Hey all,
I was flipping through my service manual on my 1995 850 turbo wagon w/ 150k miles and have not seen any PCV maintenence. I am getting about 17 around town and maybe 22 on the highway (which I seldom drive) and was wondering if this was low? Would serviceing the PCV help? Would replacing the O2 sensor help more (replaced once at about 70k)? Just curious and wanting to improve my mileage a bit. Thanks for any info.

 

Hi qadig

↓Is this something that can help you?
http://www.fcpgroton.com/volvo850oiltrapturbo.htm

I couldn't find a service instruction either, but the above URL has an illustration on the PCV components on turbo engine (I'll attach it anyway).

↓O2 sensor:
http://volvospeed.com/Repair/o2sensor1.php
http://www.fcpgroton.com/volvo850oxygensensors.htm

I would believe cleaning the PCV system & replacing the O2 sensors (only if they have failed) help increase fuel economy, as well as replacing regular tune-up items & checking for all fluid levels & conditions, keeping wheel alignments, etc...

I'll let others add more alternatives...


JPN


[IMG]local://upfiles/6892/42F94BAEFA5A4D2197CC82943866D3E1.jpg[/IMG]

 

Checking for vac leaks is another way to gain some MPG as well
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I also have a 1995 T5 wagon and it returns ahighway mileagein excess of 30 mpg when being drivenat about a steady 65-70 mph.

So, from myperspective,it does seem your vehicle is a bit heavy on petrol.

And a blocked PVC could be one of the reasons (among many, e.g. brakes binding etc.)

Best of luck with your investigation(s).

 

As I posted seperately, I had an issue with the oil filler cap leaking oil on top of the manifold. I replaced the cap and its gasket to rectify the leak, butits not right that it had enough pressure to push the oil out way up top to begin with... so I ordered the PCV kit and am doing it as early as possible when they arrive tomorrow. I'm driving in fear every minute that now that I sealed the filler cap better, its only a matter of SHORT time before I blow a seal and have a leak elsewhere. But.....to relate to your question, is there a connection between the mileage and the pcv? I'd have to say YES big time. Before replacing the cap, I was getting great MPG. I replaced the cap, and my MPG has decreased greatly. This is leading me to believe that the PCV is clogged completely, but I was still able to get good mileage while the crankcase was venting through the cap (even though it shouldnt have to). Now that I sealed it, and it really has no way to vent, mileage has gotten ****ty. My parts are due to arrive for the PCV tomorrow, and Im taking a half day at work to get it done. Wish me luck...I'd take photos like I usually do but theres already a great HOW TO that someone posted with photos. I'll report back regardless.

 

Newb question, but what does "PCV" stand for?

It sounds like perhaps you could run some seaform through the lines and unclog some of this buildup?? But i'm not sure..

 

Positive Crankcase Ventilation

 

This site rocks... Thanks for thie info, I think I will investigate the PCV system then and clean it out/replace components as neccessary. I did a tune-up about three months ago and it helped some but not a whole lot. At that time I was getting 14-15 around town on a good day (both trip computer and manual calculation). bout three weeks ago I had the timing belt and water pump replaced (would have done it myself but time would not permit, however, I love my mechanic $360 for the job) and that helped more than anything. I did the brake when I got the car about a year ago and they seemed to have good clearance, calipers etc.. I just got done replacing the struts last night and have an appointment for allignment later today, so we'll see how that helps out. I just wanted to line up my next project. Thanks for all the info.

 

would fitting a filter on the valve coverhelp with back pressure mabey like the one pictured

 

Fitting a filter on the valve cover??

The valve cover is simply what it states....A cover....

 

i mean the rocker box /valve cover not, the plastic spark plug cover ive seen these filters on a lot of v8 engines ,ive back pressure on my 850 and when removing the oil cap or dipstick there is pressure behind it so would this filter work?

 

Lancia66... what an interesting solution... don't know... I'd think it certainly would relieve the pressure,and I don't think it would pass emissions testing depending on where you live, butwould it cause a code to be thrown?

 

I would imagine putting a breather filter on that PCV hose like lancia66 would definitely help relieve pressure if you're blowing oil through the cap, you won't pass emissions of course, because you're venting crankcase blowby to the atmosphere. Also, because our cars have a Mass Airflow Sensor, you're venting out metered air, might cause you to run rich.

 

mabey not a good idea then mind you i could try it by removing the dipstick and sticking it on the dipstick tubethengetting the emissions looked at

 

just cleaned all pipes and changed the 4mm hoses to silicone a few were split and blocked all fixed ,no back pressure and what a change .1 happy volvo owner