Stoked For My "new" 96 855R..

[Volta55]

removing the carpet will only allow you access to 2 service ports, which are mostly used for replacing your fuel pump. You will not be able to replace the lines from these though, and probably wont even be able to see more then about 6" of them very well. You really need to drop the tank in order to see the whole hose.

+1 thanks man

Anytime You might also like this, I found these PDFs very useful when getting to know pieces of the 850: http://www.volvoclub.org.uk/volvo_workshop-850techdocs.shtml

thanks! i will do my reading..

i also was looking at this blog from some guy.. very cool stuff http://volvo850wagon.wordpress.com/2012/07/02/57-evap-leak-fuel-tank/

even though it is not my CEL code, it could be?

[mercuric]

Possible, the system does usually detect EVAP system leaks, the diagnostic it uses is pretty comprehensive, but not foolproof. It wouldn't hurt to inspect the hoses from the tank to the canister up front anyways. The canister is near the front driver's side corner. Start from there and follow all the hoses in question.

Personally I'd get the rear O2 rectified and reset the ECU to clear fuel trims (so it will relearn them). The ECU is in the box near the front passenger's side headlight with the plastic hose running to it, unseat the one labeled bosch (not aisin, that for the tranny) for a few minutes to reset it after dealing with the rear O2. If you still have fuel smells after a few days driving to relearn fuel trims, keep on poking around. You need to get that rear O2 rectified to pass inspect anyways

It's also not really a concern if you have fuel smell on cold start or under wide open throttle (WOT). The car runs quite rich when it's cold, and at least somewhat rich at WOT. On my 850, which runs a modified ECU capable of fairly extensive data logging, the mixture is 30% richer when the car is first started in the morning, and it works its way down to normal fueling as it warms up. It's mainly the first 10 seconds when it runs pig rich.

[volvoguy23]

Possible, the system does usually detect EVAP system leaks, the diagnostic it uses is pretty comprehensive, but not foolproof. It wouldn't hurt to inspect the hoses from the tank to the canister up front anyways. The canister is near the front driver's side corner. Start from there and follow all the hoses in question.

Personally I'd get the rear O2 rectified and reset the ECU to clear fuel trims (so it will relearn them). The ECU is in the box near the front passenger's side headlight with the plastic hose running to it, unseat the one labeled bosch (not aisin, that for the tranny) for a few minutes to reset it after dealing with the rear O2. If you still have fuel smells after a few days driving to relearn fuel trims, keep on poking around. You need to get that rear O2 rectified to pass inspect anyways

It's also not really a concern if you have fuel smell on cold start or under wide open throttle (WOT). The car runs quite rich when it's cold, and at least somewhat rich at WOT. On my 850, which runs a modified ECU capable of fairly extensive data logging, the mixture is 30% richer when the car is first started in the morning, and it works its way down to normal fueling as it warms up. It's mainly the first 10 seconds when it runs pig rich.

I always thought the rear o2 sensor had no control over fuel trim, but instead to monitor the cat?

[mercuric]

True, but VIDA does specify "fuel trim inhibited" as a condition for the rear O2 sensor codes. Not so much that the rear O2 is used for trim, but it's malfunction "inhibits" trim, probably reducing correction limits and/or what conditions are used to make adjustments. It does not specify exactly what "inhibited" means.

The rear O2 issue need to get resolved to pass inspection, so I assume get the fuel system in a sane state and let it relearn fueling before spending a bunch of effort on a potentially-related issue.

[Volta55]

okay so trying to replace rear o2.. i thought this would be a pretty straight forward procedure; but of course not ( especially on a new car to me )

please correct me if i mislabel any terms/parts..

taking off the intake pipe ( inbetween the intake filter and turbo ) was caked in oily grime towards the bottom..

the "hardline" has a styrofoam tube around it, with a small plastic tube inbetween?

then after i managed to mangle the hardline clamp, i removed the intake pipe and saw this

i'd venture a solid guess and say that is not good

the rear o2 clip came off normally ( first thing to go smoothly ) i jacked up the car and attempted to remove the plate with the 4 bolts underneath the rear o2

all 4 bolts spin and do not come out.. threads seem to be non existent.. i am not sure how to remove this plate. any thoughts on removal and reinstallation?

