overheating issue

[99sierra4x4]

dont know what to tell ya, i have a cam, and headers, and e-fans, i run mine all day long, in traffic, it was like 96 out the other day, and never even went past the normal operating temp. i would definately check to see what your coolant level is like, maybe try flushing the system with a hose.

I have to work on my heater core, its getting down to the 50's at night and im going to need heat when the snow hits.

[GasGuzzler]

The crank is what drives everything else...

[DUALLS]

Check the thermostat.They sometimes hang up.If there is a shiny spot on the inner pole replace it.

[leochevy2001]

well i checked my fluid level and it was a little low.
i wouldn't think that being less that a cup low would make it start overheating.
since i filled it up i haven't seen the temps go up.

The crank is what drives everything else...

correct but by putting a smaller crank pulley doesn't that speed up the other pullies?
maybe i'm not getting the science behind the UD pulley.
can you explain to me how the UD pulley works? (very serious)
i'm here at work asking a co-worker and both of us are a little stumped. LOL

[rutroe]

Think of it this way...if two cars are going around the same corner, the one on the outside has to travel a little faster to stay in the same relative position as the other car. If you increase the size (radius) of the corner, the outside car has to travel even faster to keep up. On a UD pulley, you are effectively decreasing the "size of the corner"...since the outside diameter of the pulley has to travel the same speed as the inside diameter, making the pulley smaller effectively reduces the "outside velocity". That's why UD pulleys are popular...you don't use as much energy/hp turning them.

[leochevy2001]

so the rotating speed of the crank is constant?
but the speed of the pulley is changed....correct?
am i getting warm or i am cold? lol

[rutroe]

The crank speed will obviously change with the speed of the engine, but the crank pulley speed will also change appropriately. Regardless if it's spinning at 1 rpm or 6000, the outside edge of a smaller crank pulley will travel slower than the outside edge of a larger crank pulley. Since this is where the belt travels, the belt will travel slower around a smaller crank pulley than a larger one. Here's a link to some good info on underdrive pulleys: Underdrive pulleys - Wikipedia, the free encyclopedia

[leochevy2001]

cool thanks for the link!

[567234ta]

in the past when i had problems like that i would turn my heater on high/hot to help remove any heat from the engine. not pleasant in 100F weather but if the air coming out of my heat was not burning hot i knew the coolant was really low.

i would say get it hot like that again and pop the hood to see if the fan is running fast. if you get elec fans and have an overide switch to get both fans on high it would probably get rid of the issue.

but i would also change the thermostat because it sounds like it wasnt fully opening. full flush and new thermo cant hurt.

[GasGuzzler]

When the DRIVE gear or pulley is decreased in size, everything it runs will slow down. If the DRIVE gear or pulley is increased in size, everything it drives will speed up.

If a DRIVEN item gets a larger pulley, it (and only it) will slow. If a DRIVEN item gets a smaller pulley it (and only it) will speed up.