MMO on long highway trip?

[Benzadmiral]

On another thread, I've detailed the slight oil loss/oil burning (1 qt./1700 miles) I've been seeing on my '03 Buick Park Avenue, the 3.8L non-supercharged engine, w/ 80K miles. It has MobilClean 5000 10w30 in the engine now, w/ 2600 miles on it. One item of BITOG advice was to top off with MMO to help clean things up in the rings; the car sees a lot of low-speed use in The Swamp. I'm planning to do that the next time the low oil level message comes on, which probably will be soon.

After Xmas I plan to run out to Austin, TX, spend a day there, wander up the old Federal highways to Tyler and spend a night, then come back via I-20, I-49, and I-10. I'd guess about 1300 miles in 4 days, a lot of it 55-75 mph.

Now I'm sure the oil can handle ~4K miles, with so much of it being easy highway time. But is there any issue with up to 20% MMO in the crankcase? It'll thin out the oil, I know, which could be a help should I run into any "old blue northers." But will it stand up to highway running?

 

[demarpaint]

I've done it many times, go for it, it will certainly help clean things up. I would however keep an eye on the oil level. Do not exceed 20% of MMO in the sump. If you are a real fanatic you can mix 20% MMO into your top up oil, otherwise just use your favorite oil if you need to top up.

 

[hate2work]

Originally Posted By: demarpaint
If you are a real fanatic you can mix 20% MMO into your top up oil, otherwise just use your favorite oil if you need to top up.


"You might be a bitoger if...you put the same amount of additive in your top up oil that you have in the sump."

 

[eljefino]

When do you get the low oil message on yours? I always assumed the warning was at the "serious business" level of the sump, eg below the "add a quart" line.

My own MMO (saturn) experience/paranoia has been to run at 20% but only for the last couple 100 miles before a change. But then again it didn't work on my rings...

 

[crazyoildude]

i would not use the mmo on a long trip it thins the oil out too much in my opinion....i use marvel all the time in my gas and sometimes in the winter i put a cup or so in my oil but dont push it too hard like i said it does thin things out a little...
if it thins out too much it could damage the bearings

 

[chubbs1]

M-Clean5k is a great oil, if you are a bitoger and by the sound of the post you are, I would bring a couple quarts of MC5K 5W30 with me and call it a day. It is a great cleaner in and of itself and with a trip that long I would just think it is unnecessary and possibly dangerous if you accidentally put too much MMO in. Just run with your oil or put the MMO in during the last 500 miles of your trip. Then do an oil and filter change.

 

[SrDriver]

I have used 20% MMO in the oil without issue in several vehicles @ oil changes over the years.

Keep an eye on oil levels.

Have you changed the PCV valve - checked the hoses?

Enjoy your trip. You may even see better fuel economy too + I would add between 3 to 4 oz per 10 gallons of gasoline before filling so it gets mixed up good.

 

[Benzadmiral]

Originally Posted By: SrDriver
I have used 20% MMO in the oil without issue in several vehicles @ oil changes over the years.

Keep an eye on oil levels.

Have you changed the PCV valve - checked the hoses?

Enjoy your trip. You may even see better fuel economy too + I would add between 3 to 4 oz per 10 gallons of gasoline before filling so it gets mixed up good.

Yeah, I'll keep a quart of oil with me, and I expect I'll be able to buy more if I need it. The PCV valve I've changed twice, both times with OEM parts. Last week I took it out, cleaned it with Seafoam, and ran Seafoam spray into the PCV intake while keeping the revs up, then drove the car for a while in 3rd gear for more revs and vacuum.

It's a little soon to tell if it's cleaned anything up, or out. At the last message, about 900 miles ago, I topped off to the "Full" line on the dipstick. This weekend I checked, and it's down to the midpoint, between "Add" and "Full."

Maybe I'll compromise, and instead of 20% MMO, a quart, I'll put in a pint, then top off with MC5000.

 

[Benzadmiral]

Originally Posted By: eljefino
When do you get the low oil message on yours? I always assumed the warning was at the "serious business" level of the sump, eg below the "add a quart" line. . . .

That's about what I see when I get the message, the oil is below the "Add" mark. A pint of oil brings it to the midpoint; a quart, to the "Full" line.

(I got surprised at the last change. My mechanic handed me back the last of the 5 quarts I'd brought him, and said, "Did you know this car doesn't take 5 quarts? We put in 4, and it registered full." I looked in the owner's manual. Turns out the 3.8L takes 4.5 US quarts, not 5!)

 

[demarpaint]

Originally Posted By: Benzadmiral
Maybe I'll compromise, and instead of 20% MMO, a quart, I'll put in a pint, then top off with MC5000.


That won't hurt, it might not clean as well but it certainly will do some cleaning. It is worth a try, and a good compromise.

 

[panthermike]

I've done it w/out issue, a pint is a good idea. If you're worried, you can substitute 1qt w/ 10w40.

 

[Kaboomba]

Originally Posted By: Benzadmiral
At the last message, about 900 miles ago, I topped off to the "Full" line on the dipstick. This weekend I checked, and it's down to the midpoint, between "Add" and "Full."


