Synthetic vs Conventional Oil

[Halgar]

Hey all, I've been giving thought to switching from conventional motor oil to synthetic. I just bought an 03 Suburban with the 5.3 and 144,000 miles, my mechanic is recommending synthetic for an older engine.

Anyone using synthetic and are there noticeable differences between synth and conventional?

[jwscab]

Synthetic is better all around. Walmart has the best price for mobile 1 in my area. I change oil about 6000 miles or every year whatever comes first.

[Halgar]

That would nearly double the current longevity at which I normally change the oil (3500 miles), which in and of itself would justify the added cost.

[Dadio]

As a mechanic with 29 years under my belt yes synthetic is best , it maintains its lubricating quality's longer and is more thermally stable , if there is one thing that has changed the life of an engine from 80.000 miles to the current expected 150.000 miles then its the oil .
Way back in the 1960's they did testing with a Morris Minor on a rolling road , they ran it for 100.000 miles changing the oil every 500 miles , they then took it apart and found no measurable wear , that's when they started to really work on improving oil quality and why we have the synthetic oils we have today , well that's the story I was told nearly 30 wears ago anyway .

[RC10th]

Synthetic oils have better cleaning properties and "can" create oil leaks in older engines by cleaning away built up gunk that could be preventing a leak. I run Royal Purple Synthetic in all my junk (old stuff) and swear by it, although it is on the upper end of the price scale. Luckily you don't have to worry about zinc levels in your oil so just a good quality synthetic should be fine.

[Halgar]

Thanks for the input so far guys, keep it coming!

[Incredible_Serious]

I run a 2000 Honda Civic, with it's patented inbuilt Oil Recycling System.... you need to "change" the oil every 5000km or so, as if you don't there's no oil left in it!!!

Sorry that doesn't help the 'synthetic vs palm oil' debate...

Alex

[TRX-1-3]

I'd take into consideration past service history and operating conditions. A synthetic oil doesn't necessarily translate to a doubled interval and if you have been religious with past preventative maintenance, there should be very little sludge build up. AND considering it's an '003, the gasket materials should be robust enough to take synthetic's "cleaning" power. If you currently have leaks, I'd consider re-sealing first.

Back to the interval comment...so I guess if you are doing a lot of highway / steady throttle at-speed driving then yes, you're more on the double it end. If it's a lot of stop and go/towing/off-road, etc., my thought is synthetic provides a superior level of protection within that 3500-5000 range (for that model year and mileage).

Oh yeah also consider a longer life filter specifically designed for synthetic and longer intervals.

And remember to clean the mating surface and lightly oil the filter gasket

Darn. One more thing with the longer interval, every engine burns oil just a matter of how much so don't run it low stepping out the interval.

Most Chevies now have the 7500 miles or bingo mileage (based on proprietary "intellilife oil monitoring system" operating conditions algorithm) /one year "change oil soon" message. Not sure when that started.

All opinion that is.

Side note: I do fleet maintenance for an outfit we use a lot of pick up trucks / gravel/ dirt roads stop and go low speed, idling etc. We run BG 5w30 synthetic (gasoline engines) and BG 15w40 synthetic (diesels) for a manufacturer's normal service interval or when prompted by the information center or one year, whichever comes first. The longest interval we have by manufacterer is the newer 6.7L Cummins at 10000mi. I don't even like to do that. I set them at 7500 and leave the 2500 as a buffer.

I run a semi-sythetic 5w30 (re branded Valvoline (NAPA)) in my '13 Toyo Taco at a 4500 - 5000mi interval. It's got 228000mi on it. I've only had it since 190000mi though but it had a smokin hot CarFax with 35 service records consisting of a total of 30 oil changes over that 190K period. But to put 190K mi on a rig in 5 years it would have had to have been highway miles so a historic 6500 mile average interval seemed acceptable.

[klavy69]

Halgar,
I run synthetics in all of my daily drivers. I'm not one to get new vehicles unless they are needed. I generally end up scrapping my decommissioned ones but its because of just worn out drive trains vs. bad motors now. Once I started using synthetics it brought my average decommissioning up from under 200000 to 250000 plus miles on them. I also go from 6k miles on oil changes on these high mile motors like mentioned above. All in all it is one of the best things I have ever done for automotive maintenance...and I used to be pretty hard on the vehicles I drove...

Todd

[Sharky8js]

I've heard, many years ago... once you use synthetic oil your not supposed to ever use conventional oil in that motor again....

In my work truck 2012 f350... I only use motorcraft synthetic oil, and the onboard computer says to change oil at aprox 7000-7200 miles... it has 149,000 on it so far

Just my 2cents ..... if that's even worth it!

[Halgar]

Really great input guys, thanks so much!

This is a new-to-me 03, so I have no idea what the service history is. The guy I bought it from said he's had it about a year, he got it from his father-in-law, who owned it for 15 years and is/was a military mechanic. FIL bought it used, but doing the math back from 2019, 1+15 is 16 years, means FIL bought a very lightly used vehicle in late 03 or 04.

By all accounts, the seller was truthful about the condition of the vehicle. I don't believe it to have been abused, other than not getting the interior cleaned out very often. I went over it to the best of my ability and it seems pretty good, though it will be going to my mechanic this week to change every fluid and he's going to do a deep inspection to see if there is anything else that needs to be addressed. So I have from now until Tuesday afternoon to decide if I'm switching to synthetic oil.

[Halgar]

I've heard, many years ago... once you use synthetic oil your not supposed to ever use conventional oil in that motor again....

My mechanic says the same thing. Pennsoil has an article on their site that says it's a myth.

[Halgar]

The comment about the trip computer calculating oil life, the 02 Sierra I drive is pretty dead accurate at every 3500 miles it wants the oil changed. I don't know if the 03 'burb has the same feature or not, I would guess it does, but without reading the owner's manual, i don't know, according to the window tag it's got another 1500 to go.

[RC10th]

Since when did cars start telling you when to change the oil?

[Halgar]

Since when did cars start telling you when to change the oil?

My '95 didn't, my '02 does, so sometime in between there. I'm guessing the new-to-me 03 will as well.