1999 formula deluxe 670 oil leaking into engine - Snowmobile Forum: Your #1 Snowmobile Forum

gary_warner4 · 10-03-2012, 01:01 PM

I have a 99 formula deluxe 670, has 1200 miles i just bought it last year only got to ride 1 time ,no snow, when sled sits not running oil leaks into engine. oil runs out exhaust when started and smokes terrible till it all burn off. this past summer like 2/3 of oil in tank leaked down. when sled runs it runs awsome some one said my rotary valve was broke i think it runs too good for that. any ideas.

**RJ Gleason** · 10-03-2012, 01:12 PM

Is it the main tank, or the small bottle that circulates to the rotary valve shaft?

gary_warner4 · 10-03-2012, 01:37 PM

i beleive there is only 1 tank it is the main tank.

aduck · 10-03-2012, 04:29 PM

Sound like its not closing all the way.

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gary_warner4 · 10-03-2012, 08:09 PM

What is not closing ,the oil pump.

**smallengineguy** · 10-04-2012, 06:12 AM

It sounds like the oil pump is letting oil by when it sits. Replacing the pump will fix the problem.

gary_warner4 · 01-13-2013, 10:51 AM

Turns out it is the seal on the rotory valve shaft. Requires complete tear down to split crankcase. Looks like its going to stay like that.

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IRONDOG · 01-13-2013, 11:22 PM

It is NOT required to split the cases on a 670 to change the rotary shaft seal. It can even be done with the engine in the chassis but it is easier with the engine out. Remove water pump cover, impeller and assorted washers, plate, etc., from front of the engine. Remove rotary valve cover, rotary valve and rotary seal retaining snap ring from rear of engine. Then drive the rotary shaft out from the front to the rear with a hammer and the proper tool. If you don't have the proper driver, use a 5/16" deep well 1/4" drive socket. You will want to replace the water pump seals as well while you are in there. This is a common procedure with Rotax rotary valve engines. It should be performed by an experienced mechanic to avoid any possible problems. It's easy screw this up if not done correctly.