I'm new to this Polaris thing so I have a few questions. I just purchased a 98 400 Scrambler 4x4 that needs some TLC. The guy I bought it from says that he did a complete rebuild, top and lower end back at the first of the year. I halfway believe the guy. Quad start right up, any temperature, has tons of power. After 2 to 3 hours of break in he says it started blowing water out of the overflow tank. I am thinking head gasket at this point but the head shows no signs of a leak. I have bled the system using the 10mm bolt on the head. I did not completely remove the bolt, just loosened it till i could turn it by hand. I never heard any air just a steady stream of water running down the head onto the jug. I tightened everything back up and topped everything off and then I noticed a radiator leak. Could the leaking radiator be allowing air into the system making some come out the overflow tank? Fan is working, but it is straight wired to the key. That has to be fixed but I can do that later. He told me that both seals in the pump were changed and he even had the pump shaft chrome plated at time of rebuild. Any help will be greatly appreciated!!!

 

If the guy is truthful on the rebuild,water pump seals,etc,(chromed the pump shaft??)then either the radiator leak depending on how large could be the problem or a warped head or cylinder from a previous over heating problem could cause problems. Start off with a coolant pressure test to see how long it can hold 10 psi. Check the radiator again,plus don't over look the radiator cap itself(if it looks original) that can leak pressure and go straight to the over flow bottle and out.Plus check that all hoses are hot ad feel full to show that it's at least circulating.

 

I know the radiator is leaking pretty good. I was thinking about just starting there with a new one and new cap as well. I know it's going to need one regardless.

 

If it's leaking bad then yes replace it and the cap.Bleed the system again and hopefully that may solve the problem. There are new or rebuild radiators fairly cheap.RADIATOR FITS POLARIS SCRAMBLER 400 1996 1998 1999 2000 / SCRAMBER 400L 1997 | eBay You can get the radiator sensor on ebay for 20 bucks or try to match up at a local auto parts supply.

 

Do you have any sort of wiring schematic available?

 

Here's 97 wiring schematic. Hardly any noticeable changes between 97-98. Sorry for a Sportsman.. If I could only figure out how to transfer pics from my pdf manuals.. Here's manual that should help.https://www.tradebit.com/filedetail....ehicles-repair A manual dedicated to the 98 alone is more costly.https://www.tradebit.com/filedetail....actory-service

 

Thanks man.