Cooland Leaking Out of Head

My bike is a 2005 crf250r. Just did my piston/rings....put it back together, and there is coolant leaking out between the head and the cylinder. I replaced my head gasket but the bike is still leaking coolant. Any suggestions? Thanks

Did you torque down the head? Are you sure you removed all the gasket residue from surfaces? Did you scratch the cylinder or head surfaces in the process? They are aluminum, so very easy to scratch with a razor

As suggested above, plus:

-did you use a torque wrench and the proper sequence  (2-3 steps to final torque values)

-stock or aftermarket head gasket

-has the engine ever overheated / blown a head gasket in the past  (possible warped mating surfaces)

Edited by mlatour

Mlatour please elaborate on the 2-3 step to final torque value? And gasket got placed on a clean surface. And never blown head gasket 

As the service manual specifies:

"tighten the nuts in a crisscross pattern in two or three steps to the specified torque"  (29 lbf-ft)


Meaning you first torque them to say 10 lbf-ft, then 20 lbf-ft, and final torque them to 29 lbf-ft.

The CRF250X procedure also specifies to lube the bolts treads, the CRF250R is likely the same.


Actually a common procedure for any type of cylinder head or major engine assembly.


Using a crisscross pattern was not mentioned in earlier post but quite important as well,

so is having a torque wrench which is known to be accurate / calibrated.

Edited by mlatour

Okay thanks for’s a pretty steady flow on the back side of the head..and a slower leak from the right side...not sure if the leak from the back could be due to improper torque procedure...what’s your thought?

Inspect everything closely,

check the head gasket for any deformation or variance in thickness which may indicate uneven pressure.

At this point it's worth checking the cylinder and head mating surfaces for trueness / warping.


Make sure your crankcase isn't filling up with coolant as well (internal leak), check the engine oil for contamination.

Edited by mlatour

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