Oil usage observations

[alrock]

My H3 has been using oil for a long time, generally with blowby on higher demand periods, like long steep highway climbs and off road in low range. Between the highway drive from Phoenix to St. George (400 miles) and the off road use over four days in UT, I had to add over 3 quarts of oil. This is using Mobil 1 5W-30.

I decided to add some snake oil as the last quart of oil - Lucas Oil Stabilizer. After that, I drove home to Phoenix and experienced strong headwinds most of the way home, reducing my mpg to 9 mpg vs. my typical 12-13. My engine got a workout. I promptly forgot to check the oil until today and found that I didn't use any oil at all during that trip. Thickening the oil did the trick. Reading the bobistheoilguy threads, they HATE the Lucas stuff (they hate most additives) but specifically pointed out that it may be prone to foaming as there are no anti-foam agents in there like there is in motor oil. They had a simple test for this, and it may not reflect real world results. But at $13 or so per quart for the Lucas, I'd rather see if a thicker grade motor oil will yield the same results as I got with the Lucas product. (Because $6 is way too much extra to spend, haha.)

My next oil change will be to synthetic 10W-40 to see if that works for me. I considered Delvac diesel oil like others are running, and some tout the benefit of the detergents and the zinc, but I also read conflicting reports that the zinc can harm catalytic converters and I'm excited about damaging that over a few (or many thousand) miles.

So, I'll change the oil in the next week or two and see how that goes for usage.

 

[06 H3]

Glad to see you had a positive experience with this!

It’s so difficult to sift through the internet on what works and what doesn’t so I try use products that I hear work from people I know and not some potential internet troll. I’ll have to give it a try next oil change.

 

[EndeavoredH3]

Glad to hear you had similar results with the Lucus. I found that adding Lucus after an oil change reduced oil consumption, but as the oil/Lucus broke down the consumption would return around 2500-3000 miles. (I normally change oil ~3k)

During the drives to Moab, it was generally a quart to get there, quart having fun, then a quart after I got home.

This year I switched to 5w-40 and it made all of the difference. Oil consumption is way down( 2k miles and maybe down half a quart), I had a rattle on the top end of the motor, GONE. As these I5’s get older, the heavier weight in oil helps them out a bit. These motors get beat up going up western highway grades.

 

[rascole]

I double down on the viscosity change. I've been using synthetic 5w-40 diesel for a few years now on all my vehicles, they all are over 150k miles and consumption is minimal. Less consumption will extend the cats, that's what I tell myself, no evidence yet to prove it but at least the random smoke plume is gone when I start it. But the number 1 killer of cats is coolant and there is no viscosity change to fix that unless you think a slurpee will work.
The internet is full opinions and rudimentary tests of oil additives but Lucas has been around for decades and they have the lab tests to back their claims, how much they actually work might be another tale. They may be best when used with no name conventional oil vs high end synthetic only.

 

[3Hummers]

Our V8 in the Alpha used oil on a regular basis. I checked the oil level frequently on that truck. Never did try additives or going to a thicker oil though.

 

[08H3]

Thanks for sharing what you found. Our first H3 started using oil around 100K, which worried me at the time. I’d not had another modern car that started using oil that early. It still went another 200k though. If one of our current H3s starts using oil, I’ll keep this in mind as I never switched from 5W30.

 

[Guerrero]

My H3 has been using oil for a long time, generally with blowby on higher demand periods, like long steep highway climbs and off road in low range. Between the highway drive from Phoenix to St. George (400 miles) and the off road use over four days in UT, I had to add over 3 quarts of oil. This is using Mobil 1 5W-30.

I decided to add some snake oil as the last quart of oil - Lucas Oil Stabilizer. After that, I drove home to Phoenix and experienced strong headwinds most of the way home, reducing my mpg to 9 mpg vs. my typical 12-13. My engine got a workout. I promptly forgot to check the oil until today and found that I didn't use any oil at all during that trip. Thickening the oil did the trick. Reading the bobistheoilguy threads, they HATE the Lucas stuff (they hate most additives) but specifically pointed out that it may be prone to foaming as there are no anti-foam agents in there like there is in motor oil. They had a simple test for this, and it may not reflect real world results. But at $13 or so per quart for the Lucas, I'd rather see if a thicker grade motor oil will yield the same results as I got with the Lucas product. (Because $6 is way too much extra to spend, haha.)

