Texas CE

Well after 68K miles the water pump has started to leak from the weep hole. Since I have to pull it out I figured I may as well replace the following:

Pump (more later)
Pump gaskets
Pump O-ring
Pump drive O-ring (on timing chain cover)
Rad hoses
Heater hoses
Throttle Body hoses
Thermostat
Coolant/ Distilled Water
Optispark Cap & Rotor
Optispark drive O-ring (on timing cover)
Crank O-ring (on timing cover)

I am omitting wires/plugs because they appear to be changeable without pulling the Water Pump. The Opti works fine so I am not contemplating replacing it since it is a late model unit. I also omitted the serpentine belt/tensioner pulley because I replaced them 3 weeks ago.

What else should I replace that cannot be accessed once I put everything back together?

Are the LT1 Water Pumps rebuildable? If so are the parts sourced from GM?

JayH

I would go ahead and replace the distributor anyway. My '95 goes through them every 50-60k; It seems that the bearing that the optical disc floats on wears out and causes a wobble.

Have you given a thought to going with a Meziere instead of the stock pump?

Good luck, have fun,

Jay

Texas CE

Actually I had not heard of the Meziere or CSR electric pumps so now you have me thinking! I found the Meziere at Summit for 199.95 & the CSR for $159.95. Which is better & why? Where do they hook into the electrical system?

Do you know a good source for the Opti?

I appreciate the help!

aggie88

I agree with the other reply that you should replace the Opti. You will feel much better if you do. In fact regardless of early or late gen LT1, a lot of folks opt out for aftermarket Optis that are supposed to be more reliable like the DynoTech http://www.dynotech-eng.com./dynaspark.htm. If you have any doubts, just open it up and look inside. You will have to get a reverse torx drive to open it up. As for the wires, true, you can do it with everything back together, but they will be staring you in the face when you have it apart. It is a lot less pain in the >#*! and less scratches on your hands to do it now. (I changed wires before the Opti and wish I did it the other way around!) If you are thinking about underdrive pulleys...another thing to do now.

MikeC4

with aggie88 on using a DynoTech Opti, if price is no object. A Dynotech Opti will set you back $600. I went for the OEM Opti, which cost me $239 for a complete unit(vented Opti for '95). As far as rebuilt WP, don't waste your time, as you cam get a new one, with thermostat housing and 180 Deg. thermostat(already installed on WP housing) for $145.

I bought mine online from Sam Taylor and received them in 3 days.

They are easy to work with, and Vette knowledable too:
http://www.samtaylor.com/html/parts.html

Good luck!

JayH

I don't have any experience with the CSR, but I installed a heavy duty Meziere about 50k ago and have had zero problems with the pump itself. If you do install a Meziere, do yourself a favor and get a good quality relay, not one of those cheap Radio SHack ones (ask me how I know ) I wired mine straight off the battery and used one of the cooling fan relays to energize the pump relay.

I get my high $$ GM parts from Superior Chevrolet. The distributor, cap, and rotor go for just over $200. I will personally never do business with Dynotech again even though I understand their product is well received.

Jay

ConeKLR

I just installed the Mez HD pump. Summit Racing one of the best prices out there. One other place is about ten bucks cheaper, do not remember the name.

The Mez pump install/configuration is actually very easy to do. The install instructions are very clear and accurate. I bought a Painless relay set also from Summitt Racing, also easy to install. If go with a MEZ pump go for the HD, it pumps a little more Gpm than non heavy duty think 55gallonsperminute. I've seen the CSR, I think the MEZ is a better quality. Make sure your electrical connections are tight or soldered, if they come loose the pump will stop and your engine will overheat. The OEM pump can still fail you and over heat your engine though.

The reasons I went with a MEZ HD:

-Much much Easier to replace if it goes bad, my LT4 has gone thru two OEM pumps in 110,000 miles.

-Slight horsepower increase because the camshaft is no longer used to spin the pump.

-MEZ pump spins at a constant rpm, this should help out some during rush hour traffic in summer heat.

