Conventional Oil to Synthetic Oil ISSUES

[asprague33806]

I have a 2007 Win. Adventurer. In May of this year w/roughly 19,000 miles on our coach I switched over to Mobile One 10W - 30W. Left on a trip to Nashville over a 2 week period and went through 3 qts of oil on the trip, not bad. Changed oil and lubed in Nashville and started to head home via Bourbon Country. Somewhere about Kansas I started having intermittent oil pressure issues meaning lifters starting to click. Backed off the throttle and the issues went away. It slowly got worse as we got closer to the Oregon Coast. The last hill I climbed was at about 10 miles an hour in first gear and 1800 rpm. Puzzled we were, was it a spun bearing, not for that distance, Oil pump failure with 26,000 miles, doubtful. So I could not find anything online or in forums that really addressed this issue, though someone here got close. Conventional oil builds up sludge lets call it, each time it gets hot and cools down, as well as when it sets for months without being operated. Bet you can see whats coming here. You also need to know that a gear pump, which almost all engines have today, will continue to build pressure unless something gives. So I questioned if there was an oil cooler bypass, which there would have to be if it plugged and the oil had no other place to go, meaning it would blow up if not bypassed. And Wallah,  the oil filter housing is also the bypass for the oil cooler as well as the filter itself. I had a truck Mech. in the Portland area research that issue and sure enough the oil cooler lines where full of sludge. The moral of this story is switching from Conventional Motor oil to Synthetic can be a little tricky. No damage was done because I listened to what the engine was doing, sounding anything but NORMAL. We also added an external oil cooler as well. Travel well my friends!

[phil-t]

Interesting - My 2010 ('09 F53 Chassis and V10) started life on full synthetic motor oil, as recommended by Ford.  When did they switch to recommending synthetic?

[asprague33806]

Recommended, I doubt it, though workhorse is out of business, forgot to mention its a workhorse W24. No reason not to as it handles the excessive loads better over time, also obviously removes grime and sludge. I have read so many articles written on the subject thought I 'd add mine

[Arch Hoagland]

8.1 gas engine? 

How many times had the oil been changed the first 19,000 miles and where did you buy your oil filters? 

Did you do all the oil changes or have it done somewhere?

[NY_Dutch]

19,000 miles in 10 years means that engine spent a lot of time sitting still, with the resulting condensation, etc., buildup in the crankcase causing it to sludge up. The synthetic oil did you a favor bringing that mess to your attention. I've switched engines from dino to full synthetic oil with well over 100,000 miles on them with no issues, but those were engines that ran daily. I've also switched questionable engines over, but they got a couple of good engine flushes first. My advice is to always flush engines first when switching if there's any doubt about the history of the engine. It can save you some grief...

[Gary RV_Wizard]

Good report - thank you.  I note that you said it used 3 quarts of oil and that was "not bad". That would seem to have been another strong indication that something was wrong in the oiling system.  The 8.1L GM V8 doesn't normally use any oil and using a lot of oil  in a low mileage engine has to be considered worrisome [in my opinion].

I suspect that Dutch has made the correct assessment - sludge build-up from condensation and simply too few trips long enough to heat things up well and run the oil system through its paces. Synthetic oil will indeed loosen up accumulated sludge and that appears to be what triggered your immediate problem. I think, though, you would have experienced it soon even with conventional "dino" oil.

You didn't mention if you were the original owner or if oil & filters had been changed religiously even though mileage is low. Oil changes too often get neglected in low mileage vehicles.

[Gods Country]

Would the pressure from such a thing be noticeable on an oil pressure gauge?

Just wondering.

[NY_Dutch]

Would the pressure from such a thing be noticeable on an oil pressure gauge?

Just wondering.

That would depend on just where the blockage occurred and whether the filter bypass hid the problem for awhile. I don't know if the Workhorse/8.1 dash had an actual gauge or just a low pressure idiot light though. The F53's have a gauge.

[Gary RV_Wizard]

Often the gauge is just a pseudo idiot light, with the needle just showing a reading when OK, and zero otherwise.

[blw2]

I'm not so sure the sludge would build up from condensation.  More likely a function of time.

I got this from a conversation I had with a lubrication engineer with Texaco, that I worked with many years ago while I was a maintenance engineer at a pulp and paper mill.  Oils contain a mix of different length molecular chains.  The shorter ones will evaporate off, leaving the long ones behind.... this, I was told, is the reason they always have a time component for oil change interval specifications...


Your story reminds me of what an old mechanic told me many years ago in my teens.  His suggestion was to never mix brands of oil because of differing detergents and formulations... Running any oil will build up sludges or varnishes over time in the engine (even with regular changes).  Changing oils might result in a different chemistry that could cause those impurities to slough off.
This idea has always sounded plausible to me...but I have always figured it's probably more of a throwback to another time when oils were dirtier and standards were either looser or non-existent...

[NY_Dutch]

Often the gauge is just a pseudo idiot light, with the needle just showing a reading when OK, and zero otherwise.

Good point, Gary. I'd forgotten about those...

[NY_Dutch]

I'm not so sure the sludge would build up from condensation.  More likely a function of time.

I got this from a conversation I had with a lubrication engineer with Texaco, that I worked with many years ago while I was a maintenance engineer at a pulp and paper mill.  Oils contain a mix of different length molecular chains.  The shorter ones will evaporate off, leaving the long ones behind.... this, I was told, is the reason they always have a time component for oil change interval specifications...

