We have to be careful here. U.S.'s use of the term synthetic actually varies quite a lot from Europe's. In the U.S. conventionally refined oil can be labeled synthetic if it has synthetic properties.
Synthetic Oil ?
- Thread starter Tyee II
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oilburner22
Registered User
When I got my '85 I knew it had leaks so I just ran conventional Oreilly's brand 15w-40 because it was cheap and at the time the truck was just kind of a backup rig/beater...but I'm in the middle resealing it all the way down to the head gaskets because it will be a daily driver and its gonna get TRC 15w-40 synthetic. Literally the best stuff out there. But like they said it might aid in cold starts but I don't see a huge advantage of running that over 15w-40 unless you live in a cold climate. This TRC synthetic is good enough to run for a long time (like a couple hundred thousand) and just change your oil filter every 7-10K and people still don't believe that but there's a guy around here that has a semi and has had his oil in his truck for a couple of years now and just routinely changes his filters. That being said, it is a synthetic so according to theory and a lot of people's experience, including my own, you will be more prone to leaks vs conventional. If you run conventional and change it every 3-5K it will be more expensive long term but that depends on how much you drive your rig. I know of people that have Dodge Cummins Pickups with hundreds of thousands of miles and just ran rotela (garbage) but they changed it all the time. So really it just depends on how often you want to change your oil, how much you drive it, and how much it consumes/leaks oil.
Synthetic oil still gets dirty from combustion by products from blowby getting past the rings, metal particles from wear, etc.. Nothing is going to get rid of all that besides taking the dirty oil out and putting new in.
Just ask the guys that run waste oil in their fuel system how many injection pumps they have gone through over the years.
Just ask the guys that run waste oil in their fuel system how many injection pumps they have gone through over the years.
Macrobb
Full Access Member
You'd better have a really good bypass filter system on there for all the soot, or you're going to have a bad day *really* quickly.
Even conventional oil doesn't "wear out" after only 5K miles... it's the built up soot and crud that needs to be removed so it doesn't clog and destroy things.
Now, if you do manage to get a good bypass system, something that actually keeps the oil clean-looking(really hard with sub-micron soot particles), yeah, I'd bet it would last a long time.
idiabuse
Full Access Member
wow
eye am like, over here, just a shaking my head. that synthetic just made my oil leak and cleaned the engine at the same time see the clean pan getting dirty with that nasty 50,000 miles used oil
eye am like, over here, just a shaking my head. that synthetic just made my oil leak and cleaned the engine at the same time see the clean pan getting dirty with that nasty 50,000 miles used oil
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compressionignitionrules
Full Access Member
wow opinions are just like ********................................
this is an interesting read.
this is an interesting read.
Macrobb
Full Access Member
What are you running? What's your setup?wowYou must be registered for see images attach
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What grade of AMSOIL, what filters are you using?
...I mean, looking at your sig, you aren't a good candidate for the whole 'leaks' argument. You have new seals in your engine. Of *course* synthetic will work fine!
It's when you've got a 15+ year old seal, and you start putting synthetic in it... that's when you get leaks. Because it cleans all the "crap" that's actually making the seal!
79jasper
Chickenhawk
I put synthetic in my psd. No magical leakage.
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Sent from my SAMSUNG-SM-G935A using Tapatalk
I can't believe this old rumor wont die lol.If your seals are leaking,replace them you lazy SOB'S! 
I have to agree on the synthetic will cause leaks being BS! When I changed the oil the first time after I bought the Jetta I used Chevron Delo 5w-40 Full Synthetic oil. Why, because I had most of what I needed on hand from using it in my 6.0 PSD. It holds 15 quarts and doesn't leak/use oil.
The Jetta had a slight drip when I brought it home and it had 15w-40 dino oil. After the switch to synthetic, the drip didn't change. Oh, and the Jetta has 304,000 miles on it. So, the it will cause leaks/leak more is BS!
Also, when I switched the 6.0 over, that didn't leak, didn't magically start.........
The Jetta had a slight drip when I brought it home and it had 15w-40 dino oil. After the switch to synthetic, the drip didn't change. Oh, and the Jetta has 304,000 miles on it. So, the it will cause leaks/leak more is BS!
Also, when I switched the 6.0 over, that didn't leak, didn't magically start.........
AcIdBuRn02ZTS
Full Access Member
Synthetics do clean better then conventional oils... keeping the containment suspended in the oil instead of letting them drop out causing sludge.
The oil leaks most experience when they switch to a synthetic oil (and blame the oil for the leak) is actually a seal that has failed or been weak for quite some time and the only thing keeping a visible leak from appearing is sludge. If changing to a synthetic caused a seal to leak, it's because the seal had already failed and needed to be replaced anyways.
As far as benefits go... I switched my 4bt cummins to 5w40 Delo 2 years back. Right off the bat, I noticed the engine was running noticeably quieter (had always ran 15w40 Delo prior) and noticeably smoother. In the cold months, it definitely cranks easier and builds oil pressure faster then it did with the 15w40 (as the only difference is COLD viscosity). I also now stretch my oil change intervals to once a year or 10k miles.. which ever comes first.
As soon as I get the front main on the IDI sorted, it is getting switched over and will also get bypass filtration.
The oil leaks most experience when they switch to a synthetic oil (and blame the oil for the leak) is actually a seal that has failed or been weak for quite some time and the only thing keeping a visible leak from appearing is sludge. If changing to a synthetic caused a seal to leak, it's because the seal had already failed and needed to be replaced anyways.
As far as benefits go... I switched my 4bt cummins to 5w40 Delo 2 years back. Right off the bat, I noticed the engine was running noticeably quieter (had always ran 15w40 Delo prior) and noticeably smoother. In the cold months, it definitely cranks easier and builds oil pressure faster then it did with the 15w40 (as the only difference is COLD viscosity). I also now stretch my oil change intervals to once a year or 10k miles.. which ever comes first.
As soon as I get the front main on the IDI sorted, it is getting switched over and will also get bypass filtration.
Hydro-idi
Full Access Member
I think the statement that some higher mileage engines might experience oil leaks when switching from convential to synthetics is somewhat true.
From what I understand, most synthetic oils have a heftier detergent package in them with the expectation that users will extend the mileage per oil change. So instead of changing conventional oil every 3-5k miles, one might bump it up to 10k or perhaps more in between changes.
A high detergent synthetic oil might make a worn gasket leak even worse than before.
I've run many different brands of oil from supertech to schaffers to Mobil 1. In the end, they all do the same thing. They will all protect your engine just like a top dollar IPA or a cheap 12 pack of Coors light will both get you drunk. It's your choice if you wanna pay $20 or $5 for the same buzz.
From what I understand, most synthetic oils have a heftier detergent package in them with the expectation that users will extend the mileage per oil change. So instead of changing conventional oil every 3-5k miles, one might bump it up to 10k or perhaps more in between changes.
A high detergent synthetic oil might make a worn gasket leak even worse than before.
I've run many different brands of oil from supertech to schaffers to Mobil 1. In the end, they all do the same thing. They will all protect your engine just like a top dollar IPA or a cheap 12 pack of Coors light will both get you drunk. It's your choice if you wanna pay $20 or $5 for the same buzz.
... They will all protect your engine just like a top dollar IPA or a cheap 12 pack of Coors light will both get you drunk. It's your choice if you wanna pay $20 or $5 for the same buzz.
Yeah but you have to drink soooooo much Coors light to get there!
Hydro-idi
Full Access Member
That's half the fun lol.
