MD22 crankcase breather PCV valve (also Perkins Prima) part identification and source

[Yngmar]

Looks line our PCV valve (#34) is blown and doesn't close anymore. I've found some oil in the hose connecting it to the air intake and around the valve, which is apparently a symptom for this. The engine is consuming more oil than it used to, although an oil change is due. I've removed it to inspect (also cleaned years of oily gunk out of the air intake mesh). As per Haynes manual, the valve should click when a vacuum is applied to the hose end. It does not, it just makes a sad feeping sound instead, so I assume it's dead. It's crimped shut and not servicable.

Volvo wants €121 for one (Part 859743 "Valve"), which I would obviously consider as a last resort only. The Perkins part number might be 2652851 "PCV Valve", but the only source I can find is one in the US (we're in Sicily).

Can you help identify the part and where to source it for less? On the bottom it says "AC" and "Made in Eng." and there's a difficult to read number stamped in that may be "3822G0" (the G could be a 6 and one of the 2s is very faint).

 

[Aja]

Not really helping but could 'AC' be 'AC Delco' car parts supplier.?
Donald

 

[RichardS]

I've had success with car PCV's by squirting carb cleaner / alcohol through them. Sometimes the non-return valve simply seems to get gummed up with old oil and carbon deposits and a good clean-out and blow through often restores correct operation.

Richard

 

[Bobc]

SWMBO works for a garage on Thursdays who specialise in old BL cars. I'll get her to ask. If anyone will know where to get one, they'll know.

 

[Heckler]

I've had success with car PCV's by squirting carb cleaner / alcohol through them. Sometimes the non-return valve simply seems to get gummed up with old oil and carbon deposits and a good clean-out and blow through often restores correct operation.

Richard

I did that to mine, it got worse! The diaphragm really disintegrated!
I looked for and bought one off Ebay. It was off a Jeep IIRC Doesnt have a diaphragm as such, more like a ball bearing type valve. I was more interested in the diameter of the pipe connections. Its been on for a few years now and seems to work ok. If Yngmar PMs me I will send him a pic
PS Like this one https://www.carid.com/acdelco/professional-pcv-valve.html?make=Jeep

 

[Momac]

Possible source ?
https://www.engendiesel-shop.com/859743---valve-15410-p.asp

 

[RichardS]

I did that to mine, it got worse! The diaphragm really disintegrated!
I looked for and bought one off Ebay. It was off a Jeep IIRC Doesnt have a diaphragm as such, more like a ball bearing type valve. I was more interested in the diameter of the pipe connections. Its been on for a few years now and seems to work ok. If Yngmar PMs me I will send him a pic
PS Like this one https://www.carid.com/acdelco/professional-pcv-valve.html?make=Jeep

Ah .... the PCVs I'm talking about are simply a lump of mass, often a ball bearing, which physically blocks the throughput in one direction only. I'm not familiar with anything with a diaphragm in it. Obviously if that is damaged, it's damaged forever. :ambivalence:

Richard

 

[Yngmar]

I'm fairly sure the diaphragm on mine is blown too, no cleaning will fix that, and it's unfortunately not the type that can be disassembled to replace.

SWMBO works for a garage on Thursdays who specialise in old BL cars. I'll get her to ask. If anyone will know where to get one, they'll know.

Thanks, any luck yet?

I did that to mine, it got worse! The diaphragm really disintegrated!
I looked for and bought one off Ebay. It was off a Jeep IIRC Doesnt have a diaphragm as such, more like a ball bearing type valve. I was more interested in the diameter of the pipe connections. Its been on for a few years now and seems to work ok. If Yngmar PMs me I will send him a pic
PS Like this one https://www.carid.com/acdelco/professional-pcv-valve.html?make=Jeep

Hmm, I thought it had to be matched to the engine to open and close at the correct amount of pressure. They seem to do a lot more than is apparent. Unfortunately none of them seem to be specifying ratings.

 

[Bobc]

Thanks, any luck yet?

She's there tomorrow and has been given instructions. Will let you know tomorrow evening.

 

[Bobc]

Ok, the answer is that the part for the Prima is no longer available, but they now use the PCV valve from the Rover 25 2.0d and the Discover 2.5d, which fits and has very similar spring pressure.

The part number is: LLN100140 (Land Rover art number) and they are about £20.

Hope that helps

Bob

 

[Yngmar]

Ok, the answer is that the part for the Prima is no longer available, but they now use the PCV valve from the Rover 25 2.0d and the Discover 2.5d, which fits and has very similar spring pressure.

The part number is: LLN100140 (Land Rover art number) and they are about £20.