My next oil change will be to synthetic 10W-40 to see if that works for me. I considered Delvac diesel oil like others are running, and some tout the benefit of the detergents and the zinc, but I also read conflicting reports that the zinc can harm catalytic converters and I'm excited about damaging that over a few (or many thousand) miles.

So, I'll change the oil in the next week or two and see how that goes for usage.

Hello Alrock! Glad that Lucas Additive worked for you!

I have no idea if you or others with oil consumption on the i5 tried or not before to resolve the issues with the PCV baffle in the valve cover, as it seems to be the culprit of majority of oil consumption issues on 3.5 and 3.7 engines.

If you didnt try yet the PCV fix, i can tell for you and others that is as simple to change the Valve cover complete on the 3.7 (i think is still not discontinued) and on the 3.5 is necessary to remove the valve cover, clean the baffles that goes on the driver side and open up the small hole that allow the oil to drain back to valve area in the cylinder head.

The issue is about design, the baffle only have a small oil orifice where the oil drain back to the valve area and is not absorbed by the intake manifold. That small orifice get clogged with time and residues and sometimes even with the gasket maker that is used from factory in that point. So is necessary to remove valve cover, clean the baffle and open the orifice that is clogged for sure. I even think would be good to drill another hole in that baffle but not sure.
I have some issues of oil consumption on my previous h3 i5 and I fix it temporaly just applying pressure air to the pcv outlet on the driver side and open the fill cap of oil, the air should flow unrestricted there, dont try on the passenger side, that side always capture pressure and you could blow something


Hope this help you out!

[Removed the link to another forum - Admin]

Guerrero

 

[chaos254]

I'm interested to see how the thicker oil works. I have 173k and probably burn about a quart every 1000-1500 miles. I tried a new valve cover at around 145k and it did nothing for my burning oil.

 

[alrock]

I'll let you know. I've probably got 100 miles on this oil change so far.

 

[scoreh3]

Perfect timing I have an oil change coming up soon. Thanks for all the good information.

 

[Jeepwalker]

OP - If old posts here, and Colorado Forums engine posts are of any value, thicker oil might be a bad idea. Supposedly the oil squirters at the base of the cylinders are calibrated for the recommended oil viscosity, and don't 'squirt' very well or at all with thicker oil. That's what others have reported ....going way back to the early days of Atlas engines. I don't have any direct experience .....but a lot of knowledgeable guys do. Same thing with other engines like Hemi 6.4's which also use squirters. Something to look into. It's possible an engine might tolerate a small bump-up in viscosity (this is not advice or a recommendation), but who knows.

Honestly, to me ...it seems like going to 10-40 to save a little blowby and $3.50 on a qt of oil vs toasting an engine you can't buy anymore, and are expensive as heck to rebuild isn't a very good risk vs reward scenario. But there's always a chance it'll work fine too. Maybe start lower first. If you go to the 10W-40...keep us up to speed on how it goes long term.

Have you done a compression check? Lot of these engines develop a burnt valve situation on the center cylinders. I have one cylinder running pretty low compression on mine. The misfire calcs are pretty high at idle (not enough to throw a code) but they even out off idle and at road speeds. Something else to look into possibly.

 

[Jeepwalker]

Basically the same atlas engine with an extra cylinder:

4.2 Engine Rebuild

So, my 2003 Trailblazer with a 4.2 has had the common piston slap ever since I've owned it. The noise would go away when the engine warmed up but the past few months it got to where the noise never really went away. I took the valve cover off a while back and some of the lash adjusters seemed...

gmtnation.com

 

[Jeepwalker]

Engines in the last 20 years (like Atlas engines) use very thin piston rings. Other tolerances are tighter too. Thin rings turns out is better for engine longevity, efficiency and power. So mfgrs have added oil squirters to help lubricate the lower cylinder. And thinner oil is used as a result. Yeah, a guy could run about any oil in older engines of the past.

