temp climbs slowly

[91rcktstang]

My 91 LX is running hot it keeps climbing to about 220 degrees, its got a new radiator , flushed out the entire system put in a 180 degree thermostat still keeps running hot. Ever since it started running hot my tranny started to leak, could these problems be linked . The temperature climbs slowly, it doesnt get hot right away. Anyone have the same problem and could give some advice, this is my first 5.0

[GhettoPop]

see if the fan clutch is still good. with the car off, spin the fan by hand, it should stop spinning on its own. if it continues to spin, replace the fan clutch. is your fan shroud installed? any debris in front of the radiator?

check to see if your water pump is leaking, if it is, replace it.

did you bleed all the air out of the cooling system. park on a hill with the front of the car elevated and open the radiator cap. fill with 50/50 antifreeze water. start engine and run to 180 degrees. u should see the t-stat open, ipper rad hose will become pressurized and fluid will go down a little. fill it to top and let it burp out all air. let car cool and fill if necessary. this is a good check to see if your t-stat is functioning properly.

do you have the front air dam on the vehicle? its the long piece of plastic under the radiator that scrapes the ground all the time. they sometimes break and its necessary to deflect air into the radiator. if its not there, get one.

try some WATER WETTER by redline. i've used it with good results and does actually lower water temps a little.

good luck and post your findings.

[PKRWUD]

All good questions and advice. The only place I'd differ is in your coolant/water mixture. You don't want any more than 20% coolant. The front air dam is very important. It creates a high pressure area in front of the radiator, and a low pressure area in the en gine compartment. This helps force the air through the radiator, as well as assists in drawing the hot air out of the engine compartment. The shroud is critical as well. Does it ever boil over? How have you determined that it's reaching 220 degrees?

[91rcktstang]

Thanks for the advice, fan just spins and spins I think with your help I've pin pointed the problem. Replacing fan and fan clutch in the morning. I have an Auto Meter temp gauge thats how I knew it was getting to 220. Thanks guys Ill keep you posted. By the way Trans leak is fixed.

[GhettoPop]

91rcktstang - sounds like your fan clutch was beat...good luck

PKRWUD- can 20% coolant/80% water protect in winter/summer climate? daily driver in 100F summer days and winters below 0 F? just curious as why you like that mix ratio

[91rcktstang]

The fan and fan shroud were the problem. The Fan shroud was not secured on the bottom of the radiator, fan clutch was toasted. A friend suggested I try a flex fan, so I did, the car doesnt get above 195 degrees, Problem solved. I also have heard flex fans seem to drain horsepower, I dont feel a difference. Anyone have any experience with flex fans.

[GhettoPop]

so u installed a flex fan and took out the old stock fan & clutch altogether? well, flex fans are supposed to flatten out (flex) at high rpm to create less drag. i dont think you will see and surely will not feel any HP difference switching over from the stock setup to a flex fan

glad to see u solved your problem

[PKRWUD]

Originally Posted by GhettoPop

PKRWUD- can 20% coolant/80% water protect in winter/summer climate? daily driver in 100F summer days and winters below 0 F? just curious as why you like that mix ratio

Didn't mean to take so long to get back to you! lol. Sorry.

It depends on where you live. If you are in an area that sees temps in the teens for 8 or more hours in a row, you would want to make it a 30/70 mixture (coolant/water).

As far as summer conditions, coolant actually makes your engine run hotter. Your engine will run the coolest with 100% water, but I still recommend 10-20% coolant in the mix to help keep the water pump lubricated, and to condition the insides of your hoses.

BTW, save your old coolant! It has rubber conditioners in it, and works awesome on your tires! If you're into the glazed donut look, stick with armor-all, but for clean looking tires, use old coolant!

[grey88gt]

Not trying to start an argument here, just curious. How does the coolant cause the engine to run hotter? If you run str8 water your boiling point is at 212 deg. There for any engine temp above 212 deg your water is turning into steam and there fore your engine is now reallly overheating, because your water pump cant pump steam. If you have antifreeze you raise the boiling point of water. Iam looking at a generic brand of antifreeze here . It says 40% mix will give you a -10 protection and raise the boiling point to 259 deg. (i am sure diffrent brands will have diffrent figures) . My car is all stock and has never run hot. About a week ago I blew a hose racing. Filled the car back up with just water to get home and the car run about 25 deg hotter. Put new hoses on filled back up with 50% mix and it run the same temp it always has. Any way just my to cents and it gets dang hot here 100+ sometimes and 90% plus humidity. Buy the way if youll drill a 1/8 hole in the outer part of the thermostat itll help vent the air out of the system when filling with coolant.

[PKRWUD]

A 50/50 mix in the radiator is WAY too much coolant! Especially in warm climates. You will rarely ever require more than 30% coolant/anti-freeze, and even then, only if you live within the Arctic Circle. 20% would be more practical. 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 8000+ 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!

THERMAL PROPERTIES
Water has amazingly superior heat transfer properties compared to virtually any other liquid cooling medium - far superior to glycol-based coolants. Water has almost 2.5 times greater thermal conductivity compared to glycol coolants. Mixtures of glycol and water have nearly proportional improvement due to the addition of water. Most heat is transferred in a cooling system by convection from hot metal to a cooler liquid as in the engine block or from a hot liquid to cooler metal surfaces, as in the radiator. The convection coefficient of liquids in a tube is a complicated relationship between the thermal conductivity, viscosity of the liquid, and the tube diameter which determines the amount of turbulent flow. Since 50/50 glycol solution has about 4 times the viscosity and only 70% of the thermal conductivity of water, the thermal convection coefficient for a 50/50 glycol solution is approximately 50% of the coefficient for water. Water in the cooling system is capable of transferring twice as much heat out of the same system as compared to a 50/50 glycol coolant and water solution. In order for a 50/50 glycol mixture to reject as much heat as water (amount of heat rejected is independent of the coolant), the temperature differentials at the heat transfer surface must be twice as great, which means higher cylinder head temperatures.

COOLANT EFFECTS ON PERFORMANCE
Under moderate load conditions, each percent glycol raises cylinder head temperatures by 1°F. 50% glycol raises head temperatures by 45°F. This increase in temperature will raise the octane required for trace knock levels by typically 3.5 octane numbers. A car equipped with a knock sensor will retard the timing to compensate for the increase in octane requirement by approximately 5°, which will reduce the maximum brake torque by about 2.1%. Racing vehicles not equipped with knock sensors can advance timing for increased torque.

For maximum temperature reductions use the most water and the least antifreeze possible to prevent freezing in your climate.

Take care,
~Chris

[grey88gt]

Antifreeze 101 LOL. Great post. Thanks Chris! Iam gona try what you say here. I honestly didnt know the the heat transfer thru the coolant was less effective. Ive never had a problem with overheating with any thing Ive drove. But I flush them once a year or every 15,000 miles. It gets down to 0 here sometimes in the winter so Ill just start flushing and going back to antifreeze in the fall when things start cooling off. I read in sevral other places of pepole using soap as a lubricant with str8 water. What do you think about that?