912ULS Water Pump Versions

Thank you, Roger.

Hi RW

Just an observation. I know Rotax changed, buttt

I've  never had 648 leak when fully applied to all the threads. The only time I saw this is when someone just put a couple of drops on the threads. The problem I've  seen when using 242 / 243 is the engine heat combined with people playing with the 17mm hoses caused the medium strength Loctite to loosen up and allow it to ooze coolant. That coupled with people not using enough Loctite to seal the entire fitting and all the threads.  I've never seen Loctite 648 leak when all the threads are covered and it's  definitely stronger than the 252 / 243 medium strength Loctite.

Hi Roger

This is from the Loctite site.  Rotax changed the recommended type to 577 as it fit better with the description of the straight threads

LOCTITE® 648 LOCTITE 648 is a low viscosity, high strength retaining compound with high temperature resistance. Ideal for retention of parts with a clearance or interference fit. 

LOCTITE® 577 Medium strength, thixotropic, general purpose thread sealant for straight-to-straight and straight-to-taper threaded fittings. Fills the space between threaded parts and seals and locks at the same time.

LOCTITE® 243 Blue Medium Strength Threadlocker

Hi RW,

 I've never used 577 since 648 has always worked and never leaked again. When i need to re-seal let's say one of the top fittings with the 17mm hose. I mark the flange and tube with a marker so I know exactly which way I need it turned. Then I remove the flange / fitting and put it in my vise (gently) because it gets hot. Then I use a small butane torch to heat it up and unscrew it. I clean all the threads with a brush and Lacquer thinner. Then I apply 648 to ALL  the threads so it seals very well. In all my years I've never had one leak again. 

Will 577 weaken or come lose over time from people messing with the hose kind of like 243 did occasionally? Does the 577 allow the fitting to move if you try and turn it without heat?

I don't use a heat gun anymore because it heats the whole area and it takes alot longer. The butane torch I can pin point my heat spot and it's faster.