Oil consumption, blue smoke, spark plug condition and compression test results - what do you think? (1 Viewer)

Joined
Jun 13, 2014
Messages
92
Location
The Colony, TX
 
Hi, all,

A little background info to start... my cruiser (see signature line) has 278k on the odometer. I purchased the vehicle when it had 242k on the odometer. I have no idea if the head gasket has ever been replaced. Average mpg is between 12 and 14 mg. It "feels" like it has adequate power, but I live on the North Texas blackland prairie, so there is that. The big issue I am trying to resolve is oil consumption and the smell of burning oil. As for relevant repairs, valve cover gasket is new, new spark plug tube seals, new pcv valve and grommet seal. Most oil leaks resolved, except for maybe upper pan arch seal.

Here are my symptoms:
* I add around 1 qt of oil every 400 miles or so (I use Mobil1 TDT 5W-40).
* I see blue smoke after starting up an already warm engine. I might have also seen it when accelerating from a long idle.
* There is an ever-present exhaust smell (I assume burning oil) whenever running it; the exhaust shop says all is well.

So, I decided to pull the spark plugs and do a compression test. I've posted the results below, but I would like your input on the results. What do you think? And is the only possible culprit at this point the valve stem seals?

Spark plug condition:
IMG_1025.png

IMG_1026.png


Compression test results (hot engine, dry, cranked 7-8 times with throttle fully open, efi fuse pulled)
#1 - 200
#2 - 205
#3 - 195
#4 - 180
#5 - 205
#6 - 215

Obviously #4 is quite a bit lower than the rest, especially since 14 psi is the maximum variation spec. I don't know a lot about what the numbers should be given mileage and age... do they seem unusually high?

Thanks for any thought!
 

enox

SILVER Star
Joined
Mar 12, 2018
Messages
281
Location
Los Angeles, CA
I had oil consumption issues at 240k mi, at that point I had had the 80 for like 18months. I threw a lot of time into trying to sort it out... The p.o didn't do the best mechanical maintenance soo...I ended up rebuilding it.
 

enox

SILVER Star
Joined
Mar 12, 2018
Messages
281
Location
Los Angeles, CA
 
Joined
Jul 15, 2013
Messages
362
Location
Lakewood, CO
 
I would maybe try some 15 or 10w 40 and see if it slows down. I had my headgasket done at 240k and it burns hardly any oil. Valve seals should fix your problem.
 
Joined
Jun 13, 2014
Messages
92
Location
The Colony, TX
 
I would maybe try some 15 or 10w 40 and see if it slows down. I had my headgasket done at 240k and it burns hardly any oil. Valve seals should fix your problem.
I have tried heavier oils in the past, like M1 15w-50, and did not see much difference in oil consumption, and actually heard some lower end knocking when the engine was cold, so i switched back. I agree with you, given the compression numbers it must be the valve seals.
 
Joined
Nov 9, 2012
Messages
9,791
Location
Olathe, KS, USA
 
Everything you have listed points to valve seals.
Possibly time to do the HG and have the head rebuilt as PM.

Constant blue smoke under acceleration = rings
Blue smoke under deceleration = valve seals / guides
Puff of blue smoke at sudden acceleration from a light = valve guides / seals
Black smoke on acceleration = too much fuel
White smoke = coolant (head gasket)
 
Joined
Jun 17, 2016
Messages
414
Location
Seattle Area
Everything you have listed points to valve seals.
Possibly time to do the HG and have the head rebuilt as PM.

Constant blue smoke under acceleration = rings
Blue smoke under deceleration = valve seals / guides
Puff of blue smoke at sudden acceleration from a light = valve guides / seals
Black smoke on acceleration = too much fuel
White smoke = coolant (head gasket)
This should be on a poster😁
 
Joined
Jun 13, 2014
Messages
92
Location
The Colony, TX
 
Everything you have listed points to valve seals.
Possibly time to do the HG and have the head rebuilt as PM.

Constant blue smoke under acceleration = rings
Blue smoke under deceleration = valve seals / guides
Puff of blue smoke at sudden acceleration from a light = valve guides / seals
Black smoke on acceleration = too much fuel
White smoke = coolant (head gasket)
This is awesome - thank you!
 

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