Lower crankcase sealant

R

RevB

Well-Known Member
Just a heads up on older Kawasaki water cooled engines.

Have a 26 year old Kawasaki FV731V with fairly low hours however when the factory built this engine they used an RTV that was not friendly to antifreeze. It has just a fair rating in that use and should never be used in contact with coolant as it degrades. True, it took 25 years to do it but that sealant became the only reason to remove the engine to reseal the bottom end.

TB1207B is the sealant class to use. It has excellent resistance to antifreeze (glycol).
 
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Auto Doc's said:
Use Honda Bond sealant and you will never have another oil leak. Of course, it will be hell to ever get apart later if needed.
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The last tube of Hondabond that I used turned black, crispy, and would start leaking within 15 minutes of starting the engine. Seems great for sump sealant but just wasn't very heat tolerant on valve covers on V twin engines with the exhaust under the valve covers.
 
ILENGINE said:
The last tube of Hondabond that I used turned black, crispy, and would start leaking within 15 minutes of starting the engine. Seems great for sump sealant but just wasn't very heat tolerant on valve covers on V twin engines with the exhaust under the valve covers.
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Never seen Honda Bond turn black before. I'm talking about the white version Honda has used on their engines for many years.

The next sealant suggestion is Permatex #2 in the tube, it takes a little bit of time to fully cure but it works great.

From there I use Permatex Ultra Gray and give it the necessary setup time before joining the parts together.

The number one rule for any of these sealants it NOT to apply them too heavy. A little is good, more is not.

EDIT: One other sealer that I like to use is 3 Bond, it prevents leaks, stays semi-pliable and resists all fluids that I have seen it used with.
 
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Auto Doc's said:
Never seen Honda Bond turn black before. I'm talking about the white version Honda has used on their engines for many years.

The next sealant suggestion is Permatex #2 in the tube, it takes a little bit of time to fully cure but it works great.

From there I use Permatex Ultra Gray and give it the necessary setup time before joining the parts together.

The number one rule for any of these sealants it NOT to apply them too heavy. A little is good, more is not.
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It has been a few years, but seem to think it was Hondabond 4 or do they make a 3. Anyway. It seemed to work fine on sumps, and some valve covers, but when used on a Kohler 7000 series it would turn black, hard, flake off if touched with your fingernail. Had the appearance of gasket shellac
 
txmowman said:
Kawasaki has never use RTV. TB1207B is what the factory used. Nice try though.
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What a moron. TB1207B is RTV. "But the original factory white sealant on those lower crankcase mating surfaces was most likely ThreeBond TB1211 (or a very close Kawasaki-branded equivalent). TB1211 is a white, lower-viscosity, oxime-type RTV silicone that was widely used by Kawasaki and other Japanese OEMs for general flange and case sealing. It has good oil resistance and a long open time, but its coolant (LLC) resistance is only moderate—exactly the weak point I ran into. Over many years of thermal cycling and coolant exposure, it can soften or lose adhesion enough to allow those slow seepage leaks along the horizontal joint, even if the engine otherwise holds up for 20+ years."

Why don't you get an education instead of being so **** sure of yourself.
 
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