1+ with Chris 850. The build up in the PCV system is like crud or sludge, you CAN'T drian it out. Also, like Chris, mine was so plugged up that I did not have a smoking dip stick and my block (lower port) was almost totally plugged up. I'm pretty sure I posted a picture here or on the other thread. I had to get a metal screw and dig the stuff out of the bottom of my block.
https://volvoforums.com/forum/volvo-...e2/#post284034

1+ with Bidulon. When our S70 blew it's cam seal, I lost about 2-1/2 quarts of oil in just 2 miles and did NOT EVEN KNOW IT. Good thing for me was that the seals blew 2 miles from home and when I walked out the door to check my mail and seen the trail of oil coming down my street and into my garage, I knew I had a serious problem. Worse yet is a RMS (real main seal) leak. It usually cost about $1,500 to have that seal replaced because the mechanic either has to pull the motor or drop the frame with the tranny to get to it. You can't assume that a leak will be a drip, it may drip for a few days and start gushing.

I consider the PCV system service as important as the timing belt change. If you don't know the history of it, change the thing. Cleaning it won't work.
https://customers.volvocars.com/owne...C/vin1996.html

These are my favorite instructions for doing the job on a turbo car. Make sure you clean the EGR if you have one.
PCV Replacement

Do you have a EGR link:
https://volvoforums.com/forum/volvo-...r-valve-58475/

 

Thank you for that information Bidulon, I will look in to replacing it than..like you said fix it before it gets to bad. Ummmm the hose that goes in to the top of the engine through the fuel rail area....I replaced the clamp on the part going into the engine. Ialso replaced my oil cap seal but I think that could be the issue(atleast some what)...because it seems to be leaking still. I think rspi mentioned after 100k you should look to replace it if I recall...my car is pushing 180k so I think its about time.

 

Unheated oxygen sensors on 1976 to early 1990s vehicles

Every 30,000 - 50,000 miles

Heated (1st generation) oxygen sensors on mid-1980s to mid-1990s vehicles

Every 60,000 miles

Heated (2nd generation) oxygen sensors on mid-1990s and newer vehicles

Every 100,000 miles

 

I have heard a few people talking about testing their head pressure on their cars by putting a glove on it or something. I know that there is a proper test that can be done to test the pressure on the PCV system to determine if it's clogged or not. I don't know if it's pressure in the head, intake or what??? Does anyone know what that test is and how much pressure is suppose to be in the system and what is considered high?

I'm asking because I just found out that the ECU tells what the manifold pressure is and was wondering if you can tell by the pressure there since that connects directly to the head? I have a code reader that reads the PSI in the intake manifold.

 

You can put a glove on the oil filler hole. While the engine is running you should not have overpressure so the latex glove should not inflate. But I am wondering what happened if it is not clogged... any risk to suck the glove into the engine...?

It is also easy to check if the oil filler cap is sticking on its place when you are speeding up the engine. If not or if it is even slightly moving (it has to be turned to the opened position), it means you have some blowby gasses escaping by this cap. Normally the gasses are sucked by the PCV which create the vaccum. That's why the filler cap should not moved and be sticked (lightly) at its place.

One good evidence of a clogged PCV is when you have oil around the oil filler cap. Oil should not be pushed out if you have the vaccuum. Some people facing this oil presence are just replacing the gasket. I think the real problem is still not solved. Source of oil presence is the overpressure which can eventually lead to shaft seal leak... and that is another story! I have faced this on my D5...

 

The ecu reads manifold atmospheric pressure or MAP. It gets it's reading from the MAP sensor which is usually located on the throttle body but can be located elsewhere. All this does is tell the ECU how much vacuum or boost is in the system so it can adjust fuel and timing tables accordingly. It also uses an intake air temp sensor to aid in timing adjustments. Also known as IAT sensor.

 

The MAP sensor tells the system how much pressure (vacuum) is in the intake system in a normal engine. I always think of the MAP as reading vacuum simply because it's easier on my mind but it's actually calculating pressure in an "engineers" mind. I'm not sure exactly what it does under boost in a supercharged or turbocharged engine.
MAP is manifold absolute pressure and it somehow measures the difference in pressure (vacuum) between the intake system and the ambient outside pressure and feeds that signal to the computer.

The intake and the crankcase are two separate systems and have nothing in common. The slight vacuum the PCV system is supposed to apply to the crankcase is not monitored by any sensor I know of. It's just there to pull fresh air into the engine usually filtered and supplied just after the air filter housing and then sucks it into the intake system to be burnt after it's picked up moisture and blow by from inside the engine.

I don't think the vacuum is strong enough to pull the glove in but you can also try a glove or balloon over the dipstick tube to get the same effect.

Cut and paste about boost sensor:
MAP sensors measure absolute pressure. Boost sensors or gauges measure the amount of pressure above a set absolute pressure. That set absolute pressure is usually 1 atmosphere (1 atm) or 14.7 psi. This is commonly referred to as gauge pressure. Boost pressure is relative to absolute pressure - as one increases or decreases, so does the other. It is a one-to-one relationship with an offset of -14.7 psi for boost pressure. Thus a MAP sensor will always read 14.7 psi more than a boost sensor measuring the same conditions. A MAP sensor will never display a negative reading because it is measuring absolute pressure, where zero is the total absence of pressure (it is possible to have conditions where negative absolute pressure can be observed, but none of those conditions occur in the air intake of an internal combustion engine). Boost sensors can display negative readings, indicating vacuum or suction (a condition of lower pressure than the surrounding atmosphere). In forced induction engines (supercharged or turbocharged), a negative boost reading indicates that the engine is drawing air faster than it is being supplied, creating suction. This is often called vacuum pressure when referring to internal combustion engines.
In short: most boost sensors will read 14.7 psi less than a MAP sensor reads. One can convert boost to MAP by adding 14.7 psi. One can convert from MAP to boost by subtracting 14.7 psi.

 

Thanks for clearing that up for me. Intake pressure vs crankcase pressure.

Other than that, my Scan Gauge II can swap the MAP for BST (turbo boost pressure).

 

HOSE ALERT!!! When you order your PCV system, make sure you specify that you want ONLY OEM Volvo hoses and connections. If you don't, you'll get crap that may not last a year.