Kia Forte Turbo Forum banner

1 - 6 of 6 Posts

·
Registered
Joined
·
11 Posts
Discussion Starter · #1 ·
Hey guys just wondering a friend of mine told me that if you go from one brand of oil to another brand (both brands being synthetic) that you have to like flush the whole engine out and start fresh? currently I have unknown oil from a dealer and I wanted to switch to royal purple 5w30 but don't wanna break anything!

also for manual transmission oil what brand is the best I'm hearing a lot of people mention redline 75w-85w are there other brands is the kia stock oil really as bad as people say? I'm trying to fix the clunky rough shifts this car seems to have but don't wanna spend the money if it wont work at all
 

·
Registered
Joined
·
1,697 Posts
No need to flush at all.
Even if you had Mobil 1 5W-30 mineral and was switching to Pennzoil Platinum 5W-40 full synthetic, you just do oil change. There was years ago a problem when mixing tow different grades, and sometimes even brands. Oils could not behave well when mixed. But those problems are long gone.
Simple change and done.


Gear oil.
It is not about the brand actually.
It is more about availability of viscosity in synthetic.
RedLine as the only one to my knowledge has GL-4 75W85 in synthetic. OEM is not bad. It is OK. Just depending on driving conditions and your spirits, oil wears down faster or slower. Then, in some cases OEM was more expensive than Redline... so that is why RL was mentioned most often.
Some claimed putting GL-5 will make no difference, some say 75W90 will work, too.
While GL-5 I think would be OK - still big debate about additives in GL-5 that could make some issues in GL-4 designed gear box - viscosity will be a bigger issue. 75W90 will not work so well.

So basically that's it.

Oh, and the grind - well, oil may fix it. See yourself.
Also, make sure the level is right. Unfortunately, it requires more than 2 quarts, so you must get 3 bottles... but in about 30k miles you may need it again.
 
  • Like
Reactions: danbfree

·
Registered
Joined
·
380 Posts
You'll want an ACEA A5 rated oil ideally, which Royal Purple is not.
Yep, Pennzoil Ultra PLATINUM is ACEA A5/B5 and is widely available...

BUT... oil that is A3/B4 actually works well too, actually protects a bit better at the sacrifice of a tiny bit, less than a half MPG... I learned this when I had my oil changed at Havoline and they used SynPower MST which is the highest rated they have and my car actually runs smoother... I'll edit this post with the info I found on the ratings, but A3 is actually higher protection, and A5 is fine ONLY when called for, which ours does, but Motul and others meet A3/B4 and a lot of tuners use it.

Here is some info:
A3/B4 Stable, stay-in-grade oil intended for use in high performance gasoline and direct injection diesel engines, but also suitable for applications described under A3/B3.

A5/B5 Stable, stay-in-grade oil intended for use at extended drain intervals in high performance gasoline engines and car & light van diesel engines designed to be capable of using low friction low viscosity oils with a High temperature / High shear rate (HTHS) viscosity of 2.9 to 3.5 mPa.s. These oils are unsuitable for use in some engines. Consult owner manual or handbook if in doubt.

I've also seen it broken down to the lower viscosity of A5 allows for slightly higher fuel economy and our car can handle it.... BUT with the A3/B4 clearly making my engine sound smoother/less knocky/clicky, I think I'll stay with that...
 

·
Registered
Joined
·
827 Posts
Hey guys just wondering a friend of mine told me that if you go from one brand of oil to another brand (both brands being synthetic) that you have to like flush the whole engine out and start fresh? currently I have unknown oil from a dealer and I wanted to switch to royal purple 5w30 but don't wanna break anything!

also for manual transmission oil what brand is the best I'm hearing a lot of people mention redline 75w-85w are there other brands is the kia stock oil really as bad as people say? I'm trying to fix the clunky rough shifts this car seems to have but don't wanna spend the money if it wont work at all
You should have asked "your friend" to present you with the facts and figures of his oil change theorem. It's hogwash. Royal Purple is some of the best motor oil out there - so put it in and be happy. RP filters are spendy and heavy-duty but work very well.

Maybe on your MTX, (mine's auto) change the shift linkage bushings to control the shift quality and consider the "dog-bone" mount change. Part of the shifting problem is unwanted engine/tranny movement - not the gearbox oil failing to lube rotating gears. Google around for the bushing kit.
 
1 - 6 of 6 Posts
Top