Merc 3.0LX excessive oil

[TNTFAY]

All,
Just trying to get some ideas on where the problem might be. I have a 1995 Merc 3.0LX with stock parts. There seems to be an excessive amount of oil coming out of the rocker cover PCV port. The other end of the tube just slides into the bracket that retains the flame arrestor. The tube itself is in good condition, but a little stretched at both ends. This oil seems to running from the pcv tube down the manifold and into the bilge. I loose about 1/2 qt when running it in a day. The oil is also getting onto the arrestor. I pulled the plugs and there is no blowby indicated. Will replacing the PCV tube stop the leak? What is causing the excessive oil coming out the rocker port? Any info would be greatly appreciated, thanks!
Tim

 

[HT32BSX115]

Re: Merc 3.0LX excessive oil

Howdy,


Check the oil level carefully.

Is it over full?

Also, you may want to remove the rocker cover and ensure that you have a good oil drain-back. It's possible that you have "crud" partially blocking the head drain-back port.

 

[TNTFAY]

Re: Merc 3.0LX excessive oil

HT32BSX115,
Thanks for the response!
Oil level should be just right or under. I only put 4qts in and I took 5 out so I should be good. I'm going to check the cover. Once I get the rocker cover off, what works best to clean the drain back? Is there a chance that the valves or springs could be damaged if I'm doing it myself?
If it isn't the drain back, what's next?
Thanks for your help!
Tim

 

[cooter2506]

Re: Merc 3.0LX excessive oil

HT32BSX115,

Oil level should be just right or under.

Should be and are are two different things. Check it. Could be over full due to water in oil. Due to a cracked block or manifold.

 

[HT32BSX115]

Re: Merc 3.0LX excessive oil

Hi Tim,

You're just looking in the rocker area for an excessive amount of sludge that *could* be preventing the oil from getting back to the pan. If you do have a LOT of sludge you may have other problems like the oil wasn't changed for a LOOOONG time! If you have liquid oil running out of the tube from a plugged drainback, the rocker area would be literally full of oil and when you pull the rocker it would run all over the place! (it's very unlikely if the oil had been changed with any sort of regularity.)

Is it liquid oil running out of the tube or is it vaporized oil?

If it's a 1/2 qt from all day running it's probably vapor. Also, looking at the plugs won't really tell you about blow-by. Excessive oil vapor coming out of the PCV valve/tube and/or dipstick is usually related to excessive blowby.

You really need to do a compression check with a "leakdown" type "tester" to check for blowby. (although a poor leak down test might be due to bad valve sealing etc...)

http://www.mobiloil.com/USA-English/MotorOil/Car_Care/DIY/Engine_Leakdown_Test.aspx

Is there a LOT of hours on the engine?

Could be over full due to water in oil. Due to a cracked block or manifold.

Well, possible.....but he didn't say it was gray oil!

 

[TNTFAY]

Re: Merc 3.0LX excessive oil

HT32BSX115,
Doesn't seem to be any water in oil. No milky or gray inside. It is just oil vapor coming out of the pcv tube. I did just change the oil and I can tell you it had been a long time since the filter took several days to get off.
What will the compression leak down test tell me? The engine probably has at least 500hrs on it, but there's no way to be certain. I'm sure the oil is only coming out of the pcv. I haven't checked the cover yet but will as soon as it stops raining. Are the leakdown guages available for rent at auto parts stores? Thanks for the help so far!
Tim