Piston Rings and Engine Heat: Do You Really Need a Bigger Radiator?

How much can the profile of your piston rings affect the amount of heat your engine generates? What we found might surprise you.

www.motortrend.com

 

[EndeavoredH3]

OP - If old posts here, and Colorado Forums engine posts are of any value, thicker oil might be a bad idea. Supposedly the oil squirters at the base of the cylinders are calibrated for the recommended oil viscosity, and don't 'squirt' very well or at all with thicker oil. That's what others have reported ....going way back to the early days of Atlas engines. I don't have any direct experience .....but a lot of knowledgeable guys do. Same thing with other engines like Hemi 6.4's which also use squirters. Something to look into. It's possible an engine might tolerate a small bump-up in viscosity (this is not advice or a recommendation), but who knows.

Honestly, to me ...it seems like going to 10-40 to save a little blowby and $3.50 on a qt of oil vs toasting an engine you can't buy anymore, and are expensive as heck to rebuild isn't a very good risk vs reward scenario. But there's always a chance it'll work fine too. Maybe start lower first. If you go to the 10W-40...keep us up to speed on how it goes long term.

Have you done a compression check? Lot of these engines develop a burnt valve situation on the center cylinders. I have one cylinder running pretty low compression on mine. The misfire calcs are pretty high at idle (not enough to throw a code) but they even out off idle and at road speeds. Something else to look into possibly.

My motor has 190k on it, and oil consumption is progressively more and more as it aged. I wouldn’t recommend on a new/newer motor. My brother did the same in his as well and it’s working for him too.

There is something to be said about going too heavy with the oil. But the small bump from 5-30 to 5-40 in a high mileage motor shouldnt be a death sentence. That being said, I always did oil changes at 3-3500 miles. Never really going over. These motors need clean oil to last.

 

[Jeepwalker]

My motor has 190k on it, and oil consumption is progressively more and more as it aged.

That's about where mine is at too....

I'm planning a rebuild one of these days. Mine needs it: low oil pressure and low compression on the 3rd cyl. Most likely a burnt valve (fingers crossed). The timing chain tensioners ...who knows (??), probably worn to a nub. But the Radio works great!! Still drives nice. lol

 

[alrock]

No compression check yet. But my consumption was a bit more than "a little" when I put in three quarts in about 300 miles, including a bunch of time at high load on road and off-road. That much blowby can't be good for downstream systems like catalytic converters.

So far with 500 miles on this 10W-40 and the oil level has not changed. It's far from a conclusive test, but normally by now I would have added at least half a quart for daily driving, if not more.

The engine is likely due for replacement or rebuild. If the 10W-40 hastens it, so be it. But if it prolongs the need for a rebuild, that's a win. To sit by and do nothing I'll learn nothing and not have the chance to gain anything. I'm comfortable with the risk and have already identified a shop to do a rebuild/bore over on this block.

Note that this is also in Phoenix. This vehicle very rarely see cold temperatures and spend a lot of time driving with outside temps in excess of 100°. Oil is a lot easier to flow when heat makes it the consistency of water vs. that of maple syrup.

 

[EndeavoredH3]

No compression check yet. But my consumption was a bit more than "a little" when I put in three quarts in about 300 miles, including a bunch of time at high load on road and off-road. That much blowby can't be good for downstream systems like catalytic converters.

So far with 500 miles on this 10W-40 and the oil level has not changed. It's far from a conclusive test, but normally by now I would have added at least half a quart for daily driving, if not more.

The engine is likely due for replacement or rebuild. If the 10W-40 hastens it, so be it. But if it prolongs the need for a rebuild, that's a win. To sit by and do nothing I'll learn nothing and not have the chance to gain anything. I'm comfortable with the risk and have already identified a shop to do a rebuild/bore over on this block.