MarkLT1

A note for if you go with a Mez pump-

There is a regular version, then a heavy duty version for ~$30 more. Do yourself a big favor, and make sure you ge the heavy duty! The regular version is no good for these cars.

Also, I second the notion of getting a GOOD relay for turning the pump on. I got a 40amp one at NAPA, which seems to work pretty well. The problem I have run into, is I have the relay in the area near the driver side headlight. Since my car does not have a garage (eek) relays have gotten wet in this area, and I have fried a couple. I always keep a standard switch in the glove compartment, so that if a relay goes, I can disconnect it, and put in the switch as a temporary fix to get me home.

BrianCunningham

You can change all the wires except the primary wire. Best to due that while it's all apart.

Texas CE

Well the Mrs. isn't thrilled with any of this but I am replacing the Opti unit, wires, plugs, seals, hoses, etc. etc. etc.

My mantra I keep repeating to myself is "At least Ii do not have a car payment, At least I do not have a car payment" over and over

I appreciate all the advice from everyone. Looks like a pretty basic repair, just a little bit more involved than my old L48 C3!

VenkmanP

If you want to do it once so you don't have to worry about it for a while and the cost isn't a big deal, then yeah go ahead and replace all that.

If you can do this work yourself, and you don't have to get it back together quickly, and money is a significant factor then I'd just pull it apart and see what the opti and seals and whatnot look like, and then decide what to replace based on actual condition.

Gar

Gooseit

I just replaced all of that on my 95 model, I too think that while you are at it you should go ahead and replace the opti. When I checked the price for the cap and rotor, I found that I could get the whole thing for about $120.00 more.

Good luck

Texas CE

I posted elsewhere but here is where I am at on this whole shindig:

I am kneecap deep into my 96 LT1 Water Pump/Opti/Cooling system/timing cover seals/whatever the &%$* else I find that needs replacing since I am already there and I have hit a snag: I need advice on how to remove the freakin Harmonic Balancer. I have tried using a bolt on puller that uses a center bolt to push against the crank. I actually got it to move about 1/4 inch and then it froze again. The center bolt on the puller is passing through the HB and contacting the front of the crank. Here are my questions:

- What do the 3 bolts on the HB hold in place? The pulley?
- If so does the pulley need to be removed from the HB?
- With the pulley attached to the HB is there enough room for removal without lifting the engine?
- How to I keep the engine from turning when cranking on the puller?
- I welcome any tips on how to get the HB loose!!!!!!!!!!!

I am going to switch to a puller that has a center bolt that uses a floating mushroom shaped head. I think the current puller may be causing a bind because it is just a straight bolt (no floating end).

Anyways, too tired tonight so I figured sleep and a clearer mind will prevail!

SharkB4C4

I recently did almost the exactly the same job recently on my 96 LT4 at around 67K miles. Just rattling off random thoughts off my head from my experience:

If you change the front crank main seal (you call it front crank o-ring), you need to be prepared to sleeve the hub because the old seal would have worn grooves into it by now, and will trash the new seal. I used CR Speedi-Sleeve 99176. Around $25 with installation tool; Fel-Pro makes a cheaper sleeve, but the tool costs extra, so you pay more. A 50-cent PVC/ABS plastic pipe fitting I found at the hardware store worked PERFECTLY as an installation tool for the seal itself.

If you buy a new waterpump from GM, it comes with a new thermostat, gaskets, o-ring for the drive spline at the pump end. The o-rings for the drive spine don't seal anything, they just keep the coupler from rattling. If you're replacing the SEAL on the timing cover for the pump drive (that one does keep the oil in), it's 10217886 at your Chevy dealer, and you need a special Kent-More installation tool (or use a turkey baster).

