I am planning on doing some seal repairs soon, on my 1.5L in my 91 civic lx 4 door. What is the best way to tell if valve seals are worn? If valve seals need replaced is it possible to do without removing the cylinder head?

I think that the drivers side main seal may also need replacement. I kinda gummed it up during a timing belt change. How difficult is the main seal replacement? Can it be done without engine or crank removal?

 

Worn valve seals will make the engine burn oil. It is hard to distinguish that from worn piston rings. I think if the valve seals are bad it will smoke at a pretty constant rate but the rings will make it smoke much worse when you floor it.

The valve seals can be replaced with the head on, but in my case it was a waste of money and time because the rings were shot so I needed to replace the whole engine anyway.

The "front" crank seal is no problem once you know how to change the timing belt. Take it all apart again and also take the crank sprocket off. The sprocket should just slide off by hand. Pry the old seal out, being careful not to damage the shaft, and carefully push in a new one. You need a special installer tool, or suitable cylindrical object to apply pressure exactly at the outside edge of the new seal. If you press on a seal near the center, it will get bent and leak.

 

Thanks.
Do you test the rings through a compression leakdown test at top dead center for each cylinder? I would think that would elimminate any valve seal leakage effects. My car doesnt smoke unless I let it get to high rpms like 4-5500 and if then its barely visible. Which isn't great for a 230k engine I know. It isn't my hot rod car but I am just trying to elliminate oil leaks and waste, it seems with combined leaks and possible burning I lose a quart every 1000 miles or so.

I suspect the valve seals leak because when idling I can smell unburned oil in the exhaust, its not like the blue smoke smell, more like its leaking into the hot exhaust ports and going out the tailpipe.

 

You will need to use compressed air through the sparkplug holes to keep the valves held closed so you can remove the spring and retainers to change the seals.

 

do a leakdown test to find out if its your rings or your valve seals. If your front main is not leaking don't replace it.

Valve seals will tend to burn more on a cold startup, then not much after that (after they expand). If you're smelling burned oil it could still be blowby or leaking valve seals....

K