a certain temp (slightly below the t'stat temp) the fluid allows the fan to freewheel. When the car is running cooler, you don't need the fan - makes sense. Above a certain temperature, the fluid in the clutch "locks up" causing the fan to be driven. So when the engine's cold, you should be able to spin the fan with your hand. Drive it til it's warmed completely up and stop it. You shouldn't be able to spin it with your hand then. If that's the case, then the clutch is operating properly.