Hello Everyone:

I have a 95 LT1 coupe with a severe coolant leak. I would like to explain what I know (and also what I think that I know) so far, and then request input from the valued members here.

In the past the leak has been come and go. I could take long trips (drive for 10 hours straight) in the Vette and not lose a drop. Go for weeks and not lose a drop.

Other times, when it was low (low coolant light) and I top off the coollant level - it drops a bunch on the garage floor overnight - sometimes not always. There does not seem to be a connection between how it is driven and any other factor. There is no timing factor (i.e. every day or every other day, week, etc) that explains this.

I placed dye in the system and viewed it with a blue light from the top. sides, and bottom of the Vette on ramps. The findings are;

1. There are no leaks associated with the radiator. I replaced it with a DeWitt last year (great product by the way). The radiator, all hoses, connections, the transmission lines, and the release value are all dry with no dye markings observed. The over flow tank, reservaor, and all other connections are dry.

2. There was no dye markings observed at the top of the engine or the area around the intake manifold.

3. There was no dye observed in the motor oil. The oil shows no signs of coolant. No issue with the oil or its levels.

4. The top and sides of the water pump are dry with no dye observed. I could not see the bottom aspect of the water pump.

5. There is considerable dye on the main crossmember that supports the engine. This is the same crossmember used to raise the Vette with a floor jack.

6. There is a large collection of dye on the bottom inside of the crankshaft pulley. It is not spread around within the inside of the pulley. It has collected at the bottom. There is no dye around the bolt on the inside. I could not see behind the pulley very well.

7. There are trace amounts of dye on the belt.

8. There was an amount of dye on the inside of the hood. This thrown by the pulley.

9. There are other dye markings around the engine that have an open area that accounts for the belt. In other words, I see some dye that was thrown by the pulley, then a clear space that accounts for the belt, then more dye thrown by the other side of the pulley.

10. There is dye coating on the crankshaft pully to the rear of the belt.

11. The front of the engine block appears clear of dye, but i cannot see everything there. There was some dye on the distributor (slight), but i could not see all of it.

I started the engine, but no coolant dye leakage was observed.

My guess is that on the bottom of the water pump is where the leak is - or - there would be a leak someone else that associates with the crankshaft pulley - but that struck me as unusual to see..

My guess in all of this. I dont that I lose coolant when the engine is running. I may be losing it after the car has been turned off and the engine cools off.

Any advice would be welcomed.

Otherwise the car runs fine with no other issues. I have no record of prior maintenance on the Vette before I bought it. It has 180k miles and is driven in the metro Atlanta area. I changed the thermo last year when I changed the radiator. Again, all areas associated with the radiator/thermo maintance work done last year appear dry.

This is a real bummer. I got laid off, so any expensive repair will have to wait. I may just have the leave the car in the garage until I can repair it.

I wonder if the recent unusal cold weather here has impacted the situation.

Thank you for your time and your attention to this request.

 

A very concise evaluation, kudos.

Suggest an inspection of the water pump.

 

I believe the LT1 waterpump has a weep hole on the bottom that, when the pump starts going bad, the coolant will come out of there. Some people have tapped the hole to accept a plumbing fitting and used clear, flexible tubing to route any overflow away from the opti. The '95 has a vented opti, so it withstands liquid a bit better. Take an inspection mirror and try and see the bottom of the water pump for the dye with the black light.

 

Strange that it only leaks at times, but it sounds like it just about has to be coming from the weep hole. Sorry to hear about your job situation - way too much of that happening. A new pump is about $175 - maybe put up a thread in the parts forum to see if somebody has a good one they'd let go cheap so you can get back on the road.

Good luck!

 

Yep, water pump is toast.

 

i've had cars that would not leak while the system was pressurized, as soon as the pressure was released they would. sounds like you are having the same problem. check the bottom of the pump.

 

Thanks everyone.

One more things that I forgot to mention. There is a chirp, chirp, chirp sound coming fromn the front of the engine. That could relate to a worn out water pump.

It's a pain, but I have two choices I believe

1. Have the water pump replaced before the leakage kills the Opti Spark, or

2. Let the car stay in the garage until I can do number 1.

 

The "chirp" could be bad bearings in your WP drive. However, it could also be something else such as belt tensioner bearings, alt. bearings, etc.

Use a mechanics stethoscope($3 at harbour Freight) to try to isolate where the sound is coming from.

 

Some folks are rebuilding their own pumps - this might be an option for you:

http://www.smokinvette.com/corvettef...ead.php?t=2812

 

I would change the water pump and optispark at the same time. Just in case you fix the water pump and the opti fails month later. You will be taking water pump off again. I would do wires and plugs and new belt at the same time if you got 180k miles.

 

yes sir, had the same problem. I am actually going threw the tear down right now. My water pump failed and killed my opti. so I ordered and new pump on ebay. ( 109.00 shipped ) and a distributer cap ( 106.00 shipped and msd wires and plugs. So far I got the water pump off and the distributer cap unbolted but not off due to a lazy crankshaft pully not wanting to come off. Once its off everything new is going in. I am no mechanic but I do mess around a little bit and this is no problem. GET A HAYNES MANUAL ! I got quoted 1,900.00 for work on this thing and so far I am only into it for 300 and I think thats all I need.

 

Since you are close and I've done this a couple times I'll offer to help.

I'll be at a toys for tots event at Millers Ale House in Alpharetta next Saturday.
You'll meet a lot of good folks and we may find someone else that has more time than me to help as well.

Water pump isn't too bad to replace.