I preformed some of the tests great white recommended preforming prior to purchasing a diesel, on the 6.5 turbo suburban I recently purchased...and the results were not good. I have some smoke coming from the oil fill and dip stick when they are removed at operating temp. I knew the truck had an oil leak but I assumed that was due to a removed CDR valve. After installing a CDR valve I still have a leak and it feels like it has some turbo lag, like it doesn't always spool up and never spools up prior to 25oo rpm. The back window develops an oily film after highway driving, and I'm looking for options. Do you all think I should be shopping for a new motor? Do you all think a rebuild is an option? Could some of these issues be caused by a fixable vacuum problem or my improper installation of a CDR valve? And I'll be needing recommendations for parts suppliers, I ordered my CDR valve supplies from ssdiesel and I've seen some postings that indicate they don't always have the best quality. ANY help would be greatly appreciated.

 

m truck has a new cdr valve with blow by, runs fine.

about the turbo, is there alot of blck smoke?

 

not a lot of black smoke, only if I get on it will I get some smoke. It runs great minus the lag, and I wouldn't have even noticed that except when it does spool up it has so much more power. You mentioned a CDR with blow by, what's that? I think for my purpose it is fine, I have a small landscaping trailer and a bunch of kids (4) so this truck made sense. now I have to ask a stupid question.... what is a PMD and why are they all moved So are you thinking I have a few more miles out of my truck? Not as bad as I thought?

 

i would get a turbo-master from heath diesel, the turbo lag wont be a 1/4 as bad.

CDR is a crankcase depression valve (PCV valve). if your getting white smoke out of the dip stick its usually clogged. they are like $50 at napa and should be changed every 30,000mi.

pmd is a pump mounted driver, it reads the fuel through an optical eye, and they **** out when they get hot, so its good to move it if you havent already away from the engine bay.

however you didnt list the year of your truck, 94 and up will have one

im sure great white can give you a better explanation on the PMD

 

oh sorry about not listing the year it is a 1994. I just installed the CDR valve, the previous owner removed the tubing and valve, got a cold air intake, and put a little filter on top of the valve cover where the tubing for the CDR valve comes out....it was a joke. I installed some tubing from valve cover to CDR valve and SSdiesel provided the CDR valve and the connecting hose, i put a whole in the intake to insert the hose from the CDR valve. I was under the impression it needed the positive vacuum from the intake to properly adjust the pressure. I will tweak it a bit more, but I might have to admit to be over my head and take it to a shop.

 

what is your chief complaint again

 

oil leak, bad enough that the back window gets an oily film while driving down the highway. That's the complaint, but I was concerned about great whites comments about if it has smoke from oil filler and dip stick then the motor is on it's way out, and was wondering how bad of a sign that was and if it would be rebuildable.
You mentioned a bad CDR valve which was my first impression too since this truck had it's removed and that can cause oil leaks, but I installed on and unless I installed it incorrectly ( which is a possibility) then I'm back to the drawing board on oil leak causes.

 

Well, blowby puffing out of the dipstick tube is an indicator, it doesn't mean all hope is lost but it is time to start planning.

Lightly used (ie: daily driver, no heavy towing), a truck with significant blowby can give you many miles of service. Just be aware that it's definable closer to the end than the beginning and don't be surprised if it leaves you stranded one day.

It usually indicates tired or roached rings.

Lots of guys cling to the CDR valve as a reason for it to puff out the dipstick tube, but it's usually tired rings. Changing the CDR is worth a try from a cash expenditure point of view (80 bucks is cheaper than 5,000 for an engine), but it seldom is the issue.

Oil leak is probably just that; an oil leak.

The CDR is there to limit the amount of vacuum the crankcase sees when the turbo gets "on speed". It's the opposite of a pcv valve. In a PCV (IE: gas engine with a throttle) the PCV opens as vacuum comes up. The CDR closes as vacuum comes up or the turbo would create enough vacuum to suck liquid oil out of the valve cover.

It does assist with seals and not letting pressure build up in the crankcase, but a high mileage engine that leaks is in all likelihood leaking because the seals are tired (IE: front or rear crank seals, maybe pan gasket, etc).

A "road draft tube" (what the PO put on there by the sounds of it) keeps the crankcase pressure at "0" also. It just vents to atmosphere instead of recycling the oil laden air into the intake tract. This is often done because the turbo and intake gets very oily in a worn engine even with a properly functioning CDR. Well, that and the fact that a lot of people seem to have something against emissions controls (what a PCV/CDR system is really for).

FYI: all engines have blowby, it's just usually imperceptible. More noticeable in diesels because of compression and the fuel type. Gets progressively worse as the miles accumulate until it puffs like a steam engine (close to end of service life).

A puff of black on acceleration is not a big deal. If your engine is a high mileage engine with a lot of blowby, I wouldn't recommend a Turbo master. A TM will have your already worn pistons/bores/rings under more cylinder pressure at all the time. The Stock vacuum system drops the PSI to "0" every chance it gets. A TM should be used on a healthy or moderately healthy engine. You can put it on an older engine if you wish, but I would say you're rushing it to the end even faster.

I'd also say your "laggy" engine is more to do with the fact that it is just worn more than anything else. Weak cylinders lead to less drive pressure at the turbine with leads to slower acceleration of the compressor....not to mention combustion pressure slipping by the rings makes fro less force pushing the pistons down...

You must have a lot of oil firing out somewhere if it makes your back window oily!

When my truck holed a piston crown trying to climb Snoqualime Pass with the trailer in tow, it was literally blowing liquid oil out the filler tube and it didn't get anything oily other than the engine bay...

So, what are your options?

These are both going to suck:

1. Buy a new engine. That will handle all your issues at once.

2. Live with it until it gives up the ghost

Chasing leaks is a nightmare and they WILL come back. There's nothing you can do for worn out rings/cylinders except replace them. Don't even think about that pour in "Engine Restore" crap. Useless and it may actually do more harm than good. Tried it once myself. Never again.....

Sorry to be gloomy about your engine, but if it failed the water test (IE: blows bubbles) and it's puffing out the dipstick tube, there's not a lot left to be positive about other than is should last you long enough (if lightly used) to save up for a replacement.

Let me see if I can find a recent write up on the PMD I recently did for another thread.

Edit*

here it is: https://www.dieselbombers.com/chevy-...tml#post861386

Sorry for the link, that's just too much to write all over again!

 

I agree with great white you only have a few options with bad blow by. New engine now, new engine later, or ship it on down the road. If it was me I would find the oil leak fix it and keep on going down the road. Even with blow by you still should get enough life out of it to save up for a new engine if you like the truck enough to put one in it.

 

Thank you all so much for all your advice. I've decided to see if we can plug up the leak enough to not be embarrassing. I dropped it off at the shop to see if he could locate the leak and we can discuss it's repair. I will get out my piggy bank and start saving up for the motor. I called around and a local machine shop quoted $3,500 for rebuilding the motor and I got a quote from a Jasper shop for a new motor installed for just over $5k. I haven't heard much about the Jasper products so please correct me if that is a bad idea. What swap options would you all recommend? Great White posted about an article: The Optimizer 6500: Engine Builder
that mentioned the 6500 optimizer and Duramax motors how are those motors for swaps? Thanks again everybody!