Burning oil

[S-west]

So my buddy has a 1986 6.9 with 170,000 miles on it. He burns 3 quarts of oil every 2 weeks. I took the air filter off and the intake is covered in oil so the cdr is bad. But does this seem like too much for a cdr? I would hate for it to be the rings since he got the truck 3 months ago and has had nothing but problems. Not to mention he overpayed to begin with

 

[Devon Harley]

My first guess would be alot more than 170k. Not that that's a bad thing. Soak the cdr in diesel fuel to clean over night. What kinda mileage is he putting on the truck in that time? Also have you checked for blow by? Water in oil cap? Changed oil since he got it? Is there any form of leak? Pressure washer the under side and watch for leaks.

 

[towcat]

DO NOT WAS THE CDR WITH ANYTHING. replace it.
the thin rubber diaphragm will desintergrate with the use of any detergent or solvent that will break down oil.
Argve/goatboy dissected a CDR years ago to show why.
they should be changed out every 50k/mi

 

[tanman_2006]

2 weeks for me is well over 1,000 miles so thats pretty close to being within operable IDI specs. Since you dont leave a mileage number we will just assume everyone DRIVES their trucks like me.

Its an IDI, its gonna use oil. A new Cdr might help, some people like their road draft tubes.

 

[Maverick1701]

DO NOT WAS THE CDR WITH ANYTHING. replace it.
the thin rubber diaphragm will desintergrate with the use of any detergent or solvent that will break down oil.
Argve/goatboy dissected a CDR years ago to show why.
they should be changed out every 50k/mi

My thought is that if you are going to spend the money to replace it you might as well try cleaning it first.....even if it doesnt work you aren't out anything and if it does work you can save money on unburnt oil but that much longer.

 

[S-west]

Ok well he uses rotella and drives about 5-600 miles in the time he burns about 3 quarts. So far he has just been routinely adding oil. It's last oil change was about 2500 miles ago. And there is no leaks to speak off. The oil pan is a little wet but it never drips. No oil in the radiator.

 

[S-west]

I would assume 170,000 is actual mileage because all the ball joints, tie rods, and u-joints are factory and still good. Also this is connecticut and typically by 150,000 the truck rots away haha

 

[whiteboyslo]

I'm only repeating what I've heard from other threads, but Rotella is somewhat known for this. FWIW, I run Delo and have no issues.

Mike

 

[PwrSmoke]

Switching from Rotella to DELO won't have a substantial effect on oil consumption. I don't give that "Rotella is consumed more easily than DELO" rumor much credence. I used both in my truck over the years and never noted a difference. Even if true, and I'm willing to be convinced by hard evidence that it's the oil and not something else, it isn't going to take an engine that uses 3qts/1000 mi into the "doesn't use any oil" category.

My advice is to make sure the guy isn't filling it to the top line. Add oil ONLY when the oil is at the add mark and then add only one quart (which will put the level midway between the high mark and add). In 25 years of owning my truck, I learned that, even when the engine was new, it would use that top quart very fast but the second quart would be very slow. Also, check the oil with a hot engine after it's had 15 minutes to drain down. As the Ford TSB 85-25-19 says, the oil expands 1 percent for every 25F of temp, so if you check oil with a cold engine it will read lower than a hot one. If you are inconsistent as to when you check, you will see changes in oil level that will be confusing if you don't know what's going on.

The engine might be in decent shape with 170K but the valve stem seals could be the cause of oil consumption.. along with the CDR. I'd start with the CDR and then think about valve stem seals. I put new seals on mine years ago ( it was 10 yers old then) and oil consumption slowed to next to nothing, The seals you get today are much better than the original ones from '86 and changing them is not beyond the home wrencher.

 

[icanfixall]

With the low of mileage I'm wondering what the maintance was done during that time. I also feel the cdr needs to be changed out. The posting about 50,000 mile change is correct. So I fel this has never been done. Some owners don't know... Others don't care... Maintance is important no matter what you own. Trying to "clean" the cdr is not going to fix anything. Once they go bad thats it. As towcat has posted per the long ago post from Travis with pics. They don't clean well if at all. This is the purpose of the cdr. It does two things. First off it allows the blowby to be sucked back into the engine to burn as fuel. Secondly it keeps the engine from bruning all the engine oil as fuel. If the engine starts to eat the engine oil as fuel and this can happen. The cdr valve will suck closed because of the diaphram in it. Now if that diaphram is damaged or broken just how will the cdr shut and stop the flow of oil mist into the intake. This is important..... Any burnable oil or fuel getting into the intake stream will cause the engine to run away. Nothing can stop a run away except cuttin off the air supply or fuel. This has happened to idi engines and the rpm goes well past the gonernored redline. Only the injection pump controls the fuel and it has the rpm govenor in it. So now that you know all this.... Do you really want to clean the old cdr and take that chance. If so please viedo the truck... PS... Heads are still made new for these engine but blocks are not being made anywhere on the planet. funny how every internal part can be made but no country will attempt to cast a block.... In all my years of watching ebay for a new idi engine I found one. It was at a diesel teaching school where the students would take apart and assemble the engine over and over. Only fire it up to prove it runs. Surely all the critical bolt threads in that block were finished so it was not an engine I could ever trust.... Also nobody has ever found a wharehouse with hidden forgotten idi engines in it....

 

[PwrSmoke]

With the low of mileage ....

With just 140K showing on my '86, that made me smile.

When I tore mine down for head gaskets earlier, the condition of the lower end was pretty remarkable. Only about 0.001" taper on the worst cylinder. I sent the bearings to an engineer at Federal Mogul and he said..."put 'em back in." (I didn't because they gave me free new ones, but I could have). The upper end was in rough shape, mostly from the heads lifting from 25 years of having a Banks turbo installed and 80K miles of towing.

 

[Hyde]

Secondly it keeps the engine from bruning all the engine oil as fuel. If the engine starts to eat the engine oil as fuel and this can happen. The cdr valve will suck closed because of the diaphram in it. Now if that diaphram is damaged or broken just how will the cdr shut and stop the flow of oil mist into the intake. This is important..... Any burnable oil or fuel getting into the intake stream will cause the engine to run away. Nothing can stop a run away except cuttin off the air supply or fuel. This has happened to idi engines and the rpm goes well past the gonernored redline. Only the injection pump controls the fuel and it has the rpm govenor in it. So now that you know all this.... Do you really want to clean the old cdr and take that chance.

Ive had this happen because of a failed CDR, trust me, you dont want that.

 

[IH POWER]

How do I know if my CDR is bad?

 

[Hydro-idi]

How do I know if my CDR is bad?

Put the CDR up to your mouth and blow air into the back side of the can...where that tiny little hole is. If you hear the diaphragm move and it holds air, its good.

 

[IH POWER]

Let me ask you this, where the hells it even at?