2009 VW Tiguan Engine Oil Separator
Mark: Hi, it's Mark from Top Local. We're here with Bernie Pawlik, Pawlik Automotive in Vancouver, Vancouver's best auto service experience, 20 time winners of Best Auto Repair in Vancouver, as voted by their customers in 38 years of maintaining and repairing cars in Vancouver. Of course, we're with Mr. Bernie Pawlik and we're talking cars. How you doing, Bernie?
Bernie: Doing very well.
Mark: So, today's victim, 2009 VW Tiguan that had an oil problem. What was going on with this vehicle?
Bernie: So this vehicle actually came to our shop with a ... It was running very roughly. The check engine light was blinking, which is a serious issue that, I've said before many times, a check engine light if it's just on solid, you need to get some repairs done some time in the future, but when it's blinking, it's serious. It'll create a catalyst damaging misfire, which basically, without getting too wordy, means it'll cost you a lot more money if you don't fix it really, really quickly. So the owner smartly brought the vehicle in and we did some testing and diagnosis on it.
Mark: And what did your testing and diagnosis find?
Bernie: Well, we found a few things. One, there was some problems with the ignition coils. They were worn out. There was misfires in three of the four cylinders. We did a visual inspection. The spark plugs looked pretty old. There was also a little bit of oil seeping down the spark plug tubes, which can cause a misfire problem. It wasn't serious enough to fill the well up with oil, which creates a definite misfire. It wasn't that deep, but there was some oil seeping in. And also, there was a code for a lean air-fuel ratio condition. We did some further tests on that, and we found the engine oil separator was worn out and causing a major vacuum leak in the engine.
Mark: Okay. Oil separator. What causes an oil separator to fail?
Bernie: Well, on these type of vehicles, and a lot of similar vehicles, the oil separator, it's like a PCV valve. It's a crankcase ventilation valve. Some cars, they call it an oil separator. They do on this particular vehicle.
What this oil separator unit does is, it allows crankcase gases to be sucked into the intake manifold to be re-burned. It's a pollution reduction device, very effective. But if it doesn't suck the right way, it'll suck engine oil right out of the engine, into the intake manifold. Of course, then you have blue smoke and a whole bunch of other problems. So the oil separator separate ... prevents the oil from actually getting into that, getting mixed in with the crankcase gases. So that's how the unit works.
Mark: So positive meaning basically that it's taking what would be negative pressure and turning it, using that to pull the gases out of the crankcase and to be re-burned?
Bernie: Exactly. In the past, and we're going way back in the past, unless you look at a Dodge diesel from the mid-2000's, which they actually still add a road draft to, believe it or not, crankcase gases were vented out to the atmosphere. This was actually one of the worst pollutants that an internal combustion engine can make. If you smell it, it's the most noxious smelling fumes, because it's not really burnt gases. It's just gases that have escaped past the pistons, mixed with a bit of crankcase oil. It's a horrific smell, and really, really bad for the environment. So, it's one of those pollution devices that actually really is very effective and really doesn't rob an engine of any power at all, by doing it. It probably does a tiny bit, but it's so minute, you'd never notice it.
Mark: So what's the difference between a positive crankcase ventilation valve and an oil separator.
Bernie: I would say complexity is kind of it. But you'll find this term used on a variety of different vehicles interchangeably, European cars. I'm just actually going to show some pictures right now.
This is our Tiguan engine oil separator, or PCV valve. The PCV part is kind of in here, but this is the top side view. This is what you'd see if you look on top of the valve cover. This is the underside view, so this is with the unit removed. This is what sort of sits against the valve cover, so there's a gasket here. There's a number of passageways and rubber valves inside. You can't really see anything. That's why you basically replace the whole unit, because there's nothing serviceable on it. But the good news is, you can actually service this unit. It's a separate replacement unit.
Now, compared to a PCV valve, this is a PCV valve that's ... this is very commonly used, starting in the 1960's up. You'd find this on American cars, Japanese cars, earlier European vehicles. Nowadays, some cars still use this PCV valve. It does exactly the same function, believe it or not. This part costs about, I don't know, you can probably buy it as cheap as two or three bucks for some vehicles. But for some reason, European vehicles, they decided to get really complicated. And they fail a lot more frequently.
