my mechanic is finishing up the rebuild on my iroc, and he told me that when the car idles for about 10 minutes, it starts to over heat. he thinks it's because of the march crank and alt pulley i put on about 7 months ago. he wants me to give him the stock crank pulley to see if it fixes the problem with the water pump... but im not sure thats where the problem is. i also removed the smog pump when i put the pulleys on, so maybe since i routed the belt differently because of the deleted smog pump, that the water pump isnt turning at the speed it should be turning? i dunno... im lost here... what do you guys think is the real problem that my car is overheating at idle? is my mechanic right about it being the aftermarket crank pulley, or could it just be that i need to get myself a smog pump delete pulley? thanks for all your help guys

 

Did you underdrive the water pump?

 

might be the new engine makes more heat, timing off, a/f mixture off

 

I'd sure try the stock pulleys. They're paid for, and it wouldn't be the first time somebody had trouble because of underdrive pulleys.

 

na, i just have the crank and alt pulley from match. the water pump is brand new... the engine should be making more heat though, i raised the compression to 10:3 to 1. im going to give him the stock pulleys and see if they help some... ill also tell him to drill holes in my 180 stat to help it out a little... i dont think it helps any that it's around 85 degrees out either, and it's only going to get hotter lol

 

You said the pump is new....Did you get a reverse rotation water pump?

 

have no clue... my mechanic is the one who bought the water pump for the rebuild... i would assume he bought the propper type of water pump for the engine. L98's use the standard rotation water pump, correct? thanks guys for all your help on this

 

When you get a chance take a look at the water pump. The easiest way I know of to see if it's a standard rotation pump is to look for 2 threaded accessory mount bosses cast into the right side of the pump. If you have them then it's a standard rotation pump.

Reverse rotation pumps won't have these bosses.

I assume since you have a '90, then you'll need the reverse rotation pump (serpentine belt only).

 

Even easier way to determine (assuming of course factory bracketry hase been used): Do you have a few skinny belts, like 2 or 3? Or one big fat belt (6 rib)?

But yes, i guess using the wrong rotation water pump is bad.

But generally, judging by year, you should have the serpentine pulley setup that requires the reverse rotation.

 

yeah, i have the serpentine setup... someone had told me that l98's use standard rotating water pumps... hopefully my mechanic got the reverse flow water pump or im going to get PISSSSSED thanks for the help guys i wonder if the stock crank pulley will fix everything, or if it's infact the water pump itself

 

If you have the serpentine setup, where the BACK (flat side) of the belt runs over the water pump pulley, then you need a reverse rotation pump.

If you have to buy a water pump, get a Stewart. www.stewartcomponents.com