Author Topic: Smoke from Oil Breather Filter  (Read 3358 times)

Utah67

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Smoke from Oil Breather Filter
« on: August 02, 2009, 06:53:55 PM »
Hello All,

I have a 1967 RS/SS with a 400 (406) small block engine. Just the other day I noticed that the engine sounded like it was missing. Also, this morning I noticed smoke coming from the passenger side oil breather filter. Any ideas what might be causing this? I'm hoping it's not a blown head gasket or a damaged piston. Any help would be greatly appreciated.

Regards,

Utah67

Oregonjam

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Re: Smoke from Oil Breather Filter
« Reply #1 on: August 02, 2009, 07:04:02 PM »
A bit more info may help.
Is the engine consuming oil? If so how much?
It is missing at idle or only under load.
68 07D SS350
John

Utah67

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Re: Smoke from Oil Breather Filter
« Reply #2 on: August 02, 2009, 07:07:40 PM »
It doesn't seem to be consuming much oil.  It seems to be missing at idle and under load.  I should add that a found a loose spark plug cable on the Drivers side but after I pushed it in there was no change.  And the smoke is coming from the opposite side of the engine.

Utah67

Utah67

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Re: Smoke from Oil Breather Filter
« Reply #3 on: August 02, 2009, 07:24:29 PM »
I just checked the oil and it's full and clean.  Do you think a good first step might be to change the spark plugs?

CNorton

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Re: Smoke from Oil Breather Filter
« Reply #4 on: August 02, 2009, 08:18:15 PM »
As long as the plugs are coming out you might find it helpful to warm up the motor first and then to run a compression check while they're out.

Oregonjam

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Re: Smoke from Oil Breather Filter
« Reply #5 on: August 02, 2009, 08:25:13 PM »
Check the spark plugs and watch for oil deposits. If build up is present on the plugs, note the mileage and track which plugs came out of which cylinders. I usually put the old ones in the new boxes and write the #s on the boxes for reference later.

If it were a head gasket, it will show by burning coolant or be very obvious on the outside of the motor. Often the collant will foam on the underside of the oil fill cap or it can seep into the radiator. Oil doesn't flow thru the head except with the push rods but a lot of collant flows thru them.

Excessive oil consumption can foul plugs but if you are not burning oil it would not be likely to be caused by blow-by either. If you drove a long way with the spark plug wire not hooked up I woudl definitely check the plugs.

When was the last service (plugs and plug wires)?
Does your car have a points distributor?
What engine is it?

If there is oil build up on a plug then I recommend doing a leak down test for the cylinders. This will check if the % of leakage is within range for your piston rings and valve seats. It will not tell you if you had a bad oil ring or valve guide. First see if the plugs are fouled though.

Lets us know what thier condition is.
68 07D SS350
John

Utah67

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Re: Smoke from Oil Breather Filter
« Reply #6 on: August 02, 2009, 10:28:53 PM »
Thank you very much for your help.  I won't get to chance to change the plugs out until next weekend but will definitely let you know the result.  I have gotten the same advice from others so hopefully it is as simple as that.

Thanks again,

Utah67

rich69rs

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Re: Smoke from Oil Breather Filter
« Reply #7 on: August 03, 2009, 04:30:54 AM »
Is the PCV (positive crankcase ventilation) system / valve working?
Richard Thomas
1969 RS

Oregonjam

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Re: Smoke from Oil Breather Filter
« Reply #8 on: August 28, 2009, 01:46:21 PM »
Utah,
 Just wondering if you figured out the situation with your ride.

John
68 07D SS350
John

zman1969

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Re: Smoke from Oil Breather Filter
« Reply #9 on: September 24, 2009, 05:48:29 PM »
Smoke from breather usually means excess crankcase pressure or blow by. an engine is an air pump as it wears(or breaks) air or combustion gases get past the rings and into the crankcase - causing the smoke, this can be from a broken ring land(misfire)as suggested above a compression test or leakdown test may be needed to further diagnose your issue - I'm afraid the prognosis is not very good by the sounds of it.  
Rich

69 RS/Z DZ302 Daytona bumble bee
69 T/A clone LS6/6sp
69 Nova SS 396

sam

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Re: Smoke from Oil Breather Filter
« Reply #10 on: September 27, 2009, 11:59:04 PM »
It doesn't seem to be consuming much oil.  It seems to be missing at idle and under load.  I should add that a found a loose spark plug cable on the Drivers side but after I pushed it in there was no change.  And the smoke is coming from the opposite side of the engine.

Utah67
maybe that one plug is fouled on the drivers side and that is your problem. Change that one plug out for now and see what happens.