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Bad Water Pump on 94 LT-1

willmike

Member
Joined
Apr 4, 2003
Messages
11
Location
Charleston, SC
Corvette
1994 Red Coupe
Before I try to replace the water pump myself, could I get some input as to how hard this is? Has anyone had serious problems with pulling one off, putting one one? Any help would be greatly appreciated.

Thanks,


Mike W.
 

Bobsvette

Well-known member
Joined
May 14, 2006
Messages
204
Location
Enfield, ct
Corvette
2019 Torch Red Grand Sport
Look for advice in the Lt-4 forum. before I bought my c-4 the water pump had to be replaced and from what I understand that if a dealership does it you get a warranty for the pump and also the opti-spark under the pump. Big buck's to replace. Bobsvette
 

John Robinson

Gone but not forgotten
Joined
May 3, 2005
Messages
1,555
Location
Muncie, Indiana
Corvette
1993 Polo Green Coupe
What do call hard

If you are at all mechanically inclined it should not be much of a problem. For me on a scale of 1 to 5 I would rate it a 2.5. You did not say how many miles are on the car but if you are thinking about replaceing plugs and wires in the next year now is the time to do it. With the water pump off the opti is much more accessible. Take a good look at the opti if it shows signs of having been wet from the water pump you may want to inspect it before you bury it with the water pump:confused
 

MARKSC4

Well-known member
Joined
Jul 2, 2003
Messages
115
Location
North Canton, Ohio
Corvette
1996 Polo Green Coupe
It's not too bad. Take your time. Worst part for me was the lower bolt on the driver's side. There are those who say you can get to it without pulling the power steering pump pulley. They would have to prove this to me. It is much easier to borrow the puller from Autozone and make it easy on yourself.

The most time consuming part was scraping off the old gaskets from the block. The surfaces are hard to reach and hard to see. I used gasket remover spray and a razor blade being very careful not to scratch or gouge the surfaces. Installed new hoses and serp belt at the same time.

It took several starts and warm ups to completely bleed the air from the system. There is a bleeder on the thermostat neck.

I got the water pump from Summit racing (GM Performance Part). I think it was $189. You can see from the pic it had been seeping off and on for a while. Bottom view shown. Replaced it at 31000 miles. Let us know how it goes and good luck to you.

 

pns0ccc

Active member
Joined
Dec 9, 2002
Messages
41
Location
Bradenton, Fla.
Corvette
1996 Triple Black
I've just completed replacing my 96-LT1 Water pump yesterday. While there may be some differences between years here are a few helpful hints I learned:
1. When removing the knock sensors (11 mm for metal shield and 5/8" sockets for sensor) have a bucket ready to catch the fluid and be careful not to receive a coolant shower. When reinstalling sensor lightly coat the threads with Red RTV and tighten to 8 N.m or 70 in lbs.
2. I had to remove the belt tensioner to gain access to the 9/16" bolt used in retaining the water pump on the drivers side. You will find this bolt the most difficult if your equipment is the same as mine. A short 9/16 socket with swivel and stub extension worked for me.
3. MARKSC4 is correct about the gasket removal process, I used a CHISEL gasket removal spray with a brand new gasket scraper to remove the old gasket. Also lightly sanded and honed the metal surface to my satisfaction. Used Electra-clean to remove insulating layer of grease, oil, coolant and dirt from front of engine casing accumlated from 92 K miles of use.
4. Preposition the new water pump in place to check for alignment to the coupling and spline shaft. Rotate the shaft so the pump slides into the coupling easily. Now pull the pump back far enough to position the gaskets (I used permatex on both sides of new gaskets) onto the pump surface, placed the four retaining 9/16" bolts through pump and gaskets and pushed everything forward just till the alignment pins made contact I then added the two outside bolts and started threading all six bolts, this helped with keeping the gaskets positioned properly.
5. Finally I torqued the bolts to 41 N.m or 30 lb ft according to the manual (three times).
6. After completing the reassembly and flushing the system twice the whole process required 5 hours of my time which is not bad. Definitely replace the coil and sparkplug wires if needed at this time since the opti is exposed and routing the wires would be easier.
PS. My operating temperature decreased to 185F-190F from 205F-210F and of course no seepage at weep-hole from the new pump. Take your time, be careful and good luck.
 

MARKSC4

Well-known member
Joined
Jul 2, 2003
Messages
115
Location
North Canton, Ohio
Corvette
1996 Polo Green Coupe
I also used some gasket adhesive, a very thin layer, on both sides of the gaskets. Then you have to very carefully fish the water pump into position past the air conditioning tubing. My brother manned the torque wrench and did what I would not have thought of: He first torqued all six bolts to 20 ft/lb then to 25 then finally all to 30 ft/lb so as not to cause any uneven pressure an possible warping of the aluminum.
 

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