Hello there. I’m pretty new to diesels and this forum as well so don’t judge me please

I have a small issue.
I’m replacing CDR valve and ran into a little problem. I took out the CDR itself and grommet to intake (no problem). But that rubber tube with metal part on the bottom that goes to the engine is moving from side to side and I can’t get it out(no matter how hard I try). Is it supposed to be somewhat lose or does it have to be tight with the hole in the engine? Can I leave it there or does it have to come out. If so how could I possibly take it out? It seems like that metal part on the bottom is holding it and I don’t wanna damage anything.

thank you in advance!

truck is 93’ f250 7.3idi no turbo

 

The tube should pull out. There is a rubber grommet in the Valley Pan,
and the Tube just pushes into it. As the Rubber grommet gets old and
hard, it might just be stuck to the tube? Maybe spray some WD-40 or
other spray lube and it will help it come out.

When I did mine, it came right out a I remember. The grommet was hard
and crumbly and broke out in pieces. Some fell down into the hole and
used some Needle Nose pliers to retrieve them.

When you get the tube out, use a rag and solvent to wipe the dirt and grit
away from the hole before starting surgery. Don`t want anything dropping
into the engine.


Charlie

 

If you are just cleaning the CDR the tube can stay, although it may be attached to the CDR? I've been running a turbo so long i forget
A previous owner may have siliconed the tube to the valley pan to stop oil from leaking there, which would explain your issue

 

Yeah so here is what happened... I think this tube/grommet/CDR was not replaced since 1993. I tried wd40 and pulling it out as hard as possible but nothing worked because the bottom of the tube was rock solid (I can’t believe it was rubber). So here is what I did and it worked like magic! I used a knife, wd40 and pliers. Cut that tube in half. Then used knife to cut that poopy grommet at the bottom and then pliers to take it all out. No mess/everything’s good.
The only downside to all of this is I spent good 2 hours trying to do all this operation and my hands are black to my elbows.

thank you guys for giving me advise and spending time reading my thread. I love this community!

 

That`s what we are here for, to help each other out.
What I have learned is the early CDR had a separate
Grommet in the pan, and then the metal tube going into
the grommet.
The later style is a rubber tube with a sort of grommet
as part of it. the end is ribbed to hold it in the pan.

Here is an E-Bay listing...not a bad price for it, seen
some over $80.

https://www.ebay.com/itm/6-9L-7-3L-I...-/233702619510

here is just the rubber pieced for $15, not including shipping
https://swagperformanceparts.com/7-3l-oem-idi-cdr-valve-grommet-seal-kit/

OOPS, this for a Power Stroke,,maybe the same?

Do not wash out the CDR in Gas or other solvents, it can destroy
the rubber diaphragm.


Charlie

 

Bang on! I seem to have had later style tube. I bought brand new CDR valve, tube and seal from the dealership already. Just waiting for it to come from Far East (Ontario)

One more thing... Should I seal the thing (grommet to pan) with silicone? Is it not gonna leak with new parts installed? Is silicone good enough for amount of heat engine produces? Or just don’t worry to much about it?
I might sound a little **** about it but I just wanna make everything right and learn things properly from knowledgeable people like you.
thank you

 

I just put a thin layer of grease on it before putting it in the pan. Same thing for the seal on the back of the intake, just a thin layer then tightened the bolts.

 

what do you use to clean one out and how can you tell if its gone bad?? also is this part necessary(as in a buy pass can be done?)

 

You can do a by-pass on the CDR, it is called a RDT (Road Draft Tube).
A piece on hose hanging down under the Engine to let out the Crank Case Fumes,
Oil Mist etc... out into the atmosphere. But will make an oily mess eventually under
the truck, and where you park, there will be oil spots on your driveway concrete or
Garage floor.

The CDR and a PCV valve as used on a Gas Engine, is used to run the fumes into
the engine intake and burn them.

The gut`s of the CDR are just a thin rubber diaphram and spring. Not much to them.
Using Laqure thinner, Gas or some harsh chemical, can, dissolve, make the rubber
weak, tear it etc... best is to wash it out in hot water and soap. Think I use this product
the $ stores sell, LA Awsome. A concentrated cleaner. Dissolves oil pretty good.

https://www.google.com/search?q=LA+A...ih=536&dpr=1.2

I have an 82 Datsun 720 KC with the Nissan SD22 Diesel engine, bought it new, still have it.
it has the Road Draft Tube from the factory.
Years later I picked up a used 83 Nissan 720 with the SD 25 Diesel engine. (83 was the name change year)
It had the CDR on the back of the Valve Cover. What the heck is this P O S? Took it off and washed it
out is some solvent, and turned the Diaphragm into a mess, and fell apart.

About 12 yrs later bought the 86 6.9, and discovered it has the CDR and what it does.
I replaced it with a new one as the rubber hose and grommet was old hard and falling apart.
At the time I found one with all 3 pieces for a good price.

There is probably a thousand threads on them on the various forums. They are blamed for
everything from high oil consumption, poor fuel mileage, hard starting to flat tires...LOL

EDIT:
Here is a thread I saved about the CDR. LMJD explain`s how it operates pretty good.
https://www.thedieselstop.com/thread...xhaust.539938/


Charlie

 

not a lot or datsun / nissan diesels left anymore, my father has an 82 diesel, 83 gas and 84 diesel. I might be backwards on the 83 and 84. still serviceable although the 83 is somewhere past 300,000 miles.
the 84 started leaking at the top of the IP where the injector lines hook, that lets air back in over night and it won't start so it has been sitting several years.

 

well i already have oil spots on my drive and i dont have a communist HOA to deal with ,so im ok with oil spots... is there a thread on how to do the RDT??

 

No cleaning is necessary unless there are rocks or something stuck in it, in which case the CDR valve isn't your biggest issue. It can be tested per a complicated procedure in the FSM, but TBH failure is highly unlikely and you can just suck on it with your mouth to see if the diaphragm is torn.

^^ What he said.

CDR valve doesn't do anything except prevent a runaway in certain limited and highly unlikely circumstances. So no, the part isn't strictly necessary. As you seem to have deduced, however, it does have some safety benefit if your crankcase vent happens to be routed into the intake- so if doing away with the CDR valve, the crankcase vent should be routed to atmosphere somehow. I'm sure there are a million posts on how to do it, but it doesn't really matter how it's done. The important part is that the now-unused hole in the intake is blocked off, and that the vent tube is arranged so as not to let bugs, water, or dust in. Most engines with a factory-installed open crankcase vent use a wad of the material that oil bath air cleaners are full of, to prevent bugs from getting in and oil mist from getting out.

Word to the wise- The crankcase vent hole on many IDI intakes has some VERY SHARP tooling marks on the backside of the hole where you won't know about them until they slice your hand open.

 

I lost #2 cylinder around 483K miles coming back from Portland, Or to Santa Cruz, Ca. was down on power she kept on trucking on.
Those were some great running engines, dependable if taken care of. Valve Adj. every 12K miles. and the back end of the IP is a leather
diaphragm that needed some Neats Foot oil added once in a while.
They were designed back in 1965, and used in everything.
The International Scouts used the SD33 6 cyl. and the last yr, 80 used the turbo version.

They were used in Fork Lift, and use to see engine parts on e-bay, probably chicom built parts now.

Here is a Datsun diesel forum Iam signed up on, haven`t been on it for a few years.
NissanDiesel Forums - Index page

Show your Father this Purdy one.
http://nissandiesel.dyndns.org/viewtopic.php?t=495


Charlie