98 600 sx water pump / cooling question

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biglsells

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Jan 14, 2012
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Location
Grand Rapids, MI
I've got a 98 600 sx and am getting ready to pull it from the garage and bring it to my snowmobiling buddies place for the winter. I just did a rebuild on this sled this last winter since we had no snow and before that it was a new sled to me so no use by me yet. Thought I would start it up and check everything over. I let it run for about 10 minutes because I wanted to check that the cooling system was ok. I felt the cooling runners on either side of the sled after 10 min and to my surprise, they were cold! The engine was hot as heck but nothing else. I took the cap off the coolant hose and started the sled and did not see any cooling moving along inside. I did squeeze the hose that comes from the thermostat on the head and then squeezed the bottom hose coming from the pump and the coolant rose in the pipe so (if there is a thermostat in there) its not stuck shut.

So - what do I do next? Do I have to pull this whole engine again to take the coolant pump off? Do they go bad? I know its spinning, I checked it when it was apart but I didnt look at the internals of the pump, do the fins go bad?

Any help is much appreciated.

Thanks!
 
No, was not sure how to but after reading more I am guessing there is a bleed bolt on the head? Going out to the garage to check that out.
 
if its the same as the other proaction sleds there is one under the seat at the rear of the tunnel. you need to remove the seat and raise the rear of the sled slightly and bleed the air out there.
 
Gotcha. I'll look here as to how to get the seat off and check for a bleeder and go from there. Probably just a few bolts and off it comes?
 
2 nuts inside the rear compartment, undo wire connector for taillight (under seat), may be some snaps and some loops at the front (this is on a srx not sure about your model) then you lift the rear of the seat and slide it back from under the gas tank.
 
Ok did that, got the seat off no prob, lifted back end, removed bleeder nut and filled coolant until it was coming out of there, put that bolt back in and made sure system was topped off, ran it for 7-8 min and nothing, all rails are cold, not even warm. Shouldn't the hoses pressurize as well? Nothing, I'm stumped.
 
I did a search and it seems like the 600s can be a bugger to get the air out of the system. You will probably have to do the bleeding procedure a few times. If you type in bleeding coolant in the search feature here you will find lots of posts on it.
 
Ok, pulled the frame rail off and took the pump apart, fins are perfect so put it all back together, read some bleeding methods on here, got it all filled, cant seem to get a bubble more of air out. Too late to run it tonight but ill run it tomorrow and see what happens. Determined to feel the cooling rails get warm before I end up on the trail overheated.
 
you havent mentioned anything about the water pump drive belt. whats the tension like on the belt that drives the pump? 98 600 should still be the twin cylinder model with the belt driven pump.
 
if the tension is within spec, is there a chance someone mistakenly installed a t-stat? i dont recall the 97-98 twins using a t-stat. those housings lead one to believe it should have one and has been a common mistake in the past to install one. just a shot in the dark.
 
I don't think so because when both cold and hot I can push coolant from the lower hose, up through the head and out the fill cap while pinching the down side of the hose from the fill cap. It's odd because you should see coolant rushing by when running, at least I would think so.
 
Here was the pic of the pump blades, look to be perfect. Started it up this morning and after three min, cooling rails were nice and warm, seems to be working perfectly post - bleed last night. Thanks for everyone's help. FWIW my procedure was like most posts I read. Sled flat except for rear, propped up about a foot off ground with seat and bleader bolt out, filled it up, used a sucktion device to pull air out the bleeder hole, add coolant, repeat about 5 times until no more air came out. Put bolt back in, dropped rear, filled more coolant up front, squeezed hoses, repeat until full. Lifted rear, checked and just coolant came out, ran and whalla!

Thanks again!
 

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Im not sure if anyone else has tried this but... I had my coolant gel up on me this winter (my fault for mixing coolant types) Anyway I needed to change the coolant and I had just helped my friend do his 99' sx700 and it was a PITA! So I thought Id try a different route, I pulled the upper coolant hose off in the engine bay, on my sled I pulled it off where the coolant hose connects on the chaincase side of the coolant filler cap. Then lift it up I was able to get mine about 1.5 feet above the engine, making that the highest point.

I then started to fill from there and could hear the system filling up, I kept pouring until the coolant poured out the collant filler cap piece. Connected the coolant hose back up, gave it one more shot of coolant through the cap to top it up and I was done. I checked for bubbles and there were none, have done about 1000kms on the sled since with no overheating.

This was much easier than Yamaha's instruction they give in the shop manuals.
 
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