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Is My Tractor Engine Head Gasket Leaking?

We want to help you test your tractor’s head gasket for leaks.

If you do not feel that you understand these steps, or can perform them safely, consult your tractor dealer, local mechanic, or owner’s manual.

Let’s get started.


A head gasket’s role is to seal the engine's head to the engine block.

The gasket must seal the oil passages, engine’s compression, and water passages. If any spring a leak --- your head gasket is blown.


The block and head of the engine are both made of steel. As the steel heats up, it expands.

Your engine is designed to tolerate a certain amount of movement. If the engine’s temperature is normal, everything works perfectly. If the engine overheats, the steel expands --- causing parts to start moving around and distort. Sealing surfaces become uneven. Areas of low clamping tension develop, and the engine starts to leak.


Compression is usually the first to leak. It has the most pressure at roughly 500psi.

Typically, compression goes into the water ports, as the cylinder is surrounded by water to keep it cold. The most common sign of a blown head gasket is bubbles in the radiator. (See “Testing for a Blown Gasket” below.)

When the engine's compression leaks past the metal sealing ring on the head gasket, it burns the gasket material. So, when the engine cools down, there is still a leak --- and the gasket needs to be replaced.


Oil can leak into your water --- and water can leak into your oil.

This can happen if a passage between a water port and an oil port fails.

Oil or water can also leak outside of the engine externally if a leak develops on the outer side of the gasket sealing area.


To determine if your engine head gasket is blown

1. Cool the tractor engine.

2. Remove the radiator cap.

3. Fill the radiator with coolant. (Leave the radiator cap off for now.)

4. Start the tractor.

5. Run the tractor for about a minute.

6. Watch for bubbles.

If you see bubbles OR if water comes out of the radiator, you likely have a blown head gasket.


Be very careful if you choose to remove your Yanmar head gasket.

Do not use a screwdriver. Use a razor blade. Do not scratch the head or block. A scratch or gouge will cause the new head gasket to leak.

Also, be sure the block and head surfaces are clean and dry. The new head gasket must also be dry.

Do not use silicone on a head gasket. Use a copper gasket coating spray.


Be sure to use a freshly calibrated torque wrench.

It is also a good idea to re-torque your head gasket after a few hours of use. This is not necessary --- just a precaution to make sure the head gasket is placed and working properly.

If you need any further help or have any questions about your tractor engine head gasket, tractors, or anything else, please contact your dealer, local mechanic, or call us at 602-734-9944. Please ask about our current new and used tractor supply.

Team Tractor and Equipment - #1 Tractor Dealer in Arizona. We sell and service most major brands of tractors including Yanmar, Kubota, John Deere, TYM, Mahindra, Kioti, Case, New Holland, Massey Ferguson, Ford, Deutz, Case IH, Farmall, International Harvester, Branson Tractors, LS, Shibura, Claas Tractor, McCormick Tractors, Valtra, Solis, YTO, Montana, and Nortrac.

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