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Lets talk water pumps, no??

Discussion in 'The Garage' started by greg mgm, Jul 18, 2005.

  1. greg mgm

    greg mgm 1/2 ton status

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    How can you tell if a water pump is pumping enough coolant. I'd like to rule out the w/p as a problem. (Engine gets hot) What applications would need a high flow aftermarket pump?
     
  2. TWISTEDJACK

    TWISTEDJACK 1/2 ton status GMOTM Winner

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    That depends on the motor. Most cooling problems are radiator problems not pump problems. When was the last time your radiator was tanked and rodded?? The other common problem is the fan/shrowd(sp) set up incorrectly.
     
  3. ntsqd

    ntsqd 1/2 ton status

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    Assuming that the radiator is dialed in there are a couple other things I can think of to look at:

    The pump impellor can get corroded and either cavitate or not move enough coolant b/c of the reduced size of the vanes.

    Pump could be over or under driven. Not likely unless someone has changed the pulley size(s), or you've radically changed the operating RPM of the engine.

    High flow t-stats can actually cause over temps in certain combos. They don't slow the speed of the coolant down enough and don't elevate the pressure in the engine high enough. So two things happen, the coolant micro-boils in hot spots, which means that area overheats and the coolant overheats (steam) even though the engine as a whole isn't really overheating. The other thing that can happen with a high flow t-stat is if you have a good pump capable of moving a lot of volume the coolant does not spend enough time in the engine to absorb as much heat as it could. Where this shows up is when there is a LARGE difference in coolant temps from the front to the rear of the engine. Note that a large temp difference isn't indicative of this problem exclusively, there could be other problems.

    Stewart Components used to have, and may still have a really good coolant system tech page.
     
  4. Thunder

    Thunder 3/4 ton status

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    Do you have the right pump for your engine?
    Using the wrong water pump can cause problems. Using a non serpentine belt WP on a serpintine belt engine. Or viceversa will cause overheating. Because the pump is turning the wrong way.
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    And if you subscribe to the theory they present, slowing coolant down reduces cooling, period.

    Advanced cooling system basics I always remember that article because of how it used to be titled. :)

    You get varied answers as to t-stat and under/overcooling. Personally, I ran without a t-stat and the car never warmed up. Others have seen the opposite.
     
  6. greg mgm

    greg mgm 1/2 ton status

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    Thanks for the info, guys. Its a 78 truck 454 with flex a lite elec fans. I put the elec fans on mainly to deal with slow moving traffic (summer heat) 'cause the stock setup wasnt keeping it cool. Now, freeway speeds are causing it to run too hot. (I cant win.) Some of this is posted in another thread, but I didnt want to hijack that thread with the water pump question. To answer the questions--rad was rodded last year. The elec fan shroud may be suspect, and I might try a different shroud/fan, but Id really like to keep elec fans. I tried 3 different brands/types of thermostats. Pulleys are stock size, and pump is 4 years old, and (I f'n hope) was the correct one for a 78, and not turning incorrectly. "ntsqd" you are clearly a scientist (hoo haa) I'll look around for that coolant tech page, thanks again!! Edit- -thanks for the link for the tech page.
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

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    Should be pretty easy to blame fan shroud or not...pull them out (if it's easy enough) and go for a cruise. Put them in the bed if you are really worried that you might have problems.

    I noticed as soon as I was off the gas, (no fan testing) the engine temp declined rapidly. Ambient air temp is going to make a difference on how well/fast the radiator works.

    If the shroud is a big problem, you'll know immediately, as long as you can replicate the conditions similarly: air temp, engine load, vehicle speed.
     

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