Smoke/Oil from CC breather

[sfelsheim]

Hello everyone,

First post. I purchased an 85 CJ7 a month or so ago. Its in very very good condition, much has been done. Thrilled with it.

While it runs fine, no issues, I do have smoke coming out the crank breather and some oil. (its a 4.0 head on a AMC 258 i6 / 4.2l ).

Any thoughts? Blow by? I don't smell coolant.

See YouTube video

https://youtu.be/n5k7OXaDWz4

Thanks!

 

[Torxhead]

Welcome to the forum, looks like you are off to a good start. And yes it is blow by, burning oil that gets by the rings. Use a good quality oil like a 15w-40 or a 20w-50.

 

[CJ]

I'm not a 4.0 or AMC 258 i6 / 4.2l exert but isn't where your breather is located is where your PC valve is supposed to go? Do you have a PC valve?

 

[Lumpy Grits]

:ww:

Sounds like 'blow-by'. How many miles on the engine?
What weight oil are you run'n?
Make sure you have the CORRECT, PCV valve for your engine. Make sure it is clean and work'n.
AMC used many different PCV valves over the years.
I would just run that breather to the intake.
I would be more worried about that hard 'knock'.
LG

 

[sfelsheim]

Not sure which oil. The oil was fresh when I got it (plan to change before I put it away for the winter).

The PCV valve is at the rear of the valve cover.

Given this is a 4.0L head on a AMC 258 i6 / 4.2l motor, should I use the PCV for a AMC 258 i6 / 4.2l ?

The odometer has 110K miles on it. I know the previous owner put a new cam in when he put the 4.0 head on (have all the receipts)

So, I will change the oil to one you mentioned above, and run it? Sounds like a rebuild is in my future.

Yeah, the knock, that was my next question...

 

[mtnwhlr]

A knock and a lot of blow by means you have a motor that is in need of a rebuild. You are running on borrowed time.

 

[Lumpy Grits]

Next oil change(make it PDQ)add a can of V-8 size of 'Restore'.
You want 20w-40 to 20W-50 for oil.
OLG

 

[slomo]

20w-50 in winter temps is a no-no. That honey is too thick if you live where it drops below 55F. Take a bottle and "try" to pour it at 50 or below. Notice how slow it pours? In cold temps you will starve the motor for oil on startups.

The PCV valve goes at the front of the valve cover, towards radiator. Breather in the rear next to the firewall. OP has the PCV in the wrong spot.

Blowby means rebuild time. Rings are dead/dying.

happy holidays!!!

slomo

 

[Lumpy Grits]

20w-50 in winter temps is a no-no. That honey is too thick if you live where it drops below 55F. Take a bottle and "try" to pour it at 50 or below. Notice how slow it pours? In cold temps you will starve the motor for oil on startups.

The PCV valve goes at the front of the valve cover, towards radiator. Breather in the rear next to the firewall. OP has the PCV in the wrong spot.

Blowby means rebuild time. Rings are dead/dying.

happy holidays!!!

slomo

20w-50 oil has been in my AMC 258 i6 / 4.2l since the first oil change in 1985. It is still being used in it today, with 120K+ miles on it.
The owners manual for my Jeep says 30* to 'off the chart' is the range for 20w-50. Pretty much covers the Mojave Desert
Anyone that uses Honey as a flow comparison for motor oil has lots to learn.
You really need to do some research.....
LG

 

[sfelsheim]

Thanks everyone. Looks like I get to do a rebuild this winter! (honestly, I was looking for an excuse :-) )

Guess I will start a new thread with some rebuild questions and advice.

BTW, just finished pulling leafs (YJ) that had the Jeep at 4.5" of lift. I thought it was too much.

Put OME 2.5" leafs in. Looks much better, and wow, it rides amazing.