Water in oil 92 CR500 help please!!

My 92 CR500 has been laid up for a long period (months) and now it wont start. It ran fine when laid up.

I went to change the oil and found the gearbox to be full of coolant which is presumably why it wouldn't start...

What i'd really appreciate is some guidance of the common reason/s (if there are any) for this so i can look for them first on strip down first.


WOW man that sucks, you may have a cracked head causing the coolant to leak into the bottom end of the engine. :busted:

There's an inner and outer seal for the water pump. If the outer seal goes bad, water will leak out of the weep hole on the water pump cover. If the inner seal goes bad, water will leak into the transmission.

A cracked head wouldn't leak water into the trans- it would use coolant while the engine was running, though.

Should it be obvious by looking at it that the inner water pump seal has gone, ie physical damage to it or corrosion marks or similar?


I've only had to replace mine because it was weeping out the cover. The shaft has a tendency to corrode and/or have grooves worn in it, so the seal may be fine. Check the water pump shaft in addition to the seal.

Hopefully somebody else corrects me if I'm wrong, but I think that's the only way to get coolant into the trans.

Think it is either the seal or the impeller shaft as you suggested so will check shaft and replace seal.

In your opinion Is it worth drifting out the water pump bearing to replace that too? And what about the small w pump seal-i cant even see that!!

Has you got any great (read as cheap..) ideas to clean out the grey water/oil sludge?


It is also a really good idea to replace the water pump shaft to go with the new seal. There may be enough of a groove worn into the shaft (that you still can't feel) that will shorten the life of a new seal and require a repeat fix (sooner rather than later).

Since it is an older motor, I would just replace everything you can while you are down there. I figure that is just saving yourself from doing it all again later to replace the bearing.

its not too expensive to replace the impellar shaft seals and bearings, should be under $100. Inspect the crankcase cover and make sure its not corroded too badly from the coolant. If its pitted really bad just buy a new cover while you're at it. Super easy to replace these items and wont break your bank.

It's likely not the water pump seal and/or oil seal. You'd have to have a very leaky water pump seal, a completely blocked weep hole, and a very leaky oil seal, all at the same time, to let the water "drain" into the oil. Leaking coolant would (or should) freely pee out from the weep hole (and not get into transmission) and that's that, unless the weep hole is totally blocked! Check that weep hole.

If weep hole is ok, you have some other issue.

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