Frustrating overheating issue in 1993 Z28
12-31-2015, 07:46 AM
#46
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Join Date: Jul 2002
Location: Kissimmee, Fl, USA
Posts: 1,942
Re: Frustrating overheating issue in 1993 Z28
The one thing I never checked in all of this was to see if the heat was blowing hot when the car was overheating. I'm wondering if I should just cut my losses and sell the car instead of putting another $500 into it, and the problem still remain. I was somewhat confident that the head gaskets were okay because the combustion test fluid stayed blue as it was boiling shortly before it was contaminated with coolant, and being able to turn the impeller on the water pump by hand led me to believe the water pump was shot. Even my friend who worked on the car for a few hours the other day kept swearing the water pump had to be bad when he was constantly bleeding and topping off the system. When the car sat for almost one week without being started, the coolant level never dropped in the radiator. Right now, I'm torn as to what to do.
I found the water pump and the cap and rotor on Rock Auto for $437. Summit Racing has the coupler for $50.
I found the water pump and the cap and rotor on Rock Auto for $437. Summit Racing has the coupler for $50.
Before you buy anything, inspect what you have in front of you. You said that the water pump impeller turned when it was on the car. Does the drive spline on the engine turn at all with the engine off? It's cam drive and should not turn in this situation.,if it does you'll have to pull the intake and timing cover to replace the drive. If it doesn't you're probably good to proceed. Look at the water pump itself...does the spline drive look good? Can you hold the spline with vice grips and turn the impeller? If so, you found the problem...the impeller is loose on the spline. If it doesn't, keep looking until you find the problem. Once found you can buy the parts with little worry.
If you decide to sell it, you'll get more money if it runs so this $500 is probably worth spending..IMHO .
12-31-2015, 08:20 AM
#47
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Join Date: Dec 2001
Location: Durahm, NC
Posts: 64
Re: Frustrating overheating issue in 1993 Z28
I cannot turn the drive spline on the engine when the car isn't running, which is a good sign. I'll need to check the spline on the water pump today.
I've decided to fix it because, like you said, I can get more money out of a running car than one that doesn't run.
I've decided to fix it because, like you said, I can get more money out of a running car than one that doesn't run.
01-27-2016, 02:57 PM
#48
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Join Date: Dec 2001
Location: Durahm, NC
Posts: 64
Re: Frustrating overheating issue in 1993 Z28
Sorry it's been so long without a response, but my water pump coupler was on back-order with Summit. I eventually canceled the order and bought one off ebay from a Chevy dealership that shipped it immediately.
I changed the Opti cap and rotor, using the red Loctite tip for the rotor screws, and I installed the new Opti cap and rotor, water pump coupler, and water pump. After letting the car sit for one full day to let the gasket dressing cure, I filled it with coolant today and fired it up. I had a leak from the lower heater hose where it connects to the water pump on the passenger side, but the leak stopped once I tightened the clamp. It took a lot longer for the car to come up to temperature, which was a good sign, and the fans immediately turned on at 180 degrees and stayed running. After driving it three different places and not seeing any movement in the temperature gauge or coolant leaking, I can safely say the car is finally fixed.
Thanks to all of you for your thoughts/ideas/input in helping me solve this very frustrating issue. Replacing the water pump coupler was definitely a good idea once I compared the new one with the one that was on the car. I could barely see the teeth in the coupler that was on the car versus the new one I ordered.
I changed the Opti cap and rotor, using the red Loctite tip for the rotor screws, and I installed the new Opti cap and rotor, water pump coupler, and water pump. After letting the car sit for one full day to let the gasket dressing cure, I filled it with coolant today and fired it up. I had a leak from the lower heater hose where it connects to the water pump on the passenger side, but the leak stopped once I tightened the clamp. It took a lot longer for the car to come up to temperature, which was a good sign, and the fans immediately turned on at 180 degrees and stayed running. After driving it three different places and not seeing any movement in the temperature gauge or coolant leaking, I can safely say the car is finally fixed.
Thanks to all of you for your thoughts/ideas/input in helping me solve this very frustrating issue. Replacing the water pump coupler was definitely a good idea once I compared the new one with the one that was on the car. I could barely see the teeth in the coupler that was on the car versus the new one I ordered.
01-27-2016, 11:22 PM
#49
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Join Date: Oct 2007
Posts: 1,174
Re: Frustrating overheating issue in 1993 Z28
Great news.I would check the coolant level tomorrow by removing the radiator cap.When I flushed my system it took a week of checking under the cap and checking the bleed screw at the same time(when the engine is cold) as I had to add a little each day till I new it was really full.I know the overflow tank is suppose to do this but I didn't trust it and everything is good for now.My02.Hope this helps.
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