Shortly after I purchased my 2004 XC90, I noticed some oil seeping from the connection between the charge air cooler and the pipe that leads to the throttle/ETM. The connection is supposed to be an air-tight one, but it’s still possible that oil seeps out from here. If you’re thinking to yourself that oil probably shouldn’t be seeping out of there in the first place, you’re right.
But, there’s a good chance that some oil does seep out from this connection, and you shouldn’t be too concerned about it. Here’s why:
Your XC90 will produce a certain amount of “blow by” – gasses that make their way past the cylinder rings and into the crankcase. These gasses are mixed with very hot oil vapors and removed by the Positive Crankcase Ventilation (PCV) system to avoid pressure buildup that can lead to blown seals and an actual oil leak (as opposed to seepage). To keep these noxious gases from entering the environment, they are routed to the intake system to be mixed with fresh intake air and burned during combustion.
These vapors enter the PCV system hot, but as they, make their way toward the throttle, specifically past the charge air cooler, they cool. Go figure.
Vapor makes it past the cooler condenses somewhere in the throttle pipe and dribbles down to the lowest point, thanks to gravity.
That lowest point in the connection between the charge air cooler and the throttle pipe.
When I first saw oil on the outside of this joint, I was pretty freaked out. Was my turbo seal blown? Were my piston rings faulty? Was it my PCV system? Was I going to have to sell my XC90? No, no, no and no. It’s totally “normal” as long as the amount that collects there isn’t too substantial. I cleaned that area back inwardly Summer 2016. By October, the seepage had re-appeared but not to the degree it was when I cleaned it.
Signs that you have more than a little seepage:
- Significant oil loss as indicated on your dipstick
- Blue smoke from exhaust at startup and under boost (when you’re turbo is spinning fast)
- Signs of oil leakage under your XC90 (make sure to look at your undercarriage cover if you have for any signs of leaking as oil may collect on this and not drip past for some time.)
If you have some seepage at the same place I did, take the ETM pipe off, clean up the area, re-attach the pipe and see how long it takes for the seepage to re-appear.
HINT: take out the driver-side headlight first to gain better access to the hose clamp if necessary. Also – if you are the first-person to remove this pipe, there is a crimp-clamp that connects a rubber hose to the pipe about halfway between the charge air cooler and the ETM. Removing this clamp+hose makes it easier to get the pipe in a position to clean it. You’ll need a new clamp (I used a hose clamp) to replace this one.