Hope that helps

Bob

Splendid! Thanks, to Mrs. Bobc as well. Will get one ordered ASAP. It looks like it has a hose fitting while the original one clamps straight onto a metal pipe on the oil filler, but hopefully a short piece of hose and two clamps should sort that.

 

[Bobc]

Pleased to be able to help.

 

[Yngmar]

Rover part LLN100140 arrived. Unfortunately it didn't fit at all, neither in the space available, nor on either of the connections. The original one has a offset fitting on the bottom, while the centered fitting on the Rover part gets it in the way of the oil filler - but the hole is also the wrong size and it looks like a hose fitting rather than being meant to clamp onto the metal pipe like the original. Back to square one.

The number stamped on the original is indeed 3822G0, but that finds nothing online.

Stu, did you find out which one you got on yours? Does it actually work, i.e. there is no oil on the bottom of the air intake mushroom from over-ventilating the crankcase?

Otherwise it looks like I'll have to cough up the ridiculous cash for a Volvo part, if available.

 

[Heckler]

I'm fairly sure the diaphragm on mine is blown too, no cleaning will fix that, and it's unfortunately not the type that can be disassembled to replace.



Thanks, any luck yet?



Hmm, I thought it had to be matched to the engine to open and close at the correct amount of pressure. They seem to do a lot more than is apparent. Unfortunately none of them seem to be specifying ratings.

Seems to work ok, it hasnt done anything that makes me say, oh there is an issue there. Ive got one of the originals in the garage off the spare donk I think, will attempt to uncrimp it tomoz!

 

[Heckler]

Looks line our PCV valve (#34) is blown and doesn't close anymore. I've found some oil in the hose connecting it to the air intake and around the valve, which is apparently a symptom for this. The engine is consuming more oil than it used to, although an oil change is due. I've removed it to inspect (also cleaned years of oily gunk out of the air intake mesh). As per Haynes manual, the valve should click when a vacuum is applied to the hose end. It does not, it just makes a sad feeping sound instead, so I assume it's dead. It's crimped shut and not servicable.

Volvo wants €121 for one (Part 859743 "Valve"), which I would obviously consider as a last resort only. The Perkins part number might be 2652851 "PCV Valve", but the only source I can find is one in the US (we're in Sicily).

Can you help identify the part and where to source it for less? On the bottom it says "AC" and "Made in Eng." and there's a difficult to read number stamped in that may be "3822G0" (the G could be a 6 and one of the 2s is very faint).

Ok Ive just taken my spare one apart. To do so use a pair of electrical side cutters and gently grip the peened lip and peel it back carefully all the way around. It is so simple, no spring to close the diaphragm so having tried blowing through it from both sides nothing happened it was just a straight through, th epuff went both ways. There is just the diaphragm with a coned valve seat in the middle which closes off the bit from the sump. Negative pressure pulls it on to the seat, positive opens it to the pipe that goes to the air intake. As I said no spring so no critical pressures to be concerned about! The diaphragm is good in this one but was covered in yucky oil residue on the sump side. Basically a crude attempt to stop slightly positive crank case vapours from coming out, I would argue that a light spring would have helped keep it shut. PM me an email address and I will send pics.
PS Looking at it again, I dont think it actually does anything in our application, because the end goes to the open air intake. In the car application of course it would have gone to the closed air filter system and so would have kept crankcase vapours in the system away from the atmosphere.?

 

[Heckler]

I'm fairly sure the diaphragm on mine is blown too, no cleaning will fix that, and it's unfortunately not the type that can be disassembled to replace.



Thanks, any luck yet?



Hmm, I thought it had to be matched to the engine to open and close at the correct amount of pressure. They seem to do a lot more than is apparent. Unfortunately none of them seem to be specifying ratings.

This action described in the link doesnt work on ours, number one, diesel engines are "open throttle" so no vacuum in the inlet manifold, the end of the pipe terminates in the open to atmosphere mushroom shaped air intake so no closed circuit as described so no vacuum as such to operate anything.

 

[Heckler]

Looks line our PCV valve (#34) is blown and doesn't close anymore. I've found some oil in the hose connecting it to the air intake and around the valve, which is apparently a symptom for this. The engine is consuming more oil than it used to, although an oil change is due. I've removed it to inspect (also cleaned years of oily gunk out of the air intake mesh). As per Haynes manual, the valve should click when a vacuum is applied to the hose end. It does not, it just makes a sad feeping sound instead, so I assume it's dead. It's crimped shut and not servicable.

Volvo wants €121 for one (Part 859743 "Valve"), which I would obviously consider as a last resort only. The Perkins part number might be 2652851 "PCV Valve", but the only source I can find is one in the US (we're in Sicily).

