07 isx leaking oil from rear

where at on the rear, of the head ,the motor.

 

Make sure your crankcase breather isn't plugged and pushing oil out the rocker cover gasket. Other than that, rear headgasket leaks are common, but so is rear cam shaft covers or even bell housing problem. So you need to power wash the area and check for the source.

 

Rear crank seal between engine and transmission

 

With your crankcase breather filter on an engine with some miles on it I recommend drilling a hole in the filter to help release the built up gases from the crankcase.
When standing at the drivers side steering tire looking at the engine, I have always drilled a 1/2" or larger hole in the FILTER, NOT the housing, at the rear vertical flat surface of the filter. If you were to look at the filter in place, you would have the drill bit parallel with the ground and pointed towards the rad.
The gases that build up in a crankcase are explosive, and excessive resistance to atmosphere release can be potentially hazardous.

 

Are there engine modifications you aren't telling us about, or possibly unaware of?
All 871's have the crankcase filter assembly on them. Number 15 on this diagram is the crankcase filter assembly. It has 8 small bolts holding the cover on, the filter I told you to drill a hole in is inside this.
Number 12 is the crankcase ventilation tube. The (stupid) point of this filter is an attempt to remove oil and fuel vapor with the filter to only vent clean air. If you look at the filter housing you will see a small line coming out of the very bottom of it where condensed oil and fuel droplets are returned to the crankcase.

 

I bet he has an 06 isx cm870 just like I do in my 07 w900 I dont have a filter on mine either.

 

Either way the c/c filter being plugged won't be the actual issue, it will only amplify the problem.


If your oil leak is along the red in these drawings, your flywheel housing gasket is leaking. No small job. You have to drop the tranny, pull the flywheel, remove the oil pan, (use blocks and jack(s), unless you have a crane to support the engine), because you then have to remove the flywheel housing and your rear motor mounts attach to it. Expect in the neighborhood of 20-25hrs labor.

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If your oil leak is at the red marks here, these are the rear cam covers.
If your oil leak is the little plugs circled in green, these are the oil cross drilling plugs.
If it's the blue line, that can be either flywheel housing gasket, or head gasket. Rarely head gasket, and most likely f/w housing. Head gasket is predominantly coolant instead of oil.

Based on the year of your truck, my money is on flywheel housing gasket. Do the rear main crank seal at the same time, you're there anyway. The f/w housing is cast aluminum, and the block is of course cast iron so they expand and contract at different rates and they also flex at different rates and this is where the torque differential is highest. The engine is trying to rotate and the motor mounts are trying to stop it.