Joined: Mon Dec 18th, 2017
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|The Glove test
Low tech and 100% accurate
You will need a latex glove and rubber band, or a balloon, or even a condom for the test
Remove radiator cap, coolant should be down at least an inch from the top, down farther is fine, drain some if it is high
Remove Overflow hose from rad cap opening, and plug the opening; gum, putty, tape, vacuum cap, ect........
Put glove over rad cap opening and seal it on with rubber band(or use balloon or condom on rad cap opening)
Unplug the Coil/coil pack, you want a No Start
Crank over the engine and watch the Glove, it will be instant feedback
If glove starts to bounce up and down then you DO have a blown head gasket or cracked head.
If glove just lays there then you do not, 100% accurate
If Glove does bounce, then you can ID which cylinder(s) are leaking.
Remove 1 spark plug, and crank engine again, then remove 1 more spark plug and crank engine again, ect......
When Glove stops bouncing , last spark plug removed is from leaking cylinder, reinstall spark plug to confirm
Useless why it happens info:
When you heat up metal it expands, heads of engine get the hottest so expand the most.
Every time an engine heats up and cools down the head gasket is compressed as head metal heats up and expands, head bolts hold it in place so it can only expand down toward the block.
And when engine cools down head metal shrinks back to regular cold size.
So head gasket must be firm but also allow for this daily expansion and contraction.
If an engine OVERHEATS that means the head will expand even more, and this can crush a head gasket, so blown head gasket.
Head metal can also crack if it expands too much, and cracked head has same symptom as blown head gasket.
A blown head gasket used to mean coolant in the oil, that can still happen but is less frequent with newer gasket material.
Glove test will tell you
So if water pump goes out or coolant hose breaks, or coolant gets low, then an engine can overheat, and this can be very very bad, crushed head gasket.
So do NOT try to make it home, pull over and let engine cool down.
A $5 hose can cost you $600-$1,000 if you run engine HOT
A blown head gasket doesn't "just happen" on its own