Blow By

[dilligaf]

I have a 92 that has 145,000 miles on it. I havent had a loss in power and it seams to be running as good as ever. The problem is when I check the oil it smells like gas, and not a little bit either, it smells like I poured gas in there, can't even smeel a hint of oil. The oil looks ok, and I really don't notice the level rising on the dip stick. Any other ideas to test my theory that I just have bad blow by?

 

[MilTownSHO]

Correct me if I'm wrong, but isn't blow-by where oil gets past the rings? If you had blow-by your dipstick level should be going down if anything, I would think. shrug

My 92 does burn some oil when you really get on it. finger

 

[gmorrell]

Blow by is when raw fuel and combustion by-products get past the rings and contaminate the oil. If blow by is really bad, such as from a fractured ring land, the crankcase will be under positive pressure with the engine running. Try removing the oil fill plug and see if there's air being pumped from the valve cover. This is probably your worst case secnario, doubt you've cracked a ring land.

First, I'd check to see if the PCV system is operating properly; all the lines are connected properly and not blocked, and the PCV passages in the throttle body are open.

If the PCV system checks out O.K., proceed to a compression test (search the board for proper techniques) and a leakdown test as a follow up.

Edited for speeling...

<small>[ September 30, 2003, 04:57 PM: Message edited by: Gary M. ]</small>

 

[dilligaf]

I think your right but the only way for gas to be in the oil is for it to blow by the rings, that is what i mainly wanted to check on, is this right?

 

[BeatDaSHO]

Yo man. Run your codes and then run the cylinder balance test and make sure everything is running correctly. If a cylinder falls out occasionaly, it will dump raw fuel in the cylinder which can contaminate the oil.

Greg

 

[rangerj]

dilligaf,

Is your engine running rich? Pull the plugs and look for black soot. Pull the codes and see if the O-2 sensors are working.

If the O-2 sensors are not giving the computer the expected information, the computer goes into the "limp-in" mode. I runs the engine rich.

Check the canister purge system also. And make sure the fuel return line is not plugged.

As suggested above the PCV system, which takes the normal amount of "blow-by" and sends it back through the engine through the throttle body, should be checked.

If you are getting "RAW" gas in your oil, the engines cylinders would have to be getting flooded with fuel. Have you checked your air filter? Just some thoughts! rangerj