Oil usage observations

[zebra]

well... just spent literally all night on some 355 forums reading about our poorly-designed valve covers, how much of a pain they are to change (if you can even find them now), and more than i ever cared to know about PCV systems - namely how our dirty side orifice often gets clogged up & leads to excessive consumption... which then draws more oily vapors out the fresh air side (through the intake tube & throttle body). that ain't to say a high-mileage engine wasn't likely already sucking a good amount of blow-by through the normal unclogged route straight into the intake manifold anyway.

i ended up pulling the spark plugs just to have a look-see: valve cover gaskets didn't look to be failing or letting oil drip in the holes, but there was definitely some on all the threads closest to the pistons (they also smelled like oil - not fuel). reso box, throttle body, & intake were all coated in oily film from both PCV ports.

cleaned up all the hardware & then sprayed a dab of brake cleaner followed by seafoam in each PCV, then checked for orifice blockages using a 3/32" drill bit on the dirty (driver's) side. seemed clear enough... but i then removed the oil cap & blew a few blasts of air through both PCV posts + their hoses just to make sure there wasn't no gunk plugging anything inside the cover.

couple test miles after just now putting it back together runs normal, so i'll have my wife report back how it's driving for her. one thing i do know is that a catch can is certainly in our future, and i might just go old-school CCV on both sides in the meantime (hoses to a coke bottle or something so it ain't just dripping on our driveway) because if it's gonna puke that much, i sure don't want to burn it. piston tops already looked like they could use another top-end treatment!

 

[Jeepwalker]

Good to hear the updates. Walmart sells T6 around here, as do the Farm n Barn stores.

Here's an idea...crazy as it seems. If dollars matter, do some commuting calculations: a smaller electric car would cost you very little to commute up over the mountains. You gain back (regen downhill) most of the energy you spend going up the mountain. Apparently companies are starting to use (or have been using for a while) electric semi's for doing milk-runs over the mountains in like CA. I've noticed it too when heading down to the ocean (when I rent an electric car), you charge back up to almost full again.

Not saying get rid of the H3.

Cheers!

 

[Jeepwalker]

I don't remember (and too lazy to re-read all the posts) ...did you ever do a compression test?

 

[zebra]

they don't make manual trans electrics (aside from one Wrangler concept)... and there are VERY FEW places to charge anywhere near us - so my wife won't go for it... and our electric rate is already high enough at the house. we also bought the hummer so she could get to all manner of places for work year-round (in crappy weather, out in the boondocks, etc).

i ain't done a compression check (never needed to buy that gauge kit before).

after reading a massive thread where some colorado guys started playing around with how to do a catch can setup on these atlas engines - documenting what worked & didn't, here's a graphic i borrowed from them as an illustration but i've modified to improve for what i intend to put on her truck. they'd been simply T-ing both PCV lines into the catch can before returning one clean line to the intake manifold (capping the resonator tube)... but while that filters all PCV air prior to getting burnt, it doesn't provide good circulation - rather, only seemingly cycling air at the blow-by's pressure.

i plan to retain the factory routing but install a catch can on the dirty side & add a PCV valve to the clean air intake so that it still brings fresh air into the crank case but won't allow it to draw oily vapor backwards up that same side. it should at least keep the throttle body clean, and the fail-safe (should the PCV orifice get clogged) is leaving the clean side PCV valve unclamped. that way, if PCV pressure builds, it'll simply pop the line off the new valve rather than blowing a gasket... a second benefit is that it's a sure-fire indicator of a clog.

 

[zebra]

PS: this will in no way fix the consumption problem. it simply prevents it from dumping all that oil into the combustion chambers.
in the mean time while i gather the catch components, i'm going to run both PCV bungs in a road draft CCV setup, which won't cause a lean condition or CEL because no unmetered air will enter the intake (temporarily capping both ports).

 

[crwalkerasla]

I have just gone through an engine rebuild. I now believe as a result of this issue. I never saw any loss of oil on the engine or under the vehicle and was only driving the H3 sporadically. The truck downshifted going up a hill, all but redlined then seized up. Following the rebuild (with the original valve cover) the engine would not hold a main bearing seal more than 20 minutes. After the 3rd seal, I made the mechanics stop and find the reason it was blowing seals and not just replace it. When I found out that the PCV was built into the VC, I had them replace the VC. It has been running fine ever since. The Valve covers ARE AVAILABLE, just not from GM. Search Amazon.

It's my belief that with almost 300K on the engine the rings were worn and the clogged PCV was pushing oil into the cylinders.

 

[zebra]

i looked around: most places were out of stock or for the 3.5

 

[crwalkerasla]

Mine is a 3.5. The Valve cover cost ~$155. Labor was rolled into the overall engine rebuild.

 

[zebra]

we have a 3.7 in our 2009, and i saw a lot of Colorado guys note that the 3.5 valve covers do not interchange.

 

[zebra]

weird... not sure why it won't let me edit the previous post.
i was just going to add that i've searched high and low for a 3.7 valve cover (12603876 and/or 12631008), and everywhere i've found that even lists them is out of stock & can't order any more.



...okay, i stand corrected: Summit says they have one for $240 (versus the other few listings ~$110). it must be constructed of unobtanium.

 

[zebra]

the truck gets to sit for almost a week with its brain exposed.

i pulled our valve cover yesterday & spent ~2hrs cleaning it out. clearly the previous owner cheaped out on oil changes - that junk was caked up bad... even after two BG engine flushes + a can of seafoam for 300mi in the oil change between them. naturally, the (assuming OE) gasket was also brittle & came off in three pieces, and nobody in town has any on the shelf. the dealers wanted $135, and i actually considered paying $85 at the box stores just to get it back together last night, but all would've had to order expecting arrival next week... so i told them i'll just buy the $20 set that ships in the same amount of time.

and now we wait.

 

[zebra]

as for consumption prior to this: blowing/spraying out the PCV from the outside seemed to have at least unblocked the dirty side because the intake resonator box & throttle body were still clean/dry when i took it apart.

the little 4oz catch can i installed has been filling up within 200~300mi of driving, though... and it ain't the normal translucent yellow distilled fuel/contaminant liquid. this has been straight engine oil sucking up through the dirty PCV.

after cleaning the valve cover, i enlarged the two fresh side drain-back holes (3/16" or maybe 7/32"... can't remember) in the sheetmetal blocker plate and then added two on the dirty side in the same relative position to the adjacent coil pack hole. we'll see if that helps once it's back together.

 

[zebra]

over the last month, we're still consuming oil... but slightly less of it now. the catch can shows more of the normal yellow condensates in the bottom of the liquid (with oil still on top of that).

i'm now thinking it's simply more a factor of climbing a mountain every day at highway speed. we typically downshift to 4th and catch 65-70mph at the bottom (just over 3000rpm) to ride that all the way up at WOT. it usually slows to & holds ~60mph (2800rpm) mid-way up.

would we be better off (PCV & oil consumption-wise) to drop two gears & ride 3rd all the way at 65mph / 4000 rpm? it's much more annoying as the clutch fan cycles on/off a lot in that regime... but we don't have to mat it to keep it there. we just ain't used to winding it out that high - especially not holding it there for miles.

 

[zebra]

after starting to foul the #5 spark plug with oil, i just bit the bullet & converted the PCV to where both lines go into the catch can (adding a breather on top). capped the intake ports, and now they won't suck the crank case at all. it'll result in less air circulation inside the case, but it's better than drinking oil all day & shouldn't hurt it. my supercharged LS1's been running similarly to that for years with no problems.