Water pump replacement

popsvette · 12-05-04, 07:10 PM

I have a 96 LT4 with 25,000 miles and it looks like I have to replace the water pump. I'm also going to replace the serpentine belt, upper and lower radiator hoses, thermostat, and plug wires. Although I've never had any problem with my opti-spark, I'm considering replacing it because it's so trouble prone. Any comments on the opti-spark or any other item that should be replaced while I have it apart is appreciated.

Goose · 12-10-04, 10:05 AM

I am going to replace the waterpump,t-stat,plugs and plug wires in my 95 this winter. The pump is not leaking and the car has only 56,000 miles but with it being ten years old and all the stories I have heard about the opti spark going out if the pump leaks and it gets the opti spark wet with anti freeze. I have also read lots of stories about cars going 150,000 to 200,000 miles with the original opti spark. From what I have read if the pump does not leak the opti spark should be Good for a long time on 95 and 96 models. on models before 95 the opti spark was not vented and moisture is prone to build up in it and cause failures, Most people with pre 95 models have replaced the their opti sparks with the 95 or 96 version which has vacuum hoses attached to keep the moisture pulled out.

Good Luck
Goose

Tim Scales · 12-10-04, 08:30 PM

Quote:

Originally Posted by popsvette

I have a 96 LT4 with 25,000 miles and it looks like I have to replace the water pump. I'm also going to replace the serpentine belt, upper and lower radiator hoses, thermostat, and plug wires. Although I've never had any problem with my opti-spark, I'm considering replacing it because it's so trouble prone. Any comments on the opti-spark or any other item that should be replaced while I have it apart is appreciated.

If I were you I would not replace the opti unless you have been exposed to a lot of heat underhood and a lot of moisture unless you are lacking performance, ie have a slight skip. This IS the time to replace the plug wires as you will probably have to remove the belt tensioner to replace the wires on the drivers side. It is time consuming but is not a big job. Just have to pay close attention to where each wire is located as replacement progresses. The ASR will probably need to be taken loose and set aside. BE SURE that you do not let any of the cables slip out of adjustment or you will have to readjust them to regain proper shift amd peformance if it is an Auto Tranny. The Passengers side is very easy with little restriction. The water pump (GM Replacement) will come with a new water neck so you may put in the new thermostat before installation. Be SURE to remove all the old gasket material from the engine block before installing the new pump. I ALWAYS stick the new gaskets directly to the engine with a sealant and allow it to set a few minutes before putting the pump on as the gaskets are very delicate and will move easily if not placed on and stuck. I will put sealant on the pump side as well. (Only a very thin layer is needed). Be certain all of the coolant is drained below the water pump before you loosen or remove it so you can avoid exposing the Opti to any coolant. If the seal is broken on the opti the coolant can enter into the opti. I have learned the above things the VERY HARD WAY. Good luck. If I can be of further assistance just e-mail me at scalestim@msn.com Tim

Tuna · 12-11-04, 10:48 AM

I've got the 'worst of the worst' OptiSparks being a 92 and it lasted 12 years - along with the water pump. I replaced them last year when I upgraded my motor with a new cam and heads. They were still working just fine. I just did it because I was rebuilding the whole motor and wanted to. If I hadn't wanted more power, they'd still be running in it today.

Maybe they last so long for me because my 92 is a daily driver and they get exercised regularly.

Personally, I think the OptiSpark and water pump have way too much bad press. Of course you hear about problems with them on forums like this and you never hear about all the ones that never have problems.

Your money, your call.

popsvette · 12-14-04, 09:41 AM

Here's the virdict. I removed the water pump and discovered that the seals in the front engine cover were leaking. To remove the front cover, I had to remove the opti-spark and front pulley. (Wow...the pulley was a pain in the a-- to get off). So I replaced the water pump, opti-spark, hoses, belt, front cover seals, and plug wires. The opti-spark and wires didn't have to be replaced but after all that labor I decided to put a little more $$$ into it. With jobber discounts from my local Chevy dealer, I put $716, including anti-freeze, gaskets, etc. into my 25,000 mile LT4. It runs like a champ and doesn't leak.

Thanks to all the forum members for tips and advise. This is the most helpful Vette forum I've found. Merry Christmas to all...