HELP:Smokey exhaust (please be gentle with bad news)

pfarber · Post by **pfarber** » Sun Jun 11, 2006 9:05 pm

Heres the scoop. Changed the oil in my GMC 353 (Rotella T 30 weight) 2 gallons, and oil filter. Also put on later cast iron carb in place of die cast on while I tried to rebuild the die cast carb.

Run the engine and she starts so SMOKE. Smoke does not smell much, but can see fluid running out of the tail pipe and smoking quite profusely. Fluid looks like oil.

Take off carb and there is fuel pooled on the intake floor. Cleaned that up and restarted (I though I may have just flooded the motor with gas).

Still smokes.

Checked the spark plugs in cyl 3,4,5 and there were not bad. Had some oil on them, but wasn't sure if it was from taking them out or from cumbustion chamber. THe engine is quite greasy and oily to start with.

Checked the oil filter, and the filter was not 'full' and the oil was cold.. the engine ran long enough to heat up to 190*F. SO I ran the engine WITHOUT the oil filter and verfied that oil was being circulated, and that it was warm from the engine.

After I ran it WITHOUT the oil filter the oil no longer ran out of the tail pipe, but still smoked pretty good.

Questions: could ANYTHING with the oil filter have caused this problem? I think that the smoke now is from oil in the muffler, not new oil from the engine.

Other than spark plugs, is there any other way I can verify oil in the cylinders without taking the head off?

Is the oil I used Rotella good for the engine? Could it be to 'thin' and seep past the valves, etc?

Looking for anything to check before I have to take out the motor.

Engine runs fine, idles with 25-30psi oil pressure and does not sputter. No unusual noises or sounds.

Bill_Wolf · Post by **Bill_Wolf** » Sun Jun 11, 2006 10:47 pm

Farber,

Are you running the standard sump.....

TM-says you are 2 quarts low.

http://www.cckw.org/cargolwb2.jpg

I run Rotella in all my HMV's.

What is the compression in the cylinders in PSI?

Did you do a leak down test?

Don't pull the motor until you do all the diagnostics.

Bill

dr deuce · Post by **dr deuce** » Mon Jun 12, 2006 6:57 am

Another thing to try is to drain the oil into a clean bucket and look at the bottom of the bucket. You may have dislodged sludge in the engine. Puting HD oil into a sludged up engine is usually quite bad.

What is the 2000 rpm oil pressure?

Pull the valve cover and see if the rockers are getting oil.

pfarber · Post by **pfarber** » Mon Jun 12, 2006 1:17 pm

The dip stick says I am over the FULL mark with 2 gal. I have the deeper sump (looks like an oil pan under an oil pan.

The oil I tool out was dumped into a bucket then poured back into the empty Rotella jugs... little if any sludge, looked pretty good actually.

I cleaned the strainer and that was a *little* dirty but again, nothing that looked like the oil was significantly sludged up.

Will take off the valve cover and see.

Engne was run previously (a few weeks) to move the fluids and warm it up (about 30 minutes) and that was when I did the tune up (oil filter, plugs, points, etc) and also switched the carbs.

Barry Churcher · Post by **Barry Churcher** » Mon Jun 12, 2006 9:13 pm

Hi Farber
I doubt that oil is running out your tail pipe. If there was that much oil in the system you would not be able to see for smoke behind the truck.

It is more likely water fron condensation mixing with the soot and carbon in the exhaust to give you a black liquid running out the pipe. This is not uncommon for even newer vehicles. That is the condensation that rots out your muffler. It is pretty difficult to get enough oil past the rings to run out the pipe. Where is the oil on the spark plugs? Is it on the threads or on the actual electrode? The other possibility is that you are burning a bit of antifreeze from a head gasket leak. Do you have antifreeze in the system or just water? Burning antifreeze will smoke like a bit*h. Antifreeze will usually give you a bit of a sweet smell though.It is also not uncommon to have a bit of gas in the intake. That is residual air fuel mixture that didn't get sucked in as the engine was being shut down.
Don't pull that engine yet.

Cheers,
Barry

armydriver · Post by **armydriver** » Tue Jun 13, 2006 7:19 am

I agree with Barry, that is condensation coming from the exaust , more than likely. As the system heats up it will dissapate.
When I first started on my truck I did the same as you and just drained the old oil, but I felt uncomfortable with it , even though the dip stick oil looked great, no water was showing up . One day I pulled the pan and was stunned at the amount of sludge and crap in the sump of the pan. It was worth the taking off of a lot of screws, and the piece of mind knowing how much cleaneer the system would be was most pleasing.
The smoking could be from your carburator setting being too rich or the choke still being partially deployed and not straight up and down when the engine is running.
Do some diagnostics before pulling the engine.

pfarber · Post by **pfarber** » Tue Jun 13, 2006 12:15 pm

I am going to run it again today.. I Have a leak down tested waiting if I have any more issues.

If it still smokes today my game plan:

leak test cylinders and see if I can narrow it down.
Take off head (engine, not mine

)