Note that this is also in Phoenix. This vehicle very rarely see cold temperatures and spend a lot of time driving with outside temps in excess of 100°. Oil is a lot easier to flow when heat makes it the consistency of water vs. that of maple syrup.

Will you be doing a v8 swap if the motor goes?

I’ll be leaning toward that route, it’ll also make it much easier to install a 6 speed.

 

[alrock]

I doubt it, but it's possible. I'm likely to get a .20 overbore kit for this block and have it rebuilt, assuming everything else is in workable shape. I'd like to get a V8 but I also only put about 5000 miles each year on the H3, so for me it's not a great ROI to go V8

 

[Jeepwalker]

Maybe you'll get lucky: The sleeves are high-nickle content and many say they tend to look pretty good after many miles. You probably know they're micro-thin too. Let us know how they look when you get to that point.

 

[alrock]

Progress update: after 700 miles, didn’t have to add oil. Then took it on a road trip about 1150 miles one way and it used 1.5 quarts. For me and this engine, that’s acceptable and a bit of an improvement. From Phoenix to east of Albuquerque there are a lot of hills, so the engine spends a lot of time above 3000 rpm and the high RPMs have been the source of the issue most of the time.

On a side note, I tried cruising at 75 mph but unless it was perfectly level or downhill, the torque converter wouldn’t stay locked, hurting my mpg. 71 mph was my max to be efficient. My fuel gauge has always been really accurate in that each 1/4 tank on the gauge = 5 gallons, so it’s easy to figure out the mpg as I’m driving. Who needs one of them fancy in-dash computers, haha? My current goal is 60 miles per 1/4 tank, 12 mpg. I got that on the trip, with one tank at 13 mpg. I expect at least light headwinds most of the way back so that’s gonna drop.

 

[alrock]

In my continued search for The World's Greatest Snake Oil™, I have an update regarding my H3. I took it to Kansas from Phoenix. About 1100 miles on the way there (a couple of detours) and 1000 miles on the way back. Between Phoenix and just east of Albuquerque, there are several long grades to climb, testing the H3's ability to keep any sort of speed. On the way back, there's typically a strong west to east wind on I-40 that can really reduce my mpg, whether in an aerodynamic vehicle or this one.

About 700 miles into the trip (and 1500 since my last oil change) I added a quart of oil. Actually, it was 600ml of Liqui Moly Motor Oil Saver, the newest candidate for The World's Greatest Snake Oil™ and the balance being 10w-40. At my destination in Wichita, I added another half quart. I cruised most of the time at 71 mph, which was the fastest I could go and keep it in fourth gear with the torque converter locked up.

On the way back, the first half of the trip was easy. No winds, flat roads, and a wicked rainstorm. But once I got to Tucumcari, NM and got onto I-40, it was time for headwinds. I ran against those headwinds to about Gallup, about 300 miles. 90% of that time I was cruising at 65 mph in third gear. 4th gear was a distant and unattainable dream. MPG was not ideal.

Got home and checked the oil (as I had been doing every 300 or so miles) and ended up adding a half quart. Not bad for a long trek with an engine sitting around 3000 rpm for at least a third of that time. Maybe that Liqui Moly helped out, maybe it's a fluke, I dunno. But my 200K H3 made the trip without incident.

 

[EndeavoredH3]

Have some miles since last comment. Drove up and did a lot of fishing up in the white mountains this weekend, including the climb getting to Hannagan meadow. Lots of high rev, 6-8% grades all weekend totaling 550 miles.

Only burned fuel.

One thing to note is that at 9k feet the truck had no power. Would take a horrendous amount of time to get up to 55mph. Probably will do a compression test as the motor has 194,000 miles on it now.

Side note: Drove back to the valley today and the 109*F and 17% humidity makes me want to go back.

 

[08H3]

I don't have anything constructive to add at this point ..other than bragging maybe! We took our first road trip in Hummer #3 last week. For reference, by the time Hummer #1 was forced into retirement at 303,000 miles, it was a pretty heavy drinker. On long trips I always carried plenty of spare oil and diligently checked every couple hundred miles. It probably got to about a quart every 500 miles, which very surprisingly if you read GMs documentation is still considered acceptable .