At 67K miles, the primary side of my Opti was still surgically clean and the bearing was smooth and quiet, so I just got a cap/rotor/seal kit from AC Delco, and rebuilt my Opti. In retrospect, I should have spent the additional $100 to buy an entire Opti because I must have burned up at least that much in gas running around all over town to find the E4 inverse torx (E5 will also work) and the teeny-tiny T8 torx sockets that I needed to take apart the Opti. Oh, and you need about 3 feet of 5/64" vacuum hose and 1" of 5/16" fuel hose to replace the vent lines to the Opti because if you had an oil leak, the rubber will be as soft as sponge by now.

If your ignition wires aren't new, you really need to re-consider doing them at this time while everything's apart. Yes, the wires CAN be changed later, but it'll be MUCH easier to do them now (especially the driver's side).

And it's just me, but I found that this was a good time to replace my intake gaskets also. Doing the gaskets isn't any easier while the front is apart, but I didn't want to take any chances of seeing any oil leaks from up front after I had gone through all the trouble of replacing all those seals.

At 67K miles, I also found that the serpentine idler and tensioner were already shot, so I replaced them ($11 each). Also, in addition to the radiator hoses, I replaced the heater hoses and by-passed the throttle body. Note that the upper heater hose sold by AC Delco is now routed BEHIND the power steering fluid reservoir, not in front of it like from the factory (I wasted about an hour trying to figure that one out!).

This may or may not apply to you, but when I was pressure-testing the cooling system after I buttoned everything up, I discovered that my radiator side tank was cracked!!!

Oh, and the problem you're having with the harmonic balancer--it's in 2 pieces; the 3 bolts hold the balancer to the hub, and the hub is held onto the crank with 1 center bolt. The balancer comes off with patience with a 2-claw puller (or 3-claw, if it's tiny), and the hub comes off with steering-wheel-type (bolt) puller. To reinstall the hub, you can spend $250 for a special installation tool, or spend $0.88 at your local hardware store for two 7/16" NF (fine thread) bolts in 2-3/4" and 3" lengths, and use them and your stock bolt to progressively screw the hub back in. (Don't forget the mark the hub so that it goes back in the same way; it's not keyed to the crank. The arrow on the balancer points to the white paint mark on the hub.)

Good luck. It's a 2 or 3 weekend job (or longer, if you discover a cracked radiator like me). If you get stuck, you can find a lot of helpful information using the search feature on this forum, and on Google (the Camaro and Impala guys have a lot of write-ups that include helpful photos). The Helm factory service manual was helpful for providing the proper torque specs, but not for much else . . . for example, the GM engineers wants you to unbolt the mounts and raise the engine to remove the balancer and hub.

MarkLT1

The three bolts connect the HB to the hub

Yes, it goes much easier if you remove the HB from the hub first. When I did my cam/opti/all that junk a year ago, I removed my HB the "bad" way- 1) removed the 3 bolts, 2) used a 2x4 and a hammer, and gently tapped the hub, then rotated the engine 90 degrees, then tapped again. Had to go around several times, but she came off, and it didnt do any damage (be sure to just try to do a little move at a time. It goes real slow at first, but speeds up once you start getting the HB off)

I wouldnt recommend trying to pull the hub with the HB still connected- if you pull the HB, then the hub, you should have enough clearance to get it out without lifting the engine (all I had to lift the engine for was to remove and install the new cam).

If you take the hub off first, then use a steering wheel type puller (looks like a peace sign, with a bolt on each "leg" and a fine threaded bolt down the middle) then you shouldnt have too much of a problem with this.

Like I said before- the hammer and 2x4 method worked for me, but make sure you are GENTLE. Dont try to do it all in one whack- get it moving a tiny tiny bit, then rotate, and repeat. Make sure you take out those three bolts that connect to the hub first though! Some say this is a good way to break a HB. It may very well be, and I got lucky, so be cautious.

Texas CE

Thanks for all the help & tips.

I got both the HB and hub off, pulled all the seals, cleaned up the muck from the leaking crank sensor and am reorganizing my tools/garage in preparation for installing the new parts.

Even though this is a PITA I have learned a few things:

- This Forum flat out rocks! The support is awesome and I want to say Thanks!
- The more I work on this car, the more I learn and the more I like the vehicle!

Happy Easter!