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Synthetic Oil?
I am leaning towards avoiding synthetic motor oil in my 1990 Chevy G30 with 23k miles. What say you?
LD 22', 1989 Custom Build. Chassis 1990 Chevy Van G30, 5.7l.

Re: Synthetic Oil?
Reply #1
I am leaning towards avoiding synthetic motor oil in my 1990 Chevy G30 with 23k miles. What say you?

No reason not to use it except for the cost. IMO, synthetics are only worth it when running longer change intervals.
If staying with the 3000 mile interval, regular, dyno oil is more than adequate.
When switching our 1983 LD to Mobil 1 synthetic, the oil burning was reduced, in return, the engine developed several small oil seeps.

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze

Re: Synthetic Oil?
Reply #2
No reason not to use it except for the cost. IMO, synthetics are only worth it when running longer change intervals.
If staying with the 3000 mile interval, regular, dyno oil is more than adequate.
When switching our 1983 LD to Mobil 1 synthetic, the oil burning was reduced, in return, the engine developed several small oil seeps.

Larry
What I want to avoid is increased seeping.
LD 22', 1989 Custom Build. Chassis 1990 Chevy Van G30, 5.7l.

Re: Synthetic Oil?
Reply #3
This incident happened several months ago. I had a 1992 Ford Aerostar van with 270,000 miles. It always ran on Mobile1 15w50 oil with normal oil change intervals. I gave it away and the new owner took it to the local emissions station to have the emissions checked for licensing.

As he is sitting in the owners booth with trepidation he notices great concern among the testing staff. They test the vehicle three times on the dyno bringing in other staff. Of course he is quite concerned figuring his "new" car is failing. Those that have sat in the emissions box with a marginal car can identify.

They finally let him back in the van and give him his paperwork. They had never seen a car with this many miles be so clean and figured their equipment had failed. "We have seen cars with 10,000 miles that aren't this good."

Why? Dunno. The car does burn a little oil (1qt/1500miles or so). My second Aerostar, 1997, has 153,000 miles with the same diet and doesn't burn oil. Anecdotal, for sure, but first hand. I use 10w30 Mobile1 in the 2006 LD with 60,000 miles. It can blow blue smoke on startup and does burn oil about a qt every 1500 to 2000 miles. I assume it is valve seals which some V10s have a problem with and some don't. Anyhow, I'm sticking with synthetic.
Harry 2006RB

Re: Synthetic Oil?
Reply #4
The benefits of using synthetic oils are numerous and are well worth the additional cost.

In short - synthetic operates better at extreme temperatures since it flows better when cold and most importantly is more resistant to breaking down under very high temperatures. Speaking of breaking down, oil breaks down faster under extreme conditions such as heavy loads on the engine - synthetics are more resistant. Synthetics also are not as prone to producing sludge and possibly blocking small oil passages.

To me the additional few dollars spent is well worth the additional benefits and can be considered a cheap form of extra insurance.
Chet in Yorktown, Virginia

Re: Synthetic Oil?
Reply #5
I go with what the manufacturer recommends.   I'm guessing the folks that make and warrant the car/truck know a bit more than I do. 

  5w-20 Motorcraft semisynthetic oil and Motorcraft FL-820 filter.
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It's all good .......
2014 Twin King

Re: Synthetic Oil?
Reply #6
I go with what the manufacturer recommends.  I'm guessing the folks that make and warrant the car/truck know a bit more than I do. 
 5w-20 Motorcraft semisynthetic oil and Motorcraft FL-820 filter.

A close friend has 170,000 miles on her LD and has exclusively using 5W-20 Motorcraft oil. As long as the proper change intervals are follow, the stock oil is more than adequate. Ford's engineers know what they are doing and specified oil that satisfied the V10's requirements..
If you want to extend the change intervals, synthetic oil is the better choice .

As mentioned before, when I was still gainfully employed, we ran a long-term test on the fleet at LAX, comparing regular oil to Mobil 1, using periodic oil analysis. Regular, dyno oils tested fine up to 7,000 miles but the synthetic oils were still in good condition at 12,000 miles, where we discontinued the test. We settled on dyno oil with 7,000 mile intervals, the longest we wanted vehicles to run without being serviced and inspected .
At the time, I bought a new Dodge Dakota and ran 12,000 mile change intervals, with Mobil 1, for the first 110,000 miles before selling it to my brother and then to another friend, It now has over 250,000 miles on, with no major engine work, still running on Mobil 1.

All major brand oils today are superior to the oils of a few decades ago.

Larry

Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze

Re: Synthetic Oil?
Reply #7
There is no  point in putting expensive oil in an engine of that vintage.   If you want to baby your baby, give it more frequent changes of regular dyno oil.   Find the best price you can on a name brand oil.  Use it.  Move on.      Frank
plan B - 2023 Travato

Re: Synthetic Oil?
Reply #8
There is no  point in putting expensive oil in an engine of that vintage.   If you want to baby your baby, give it more frequent changes of regular dyno oil.   Find the best price you can on a name brand oil.  Use it.  Move on.      Frank
Exactly my plan.
LD 22', 1989 Custom Build. Chassis 1990 Chevy Van G30, 5.7l.

Re: Synthetic Oil?
Reply #9
I asked this question of Paul Brow (owner of All Car Specialists in San Gabriel and Automotive Service instructor at East Los Angeles College).  Paul said that because Motorhomes are often run for a relatively short time and let sit for longer times, water can be trapped in the crank case. He went on to say that Dino-oil is a reasonably good scavenger of water whereas Synthetic oil is not. Paul stated that this is one reason why motor vehicle manufacturers recommend regular oil over synthetic.
Warren
2019 MB “Dream Catcher”
Jeep Wrangler JL

Re: Synthetic Oil?
Reply #10
I’m not sure about all Subaru’s, but my 2017 Outback requires synthetic.
Greg & Victoria
2017 Mid-Bath  “Nocona” towing a manual 2015 Forester
Previously a 1985 TK
SKP #61264

Re: Synthetic Oil?
Reply #11
He went on to say that Dino-oil is a reasonably good scavenger of water whereas Synthetic oil is not. Paul stated that this is one reason why motor vehicle manufacturers recommend regular oil over synthetic.

The best source of what type of oil to use is your year LD's Ford Owners Manual.
Many car's owners manuals specify synthetic motor oils, including our Subaru.

The recommended oil for your 2019 E450's V10 is either Motorcraft SAE 5W-30 Premium Synthetic Blend Motor Oil or the optional Motorcraft SAE 5W-30 Full Synthetic Motor Oil.
Our 2003 V10 OM specifies Motorcraft SAE 5W-20 Premium Synthetic Blend Motor Oil.
If Ford's engineers still feel the V10s require a synthetic oil type, after building them for 22 years, following their recommendations is advisable .

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze