97 850 NA auto PCV confusion

Post by **scot850** » 26 Jul 2016, 20:11

I ordered the short PCV 'J' hose from FCP based on their website, and in fairness to them it is the correct one listed for all 850's but it is wrong for my car. I thought maybe someone had fitted the wrong catch tank from a P80, but on checking the one from the car it is the correct one for the engine number (engine # is >900000) as Vida says it should be PCV catch tank # 1271650. Vida only lists one option of short ''j' pipe that runs from the top of the tank to the middle of the block as below:

: PCV J pipe as fitted to the car

Problem is Vida lists the part number of the 'J' pipe for all 850's as # 1271771 but that looks like this (sorry for bad picture as still in bag):

: part # 1271771

From this you can see that the pipe is straight, but what is not obvious is the diameter is smaller. The top outlet pipe is higher than the input to the block so this pipe would have to be bent as per the one fitted originally, which is part # 1271653 which looks like this:

: part # 1271653

Has anyone else come across this issue? Clearly something is wrong? When I place the catch tank from the 850 (correct part # as listed on Vida) beside the later one from a P80 (part # 1271988) the look virtually identical, and all the pipe outlets are in the same position and height.

So now I will have to go buy the later PCV hose from the dealer after all. Crap!!

Neil.

Post by **erikv11** » 26 Jul 2016, 22:37

Hi Neil. Bummer!

As far as "has anyone seen this?" my answer is yes. See my posts in https://www.matthewsvolvosite.com/forums ... hp?t=67581 and https://www.matthewsvolvosite.com/forums ... p?p=351093. There are also two different hoses from the trap to the top of the valve cover, to match turbo vs. NA, i.e. whether the manifold has a cutout between 1 and 2 or between 2 and 3. The latter hose you can make it work by forcing it so it is not as critical to match it to your car.

Post by **abscate** » 27 Jul 2016, 05:19

Neil..I'll check my stash from the 1999 job and see what I have, unless that's a cheap part

Post by **scot850** » 27 Jul 2016, 08:30

Thanks Steve and erik. What I also discovered by chance (I have a weird brain that has a delayed alarm to seeing something wrong), is that the 850 and P80 use the 2 top ports in reverse! The 850's use the rear port to the head and the P80's the front. I have a good P80 PCV catch tank I was going to use but to use the ports correctly means the thin breather pipe to the intake cylinder #1 end, isn't long enough.

The correct pipe is not too ridiculous, and now I am under time pressure I will have to buy a new trap and pipe from the dealer (old trap has clumps of oil in ports). I had considered trying to clean it but it is probably the original and 20 years of crud in it. Emissions in California are a pain so don't want to take a chance.

It is all the small stuff that is becoming a pain as usual on these cars, and Volvo's random changes to parts for reasons we will never know. Like why 3 versions of PCV trap on the 850, and another on P80's to do the same job with basically the same part?

Appreciate the wise inputs as usual!

Neil.

Post by **sleddriver** » 27 Jul 2016, 19:44

scot850 wrote:It is all the small stuff that is becoming a pain as usual on these cars, and Volvo's random changes to parts for reasons we will never know. Like why 3 versions of PCV trap on the 850, and another on P80's......

+1
Nuts.......

Post by **erikv11** » 28 Jul 2016, 07:29

The 850 *is* a P80 car, not sure where you are going with this. All P80 cars use the same routing on the oil trap, i.e., all 93-98 are the same. Was it hooked up backwards on the 850 you just got?

I don't really have time today to wade through the details (devil is in the details!) but I always thought there are only two P80 trap setups for 98 and earlier, see my links up above.

Post by **scot850** » 28 Jul 2016, 08:37

Vida lists 3 different ones based on eng # breaks for the 850. Then a different one for 98 on C/V70's.

There are 2 PCV swap write ups out there and both show the rear port closest to the block sending the pipe up to the top of the head and the other to the flame trap other pipework including the pipe to the end of the intake.

Vida shows more clearly for the later cars (98-) that the front port goes to the top of the head and the remaining pipework goes to the rear port closest to the block.

When I find my notes I can list the part numbers for the 3 PCV traps for the 850's.

Actually have Vida up:

1) Part # 1271652 - For engines - 139319
2) Part # 6842718 - For engines - 373487 (replaces 9146756 and 978173 and 3547763)
3) Part # 1271650 - For engines 373488 - (as fitted to my 97)

There is another part # for 98 - 1271988 for turbo and non-turbo

Neil.

Post by **erikv11** » 28 Jul 2016, 13:25

scot850 wrote:... Vida shows more clearly for the later cars (98-) that the front port goes to the top of the head and the remaining pipework goes to the rear port closest to the block. ....

This is either a mistake in Vida or it means the order of the ports doesn't matter, given that the oil traps are all the same inside. I favor the former, given that many people have posted up about re-doing the PCV, still failing the glove test, and then remedying the situation by reversing the mounting of the pipes to the oil trap; i.e. by using the rear port to the top of the head and the front/right port to the PTC or flame trap.

Interesting about all of the part numbers for the oil trap. But are they all really different? As mentioned, I have (to the best of my knowledge!) only seen two different geometries in working on P80 cars from 95, 96, 97, and 98.

In the end the oil trap is just functioning like a catch can, there is no voodoo inside of it, you just need one that mounts up right. But I think you know that, hence your frustration.

Post by **scot850** » 28 Jul 2016, 13:45

At some time in the future, when I am at PnP I will look for 2 scrap/used catch tanks for a S/C/V70 and an 850 and cut them open to look inside. It may be a baffle issue inside, but this is the sort of issue I like to get to the bottom of. Like you say, I have seen several messages about reversing the 2 top pipes resolving over pressure issues in the PCV system after re-build it. There has to be differences internally to cause this, and I'm not willing to take the chance for about $40 CDN to find out! As you know the plan is for the car to go to my 16 year old niece in California and my brother does not have anywhere to work on the car or the money so I want to make sure it is as good as we can get it without going too crazy on re-building everything (although I am getting close to that!!). Also, pulling the PCV system is not too bad, but a job I prefer to do once every 10 years!!

Neil.

Post by **abscate** » 30 Jul 2016, 04:20

I'll try to find and post my 1999 PCV pictures today

Ok, picture from mikes 1999 NA thread...wait a minute...are 1999 NAs not thermostatted PCV?

: 1999 NA PCV tank

Picture from my 1999 shows front connector for manifold, rear connector to top of cylinder head