“Leak” is a bit of a misnomer when it comes to oil and the Volvo XC90 oil leak sources – at least when it comes to my 2004 2.5T, and I know the same theory can be applied to other years and engines as well. I suppose that any place oil escapes from the oil circulation system, only to find itself in a place where it should not be (ie your driveway or all over your valve cover) could be considered a leak. I’m sure I’m on the same page as most XC90 owners out there. But keep in mind there are a few other ways you could be losing oil in a Volvo XC90 that may not fall under the category of a true leak. There’s also a way that you could be losing oil, in a way that’s expected, but just not in the manner it was intended (I’m looking at you, charge-air-cooler-to-throttle-pipe-connection). That sounded confusing, so let me explain:
XC90 Oil leak at the cam seals
When cam seals wear out, oil can seep past them and leak down the front of the engine. What makes this leak hard to diagnose is that you have to take the timing belt cover off and really look hard to find the source. Now, it could also be that the seals were fine and that excess crankcase pressure is the culprit. In which case, you’ve got a likely PCV problem – which has grown into a cam seal problem. If this is the case, you may be looking at some repairs in your future. – perhaps even a complete timing belt service if it hasn’t been done since replacing the seals involves removing the timing belt, which gives you access to the water pump, idler pulley and tensioner. It’s just one big “since you have access, you might as well change this” scenario.
XC90 leak at the oil fill cap
A leak from your oil fill cap could mean that you have excess crankcase pressure and the pressure is finding its way past your old, tired oil filler cap gasket. Contained in that crankcase pressure are blowby gases (from combustion) along with hot oily vapor (which is essentially the gaseous form of oil). When you have excess pressure in your XC90 crankcase, that pressure wants to escape, and will do so starting with the weakest spots – usually a seal or gasket of some sort. This could be a cam seal (as noted above) or it could be your valve covergasket and it could also be your filler cap gasket.
The tricky part about this leak is that there’s rarely any evidence of a leak from here until you take the plastic coil/spark plug cover off and see the oil pooled in the recesses as well as, possibly, in your spark plug holes. If you have a leak here, get a new gasket. It’s around $10 online for a Genuine Volvo one. If it still leaks, do some testing to see if it’s possibly your PCV system. Speaking of which…
XC90 PCV system oil leak
If you have oil in your spark plug holes or along the top of your engine where the coils are, you could have oily vapor seeping out of the PCV hose that comes out of the top of your engine and goes to your catch can that’s attached to the front of your engine. This hose was a weak point on earlier models and has since been modified, bu there are still a lot of XC90s out there with the old hose. The hose gets brittle and cracks. Hot, oily vapor escapes into the relatively cooler atmosphere, condenses and pools. Yuck.
This one’s a little trickier to fix but it can be a DIY job with the right instructions and intestinal fortitude. PRO TIP: If you’re going to change this hose, and your XC90 has over 100,000 miles on it (which many older models do at this point) consider having your PCV system serviced. This is a vital system on your XC90 and when it gets backed up it causes oil leaks. Essentially the system relieves the crankcase of pressure, which avoids many of the leaks noted in this post. It can be on the pricey side but I liken it to a timing belt service – you don’t do it every day, and it’s usually worth every penny.
XC90 charge air cooler oil leak
This one seems to freak out a lot of people but it’s explained very simply in this post. Crankcase gases from the XC90 are removed from the crankcase by vacuum (or by pressure when under boost) and sent into the intake airstream prior to where the intake air passes through the charge air cooler. Still with me? As the filtered air and the blowby gasses pass through the cooler, the hot air that contains oily vapors cools, condenses the vapor into oil, making it heavy. The force of the intake carries some up and through the throttle where it dirties the throttle plate and then gets burned in the cylinders. However, some of the condensed oily vapor settles in the throttle pipe and rolls down to the lowest point – the junction between the charge air cooler and the ETM pipe.
This joint has no rubber to help with the seal – just two plastic pipes held together with a hose clamp. This is where the oil seeps out. The good news is that it’s easy to spot from below the car without jacking it up. If the area is shiny and coated with oil. It’s a leak. Your best bet is to Take off the intake pipe, clean the pipe and the connection on the air cooler, and re-install the pipe making sure the hose clamp is tight. Since you’ll have this pipe off, you may also want to clean the throttle plate of your XC90 in-place if it’s dirty (which it likely is). Slide under the car and look up using a flashlight. You can see the plate. If it’s dirty, clean it.
XC90 oil pan drain plug leak
If you aren’t using a fresh crush washer every time you change your oil, you run the risk of this leak occurring. Also make sure you’re using the right amount of torque on that bolt and that it’s not cross-threaded. The crush washers are cheap. I think I pay $.49 for them and they’re cheap insurance against an oil leak on your XC90. If that doesn’t solve your problem, get yourself a new plug. Get one with the magnet in it – BUT – don’t get one with the magnet covered in chrome. Call my cynical but I’ve seen the chrome flake off off those – and nobody sees it anyway so why does it have to be chrome? There are plenty of reputable sources out there to buy from online.
XC90 turbo drain seal oil leak
Some people experience a leak where their turbo drain meets the tube that carries the oil back to the pan for recirculation. It’s a thought spot to get to, by it’s possible to replace the seal. You can get it at FCP Euro or one of many websites out there.
Ok, so there are definitely more places than these for your XC90 oil leak to happen. Assuming you have an oil leak. Many cars go their entire life with no oil leak. However, these are some of your basic, more easy-to-spot leaks that I’ve had experience with on my XC90.