Well, it looks like it might be summer around here, and its got pretty hot today and so did my truck! I sat in traffic at a dead stop for about 30min with the AC on and I looked down and my temp gauge was up pretty high, a bit later my check engine light came on. i shut off the ac and finally got on the freeway and it went right back down to normal. Now, i do have those under drive pulleys, but i think my fan clutch was shot, so i went and got a new one ($110 for the dumb thing!) and also my fan shroud had been cut on the top by someone else for who knows what, so i fixed it with some sheet aluminum, it actually looks pretty trick. I will give it a try and if it doesnt fix it, im going to have to start looking at other things, like removing the underdrive pulleys. what do you guys thing?

 

The A/C puts a huge load on the cooling system and idling in traffic make it worse. Fixing the fan shroud should help. I would also change your coolant with a proper 50/50 mix if it hasn't been done in awhile. There are also great products like "water wetter" made by redline that lower coolant temps.

-Jon

 

I agree with everything Jon said, except the coolant mixture. Coolant actually retains heat, and will cause the engine to run hotter. The name "coolant" is really very misleading. 100% water will run the coolest, but the coolant does actually serve a few other purposes, so adding 10% - 20% coolant is a good idea, but no more than that. In the winter months, depending on where you live, you're going to want to add a little more.

Take care,
~Chris

 

A bottle of Water Wetter by Redline will help.

 

Chris is right, more water will make it run cooler, but the truck should be able to run cool enough on 50/50. Actually i mix mine about 70/40, water/coolant, and it's good for summer and subzero winters.

-Jon

 

Never knew "coolant" runs warmer than water, guess ya learn something new every day (it makes sense though)
I run straight 100% coolant and a 160 thermostat and I live bout as far south as you can get, its already in the 90's here. I also pull a trailer and tractor with my rig and have never noticed the needle even move when idleing until the day I put underdrive pulleys on and even then it was almost nothing.
I think the cooling systems on our trucks are so over kill the difference between water and coolant or any mix in between is nominal at best.
The one time mine started running about 10 deg warmer than usual on a daily basis and i knew the pump was not bad I installed and used a radiator flush kit, man you should a seen the crap that came outta there. After the flush I filled it back up with antifreeze and the temp went right back to where it always runs.

 

Coolant serves five purposes, none of which keeps the engine cooler. It:
1) Acts as a lubricant for the water pump.
2) Helps protect the hoses from the inside (BTW, save your used coolant for wiping down your tires! It will restore the "new tire" look, rather than the "glazed donut" look you get with aftermarket tire dressings).
3) Helps reduce the electrolysis that naturally occurs in cooling systems that deteriorates metal.
4) Lowers the freezing point of the cooling system mixture
5) Raises the boiling point of the cooling system mixture.
This last one is the most deceptive. A cooling system in proper working order is a sealed system. That means that no outside air can get in, and as the temp rises, the system becomes pressurized. Pressure, combined with no added air, will keep the system from boiling under normal circumstances. By raising the boiling point, coolant actually raises the cooling mixture temp. The info on the sides of the coolant containers brag about being able to reach 260 degrees before boiling over, but guess what: DAMAGE CAN OCCUR AT OR BELOW 260 DEGREES!!! You want it to boil over before it gets that hot! That way you will stop driving, and let the system cool down. Coolant also retains heat, which makes it harder for the cooling system to dissipate the heat, like it's supposed to. Here in California, I never use more than 10% coolant, even when I go to the snow in the mountains. I worked for Bill Elliott in 1998, and was shocked to discover that those cars, with their 900 horsepower engines that drove for 500 miles straight, averaging 7000+ rpms, ran with 100% water in the cooling system. The only thing they use coolant for in NASCAR is to measure the cc's of the combustion chambers in their heads. Because they don't use coolant, they have to use a higher pressure rated radiator cap (28 - 30 psi), but since everything is new, it can easily handle that much pressure. Don't believe the hype: coolant actually makes your engine run hotter!

FYI: That is so wrong, on so many levels. Running 100% coolant isn't healthy. It will give you false temp readings, and will encourage deposits to form and collect in the block and the radiator. And a 160 degree t-stat creates another thread full of other problems. If you're happy doing it that way, I'm not about to tell you to change, but I would never recommend that to one of my customers or one of my friends.

