oil in air intake?

[KevinIH73IDI]

when i was taking off my air intake, i noticed the bottom of the wingnut and screw had some black oil on it.. is this normal or is something wrong

[exekiel69]

Clean/replace the cdr valve.

[Runboy]

Can you explain to me how replacing the cdr valve is in any way going to stop oil from reaching the intake manifold?
Mike

[LMJD]

You're right, it's not. You'd be hard-pressed to find ANY diesel engine that doesn't have an oily intake due to design (no throttle plates and pretty much zero vacume). The CDR never needs cleaning, it's just a 1" diameter always open diaphram hole with a small air bleed on the other side. Maybe exekiel69 can explain how it can "clog" up? Matter of fact, a full time 7.3/6.9 mechanic that actually knows what he's talking about once said it's easy to destroy the paper thin diaphram rubber with most any strong cleaning solvent and I agree. There's about one other guy on this site that has a clue as to how the CDR operates, (Ziggster) but of course he's ignored when he tries to explain that they don't need cleaning or replacing.

[Powerstrokedogg]

its normal theres nothing wrong with the CDR valve and it really doesn't need to be cleaned. the CDR valve prevents the engine from "running away" on oil from the crankcase. at high RPMs the diaphram is sucked against the outlet preventing any oil from being sucked through the valve.

[LMJD]

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at high RPMs the diaphram is sucked against the outlet preventing any oil from being sucked through the valve.


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That's a little hard to occur especially since the higher the rpm the more crankase pressure you have. In fact, to check for excessive blowby, you block off the CDR valve, hook up a manometer and if your crankase PRESSURE (not vacume) is over 6" on the manometer at something like 2000RPM, IH considers that excessive. However, you're right, under an odd circumstance like a suddenly closed off intake duct you'd get a high vacume condition in the crankase through the CDR ducting and that's when the vacume will overcome the spring pressure and the valve will close.

[cdnsarguy]

The following was written by someone who new what they were talking about..........

Do you know when to service your CDR valve?

All 6.9L and 7.3L diesel engines are equipped with a CDR (Crankcase Depression Regulator) valve. Even the new 7.3L Power Stroke is also equipped with the same valve. The CDR valve is one of the leading causes of head gasket failure in these engines. The CDR valve is responsible for controlling the pressure/vacuum in the engine crankcase, and seperating the oil mist from the air and returning the oil to the crankcase. The CDR valve should be serviced every second oil change or when signs listed below are seen.

When the CDR valve is not properly serviced, engine oil enters the air intake and is drawn into the engine. The diesel engine will burn this oil as fuel, however, it is heavier and thicker than diesel fuel and, having greater BTU output, causes excessive heat in the cylinder. Due to the intake manifold design, most of the oil will migrate to #7 and #8 cylinders; the last two cylinders in the rear by the firewall. The increased temperature here will cause the cylinder head to lift off the gasket and allow water or oil to leak out the back of the cylinder head where it meets the block.

To check your CDR valve, remove the air cleaner hold down bolt and inspect it. If the bolt is covered with engine oil mist, it's time to service your CDR valve! Ford calls this item a "Adapter assembly for Crankcase Ventilation" Part number E3TZ-6A665-A or IH part #1805319C1


To service the CDR wash with a solvent, allow to dry, do not use compressed air to dry. There is a small hole in the CDR back cover, ensure it is clean and open. If black chunks of rubber are visible in the intake, on the screen then the rubber membrane has disintegrated, replace the CDR.

[LMJD]

I've read that on the same site. Unfortunately everything you read on the net isn't necessarily the gospel truth. I try to base my opinion on 30+ years experience as a truck mechanic with some common sense thrown in. After removing and inspecting the construction of a CDR valve their operation is not too complicated. By design it can't help but have an oil coating on the diaphram, clean it and no doubt within an hour's driving it's oil coated again. But if it pleases you, like suggested, I'd clean that baby after every other oil change. Since it's there to allow all crankase blowby (translation: oily mist) to pass through it's 1" hole and dissapate in the intake system I'm confused as to how cleaning any oil off it's surface prevents the same amount of crankase blowby from passing through it and then going through the intake system and coating the intake manifold, etc, same as before. Seems to me that's what it's designed to do???

[Runboy]

LMJD, you are my Hero! This is the exact situation I am currently working on with my truck. Oil build up is so bad in my first genertation banks turbo intake that it drips out the water drain all over the top of the engine.
I'm going to erase, not replace my CDR (which had been replaced). I'm going to an air/oil seperator that does not recirculate back to the intake.
One other issue seems to be the location and sizing of the crankcase breather outlet, right off the timing cover where oil is being nicely atomized. So I am going to add a second breather location to minimise the velocity of the crankcase blowby coming out of the hose somewhere on the engine(maybe valve cover?), and vent both hoses to the air/oil seperator.
Sound good?
Mike

[LMJD]

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LMJD, you are my Hero!

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Oh thank you my friend, long time Jackass, first time hero! [img]/ubbthreads/images/graemlins/biggrin.gif[/img]
It's been so long since I've looked at a Banks, I recall your outlet off the timing cover, but I can't remember where it dumps back in, sorry.
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minimise the velocity of the crankcase blowby coming out of the hose somewhere on the engine(maybe valve cover?),

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That's how my ATS system works. The kit came with a new driver's side valve cover with the CDR located on it (I think that's where they were on the non-Ford 7.3 engines), then there's a metal tube adapted from it to the clean side of my air-cleaner air box if that gives you any ideas. To me, it works very well, the blowby goes to all cylinders equally. Before I put my ATS on at 30,000 miles I was getting a very slight amount of oil oozing out at the rear of both heads. However, over the years I've found very few diesels of any breed that didn't show the same problem sooner or later between head and block. As odd as it sounds, we got most of our heavy truck parts from probably the biggest heavy Ford truck dealer in the nation rather than Kenworth or Peterbilt, IH, etc---better price, quicker shipping. They don't sell pickups, just big trucks, but they had to work on customers' pickups and when I mentioned to the shop foreman by phone my slight oil leakage, but mainly wanted his opinion of the new ATS systems, he said they actually install ATS kits and they NEVER put one on without first re-torqueing the heads. I took his advice, and no more oil seepage even at 232,000 miles now and still haven't touched that pesky CDR valve.

What is the water drain you mentioned? Any chance you have way more blowby than the system can handle? Even so, if you could get a good seperator that sounds like a good idea. Whatever you try, make sure it doesn't cause a big crankase pressure buildup or you'll be blowing oil past your rear main seal, front crankshaft seal, etc.

[KevinIH73IDI]

ok thanks for the help, i'll probably just clean the CDR valve anyway.. but i have another question.
i just fixed my cold starting system, but im still putting out smoke. if the CDR valve wasn't working and im burning oil won't that cause smoke? its only when its cold but its still a problem.
also, when i had my straight pipe in it would break up reeeeal bad around 2500 and would just not go any higher. it would start around 2200 and just get worse as the rpm's went up. i didnt think that was too good, so i put a glasspack on and it seems to be working fine for now