Advertisement

Dear Jim,

A few days ago, my 1999 Honda Civic (1.6L, L4) started having big problems on a long, uphill stretch of I-15 near Baker, Calif. The red oil light came on and the engine started knocking badly. When I checked it, the oil level seemed to be fine, but the knock was still there when I restarted the car. It's still parked at a service station in Baker until they can get to it. Do you know what's knocking under the hood? And why would the oil light come on if the oil level is fine?

-- Tim Richards

First, bro, here's a little truth about oiling systems: Just because your car isn't losing oil to the outside doesn't mean the oil is going where it's supposed to on the inside. You don't have an oil-loss problem, you have a pressure problem.

But let's back up just a bit. It sounds like your Civic now has what they call a "spun" rod bearing, which is the part that connects each piston rod to the crankshaft and keeps it in place as the motor runs. That knocking you hear is a result of the rod moving around way too freely, since that particular damaged rod bearing is no longer doing its job.

On top of that, oil volume (thus, pressure) is being lost at the spot where this bearing has gone out. It's not leaking out of the car, but the pressure means it's not getting to the parts of your engine where it should be. That's bad, and that's why you're getting the oil light without any actual loss of oil from the car.

So, about that oil -- how often are you changing it?

These parts typically fail because engine oil has degraded over time and stopped lubricating like it once was. Friction increases, the engine runs hotter and hotter, and eventually something goes out -- such as a rod bearing.

Anyway, brother, you're not alone in terms of where this whole thing happened. That long, uphill grade just north of Baker claims many a motor, even in the winter.

Tip of the Week:

Now's a great time to think about your air conditioning, drivers.

You're not using it these days, it's true, but that's the point. Running the A/C for a few minutes every couple of weeks during the winter will keep the compressor's front seal lubricated, so it doesn't dry out and crack months from now -- when you really need some cool air.

Buffalo Jim, owner of Allstate Auto & Marine Repair in Las Vegas, writes a weekly column. Send your automotive questions to him at buffalojim@lasvegasniftynickel.com. If Jim picks your question to answer in Nuts & Bolts, you'll also be the proud recipient of a deck of official Buffalo Jim playing cards, presented in a classy, tin box bearing his hairy image.