Okay, recently my bike overheated since it was secretly leaking coolant. Never could find a blockage but someone did mention to that my thermostat looked wrong. Well, I got the 351 kit and it started first time after getting everything back together. BUT I have one problem, coolant is leaking from the gasket around the pump that spins and ciruclates the coolant. I changed to a brand new gasket and still had the same problem. Didn't run it too long as this seemed wrong. I go to pull the thermostat and coolant is spraying out as I slowly loosen the bolts, that doesn't seem right. Anyway, pull the thermostat out in some boiling water and nothign changes, it isn't moving. So I am thinking this thing has failed and was likely my initial down fall. Here's some pics. It looks as if the disc that would shut off the flow is stuck open. Am I right there? Can someone explain how the coolant flows and what this should be doing if functioning. Thanks gents.

Also, after I pulled the thermostat there was some junk on it. It looked like a goober of grey metallic paint. I am assuming this is normal residue from the initial 2 minute break in, am I assuming correct?

 

Looks like it's messed up. Everything should be in line from top to bottom. Yours looks cocked. Everything is mashed off to one side.

 

That's what I thought. So I went back out and ran the bike with no thermostat for about 30 seconds and sure enough the leak was gone.

I was also worried about all the smoke coming out of my exhaust but a simply removed the back portion of my pipe (where the packing that was soaked with coolant from when my head gasket blew and literally shot coolant out the back of my exhaust) and no more smoke. That packing was brand new and I would rather not buy more. I would think that after a few miles on the bike that all the coolant residue would simply bur out of the packing. Anybody think that's a bad idea?

Dan, thanks for the initial assessment because I was thinking I was just seeing things.

 

Yes, your thermostat definitely looks like it's cocked to one side, not allowing it to ever open fully to allow the proper coolant flow to the radiator. Check out theremo-bob's website for a good explanation:

http://members.***.net/watt-man/TB%20Testing1.htm

Cheers,

Anthony

 

Thanks Anthony, that makes more sense now.

 

That Thermostat is junk! Are you sure it was installed correctly? It seems wrong to most people, but the spring goes on the hot side. Your picture shows a "stuck open" thermostat. Removing it should have made no change, since it was "stuck open", it was the same as "removed".

 

I disagree. I can't tell by your picture how much it is open but manual has full valve lift at 3 mm (0.12 in) or more at 85°C (185 F). When the valve opens, the spring compresses to allow coolant flow to the radiator. What the picture is showing is a partially open valve, probably goofing up the flow pattern pretty well. Remember, that water pump is not very powerful and doesn't produce tons of flow, so a small restriction would result in significant flow decrease. It would not make a difference with a cold engine, but once the engine warms up, if the thermostat does not open all the way, there is a good chance adequate flow is not established.

I would compromise your statement with "stuck partially open" as opposed to "stuck partially closed".

Are you an optimist or a pessimist LOL?? Either way once the engine warms up, that cocked spring would not allow the thermostat to open fully.

 

That thermostat looks to be open a 1/4" or so. Unless it just came out of boiling water it's junk. At room temp it should be closed.

 

It had jsut come out of boiling water actually. When I took it from room temperature and put in the boiling water nothing changed. After I removed it and ran the bike the coolant leak from the water pump gasket housing stopped. I think that is fairly good evidence that it was more "closed" than open, at least that's my diagnosis.

 

1st off: it's inexpensive
2nd: It was never intended to be in "boiling" water

so I'd trash it and get a new one.