I have been troubleshooting a rough idle, white smoke, loss of power issue and today noticed I am getting oil blowby on the dipstick and when I pulled the dip there is positive pressure and smoke coming out.

What could be causing the positive pressure on the crankcase side? More importantly, steps to identify and fix issue?[/FONT][/SIZE]
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Could that be cause and/or symptom of the rough idle, white smoke and loss of power?[/FONT][/SIZE]
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Note, previously I have troubleshot the following:
1 – Smelled exhaust and more acrid than sweet, so not likely coolant.
2 – Checked fuel filter and ran/soaked overnight 100% Diesel Kleen.
3 – Checked for leak from under IP and none.
4 – Checked exhaust ports temps with infrared thermometer for “dead cylinder”, and all seem to be firing with temps at 175-190.
5 – Checked coolant reservoir and doesn’t seem to be consuming
6 – Serviced CDR (solvent, washed out and dried ad then reinstalled)

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Was going to next confirm lift pump fuel pressure and then replace and time IP, but then noticed the positive crankcase pressure, so going to refocus on solving that first as it may be my root cause. First stepd with the CDR service which didn't fix it.
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Any coaching on next steps to troubleshoot the positive pressure are much appreciated.

Thanks all.

 

A compression test would be a good step... Loss of compression in one cyl could explain all the symptoms.

 

Blow-by means your getting more and more oil than the oil control rings on your pistons should be allowing, it comes with age. My fathers '86 had positive pressure like what your saying, that was bout 250k before the engine blew a head gasket @ 575k. How many miles are on your Engine? If your exhaust is acid smelling, it might be because your just burning oil, you have dropped an injector, or your IP is just about dead. I would check your IP, it might be too retarded or advanced too far. Have you adjusted it in any way?

 

check and clean youe cdr. If it's not clear then te pressure is gonna build up and come out any hole it can

 

Update: Pulled the glowplug on the front drivers side just to get part# in prep for doing compression test and replacing glowplugs while i had them out for the compression test.
The glowplug tip was soaked in oil. Not sure if it was sotty fuel or somehow it was engine oil comgin inn from either the intake or past the piston.

I repalced glowplugs once years back, btu don't seem to rememeber them being wet, nor does it seem like there shodul be unburnt fuel on them.

Thoughts?

Either way going to do a compression test on all cylders this afternoon and will post back afterwards.

 

Update: I did a compression test this weekend and 1 cylinder was significantly lower than all others. The forward most cylinder on the passenger side (Not sure of the firing order cycler #) topped out at about 200 while all others were 300-350. That same cylinder is also the one that has oil and/or wet sooted fuel all over the glow plug tip when I pull it.

Given that I am also having a positive pressure issue in the crankcase (dip stick blow by and what seems to be excessive oil into the CDR), does this definitively confirm that the piston rings are no longer sealing on that cylinder?

If so, is removal and rebuild the only remedy?

Update: I did a compression test this weekend and 1 cylinder was significantly lower than all others. The forward most cylinder on the passenger side (Not sure of the firing order cycler #) topped out at about 200 while all others were 300-350. That same cylinder is also the one that has oil and/or wet sooted fuel all over the glow plug tip when I pull it.

Given that I am also having a positive pressure issue in the crankcase (dip stick blow by and what seems to be excessive oil into the CDR), does this definitively confirm that the piston rings are no longer sealing on that cylinder?

If so, is removal and rebuild the only remedy?

Alternative explanations and remedies very much welcomed!

 

next step is to do a "leak down" test on that cylinder. you can get the tester on load from autozone, you will need a compressor though. that will tell you if its your rings

 

Ok, but if i understand the leak down will give me whether the leak is valve, head gasket or piston...all those fixes are way beyond the $ and labor i'm willing to throw at this truck. I guess it does make a difference for the next owner/buyer to know if it's the head or a full engine pull to fix.

Thanks.

 

Also, anyone have instructions for how to confirm a cylinder is at TDC on the compression stroke or otherwise in a position where intake and exhaust valves are both closed?

 

It really does sound like your CDR valve. Its letting oil mist and other impurities into your engine, most likely whats causing you to have some wet stuff all over your glow plugs. I would bet that the cylinder is being affected the most. A head gasket is a 4 hour job, nothing too major just gotta pull injectors, gps and whatnot then new gasket then throw it back together.

 

If you can do the head gaskets in 4 hours you are one skilled guy.

 

removing the ip lines on that side, wiring harness, intake manifold, exhaust manifold, valve cover, head bolts. pull it, replace the gasket if its as simple as the gasket, bolt it all back up. its worth taking down to a machine shop though and having them check it for cracks and make sure the head is flat. if not, they can machine it down to give you a nice tight seal. if its low where its blown then it will just happen again and all your time was wasted.

 

oh, also id remove the hood for ease of access (hope you dont have a/c) and either have a strong back or get a cherry picker. the loaded head is about 110-115 lbs.

 

There's no way you are doing that start to finish in four hours. I'd rather just pull the motor to do the headgaskets, getting the 125 pound heads back on the engine is a trick in itself if you don't have machinery to do it for you.

 

i never said 4 hours, i agree its a chore. and id personally pull the engine too. drop the oil pan, change the front and rear seals along with the oil pan gasket, change the thermostat and do a good cleaning and paint job on it. the better you do it now, the easier it will be to spot a problem later