CDR Valve.

So I have done some reading in regards to this unit. With my 330,000 mile honey I’m assuming it needs replaced although I’ve yet to remove and clean/ inspect it. When reving the truck with the air cleaner removed I can see a jet of vapor firing into the intake manifold. It’s quite a stream of vapor.

I have also removed the oil filler cap and was shocked to see very little to no blow by pressure on the open filler neck while throttling the engine. The truck does smoke at start up (blue) and though it lets up it never really goes away.

I did throttle the engine with the dip stick removed to find a substantial pulse of oil vapor jet coming from the tube. I assume this is normal as the crank case is going to build pressure, eh?

Your thoughts are appreciated.

You only need to replace thE CDR if it is physically damaged, diaphragm torn, or internal spring broken.

Yours sounds like its operating normally. Its not a PCV, it operates completely differently. Its nornally open, and only closes on hard acceleration.

The big thing about them, on the back side of the can there is a pinhole, it needs to be kept clean, as its the vent for the diaphragm. Otherwise they almost never fail.

Nero said:

You only need to replace thE CDR if it is physically damaged, diaphragm torn, or internal spring broken.

Yours sounds like its operating normally. Its not a PCV, it operates completely differently. Its nornally open, and only closes on hard acceleration.

The big thing about them, on the back side of the can there is a pinhole, it needs to be kept clean, as its the vent for the diaphragm. Otherwise they almost never fail.

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Cool. Thanks for putting that to bed Nero

Have you changed the oil? What oil are you using?

Kdo58 said:

Have you changed the oil? What oil are you using?

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I just put T4 in it.

I don’t think mine has ever been changed I had to break apart the rubber/plastic down tube and dig it out. It was so brittle it had no give to unthread from the crankcase opening. I’m just going to replace the entire setup Swagperformave has the replacement on eBay for like $70 with OEM tube and grommet I’ll just keep the old canister for a backup in case the aftermarket is crap

Ohiogoldfever said:

I just put T4 in it.

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Mine had a lot of blue smoke, I was running 15/40 change to a straight 30 weight diesel oil, made a huge difference, when I can find straight 40 weight I will change to that.i would also check your throttle cable, the new ones tend to be to long, I had to add zip ties for spacers to take up the slack, where it come through the firewall under the dash.

Kdo58 said:

Mine had a lot of blue smoke, I was running 15/40 change to a straight 30 weight diesel oil, made a huge difference, when I can find straight 40 weight I will change to that.i would also check your throttle cable, the new ones tend to be to long, I had to add zip ties for spacers to take up the slack, where it come through the firewall under the dash.

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Thanks for the heads up. I should have mentioned it’s 15/40 T4.

Makes sense that running a heavier oil would help with the blue smoke. Once I get this hard shifting trans worked out I plan to run the **** out of her. That’ll help. Lol