*side note- the guy had some shotty exhaust clamp about 6" downstream of the o2 sensor, i'd take a guess and say that is where my exhaust leak is from

then to get my mind "out of the box" i crawled to the front engine area to see where this oil leak is coming from

thankfully it LOOKS like it is just some sort of oil return lines?

then alittle bit of liquid underneath the transmission area ( i cleaned the area with alcohol and will see how much develops )

now i know what a winter commuter from NH looks like

[mercuric]

First picture is of the PCV connections to the intake pipe. Grime there is fairly normal, but can be a sign of a clogged PCV system.

Second picture shows significant oil seepage on the inlet of the turbocharger. This can either be from oil coming in through the PCV system connections in the first pic, or oil leakage past the turbocharger's cold-side seals. Both are normal on higher mileage vehicles, and if it's never been cleaned, not terribly surprising. This can be made worse if the PO didn't change the oil on a regular basis. Clean it up and check back in a few hundred miles. I wouldn't worry too much unless there's signifcant shaft play at the compressor wheel or you find oil keeps coming into this area quickly. You might want to remove the intake pipe between the turbo outlet and the hose going down to the intercooler, you may find the entire system is full of heavy oil residue, which could be a sign of failing turbo seals and/or excessive blowby. Regardless, you are likely due for a PCV system refresh. At the very least the nipple in the intake hose where the smaller and larger hoses attach should be cleaned out. Then remove the dipstick and attach/secure a latex glove or condom to the oil filler tube, start the engine. If it inflates, you have PCV system pressure and should remedy that ASAP. See also: http://www.___.com/forums/viewtopic.php?f=1&t=28487

The third picture, with that plate, is going to be fun. If the threads have rusted out and you can't remove the bolts, the usual methods of destruction apply. I forget what exactly provides the threads on the car, if they are machined into the underside chassis or provided by spot-welded bolts. I seem to recall the later. Either way, it's going to be a pain to remove those bolts. I'd first try a pair of vise-grips, tight on the bolt head, tool vertical -- and pull down on the bolt while turning. This may help engage any remaining threads and you might be able to get it out. Another option is to use something like an angle grinder to cut off the bolt heads and then drill out the remainder. You're probably going to have to repair the body-side threads one way or another to get the plate properly re-attached. You likely can thank road salt for this :| Oh how I don't miss living in new england! The plate isn't critical but may help to reduce chassis flex. There's nothing attached to it.

The oil lines are for the oil cooler. search oil cooler lines on the forum and you'll find a bunch of posts about them. They are a routine problem on these cars. Get in touch with forum member "jdlc", he rebuilds these. See: http://auctions.volvospeed.com/DISCOUNT-9498-850VSC70-Turbo-Cooler-Lines--3-Money-Saving-Options,name,100046,item_id,0,ad_type,ad_details

[Volta55]

First picture is of the PCV connections to the intake pipe. Grime there is fairly normal, but can be a sign of a clogged PCV system.

Second picture shows significant oil seepage on the inlet of the turbocharger. This can either be from oil coming in through the PCV system connections in the first pic, or oil leakage past the turbocharger's cold-side seals. Both are normal on higher mileage vehicles, and if it's never been cleaned, not terribly surprising. This can be made worse if the PO didn't change the oil on a regular basis. Clean it up and check back in a few hundred miles. I wouldn't worry too much unless there's signifcant shaft play at the compressor wheel or you find oil keeps coming into this area quickly. You might want to remove the intake pipe between the turbo outlet and the hose going down to the intercooler, you may find the entire system is full of heavy oil residue, which could be a sign of failing turbo seals and/or excessive blowby. Regardless, you are likely due for a PCV system refresh. At the very least the nipple in the intake hose where the smaller and larger hoses attach should be cleaned out. Then remove the dipstick and attach/secure a latex glove or condom to the oil filler tube, start the engine. If it inflates, you have PCV system pressure and should remedy that ASAP. See also: http://www.___.com/forums/viewtopic.php?f=1&t=28487

i will clean the intake pipe, inlet of turbo, and do the latex glove trick.. is idling enough to blow the glove up?

