Synthetic, blend or regular

[borispeed]

On Friday I going to make the oil change and I'm checking what's the better oil for my 3.8 with 70,000 miles. I used synthetic when my car had about 50,000 miles, and after that my car started having oil leaks. It cost too much to replace gaskets and the rear seal. I've read some opinions on the posts that synthetic is good for the engine. Others say that the synthetic will cause what it happen to me. What about the synthetic blend? Is it not a good combination to protect seals, gaskets and engine?

[slow6]

Re: Synthetic, regular, o blend for High Mileage

good question
Its probably not a good idea to switch back and forth without using an oil flusher. Maybe you could try a heavier weight synthetic like 10w-40 or something higher. I use FULL synthetic
You might wanna try that Engine Restore stuff on your older engine.
Dont take my opinions seriously ;)

[RicE-ter]

Re: Synthetic, blend or regular

from what ive heard on here for the most part is the synthetic doesnt really cause it, its just thinner or sumtin so it leaks easier. leaks happen, so you might consider ponying up the cash eventually, but theres like stop leak stuff you could poor in, which i think worked for the most part on my sisters eclipse.

[Loochy88]

Re: Synthetic, blend or regular

For what its worth, this is from the mobil 1 website:

Myth: Mobil 1 will leak out of the seals of older cars.
Reality:




Mobil 1 does not cause leaks. In fact, new Mobil 1 was tested in dozens of industry standard and OEM tests to prove its seal performance. It is fully compatible with the elastomeric materials from which all automotive seals and gaskets are made. If an older engine is in good condition and does not have oil leaks, Mobil 1 provides the same advantages as when used in a new engine. ExxonMobil recommends taking measures to repair the leaks, then using Mobil 1. ExxonMobil also recommends following the automobile manufacturer's manual for the proper oil to use.

[borispeed]

Re: Synthetic, blend or regular

Is mobil 1 synthetic?

[car-show-crazy-firebird]

Re: Synthetic, blend or regular

I kind of the same question. I've always heard you shouldn't switch oil types or brands esp. in higher mileage engines but i was considering changing over to synthetic. I've always used reg. PennzOil 10W-30. My '98 has less than 70k miles would it be safe to switch to a synthetic oil even after using an oil flusher?

[astroglyph]

Re: Synthetic, blend or regular

from all my knowledge, theres no problem switching to synthetic, i only run castrol syntec anymore, cause, i dunno really, no reason, just the brand i prefer. And also from my knowledge, dont switch between synthetic to regular back and forth, just stick with synthetic, and youre oil will be alot more reliable, cause of synthetics ablility to resist breakdown, unlike regular oil. o yeah...and mobil one is a full synthetic.

[slow6]

Re: Synthetic, blend or regular

There is a brand named GUNK its a Motor flusher (flushes oil)
use it to flush out the old dyno mineral oil

[Publican]

Re: Synthetic, blend or regular

Mobil 1 or Pennzoil Platinum 5-30 in 3.4; 10-30 in 3.8. I have 95K miles on my 3.4 and hums like new.

[borispeed]

Re: Synthetic, blend or regular

What about "High Mileage Oils") that have additives to protect seals on high mileage cars?

[terminaldegree]

Re: Synthetic, blend or regular

If you have leakage problems now, don't go with syn or syn-blend until they're fixed.

No offense, but the need to "flush" the engine before switching oil brands/types is completely unneccessary.

All Mobil 1 is synthetic. A group IV PAO synthetic, to be specific.

High Mileage oils have a chemical that swells seals. It's not a miracle cure, though. Most people that have success with that stuff only have very minor problems to begin with. Those oils are on the thick side of their indicated viscosity, have more detergent additives, and the seal swelling stuff in it.

None of that is a problem-- the only issue I have is that it costs twice as much as traditional oil and it ain't twice as good...

[ChronoGN]

Re: Synthetic, blend or regular

I've been just using whatever I feel like using and its been fine for me. Most of the times I would use synthentic blend but lately I've been using the cheapest regular oil I can find (College FTL).
I think its more important to change the oil often than to use a good kind of oil. Even if you have synthentic, I dont think its a good thing to be using it for 5000miles. I always change my oil before 3000miles.

[SpeedingFirebird]

Re: Synthetic, blend or regular

I dont think its a good thing to be using it for 5000miles. I always change my oil before 3000miles.

BMW recommends changing the synthetic oil every 15K. I do it every 7k. 3k for synthetic is not neccessary. (not a bad thing, but a waste of money).

[slow6]

Re: Synthetic, blend or regular

i have the Mobil 1 synthetic extended coverage*
it says it will last up to 15k miles, but I change it every 5k

[cant_go_fast_enough]

Re: Synthetic, blend or regular

well the problem with going further than 3000 miles isnt the oil, its the filter. the filter isnt designed to go much further than the 3k point. when the filter clogs it has a built in bypass, and your oil isnt getting filtered(but still getting oil), and all those little metal chips are floating around in it, and cause more wear on the engine.