I have a 1994 z28 with 107,000 miles. It's white with a black top and is a head turner. It looks absolutely showroom condition . I bought it from my sister-in -law in Florida almost 5 yrs ago. Recently it runs terrible after it warms up in 10 minutes and stalls. I need to wait 45 minutes before it starts again. I took it to a dealer for a diagnosis and the mechanic sd. the distributor is bad and has water dripping on it from the waterpump. I haven't seen or smelled water . He also sd. water is leaving the radiator and entering the engine and not going back in the radiator but possibly entering a cylinder. My personal mechanic sd. it might have a cracked head or bad head gasket . It runs fine when it's cold and rough ( stalls) after 10 minutes. My mechanic will check the plugs for wetness to determine water in the cylinder. It doesn't blow white smoke and has perfectly fine looking exhaust. Does anyone know what this could be?

sincerely ,
Galen

 

If your waterpump is bad and leaking on your optispark (distributer) then that could easily happen. That same scenario happened to a friend of mine with a 93 LT1. Most likely you'll need to replace the opti and waterpump, but they're all right in there about the same spot.

As for the coolant leak in the cylinders, you'd have to check that one for yourself...maybe someone else could offer feedback on that part.

There are plenty of threads about doing WP and opti swaps, common high-mileage LT1 problems. I've done a few of each myself.

 

Check your oil and see that is it black, not foamy, and doesnt have coolant mixed with it. this is a sign of cracked head or blown head gasket.

Yes it's your 'distributor'. It's called the Optispark on our cars, runs directly off of the cam and the water pump sits directly above this. If it leaks, your opti gets wet, and it stops working. Being you have a 94 your Opti isn't vented which means it wont dry out, and if it does it will take alot longer. Your opti is gone man. You will need to replace it, and the water pump seal. I would go with an elextric water pump when you replace it. These don't leak.

 

If you need to replace the distributor (optispark) before you purchase, be sure and look at www.dynotech-eng.com.

Ignore anything negative on this board about their product. I have had one on my car over a year now and it runs perfect. They will rebuild it for you regardless of mileage as long as their seal is not broken and it is not an all out race car. No other optispark replacement offers that kind of warranty and installation is very simple.

I recommend investing in a completly new water pump and put a drain hose in the weep hole with a tube running around the optispark.

You should be able to find a lot of info on the board about the optispark and plumbing a hose around the optispark.

I am 100% pleased with the dynaspark and I have no affiliation with them other than being a customer. I am in Mississippi and they are many miles from me.

good luck

 

This most deffinatly looks like a dripping water pump. Its happened to me before, and being your car is a 94 you have the non vented opti so your pump leaks right on to it.