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Old Mar 22, 2013 | 09:43 PM
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Default new water pump problem

I just put a new water pump on my 99 and have run into a weird problem. I let the car warm up to purge the air from system and it was running a little hot. At idle the car was running ~190* which isnt normal, the car usually runs 178-180.* I took it for a drive and through town it comes down to about 187 and wot it comes down to "normal." Now my thought is that the thermostat isnt fully opening and I know for a fact that this thermostat is good because it was on other water pump, so is it possible that this new water pump is an 04+ water pump that needs the separate housing and thermostat? The part number for water pump is ac delco 252-846, apparently both housings fit just the older style not properly. Thanks in advance.

Another note the lower radiator hose is cool to the touch so I know the thermostat isnt opening (or at least all the way) to circulate the coolant.
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Old Mar 22, 2013 | 10:52 PM
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I did both methods, as soon as I cracked the ones on each head fluid came out and I let it run a few extra seconds just to be sure.
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Old Mar 23, 2013 | 12:47 PM
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Heres a pic of thermostat mounted on new water pump, notice the huge gap there. Im almost certain that this is a new style pump that requires a 2 piece housing and thermostat, which would explain why its not fully opening.

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Old Mar 23, 2013 | 12:50 PM
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I thought the new pumps had the stat and everything in them and the old style was 2 piece. Maybe I am confused as I have changed a couple of them between the 99 and the 02.
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Old Mar 23, 2013 | 06:04 PM
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Water pumps used to come with the thermostat installed... Did that change?
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Old Mar 24, 2013 | 10:33 AM
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Originally Posted by TEXHAWK0
Water pumps used to come with the thermostat installed... Did that change?
I guess in my case yes
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Old Mar 24, 2013 | 12:14 PM
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Im not sure if its a new style pump, i bolted my 1 piece housing on and started having weird temp problems (first post). Chevy never changed part numbers or anything so theres no way to tell if its old or new style, I was told this is old style but think someone was blowing sunshine up my a$$.
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Old Mar 24, 2013 | 01:35 PM
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Still don't see a problem here with these numbers, still way below thresshold for fans to come on.
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Old Mar 24, 2013 | 04:18 PM
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Originally Posted by 3boystoys
Still don't see a problem here with these numbers, still way below thresshold for fans to come on.
Cars tuned for a 160 thermostat and would consistently hold 180* no matter what until I intalled this pos water pump, so there is a problem.

Ordered a new housing so hope fully tomorrow I will have a resolution.
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Old Mar 24, 2013 | 04:51 PM
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Originally Posted by mustangracer
Cars tuned for a 160 thermostat and would consistently hold 180* no matter what until I intalled this pos water pump, so there is a problem.

Ordered a new housing so hope fully tomorrow I will have a resolution.
If you order the same pump, expect the same outcome. According to EvilTwin 190 is what you want anyway.
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Old Mar 26, 2013 | 11:10 PM
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Well its what I thought the problem was, water pump is for an 04+. Bought a new housing and 160 thermostat and the car is rock steady 178 cruising.
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