So this has happened a couple of times over the last few years. When the weather gets cold I start to develop some really minor coolant leaks. The first couple of times it was usually a coolant hose at a fitting. Just a few ounces of coolant and usually fixes itself... (right.) The last couple of times it seems to be coming from somewhere way up near the water pump. Of course anyone who has the ISM knows how difficult it is to see up in there to determine the exact spot. It could be the small weep hole in the water pump? It's dried up now I just see the residue on the garage floor. I think it's probably nothing to worry about but I was wondering if anyone has experienced similar?
On most of the versions of the M-11 you could have a o ring seeping at either the water pump piping slip joint or the oil cooler o rings slip joint. The water pump seal would be down the list in 3rd place at the location you describe.
Mike
I experience this phenomenon every Winter.
When it gets cold, there is shrinkage. :(
That, for me. Our 1998 U320 leaked between the water pump and the block when it got cold. I was able to replace the o-ring without removing the pump - it swivels! Tight, but do-able.
If this is your situation, AND you can't easily source the o-ring. send me a PM. I think I have a couple. I assume the part would be the same for your ISM.
Matt,
IIRC that is the same o ring all the way up through the M-14
Mike
To answer a P/M question: The 8.3 block is a hog in a different wallow this info is for the basic M-11 block. So if you have a 8.3 no need to worry about caring any of these in your parts bin.
Mike
Not easy to make it out in the photo but this shot is looking up into the water pump area. The weep hole is visible and it looks like the coolant was coming from there but it's dry now. Also worth noting that this did not leak right away after I parked it about a month ago. This leak started when the garage got cold. I've since turned the heat on and I keep it at 55 degrees. I'm not going to worry about this unless it continues or gets worse.
Have you tried to tighten the upper hose clamp?