If your ride is suddenly getting less fuel economy, misfiring, or you get a CEL, it may be time for a Volvo PCV system repair.
Justin’s PCV Post
As any engine runs, there are gases from the top of the cylinders that escape past the piston rings and into the crankcase system. These gases are illegal in most countries to vent into the atmosphere. Therefore, some kind of crankcase ventilation system must be designed for all cars. Volvo’s is one of the more complicated systems, and over time they inevitably clog up and stop functioning correctly. The most common symptoms of a clogged PCV system are oil being inexplicably blown all over your engine (mainly under the spark plug cover), smoke or positive pressure up the oil dipstick after the engine has been running for 10+ minutes, horribly noxious odors coming through your air vents when stopped, or blown engine seals. If it’s gotten bad, you may notice smoke coming out of your exhaust at all times.
This tutorial will help you clean the PCV system on your 1993-2000 5-cylinder Volvo engine. Keep in mind that this is focused on a later-generation Turbo model (I have a 1998 S70 T5), there will be some differences between each year and depending whether yours is a N/A or earlier model. P.S. You can click any of the pictures in this topic for a larger view.
If you own a turbo, it is a good idea to clean the PTC nipple periodically every 40-50K miles or so (see step 7 and pictures further below in this post), or get rid of the flame trap if your N/A car still has it installed. *You may want to start here if you see excess pressure; then re-evaluate replacing the rest of the system once clear.*
Some PCV introductory notes
Before you even start this job, make sure you’ve got all the tools you’ll need together, especially if it’s your only car.
I found a 1/4″ socket and extension bar (and a U-joint), along with all the metric sockets, to be the most helpful in this job. I have a $15 Companion car kit I bought at Walmart that was actually great for the task. Get a pair of long needle-nose pliers if you don’t have any, they are quite a life-saver if you drop things. A magnetic or claw-arm grabber would not be a bad idea at all. You’ll also need a couple Torx sizes (T-20 and T-25), one of the screwdrivers with multiple bits would be just fine for this.
For the 12mm bolts underneath, you’ll need a 3/8″ wrench, 2 long extensions, and 2 U-joints to reach the nearly impossible bolts underneath.
I’d go ahead and get a few extra small clamps from what FCP or IPD sent you with the kit just in case you knock anything else off. You can always return unused parts.
**Many people (myself included) have found that the URO parts put in kits by IPD/FCP Groton are absolute garbage. Please, save yourself the hassle of having to do it again in 2 years and buy OEM Volvo parts that will stand up.
Make sure you’ve got your radio code before you unhook the battery. Driving along without a radio can be quite lonely.
Step 1: Drive your car up on ramps (I highly recommend ramps rather than jack stands). You’ll need the front to be elevated to reach the lower manifold bolts.
Step 2: Start removing components. I disconnected my battery and removed it from the car for extra space (negative cable first), then the 3 hoses and electrical connector from the back of my air box. Your car may be different here, I have a SAS injection pump, and on non-turbo models, there are two vacuum hoses on the back of the air box. Make note of the orientation of these, they control the air box thermostat flap. If you have never removed the air box before, just disconnect the hoses (two torx screws hold the MAF sensor to the box, the other two pop right off), grab the airbox and shove it towards the engine. This will let go of the clamp holding it to the fender, and then you can lift it right out.
You’ll also need to remove these two turbo hoses if your car is a turbo model. The front one connects to the underside of the idle control valve (silver cylinder). I removed this hose and the idle control valve to clean it as well – you can spray carb cleaner straight through it and it will do a good job. The original Volvo hoses have 7 mm clamps on them, most of which can be gotten to with the small socket wrench. I find it easiest just to remove the hoses and leave the clamps on the ends so you know where they go later. I had to take a small 7 mm wrench to the back one by the turbo, because there is no room for anything else.