Strange loss of coolant

[1973stang]

Let me start by...there is not a single drop on ground.

2 days ago by-passed the heater core and replaced the water pump.

Yesterday, i drove to work (4.5 miles)...temp barely got over 180F. After 1 hr of car sitting ...i opened the radiator cap and noticed the radiator was completely full....upto radiator cap.

I topped-off the over-flow tank to a mark...so I can see if there is change in level.

After about 2-3 hrs I opened the hood to chk.

1) I noticed that the coolant pipe to overflow tank was full Ii.e coolant was flowing back in radiator)

2) Opened the over-flow tank....the level had dropped 1-15" (3" dia).

All this time did not turn-on the car.

WHERE IS THE FLUID GOING??? Not on the ground.

There is a leak...I still see temp creaping up as I drive (205-even after hearter-core by-pass and new hi-flow water pump)


One more thing

At the same time we did chk..dip stick and oil cap and did not see any signs of water going in oil

 

[VegasFastback]

Do you have a cleveland or 302? If it's a 302 the intake manifold can leak sending coolant into the combustion chamber through the intake ports. Does the car smoke at all?

 

[1973stang]

351C 4V Q code

Dont see smoke from tail pipe or from engine ...

But the engine gets hot...you feel the heat as soon as you open the hood.

Do you have a cleveland or 302? If it's a 302 the intake manifold can leak sending coolant into the combustion chamber through the intake ports. Does the car smoke at all?

 

[mdan575]

Are you getting any popping in the exhaust?

That is what mine was doing with a bad head gasket. Couldn't see anything in the exhaust but it was using coolant.

 

[Don C]

A one hour cooldown may not have been enough this time of the year and engine may have been still warm enough to continue cooling and drawing more coolant in. It may also take a while to get all of the air pockets out of the engine. If you don't have the 351 correct thermostat and restrictor plate the coolant won't circulate through the engine properly. Another possibility is a slipping belt.

 

[1973stang]

mdan575

I haven't stayed back of car and listened to sound...I will later

Don C,

I have restrictor plate and robershaw 333-180 thermostat

I have been searching the web for reasons..and almost points to head-gasket

Here is a summary of lot of what I read

http://www.ehow.com/info_8304175_losing-antifreeze-apparent-leak.html

One of the signs is also car running hot..mine does.

What do you guy think and how should I proceed

 

[MotoArts]

Pull the spark plugs.

They should all be the same color.

If one appears to be steam cleaned, there's your offending cylinder.

Even a small coolant ingestion will at least clean the carbon off of the chamber and its components.

 

[goodnigh]

Same thing happened to my engine, unexplained water level drop in radiator.

Car ran fine, no smoke from exhaust, just had to keep adding coolant.

Nothing on the ground. One day the engine would not turn over, even when

using a jump from a tow truck. Cracked block. Oil looked fine, no indication

of water contamination. I hope that is not your problem.

mike

 

[1973stang]

mdan575,

How much did you pay for labor + parts for changing the head-gasket ?

Did you grind the head surface for flatness? Is that recomended ?

Rush

Are you getting any popping in the exhaust?

That is what mine was doing with a bad head gasket. Couldn't see anything in the exhaust but it was using coolant.

 

[mdan575]

Doing all the work myself, and currently I am in the middle of building an Aluminum Head Stroked 331 to replace it.

Cast iron heads suck to replace on our cars while the engine is installed. They weigh alot and force you to pick them up leaning over unless you have overhead equipment and remove the hood. Short like me really sucks.

But personally I would have the heads checked since they will be off anyway. Any good machine shop will check them and let you know if they need milled flat. The gaskets really doesn't cost that much and arent that hard to replace on these older cars. Its just the cast iron heads are heavy and a pain in the butt to remove in the car.

 

[wwhite72]

If you replaced the pump then you drained refilled the coolant? There are a lot of air pockets. Try parking on a steep up hill street or put your front end on ramps and run the engine with the cap off. Can sometimes take a while. My car takes a couple days and then suddenly the level drops and it runs cooler.

 

[matrixx]

Im sure you have air in the system and its just creaping out slowly and using your overflow to fill that gap. Now if the whole reservoir keeps going empty then i'd be worried.

 

[1973stang]

i hope that is true.

Big question:-

If I pressure test now...and lets say there is a head-gasket problem....will it LOOSE PRESSURE.

The mechanic said he pressure tested after water pump replacement and did not see any pressure drop...DOES THAT MEAN there is no leak thru head gasket or no cracked block???

 

[wwhite72]

Search "burp cooling system"

 

[marks73]

If you pressure test you should let it sit overnight. If pressure holds. you may have what is termed a "zipper crack" in a cylinder. The crack is so small that when the engine is cold the fluid won't seep through it. When the metal gets hot and expands, fluid seeps through and vaporizes in the cylinder. Mine only ran about 8 degrees hotter on the gauge but the temps in the crankcase wiped my bearings. The only indication I found was one small drop of coolant hanging off the skirt of my #5 piston when I dropped the pan.

 

[1973stang]

Marks73,

AS Motoarts said would you have noticed steam cleaned spark-plug on cylinder 5 ???

Because that would be the easiest/cheapest test of the problem.

Rush

If you pressure test you should let it sit overnight. If pressure holds. you may have what is termed a "zipper crack" in a cylinder. The crack is so small that when the engine is cold the fluid won't seep through it. When the metal gets hot and expands, fluid seeps through and vaporizes in the cylinder. Mine only ran about 8 degrees hotter on the gauge but the temps in the crankcase wiped my bearings. The only indication I found was one small drop of coolant hanging off the skirt of my #5 piston when I dropped the pan.

 

[marks73]

Didn't see it on mine because it was being superheated from under. Only thing that would have given me a warning would have been an oil temperature gauge that I didn't have. The temp outside the water jacket temps was what killed my engine. Flashing steam is extremely hot.

 

[1973stang]

IT WAS THE RADIATOR CAP.

I had recently replaced the radiator cap (STANT; same as old cap).

Just on a whim I ordered Motorcraft cap and have used it for 1 wk...NO LOSS OF COOLANT. This is my everyday car....so it gets driven.

 

[marks73]

EXCELLANT!!