Oil mystery


#1

losing oil on 1997 honda civic HX. replaced following: camshaft seal, crankshaft seal, all valve cover seals, new pvc, oil pan gasket. Compresion is about 185 psi across. Leak down test on all cylinders is sat, all cylinders registering in white zone at about 1% leak. Have noticed that when increasing speed to over 60mph the engine tends to lose oil quicker. Could it be valve seals and valve guides?


#2

How much oil does it lose? If it’s less than a quart every 1000 miles it’s not a problem. Some say a quart every 600 miles is tolerable. Replacing all those seals and gaskets sounds like blindly throwing parts at the problem, unless it looked oily or was dripping from the areas. It’s normal for an engine to burn a little more oil when running at constant high speed.


#3

Valve guides tend to leak more oil when the engine isn’t running.

Loosing oil more at highway speeds tends to tell me it’s the rings. The compression rings may be fine, but the oil ring(s) may have a problem.


#4

How can the oiler rings be tested? I am going to replace the valve seals(inexpensive at $20 for a full set) myself. I am now losing about 1qt every 800 miles vs 1qt every 500 miles.


#5

“How can the oiler rings be tested?”

If the compression were low (which it isn’t) you could squirt a little oil into the chambers through the spark plug holes and repeat the compression test. Then the compression would come up if the compression rings were leaky. The only way to test the oil rings is to replace them.


#6

I may be way out in left field. Firstly, how many miles on this engine? Secondly, I have never seen an engine with 1% leakage, 10% on a recently broken in set of rings on a completely rebuilt engine. I am wondering if the cylinder walls are being overloaded with oil. The oil control rings and the scraper ring can only handle so much oil before they let too much get up into the combustion zone. How is the idling hot oil pressure? Are there any signs or noises that might be suspected as excess bearing clearances.

Let us know when you discover what cures this oil loss.


#7

It is possible that the oil rings are either tired (lost spring tension over the years) or are gummed up. Perhaps this is the rare good application for an additive flush treatment. If you follow the directions carefully it will do no harm. Might help.

Let me posit still another idea. Perhaps your returns are partially clogged and when you get over 60 the added oil up top under the valve covers is not draining down fast enough and some small amount is getting ingested via the PCV valve. I know, I know, it’s a wild theory, but of a flush doesn’t help the only other option is the rebuild as Mike suggested, so it’s worth considering.


#8

I just replaced all the valve seals. There was one or two seals (exhaust side) with a bit of carbon built around the area were the stem and guide mate. I havae since put about 250 miles on the car. I checked the oil level today in an even surface and there is no loss. I am not assuming that my problem is solved just yet, but i will keep an eye on it for a couple of weeks. I am also going to do an additive flush as recommended by you folks just in case. I’ll keep this posting updated… Thanks guys for the cool advice…