Can you help identify the part and where to source it for less? On the bottom it says "AC" and "Made in Eng." and there's a difficult to read number stamped in that may be "3822G0" (the G could be a 6 and one of the 2s is very faint).

 

[Heckler]

View attachment 73471

Looking at it for a while I am more convinced than ever that it does nowt in our application with its open ended air intake. In the car application, in a closed filter box there would be a slight vacuum which would suck that valve on to the seat stopping slight crankcase vapours getting to atmosphere, bearing in mind that in California where a lot of this environmental stuff originated, you can be fined for not having caps on petrol tanks, ie NO VAPOURS at all! If crankcase pressure started to rise then it would open the valve and allow the vapours to go to the air filter.

 

[Yngmar]

Stu, many thanks for that photo and cracking open your spare valve! Very useful. Do you happen to have a photo of the underside of the diaphragm too?

As for intake vacuum, yes there is one, or suction at least. The pistons down-motion generates suction on the intake manifold (which moves air into the cylinder), and the open hose does get some of that suction applied to it through the air intake mushroom. Bit like a hoover sucking up dust despite not having a vacuum-tight connection to the floor. You can check this yourself by holding your hand around the underside of the mushroom as the engine runs - definite quite a bit of air being sucked in.

When taking off the hose from the breather valve while the engine runs, I can hold it partially shut with my thumb and also feel air moving through, so that's how the crankcase fumes are sucked through and into the air intake manifold for burning up (so they don't get vented out the car, or in case of a boat, all over the engine room).

It only needs a small vacuum to have a light airflow through the crankcase, you don't want too much - which is where that valve comes into play. The way I understand its workings is that the diaphragm gets sucked down a bit in case of too high suction from the air intake and restricts the airflow, thus reducing the flow through the crankcase to the desired amount. If it's stuck and doesn't do that job, too much air goes through there and you end up sucking oil out of the crankcase and into the air intake manifold, which in extreme cases could lead to a runaway engine, although in my case I just noticed the clear hose had oil in it and it was dripping from the bottom of the mushroom. Also, oil consumption went up to something like 200 ml after a day or two of motoring (bit fuzzy on the exact numbers here). That fits the picture too, as the engine was slurping its own oil into the air intake, instead of just whatever blow-by fumes end up in the crankcase.

Having nothing to loose, I've meanwhile sprayed a bunch of degreaser into mine (after removing it from the engine), shaking some now liquefied black crud out, then poked it with a screwdriver to get the diaphragm moving again and finally applied repeat suction/pressure on the tiny breather hole at the top of the cap, which eventually dislodged something and it now shuts again with a click as per the test in the Haynes manual. Having seen your disassembled photos now tells me that if the tiny breather hole at the top can hold pressure, the diaphragm must be intact, so there's hope it'll work again. Hard to tell without motoring for a few hours, but we'll find out eventually.

As for the replacement part hunt, I've found a few cross-reference numbers, which I'll leave here for future reference:

1W8361 CATERPILLAR INC. DBA CATERPILLAR
8N7680 MITSUBISHI CATERPILLAR FORKLIFT AMERICA INC

Seems some distant relative of our engine was also used in forklifts. With the help of that, I've found one in the US for $38 with a photo that looks pretty promising: https://www.ebay.com/itm/CT1W8361-NEW-VALVE-PCV/262924757590

Will see if I can find someone in the US to forward one to me.

 

[Bobc]

Rover part LLN100140 arrived. Unfortunately it didn't fit at all, neither in the space available, nor on either of the connections. The original one has a offset fitting on the bottom, while the centered fitting on the Rover part gets it in the way of the oil filler - but the hole is also the wrong size and it looks like a hose fitting rather than being meant to clamp onto the metal pipe like the original. Back to square one.

The number stamped on the original is indeed 3822G0, but that finds nothing online.

Stu, did you find out which one you got on yours? Does it actually work, i.e. there is no oil on the bottom of the air intake mushroom from over-ventilating the crankcase?

Otherwise it looks like I'll have to cough up the ridiculous cash for a Volvo part, if available.

I ordered one for myself at the same time, as the one on my engine has never been changed, and I managed to get it to fit ok. The old one seemed to be stuck open, and with the new one on, the tickover revs were up to about 1,000 so I had to wind the throttle stop back to bring the revs back down, so it obviously does have an effect on the engine.

I got a new piece of hose, which was a tight fit INSIDE the ports on the PCV. So I cut a short bit and pushed it over the metal tube on the filler and then pushed the PCV onto it. On the outlet, I pushed the hose inside the PCV port and wrapped some insulation tape around it to make sure that it is sealed. If you remove the filler cap, you can get it onto the tube.

I'm at the boat next weekend so can take a photo to show you what I've done.