1985 K100RS head to block coolant leak?

Well, I ain't a happy camper, kids. It certainly appears as though I have a coolant leak between the cylinder head and engine block. I had seen the green/blue dried remnants of coolant before and often wondered why I could detect a faint odor of coolant when the bike was hot yet there was no drip. Now I know why. I had the left and right lower fairing covers off today while doing something else and happened to be shining a flashlight in there while the engine was running. That's when I saw 2 or 3 tiny wet spots at the head to block joint. I suspect that whatever was oozing out was sitting along the joint and evaporating. I don't know if the gasket is leaking on the underside (I'd have to pull the belly pan) but it doesn't really matter I suppose.

Do these gaskets fail? All of my previous bikes were air cooled. This will be my 3rd season with the bike and I know I've never overheated it as I have a temp gauge. Can't speak for what may have gone on in the past.

The bad news? Clearly the work I need to do and wondering if anything may be warped. The good news? I'm up for it. Not intimidated by what would be required as many years ago I had two Suzuzki GS750 engines completely apart for rings and valve jobs. The valve jobs and cylinder honing was done at a shop but I did all the rest.

Any advice or anything else I need to consider doing while in there? AHHHHHHHHHHHHHHHHHHHHHHHHHHHH! And whatever expletives you deem appropriate!

Between the engine block and that fitting is an o-ring, P/N 11111460312 (27.3 X 2.4 mm). That is the outlet pipe from the engine to the radiator. A leak in that area is not common but not unheard of. With the age of these bikes, you may consider replacing the hoses while you are in there.

Frank

51797 said:

Between the engine block and that fitting is an o-ring, P/N 11111460312 (27.3 X 2.4 mm). That is the outlet pipe from the engine to the radiator. A leak in that area is not common but not unheard of. With the age of these bikes, you may consider replacing the hoses while you are in there.

Frank

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Hi Frank,

Thanks for the reply. I cannot see evidence that the leak is starting from the outlet pipe (look at my first photo and where the black arrow is pointing) but I am going to have a better look today.

Tom

1985 K100RS head to block coolant leak

While you're in there take a look at the crush washer on the temp sensor. And a quick look at the hose and pipe gasket before you go further. Pulling the radiator is a must to inspect this area. Been there, done that just recently. Patience young fellow..........................