Benz,

Have you replaced the Upper Intake Manifold and its gasket with updated parts, and the Lower Intake Manifold gasket? If not, you are likely due.

These Series II 3800 engines tend to use a bit more oil than many other engines for several reasons:

1. Defective valve stem seals
2. Defective or compromised UIM/LIM gaskets
3. Low-tension piston rings (by design)

(1) and (2) are repairable, (3) is nothing to worry about, although the rings will work much better when they are very clean.

(2) you should be concerned about, as these gaskets can suddenly fail and destroy the engine.

 

[Benzadmiral]

Originally Posted By: Kaboomba
Originally Posted By: Benzadmiral
At the last message, about 900 miles ago, I topped off to the "Full" line on the dipstick. This weekend I checked, and it's down to the midpoint, between "Add" and "Full."


Benz,

Have you replaced the Upper Intake Manifold and its gasket with updated parts, and the Lower Intake Manifold gasket? If not, you are likely due.

These Series II 3800 engines tend to use a bit more oil than many other engines for several reasons:

1. Defective valve stem seals
2. Defective or compromised UIM/LIM gaskets
3. Low-tension piston rings (by design)

(1) and (2) are repairable, (3) is nothing to worry about, although the rings will work much better when they are very clean.

(2) you should be concerned about, as these gaskets can suddenly fail and destroy the engine.

I checked into the gasket issue earlier this year. My regular mechanic did a pressure test on the cooling system, and it passed without any red flags. He said he's done the gasket replacement on a number of cars, but they'd all failed the cooling system test. On his advice, I crushed and poured one of those GM cooling system sealant tabs into the radiator. Also, the coolant tank keeps a relatively stable level, and there doesn't seem to be any coolant in the oil.

How would I know if it's the valve stem seals? Is the only way to tell to open the engine up and look?

I'm trying the inexpensive fixes first; who knows, they may reduce the loss/consumption.

 

[Kaboomba]

Originally Posted By: Benzadmiral

How would I know if it's the valve stem seals? Is the only way to tell to open the engine up and look?


Weepy valve stem seals usually show themselves by causing a puff of smoke on startup, higher oil consumption on sustained hot driving as opposed to cooler or shorter trips, consumption that slows down in cooler weather and also slows down as the oil level drops.

IIRC, to permenantly cure the weepy valve stem seals requires some machining on either the heads or the valve stems in order to accept a better type of seal--this is not as expensive as it sounds if you remove the heads yourself, and I know some people have had success with using revised seals that didn't require head removal or machining.

If I were you, I would agressively flush the engine by adding some MMO for a period of time, then using the new kinder-gentler Amsoil Flush to really wash out any muck. After that I would closely monitor oil consumption while watching for the symptoms mentioned above, running known commodities like 5w30 PP and PureOne PL24011 for several 3-5K OCI's.

DO FIRST: Also, do an Italian Tune-Up or two to make sure the rings are blown out, clean, and sealing up nicely.

Yes, I went through this with my Series I 3800, and elected not to do the seals unless I end up needing UIM/LIM gaskets. My Buick's consumption stabilized at 1qt/3500-4500mi for the last 60K mi.

I hope this helps!

Cruise on!

 

[Lethal1ty17]

running 20% MMO will be fine and wont hurt anything. it may thin out the oil a little bit, but only a little and its not a big deal. engines can run with a bith thinner oil and not hurt a thing, 20% MMO changes a 5w30 to about a 5w25 or something like that. its not a huge difference and certainly wont hurt anything.

 

[HangerHarley]

Originally Posted By: Lethal1ty17
running 20% MMO will be fine and wont hurt anything. it may thin out the oil a little bit, but only a little and its not a big deal. engines can run with a bith thinner oil and not hurt a thing, 20% MMO changes a 5w30 to about a 5w25 or something like that. its not a huge difference and certainly wont hurt anything.


The concern is cars that need an xW-40, or even an xW-50 for older vehicles that seem to do well with that thick grade. MMO at 20% is still a helpful thing, right? Many think it "Helps the engine to an early grave." Thoughts on this thicker Oil scenario?

Sometimes the engines have the Thicker Oil due to Fuel Dilution issues. For example, a car where the Oil smells VERY gas-like, so much so that a problem is suspected. (Gasoline washing Oil away... Thick Oil?)

 

[unDummy]

It helps an engine last longer. Earlier grave is caused by lack of maintenance.

You can use the MMO with any weight oil.

Once oil is up to temp, it should evaporate any fuel. Short trippers might have a problem.

If you're afraid of the viscosity of MMO, just add 1 quart of a thicker oil to your blend.

 

[crazyoildude]

3800 v6 are great engines we see some here for rebuilds but there are so many of them on the road... their gaskets are not so bad like people say otherwise we would see hundreds of those engines.. we are a fairly large engine shop and happen to like this engine

 

[jc1990]

WHAT ABOUT THE OLDER 4.3 TBI ENGINES WHAT PROBLEMS DO THESE HAVE BESIDES THE VALVE SEALS

 

[ARB1977]

Keep an eye on your oil level. I ran a qrt in 6 qrt system in about 2000 miles I had to add a qrt of oil. Never burned before. Ill never go that long so 800 miles or 1 month is all ill do.