The third picture, with that plate, is going to be fun. If the threads have rusted out and you can't remove the bolts, the usual methods of destruction apply. I forget what exactly provides the threads on the car, if they are machined into the underside chassis or provided by spot-welded bolts. I seem to recall the later. Either way, it's going to be a pain to remove those bolts. I'd first try a pair of vise-grips, tight on the bolt head, tool vertical -- and pull down on the bolt while turning. This may help engage any remaining threads and you might be able to get it out. Another option is to use something like an angle grinder to cut off the bolt heads and then drill out the remainder. You're probably going to have to repair the body-side threads one way or another to get the plate properly re-attached. You likely can thank road salt for this :| Oh how I don't miss living in new england! The plate isn't critical but may help to reduce chassis flex. There's nothing attached to it.

destructive i guess is the way to go.. i can re-tap the chassis? i dont see why not ( maybe a larger bolt so i can get new threads )

The oil lines are for the oil cooler. search oil cooler lines on the forum and you'll find a bunch of posts about them. They are a routine problem on these cars. Get in touch with forum member "jdlc", he rebuilds these. See: http://auctions.volvospeed.com/DISCOUNT-9498-850VSC70-Turbo-Cooler-Lines--3-Money-Saving-Options,name,100046,item_id,0,ad_type,ad_details

i will keep a close eye on this leak..

thanks again man

[Volta55]

im gunu have to cut the bolt heads off, then possibly drill the holes alittle bigger for larger thread and bolt

could my gasoline smell possibly be due to a clogged PCV system? the intake pipe is caked with sludge :/

[mercuric]

Re-tapping is certainly a possibility, if necessary. I doubt the gas smell has anything to do with the PCV system, no real relation there. It's crankcase vapors that flow there.

Plan on digging into the PCV system sooner, especially if you see crankcase pressure at the filler tube. Failure to remedy can push out the rear main seal, and removing the tranny on these cars is one of the less fun tasks from what I understand. Haven't done so myself, but my indie mechanic was pretty adamant about it being quite a chore. One forum post I read joked about the car "being built around the transmission". It's possible the turbocharger needs seals, but luckily the TD04 on these cars is about as simple as it gets, and if you're comfortable removing/replacing the turbo yourself, it's not an expensive proposition to have it rebuilt.

Monitor your oil use closely over the coming miles.. between a possible leak into the intake system and cooler lines leaking, you might be losing a good bit. Only time will tell.

[cupdriver91]

On the rear plate under the o2 sensor there are nut on top of the plate,you have to get a wrench in there to hold the nuts while you turn the bolt it's a pain in the ALL GLORY TO THE HYPNOTOAD but that's what you have to do.

[mercuric]

Ah, interesting, I thought I remembered some sort of nut there but couldn't recall the details. Mine seemed frozen in place, next time I'm under there I'll have to have a closer look.

[Volta55]

i will check after work

how on earth are you supposed to access the nut? from this image i snagged from google it seems like it is recessed inside the frame

[cupdriver91]

It isn't that easy to get to I think I had to modify a wrench to get to it Like I said pita..

[cupdriver91]

Just an after thought remember if you just cut them off you still have to replace them,I put mine back in with the bolt on top and the nut on the bottom it was alot easier this way.

Hope it helps

[Volta55]

im sorry i must be very lost.. where is the nut? and how to you access it?

to me it looks like 1 large molded plate for the under body, and this nut is ontop of the under body?