Mix in rust from the oil pan that condensation can cause, and you get even more sludge. I've replaced several pans for folks over the years that had rusted from the inside out.

[Gods Country]

Often the gauge is just a pseudo idiot light, with the needle just showing a reading when OK, and zero otherwise.

Yeah that makes sense.

[Lou Schneider]

Back in the 1970s, my sister bought a 1959 Rambler with 20,000 miles on it ... the original little old lady's car, literally used only to go to church on Sundays, plus an occasional trip to the grocery store.

I agreed to check it out for her, the first thing that jumped out was the engine oil looked extremely dirty.  I changed it and it only took 3 quarts to refill the crankcase including the filter.

I ran it a couple of hundred miles, and changed the oil again.  Same thing, the oil looked very dirty and again it only took 3 quarts to fill it.

I filled the crankcase with kerosene, then let it sit overnight without starting it.   It only took 2 quarts of kerosene to get it to the full mark on the dipstick, when I drained it the next day I  got over a gallon of goop out.

I gave it one more kerosene flush, then I filled it with cheap oil.  It took the normal 5 quarts including the filter.

I let it idle for an hour to get the engine up to operating temperature and did another oil and filter change.

She drove that car through high school and college, over 50,000 miles, without further problems.

[A Traveler]

What gets my attention from the OP's post was that he went through 3 quarts of oil on one trip over a two week period. Something is wrong there.

My ISL doesn't use ANY oil between oil changes. That's 10,000 to 15,000 miles with zero oil used.

[NY_Dutch]

What gets my attention from the OP's post was that he went through 3 quarts of oil on one trip over a two week period. Something is wrong there.

My ISL doesn't use ANY oil between oil changes. That's 10,000 to 15,000 miles with zero oil used.

Yep, that sure does seem to indicate there was a problem well before the synthetic oil came into the picture.

[John From Detroit]

Someone said the 8.1 does not normally use oil......

I have driven 40,000 miles using 2 8.1 engines.. On relatively flat ground I can go oil change to oil change and never add a drop.. I go over the mountains..3 quarts.  Both engines are consistant in that.. I go over the mountains and it sucks 3 courts.

[Gary RV_Wizard]

The 8.1L GM V8 in our 2002 motorhome never used a drop of oil in 50k miles, including a journey from Florida to Alaska and another from Florida to Washington, with many a mountain on the way. Maybe some of them have were more prone to oil loss than others?

[KandT]

I just drained only 4.5 quarts plus filter out of my v10 that should have 6 quarts and had run it 3400 miles.

I checked it before I changed it and winced to see it below low on the stick.

Opinions if I did damage?   

I am guessing "no" because it would have had enough to keep the oil pressure up but will be checking it every 1000 or so.  The 6 quarts the manual tells you to put in only brings it to the middle of the stick.  I'll be filling it to full now.

[Rene T]

I just drained only 4.5 quarts plus filter out of my v10 that should have 6 quarts and had run it 3400 miles.

I checked it before I changed it and winced to see it below low on the stick.

Opinions if I did damage?   

I am guessing "no" because it would have had enough to keep the oil pressure up but will be checking it every 1000 or so.  The 6 quarts the manual tells you to put in only brings it to the middle of the stick.  I'll be filling it to full now.

As long as the engine wasn't making any unusual noises, you'll be fine.

[blw2]

Back in the 1970s, my sister bought a 1959 Rambler with 20,000 miles on it ... the original little old lady's car, literally used only to go to church on Sundays, plus an occasional trip to the grocery store......

Lou, great story.
that was back even before the day when we'd dump the old oil out behind the garage to kill the weeds
Now days all those oil changes would break the bank, not to mention wear you out running back and forth to dispose of all the waste!
It would be much easier most likely to drop the oil pan!

[asprague33806]

Lots of great feed back!! To answer some of the great questions; I bought the rig with 15,984 miles in 2014 had a full service done by brazel's with conventional oil along with me adding a 2" sway bar and they did shocks and track bar along with what WorkHorse should have put in as a steering gear box, lucky to get one of the few remaining. Anyway it sat after we got it for the most part over the next two years, maybe 3000 miles. Before leaving on our 7,000 mile trip I changed the engine oil over to mobile one 10-30W. As for the filter, I put in the AC Delco 1 Qt filter instead of the 1/2 Qt filter. No Issues for approx. 3000 miles to Nashvile (Yes the long way). changed oil again and this time went with the Wix filter that has come out for Syn. oils. That was when we started having issues. Some where west of KY I had the oil changed again along with going back to the AC Delco filter. not much difference. Issues as I said got worse.  Anyway I think a lot of the ideas as to why it slugged up are likely I live in a very high moisture area The North Oregon coast where we get any where from 75 to 100 inches of rain a year. I also think just sitting with conventional oil oxidizing had something to do with it as well. Anyway we are heading east for a few days then south west with some good hills. I will let you know how it goes. AGAIN my main reason for writing this was to hopefully giving some one the info. Some one mentioned something about the filter bypass, that's why the oil was getting so hot and kept the oil cooler in the radiator from blowing up. As I said with gear pumps the fluid has to go somewhere or the pressure will continue to build.

[asprague33806]

One other thing I forgot about the oil consumption. Going down to CA we used very little oil, I am pulling about 29,000 pounds with the HHR in tow. She worked very hard from LA through AZ and NM VERY hot and lots of BIG hills, so I am not surprised it used some oil working that hard. Local flat trips does not burn anything. Keep up the good work folks