Dear Roy, The oil in this (2001 Chevrolet K 1500's 5.3 Vortec) engine becomes contaminated with water after less than 200 miles after an oil change. There's no antifreeze present, and we pressure checked the cooling system and it holds pressure. There are no external intake manifold leaks, the PCV valve is clean and there's no moisture visible on the rocker arms. We checked the oil filter and found a peanut sized chunk of ice in it. (It gets pretty cold here in South Dakota in winter.) This pickup is used for short trips, but we have others used the same way and no problems with them.
Help!
John Thelen, Redfield, S.D.
Dear Mr. Thelen,
I assume that you have antifreeze in the cooling system, and by the statement "no antifreeze present" you mean that there is only signs of water in the oil. So this would eliminate the cooling system as the source of the problem. Therefore, the water has to be the result of water entering the crankcase externally through an unsealed area and extreme operating conditions.
I would examine any areas of this nature, such as dipstick tube, oil fill cap, PVC, seals, etc.
Good luck, Roy
Lots of Codes
Dear Roy, The check engine light is on (in a 1995 Chevrolet K 1500 pickup) and the (5.7L) engine starts missing after it idles for 4 to 5 minutes. If I increase rpm slightly, the engine smooths out. The exhaust stinks and has moist black soot. The scanner showed initially P0300, P0174 and P0152. I cleared the codes, and P0300 and P0304 reappeared after a while. The scanner shows all four right bank cylinders misfiring — especially No. 4 and No. 8. I checked fuel pressure and the wiring harness on top of the plastic plenum for connection problems. All seems OK. The scanner shows the left bank alternating lean/rich, but the right bank is locked on lean. I replaced the cap and rotor and spark plugs. All the left bank plugs looked normal, but all four right bank plugs were black and sooty. I pulled the oxygen sensor on that side (B2-S1) and ran the engine to check for a plugged catalytic converter, but still it ran poorly and showed misfires on the right bank cylinders. Please help.
Ron Rhynard
Dear Mr. Rhynard,
The conditions that you describe have all the makings of an intake manifold leak. This is a common problem with these engines as the composite intake manifold and iron engine expand and contract at different temperatures. When the oxygen sensor sees this lean condition due to un-metered air, it will send a lean signal to the ECM, which will increase fuel injector pulse-width. Check that intake and gaskets.
Roy