These PCV valves used to plug up, in the olden days. Again, they were cheap to fix and you could, every time you changed the oil, or every second oil change, you could pull it out, shake it, rattle it, if it moved, then it's good and you could keep it. But anyways, that's not the case in the Volkswagen. It's much more complicated. So there's our little picture show for the day.
Mark: Any idea why it's mostly European or VW vehicles?
Bernie: Yeah, well it's interesting you say that, because it seems to be mostly European vehicles that have this type of system. It's not just VW, it's even Range Rover, which is an English vehicle. I don't know, maybe there's an engineering school in Europe that all the automotive engineers go to, and they all learn to make a crankcase vent valve. Because it's interesting, when you look at cars, how on different continents, they have their unique ways of doing things, even though they're all the same, the internal combustion engine is the same thing.
But you won't find these kind of PCV valves, generally, on American cars, although they're starting to get more complex. But yeah, you'll find these on Porsches and Volkswagen, BMWs are famous for failing, Mercedes almost never. So they've got those built pretty different for Mercedes, but certainly the Porsche, VW, Audis, BMWs, they're all common failure. Land Rovers as well.
Mark:So what's involved in replacing this oil separator on the Tiguan?
Bernie: Well, on a Tiguan, fortunately it's not too difficult. It bolts on top of the valve cover, reasonably easy to remove and replace. So that's positive, because a lot of them are not such. A lot of BMWs, and it's a high failure item on a lot of BMWs, involves removing the intake manifold to access the crankcase vent unit. And there's a bunch of other plastic pipes that tend to break and crack at the same time. There are certain VW and Porsche products where you actually have to replace the whole valve cover, because that actual ... All the components are inside the valve cover. I mean, really brilliant idea. I mean, great from a manufacturing point of view. I'm being a little cynical. But when it comes to repair and replace, it becomes much more complicated. So on the Tiguan, it's pretty good. It's a decent job, not too crazily expensive.
Mark: So you mentioned oil leaking into the spark plugs. What did you do about .... spark plug tubes. What did you do about that?
Bernie: Well, at this point in time, we determined the leak wasn't severe enough to actually repair the leak. Normally, we would say, "Hey, let's just do a valve cover gasket and put new spark plug tube seals." But, that's not possible on this one, here. The good news is, the crankcase vent valve is easy to replace. The bad news is, doing a valve cover gasket on this particular engine is extremely complicated. You actually have to remove the entire cylinder head, and then disassemble it and the valve cover's all part of that. So we determined with the amount of cost and the amount of leakage that it would be best for the owner just to leave it and monitor it for the time being. It would have been a very expensive job. So, from an engineering perspective, that wasn't such a win for Volkswagen. But I'll give my thumbs up for the crankcase vent valve, or the engine oil separator, I should say.
Mark: How are Tiguans for overall reliability?
Bernie: They're not too bad. The key with any of these modern vehicles is maintenance. Change your oil regularly, and change it more frequently than the manufacturer recommends. A lot of them have very long oil change intervals with synthetic oil. Just do it, run it 75% of the time or less than they recommend. Then you're in the safe margin. You're in the safe zone. Combustion chamber cleaning, really important on these things, because they're a direct fuel injection, the valves can gum up. Or not gum up, sorry, get pretty serious deposits. So it's best to deal with those sooner than later. I'm losing my voice here. Sorry.
Mark: If you're looking for service for your VW or European vehicle or you've got a ... any vehicle that has a check engine light blinking, the guys to call are Pawlik Automotive in Vancouver. You can reach them at 604-327-7112 to book your appointment. You have to book ahead. They're really busy. Or, check out the website, pawlikautomotive.com. Hundreds of articles and videos on there, as well as on the YouTube channel, Pawlik Auto Repair, over 320 videos on all makes and models of vehicles and more every week. And of course, thank you, so much, for listening to the podcast and thank you Bernie.
Bernie: Thanks, Mark. Thanks for watching and listening. We really appreciate it.