Blower Motor Question...

Has anyone ever experienced loss of water from the overflow while driving down the interstate? I can top off my roadster, take off and after 75 miles or so it starts getting warm. When I check the fluid, it's almost out. I'm running a 350 with a 671 BDS huffer. Standard Walker T-bucket radiator with an overflow tank. I also run a 13 lb. cap.

I can fill it up and let it idle and it never leaks a drop. I can also run around town quite a bit before it looses any water. It's mainly at higher RPM's. Like between 2800-3200 rpm range.

Suggestions, thoughts????

thanks,
monkey

 

It wasn't blown, but I had an SBC with a crack in the combustion chamber that used to lose most of the water after about 50 miles or so. I'm not sure if it was being pushed out of the overflow, or going into the cylinder, but it was going somewhere.

 

Combustion leak into water jackets is first thought into my head...what sort of boost are you running at 3000rpm?

 

if it aint on the ground its going somewhere..and where its going your probably not going to like.

possible head gasket leak..(into maybe 1 cyl?)
slight crack in a piston bore?
sucks...dont it?

pull each plug and see what they look like..

 

I would bet it is a boost problem. Head Gaskets ,combustion chamber crack into water jackets. Have a radiator shop or macanic check for exhaust gasses in cooling system???

 

you need to track down the leak first.i would add size wise,a quart bottle to your overflow tube.take for a drive and see if any coolant in the bottle.if not you know you have a internal leak.beats tearing the engine apart for no reason.take it from there.

 

Are you using a catch can? if not when filling rad level must be just to top of core for room for expansion or you will push out coolant when it gets hot. when it cools it will have air in it .If it is combustion in the cooling system put a pressure tester on it,pressure will rise fast if it has a cracked head or headgsk problem

 

Don't be so quick to assume a combustion issue, could be something as simple as over filled radiator and the coolant expanding doesn't have enough room, so it spills out. Problem then is if is loses too much, then there's not enough for cooling and therefore a boil over is eminent. The wierd part is that you have an overflow tank.....

To be sure though do have like was suggested, a block check on the radiator to see if you are getting combustion gases in the cooling system.

Again this is just an opinion.

 

If I over fill my radiator it will spit some out .Are you noticing the drop in fluid due to over heating ?

 

I've almost ruled out head gasket. The oil looks fine and my plugs look good as well. It seems like it's leaking out the bottom of my overflow. I thought about putting a hose on the end and running it into a catch can just to see how fast it fills up. Last time I did a compression check it seemed to be right on. I just don't understand why it would push though the radiator, overflow and out.

I believe at 3000 I'm running about 5 pnds of boost. It's a 5% underdrive on the blower.

monkey

 

should be running vacuum in the intake manifold under cruising conditions...I think mine is usually around 10 inches

Sounds like it's leaking coolant into the chamber somehow. Are any of the plugs cleaner than the others? Do you ever see white smoke out the exhaust? And I second the recommendation to take it to a shop that can test for exhaust gas in the coolant, that would confirm you have a head gasket leak or a crack somewhere. And these type of small leaks do NOT show up on a compression test.

The coolant will expand as it heats up, but once it reaches operating temp it will not expand any more, and even if there is no coolant recovery tank it will only loose a pint to a quart maximum if you filled the radiator full when it's cold. Older cars without a recovery tank usually have the coolant up to one to two inches below the filler neck, and never lose any more than that.

edit: I was assuming you're losing water from the radiator. If it's only losing water from the overflow tank, then the tank has a leak.

 

If your radiator is in good shape try using a 16 lb cap and see if this helps your problem

 

Who can test for exhaust gases in the fluid? Any radiator shop or can a parts store do it?

 

radiator shop should be able to.

 

Here's a couple of bad shots of the radiator and overflow tube...

Sorry, my photobucket is down right now so I had to post the pics to the message board. Sorry Ryan!

monkey