oil control rings- design problem?
 

gents:

noticed that there are a number of posts regarding high oil consumption and no visible leaks (900 mi/qt) w/ engines that have good compression - mine is one of them (2000 ex 180K mi) - 160 TO 180 psi. Is there a design problem here? Has anyone had success with seafoam and/or MMO treatments? Any suggestions on fixes welcome.

northwoods

It could be worn valve seals. Piston rings sound fine judging by compression test.

is there a way of checking the valve seals without too much trouble?

Well, not really... that I know of.

You already checked the compression, indicating the rings are probably fine, but just to be sure check the spark plugs to see if there is oil on them. If a piston ring is bad, the side of the spark plug facing that cylinder will have oil on it.

Do you have blue-white smoke coming out of the tailpipe? If so, is it only during cold start, or after it has warmed up? Usually bad seals only leak much during cold starts and then start sealing properly when the engine is warmed up. So, if it's the seals you'll probably only see smoke during the cold start. Bad piston rings will cause it to smoke always or at certain RPMs, but regardless of engine being warmed up or not.

If there is no smoke at all, you are most likely not burning oil. Burning that much oil you will notice smoke at some point. So in that case, you'll need to look elsewhere. Inspect the engine from top to bottom looking for oil residue, because you likely have a leak. My guess would be rear main seal, which is at the transmission end of the crankshaft, or front main seal which is behind the pulley (harmonic balancer).

no leaks that I can see. fixed several recently.had 2 tanks of no oil use at all after this,then the oil started disapearing again. No smoke either, at any time. coolant level is constant. I know about rear main seal, and if it were leaking there I would see a puddle. Same for front seals. Just replaced them, and do not see any oil around this area. replaced pcv valve as well as grommet. Bit of a mystery. several guys have had this type of problem and replaced the valve seals with no change in oil use. Which leads me to the oil rings. trying SF and MMO soak.

A blown VTEC solenoid gasket can leak oil rapidly, but intermittently.

Have someone follow you in another car and watch for smoke. Bad rings will smoke constantly, getting worse at high rpm and/or with the gas pedal floored. Bad valve seals don't do that.

I did replace the vtec solinoid gasket - but only one of them. the one that seals the vtec assy against the block. There is another one inside the vtec assy but I have not noticed any leaks to the outside of the engine. I am doing the MMO overnight soak and will blow it out in morning and change oil. I will try the observer-follower test and see if that shows anything. BTW the plugs look OK.

thanks for the replys

northwoods (of MN)

its a leak..... after cleaning the engine and driving it for a day I spotted the leak at the oil pan gasket. maddening - never spotted the driveway. Only thing I can figure out is that it leaks under load and higher RPM. Simple fix....

Glad you found it. I thought it was probably a leak. Don't forget to use black RTV or Hondabond gasket maker on the oil pan gasket where there are arches for the crankshaft and to torque in sequence.