Water Pump Question

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Mar 25, 2007 | 02:12 PM

Fast Cop

Thread Starter

Melting Slicks

Joined: Feb 2006

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From: Columbia SC

Water Pump Question

One of the winter projects for my car was a new water pump as the old one was weeping. I bought a new AC Delco WP and replaced the old one, at the same time a new ECT sensor. The new WP came with a thermostat already installed.

Prior to the change if the car sat at idel it (like designed) would get to 228 and the fan would come on promptly cooling it down. In traffic would run about 206 - 212. On the open road would run 185 - 190.

Since the WP change (I also did a coolant flush) at idel it will go to 228 and the fan will come on and promptly cool it down. In traffic it will now go to 220 - 228 and fan will come on cooling it down. On the open road it will stay at 201 - 215m but what I have noticed is that as the RPM's go up the temp goes down. If I run it up to about 3,000 rpm the temp will drop to 194, but even on the open road at 75 mph and the rpm's at 2,000 the temp will stay between 201 and 215.

WHAT GIVES. Is it as simple as the new WP is not as efficient as the old one? Am I missing something here?

Also does anyone know of a kit to rebuild the old WP?

Thanks in advance for any and all suggestions.

Mar 25, 2007 | 02:33 PM

bogus

Team Owner

Joined: Aug 2000

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From: San Pedro CA

makes me wonder if someone has installed a lower temp t-stat in the old pump.

Mar 25, 2007 | 03:46 PM

JD'S WHITE 93

Le Mans Master

Joined: Dec 2004

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Sounds like it's operating as it should now. I agree with Bogus. Do t-stats have their temp scribed into them ? If they do you could pull the old t- stat out and look at it. Or you could just swap t- stats.

Mar 25, 2007 | 04:20 PM

MikeC4

Melting Slicks

Joined: Oct 2004

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From: Austin Texas

Quote:

Originally Posted by Fast Cop

Prior to the change On the open road would run 185 - 190.

new WP 75 mph and the rpm's at 2,000 the temp will stay between 201 and 215.

WHAT GIVES. Is it as simple as the new WP is not as efficient as the old one? Am I missing something here?

since the engine is at operating temperature during your comparison tests, it would not matter what range T-stat you have , as these engine temps are high enough for any T-stat to be wide-open. Did you use same type of mix after you flushed, like 50-50 coolant/H2O ratio ? Are you sure you adequately "burped" your system and have proper level in your over-flow resevoir?

Regardless, these temps from your new AC Delco WP do not seem out of range or abnormal to me.....In fact, the 185-190 seems a little low, as the LT1's were designed to run hot!

Last edited by MikeC4; Mar 25, 2007 at 04:23 PM.

Mar 25, 2007 | 10:43 PM

VenkmanP

Safety Car

Joined: Apr 2003

Posts: 3,793

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From: VA

Quote:

Originally Posted by Fast Cop

...at the same time a new ECT sensor.

Is this the sensor for the readout you're giving us numbers from?

Your new readings seem to be the more normal of the two.

Mar 26, 2007 | 06:52 AM

Strick

Race Director

Joined: Feb 2003

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From: Lake Wylie SC

The General designed the LT1/4 to run at the range your new water pump and T-stat are operating at. Why so hot? emissions. Because it runs hot they required a synthetic oil that won't break down at these high temps. My guess is that your new pump assembly has a 195 T-stat in it which is normal. IMHO, the 180 works the best. Now let me clarify that. I run an electric water pump which runs at a constant flow even at idle with the A/C on. I also wired my fans so that I can manually turn them on sooner than 228 which is nice in traffic. With all this said, make sure you clear all the debrie from between your condensor and the radiator and please tell us you didn't mix types of anti freeze. If green stay green, if red/orange stay red /orange.

I see you're from Columbia. Good bunch of Corvette folks down there.

Mar 26, 2007 | 10:13 AM

Fast Cop

Thread Starter

Melting Slicks

Joined: Feb 2006

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From: Columbia SC

Thanks for all the great feedback. I was not too overly worried about the numbers as from what I have read here the LT1 runs hot by design. The was burped, several times to make sure all air was out, and the mix was 50/50 coolant/distilled water. The numbers are from the ECT on the WP as this is the one that goes to the ECM and displays as numbers. It seams that the other sensor always reads about 15 degrees higher.