Hey guys, brand new professional built 383 losing water fast. No white smoke, nothing hitting the ground, no leaks or anything. I did a pressure test at the radiator and got this:

Engine cold = 15 psi 5 hours, no problem water level stays the same looks good

Engine warm = Started at 15 psi, lost 3 psi in 15 mins, water level dropped quite a bit. Bad...

Oil level remains the same so I don't think it's going into the crankcase.

This motor was broken in easily and carefully and only has 600 miles on it today.

Any ideas? I love the car, blast to drive but everytime I think I have it running good, something else goes wrong...

Head gasket? After 600 miles? I just don't get it.....

 

What head gaskets?

Check the plugs.....that will tell you, its not going to just evaporate so its going somewhere

 

Did you use any cooling system sealer during your build?

I use the GM (or Bars leak Gold seems to be the same thing) on my LT1 since the FSM (factory service manual) for my Corvette calls for it.


If you didn't I'd add it prior to pulling the engine apart.

 

What do you mean "what head gaskets"? I am not sure I understand. Typically a head gasket goes, you'll either find water in your oil and/or white smoke. I don't have either. What bothers me the most is the pressure dropping when the engine was warmed up.

I am checking plugs now but they look good, brownish and dry. I have pressure on the system now. It would seem the cooler the engine gets the slower the pressure drops.

#1 and 2 seem a bit whiter than the others. When a H/G fails, is there a typical cylinder that the LT1 blows?

He!! of a Christmas season in Florida......

 

Have you kept track of how much coolant you put in it prior to starting it? I'm wondering if the system is trying to burp out a lingering air pocket.
The coolant system holds just shy of 15qts.

 

I am keep track of how much is uses. I thought the same thing but again, even if it is burbing/bleeding, that is ALOT of pressure loss in a short time. After warming up the engine, applying 15psi of pressure, the radiator level drops approx 1/2 quart in 30 minutes. I am afraid of driving it out past the mailbox

 

What brand head gaskets?


Don't worry about pres drop...it not going to stay constant. Also the level will go up and down as the system operates, thats what the side tank is for.

What water pump do you have? I say you need to go ahead and take a test drive

 

Not sure what brand. I had it professionaly built. I put the plugs back in, did not see anything out of the ordinary except for #1 & #2 where whiter than the others, more so than just leaned out brownish.

I have a CSR EWP and B/P the T/B.

With the engine cold, I marked off the side tank at "full cold". I topped off the radiator, closed the cap and ran it at idle (normal operating temp). I need to run to the store so I'll take it (along with a gallon of water) and check the levels tomorrow. I will keep track of how much I have to put in the radiator (if the side tank stays at the mark I left it when cold). If I hit the 2 gallon mark (8 quarts, right?), then I know I got a problem.

Please keep the ideas coming, I am running out of money and hair

 

Well, I took it out and made it 1.5 miles before the light came on. This much loss should show tons of white smoke or a lake under the car, right? I don't have either one. Anyone have this happen?

I have flushed and filled this car before several times cleaning the radiator and NEVER had a problem like this. I don't think it's air in the system, what else could it be?

 

You have to remember that the motor probably wasnt empty of water when you did the "flushes." This time around however there was NO water in the block. I got scared when I put my motor together and did the same thing. I just kept filling it until the fluid level wouldnt drop anymore. Also you shouldnt baby the motor when you break it in, as long as your tune is good you should give it some abuse to build cylinder pressure and seat the rings correctly.

 

Try replacing your radiator cap. It could be allowing air into the cooling system.

 

Didn't have this problem until about 30 miles ago. Cap is new (about 400 miles on it). I may try the original just for S & G's but don't see why, all of a sudden this would happen, again, it points to a H/G but don't have any secondary symptoms.......

 

I had the same problem with my le2 heads. Loosing water with no smoke, no smell of anti freeze and after checking plugs still no luck. Pulled the heads and took them to a machine shop and they found a crack in #7 exhaust port. Had it re welded and a valve job and milled the heads and no further problems. Took several months to figure out but is now fixed. And how I found it was I started to get excessive what I thought was condensation out out the passanger side exhaust but it took a while for it to get bad enough to tigger an alarm that something was wrong. Good luck.
HVY SS

 

i was doin donuts once and my hose came out my waterpump. i just putit back in and made sure it was tight and have not had any problems since.

I have the white lt1 notice at the end youll see the water pouring out the bottom.

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I had a pin hole leak in the head gasket. The gas Pushes the water out the cap but lets only a small amout of coolant into the cylinder. I suggest you check compression, especially on the cylinder with the unusually colored plugs.