how to tell if Head Gasket is blown?

[Hognosh]

Just wondering how to tell if your head gasket is blown. Ive been having issues getting tractor over 2200 rpm. and i have another post on this talking to others now im wondering if it is head gasket issues or just air issues. what do i look for to rule out head gasket.
thanks

http://www.tractorbynet.com/forums/parts-repairs/305474-cant-get-over-22-000rpm.html

 

[pmsmechanic]

Run the engine with the rad cap off. If you see bubbles in the antifreeze that would be a good indication of a blown head gasket. Check your oil and make sure it's not a greyish color. You can also stretch a balloon over the radiator neck and see if it fills up.

 

[2458n]

You could also do a pressure test on your radiator. pump it up and set the pressure and see if it bleeds off. Are you using antifreeze without it leaking. Can you smell antifreeze at the tail pipe? All are good clues.

 

[tractorboy3011]

I had this ploblem too look for water in oil.

 

[GManBart]

White smoke in the exhaust, and coolant in the oil are two primary indicators.

 

[LD1]

Three ways a head gasket can fail.

1. Cylinder to water jacket.
2. Cylinder to oil passage/pushrod passage
3. Cylinder to air
4. Cylinder to cylinder

No way to pin things down 100% without popping the head. But advise given so far is a good start.

Looking for bubbles in the coolant is a pretty good bet that the gasket is blown into a water jacket. But not seeing bubbles dont rule out the gasket.

Water in oil is also a good indication of being blown, (or cracked block). But clean oil dont rule out the gasket either.

If it were leaking to air, a simple walk around feeling and listening around the head should tell you.

After those quick visual checks, you need to do a compression test. Cause even if all of the visuals pass, it could still be blown cylinder to cylinder.

And even the compression test isnt foolproof. You may show a low cylinder or two, and think that you have a head gasket problem, so pull things appart and it could be something like a busted piston or ring in that cylinder.

So I guess to sum up what I am saying, there is nothing you can do to 100% verify if it is a head gasket short of pulling the head. But there are alot of steps that can help point you in the right direction.

Now if she passes all the tests above including the compression test, I'd be looking elsewhere for the issues you are having. Valve adjustment?

 

[john_bud]

Head gaskets keep the combustion gasses in the cylinder and separate from the liquid coolant. A leaking head gasket can leak ;

1) cylinder to cylinder
2) cylinder to coolant
3) cylinder to environment

symptoms can be hard to start if pressure is bled off to adjacent cylinders. Can be coolant out the exhaust or exhaust bubbles in the coolant that you can see in the radiator. Can also be a pulsing sound as cylinder pressure is leaked out between the head and block to the environment.

Pretty easy to determine a bad leak by inspection of the exhaust / radiator flow. A leak down test will tell you more and let you determine which cylinder is leaking and where it is leaking to.

My suspicions are more toward fuel system than head gasket, but from this distance .... its only a guess.

 

[rsallen]

I've run into head gaskets burn between cyl.'s as well or into an oil gallery.
They don't always burn into the coolant system.

 

[rsallen]

The most reliable way to test for head gasket leakage is to pressurize each cyl. in turn.
While it's not possible to pressurize the cyl's to ignition pressures it is the most reliable way to test head gasket integrity as well as a number of other suspect causes of problems.
Pressurize the cyl's and check for where the air pressure escapes. Simple concept and it works.

But from the op it sounds to me like he's looking in the wrong place for his problems.

 

[LD1]

The most reliable way to test for head gasket leakage is to pressurize each cyl. in turn.
While it's not possible to pressurize the cyl's to ignition pressures it is the most reliable way to test head gasket integrity as well as a number of other suspect causes of problems.
Pressurize the cyl's and check for where the air pressure escapes. Simple concept and it works.

But from the op it sounds to me like he's looking in the wrong place for his problems.

But even that is still no gaurentee. IF you pressurize a cylinder and get bubbles in the coolant, it "could" be a head gasket. Or it could be a cracked block, or cracked head.

There is NO way to be 100% sure until you pull the head.

I would do some of the checks that people have advised. if any of them checks fail, pull the head and see. But if they all pass, it "could" still be a headgasket, but that would be my last resort to look into. There are far simpler things to check and rule out that could be causing your issues.