Anyway, fast forward to this trip, it totalled 2,103 miles and I used no oil at all. Still at full on the dipstick. These were not easy miles either. I75 through southern KY and northern TN are very hilly. I-40 East to Asheville and even I-26 into SC require a lot of downshifting. I am also a fan of the skinny pedal, so it's a lot of high load, high RPM. I was extremely pleased. This was with Dexos 5W-30.

For reference, at this mileage (128,000), Hummer #1 was using about a quart/1500 miles. At the time I was concerned about that much usage, but it ran great and went another 175,000 so it must have just been a characteristic of that particular engine. Hopefully the fact that this one is so much better at this point bodes well for its longevity

 

[zebra]

weird that i hadn't come across these discussions over the years.

ours is approaching 160k and didn't used to burn but a quart of oil every 5000mi change interval... but ever since we moved up into the mountains last summer - where our road is at the top of a three mile 6% grade @ 4000ft elevation (with another 1mi 5% grade just beyond that) - i noticed it's been burning ~1qt/1000mi. just to maintain 65-70 requires downshifting to 4th (3000rpm) minimum... but if dipping below 65, it's almost a guaranteed 3rd gear hit to stay above 55. that said, my wife now does a LOT of 3000+ rpm driving now, and i figured that had a lot to do with the extra consumption.

fortunately, i buy 5w40 synthetic by the bucket for both my dodge (3gal changes) and built corvette (7qt changes), so maybe i'll give it a shot in this truck.

 

[zebra]

well, it's been a year since the viscosity swap (Rotella T6 5w40 synthetic). it burns more now than it was during my last post.

bought the truck in Nov '19 with 103k, and from then until a couple years ago (at 140k miles), it only burned a normal quart of 5w30 (usually a high-mileage syn blend) in a 5000mi change interval. normal daily driving anywhere from ~1500ft elevation up to 3200ft (occasional trips into the mountains at 7000ft).

after we moved outside of town in summer '22 - where we now have a 1000ft climb to our house at 4200' every day - the ups & downs make for 3 routine 6% grades that are each 2-3 miles long (uphill once going into town, uphill twice going home). this was when i noticed our oil consumption going to crap. noticed it'd started burning roughly 1qt every 1000 miles, so i simply kept it topped off and still changed at 5000.

in Sep '23 (after the post above), i swapped to my diesel oil at 160k miles thinking it might slow consumption & alleviate a slight tick i'd heard developing when the engine was warm. consumption was roughly the same & the tick never improved, so after 10k miles, i went back to a 5w30 except full synthetic.

ended up taking it into a shop in Feb because it'd also started idling rough & occasionally not starting (just cranking... but with good fuel pressure). MAF reading was all over, so we put a new sensor in & reinstalled a stock air filter + factory resonator/tube. didn't fix it after a week, so i took it back & after pulling the #5 spark plug and noting that the electrode was gone... they scoped the cylinder. it was all caked up from not burning right & one of the valves was stuck slightly open (caked with carbon) - which explained the ticking (gap between stem & cam). i had them perform a BG computer-controlled top end flush/cleaner & replace the bad plug (other plugs looked great). had also fouled an O2 just prior, so i swapped both of them at home. tick was gone; truck ran smooth again... but still burning oil.

by April, i'd added 5qts of oil in 3700mi, so thinking maybe the rings got caked up with the bad cylinder earlier, i performed a BG oil treatment/flush (a can of EPR in the oil & ran at 1200rpm in neutral for 20min) just prior to 174k. drained oil; refilled with T6 5w40 + BG MOA (supposed to counteract any remnants of the cleaner). also used a can of 44k fuel system cleaner in the gas tank.

now it's August: 5700mi later (179,500 on the clock), i've topped off 9qts and plan for a full oil change next weekend. does a new valve cover really fix this? comments above seem to be hit or miss. also, now that newer diesels are starting to use 5w30, more places are stocking T6 in that weight (which was hard to find). i've got some for my vette but might think of using it in the H3 next. thoughts?