Take care,
~Chris

 

Hey, do they use distilled water in those racecars or do they put in some kind of anticorrosion additive? Or do they not worry about corrosion because they replace most of the engine and cooling system after every race? I have friends with expensive cars that sit in storage most of the time and i always recommend that they use a 50/50 mix of coolant and distilled water to keep minerals and corrosion from building up in the system.

-Jon

 

im running about 60/40 water/coolant and I think fixing the fan shroud and the new fan clutch fixed it, but ive been in the mountains all weekend and it was only between 75 and 80 degrees up there. i will see tomorrow when im downtown in traffic. I run water wetter and premixed coolant in my dirt bike, it used to boil over ocasionaly without the water wetter.

 

I work in a power plant where it is my business to boil water, and I can assure that what PKRWUD says is correct.

1. Glycol, the main component of anti-freeze, does not transfer heat very well, it is the water that keeps your engine cool by transferring heat to the radiator.

2. Pressure in the cooling system does more to raise the boiling point of the water than the Glycol does. Pressure is direcly proportional to boiling point, thus a 15lb cap will only allow pure water to reach 250F, it physically cannot get any hotter at that pressure no matter how much heat is applied until its all converted to steam. 250F is already enough heat to break down your oil and lose the oil wedge in your bearings and cause your pistons to swell and score the cylinder walls. (300F will melt the babbit in your bearings) Why would you want to raise the boiling point anymore? Anti-freeze is to prevent freezing and to treat the cooling water to lubricate the pump seals and prevent corrosion and deposits (and the other things PKRWUD mentioned). Anti-boil is vendor hype to ensure you buy thier product all year long. If the manufacturer wanted to raise the boiling point, all they would have to do is raise the system pressure. (as PKRWUD indicated they do on race cars, where I'm sure they use synthetic oils or special metals in the engine that can handle the extra heat)

3. Just because you can "get away" with 100% anti-freeze, doesn't mean you're not doing long term damage. Anti-feeze also contains additives to treat the water to bind the suspended solids and control the pH. These chemicals in too high concentrations (ie. 100% anti-freeze) will plate out in the hottest parts of your engine and eventually restrict or plug the water passages.

Ford4ever
How do you run a 70/40 mixture? Wouldn't that overflow the radiator?

 

Ok so i'm a mechanic, not a mathematician.

Actually pure water under 15lbs of pressure boils at 257 degrees, the BP goes up abot 3 degrees for every pound.

Another thing to remember is that antifreeze needs to be mixed with water even to prevent freezing. Pure antifreeze freezes at 0 degrees whereas a 50% mix freezes down around -30.

-Jon

 

We used distilled water.

You guys just helped me to understand something, too! Kinda.

We usually used a 30 pound radiator cap on Bills cooling system. We taped over the openings on the front clip (for less drag) during qualifying, blocking the radiator from getting any direct outside air. The bypass valve we had that led to the overflow tube on the "passenger" side was rated to open at 265 degrees. I always thought that was simply a back-up incase the cap was defective, but using the formula you both mentioned, that 30 pound cap would have allowed the system to reach over 300 degrees. I guess that explains why the cap never blew.

I wish I was still in touch with those guys, because I'd like to know the physics of this now. What was the benefit of running a 30 pound cap? I guess I just assumed a 30 pound cap would release the water around 265 degrees.

I hate it when something like this comes up. There are so many questions I've come up with since then. I had so much information available to me, and I learned what I could, but damn, I could have learned so much more.

 

Combustion Engineering Properties of Saturated and Superheated Steam:

14.7 PSIA atmospheric pressure
Plus
15.0 PSIG
Equals
29.7 PSI Ablolute
Rounded up to 30PSIA = 250.54F

30PSIG would equal approx 274F

Of course this is at sea level and pure water

 

PKRWUD, thanks for the info, I knew antifreeze was a lubricant for the pump, prevented corrosion and I knew that it raised the boiling point just like pressurizing the system with the proper cap, didn't understand why coolant was warmer though. After reading the posts I think this weekend I will drain out a bunch of coolant and replace with water since that is the general opinion.

1 point: my truck has 300k on it and the cooling system was never worked on until a few months ago when the fan clutch went out and the wobbling clutch wore out the water pump bearings. The radiator is original and has never been cleaned. Seems like if 100% coolant is dangerous to a system 300k miles would have showed it.

Thanks again for the info

 

I agree completely. You have defied the laws of physics and probability. This might be a good time for you to go to Vegas, or play Lotto. Really. I can't explain why your luck has been so good, but I can tell you that your results are extremely unusual.

Maybe I should hang out with you! I could use that kind of luck!