LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

97 Z28 Running hot

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Old Apr 23, 2025 | 01:22 PM
  #1  
weedog's Avatar
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97 Z28 Running hot

Got more problems now this motor has 17 miles on It. Started running hot all at once the gauge went up really fast. Got back to shop pulled everything off and the gear coming from timing chain i can turn easy with my hand. Should I put a electric pump on it or should I pull timing cover to see what's going on. Thanks
Old Apr 23, 2025 | 11:07 PM
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Re: 97 Z28 Running hot

Well, the first thing I’d do is bleed the coolant.

Beyond that, sure, figure out what's going on. Never throw random parts at your problem — diagnose first! Anything else is a great way to waste money.
Old Apr 23, 2025 | 11:42 PM
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Re: 97 Z28 Running hot

Not sure I understand the question. How could you see the gear that drives the water pump, but appear to be indicating you would have to pull the timing cover to fix it?

Are you indicating the water pump drive gear, which normally engages the teeth on the cam gear, is not engaged and is turning freely? Hence, not driving the water pump?
Old May 7, 2025 | 11:57 AM
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Re: 97 Z28 Running hot

Whatever you do, don't buy the summit racing ewp. Mine failed catastrophically last week, after 3 years of seemingly working great. I've seen some people mentioning that their meziere ewp are going on 10+ years without a problem. I'm going to make a post about it after I contact summit and see what they say.
Old May 7, 2025 | 04:11 PM
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Re: 97 Z28 Running hot

Hasn't come back to this site since post #1.
Old Jun 25, 2025 | 01:25 PM
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Re: 97 Z28 Running hot

[QUOTE=Injuneer;7019430]Hasn't come back to this site since post #1.[/ yes, the water pump drive gear that engages the teeth on the cam gear when i pulled the water pump back off I could turn it with my hand. should you be able to turn it with your hand. do you think something is broke in there. Thank Sorry took so long to get back on.
Old Jun 25, 2025 | 08:44 PM
  #7  
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Re: 97 Z28 Running hot

The pump shaft gear, sitting in front of the engine block, is rigidly engaged with the teeth cut into the back of the cam sprocket. Water pump rotates only if the cam sprocket rotates. Something is loose, missing, or broken inside the timing cover.

http://shbox.com/1/engine_front_diagram.jpg
Old Jun 25, 2025 | 09:22 PM
  #8  
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Re: 97 Z28 Running hot

Thanks. is there a easy way to fix it without dropping motor again. I'm going to put a electric water pump back on it.
Old Jun 25, 2025 | 11:43 PM
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Re: 97 Z28 Running hot

Have you reviewed Shoebox's cam swap procedure? It has a section on pulling the timing cover. Tells how to drop pan, rather than drop engine.

4th Gen LT1 F-body Cam Removal
Old Jun 26, 2025 | 08:19 AM
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Re: 97 Z28 Running hot

Was it ever spinning after whatever work you did? Perhaps a cam gear with no w/p drive teeth was used? If you are going to put an electric pump on, then you don't really have to do anything to it. Just leave the non-spinning shaft there (assuming seal is good) and put the e-pump on. If something failed and caused the shaft to stop spinning, then you should consider opening it up and investigating. You could have metal in your oil.
Old Jun 26, 2025 | 12:04 PM
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Re: 97 Z28 Running hot

R&R Speed Shop built the motor nothing but problems with it since I got it back the road I live on and the road it runs in to is about a 6-mile trip. The first 3 trips temp never got above normal. The last trip after about 5-miles the temp gauge went all the way over real fast. I have about 24 miles on the motor since I got it back from Speed Shop. They installed the Opti wrong, and the rear main has a Drip not bad, but I did not pay for a drip. I put another new Opti on it. If drain the oil and there is no metal in it, would it be safe to put an electric water pump on it or should I take the motor back out and see what happen. I'm going to drain the oil later today. But it ran like a dream the first 3 trips. Thanks Again
Old Jun 26, 2025 | 12:31 PM
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Re: 97 Z28 Running hot

Sorry shoebox you ask if it was ever spinning, I don't know the Opti was on it when I got the motor back. Lloyd Elliott done the heads and matched it with a cam but like I said first 3-trips no problem. Thanks
Old Jun 26, 2025 | 04:49 PM
  #13  
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Re: 97 Z28 Running hot

You indicated you “pulled everything off”. Do you mean only the water pump? And you are able to turn the splined pump driveshaft (part #63 in diagram below)?

http://shbox.com/ci/water_pump.jpg

I’d be concerned about the cause of the water pump problem. Is something coming apart behind the timing cover? I can understand that tearing the front of the engine apart is daunting. You need to find a reliable shop the check the multiple issues with the engine. Who knows what is going to show up when you actually start putting miles on it.
Old Jun 26, 2025 | 05:20 PM
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Re: 97 Z28 Running hot

Yes
Old Jun 27, 2025 | 10:34 AM
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Re: 97 Z28 Running hot

I drained the oil, and it has tiny metal sheaving in it and that's a problem. Thanks



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