syntetic to standard

[crash98]

ok so i work at a shop and have herd that you shouldnt switch between synthetic and standard oil but never got a good answer why. also i was wondering if its worth it to put synthetic manual trans fluid in

[broknindarkagain]

That has some truth behind it, but for the most part its not true.

 

Most commercially available "synthetic" oil is based off of conventional (regular) oil. Its broken down and basically "rebuilt" in a lab. Its safe to mix this type of synthetic with conventional, or switch between the two as much as you want.

 

The other kind of synthetic oil is REAL synthetic oil. There isn't much around, and what is around is VERY expensive. Amsoil is the only company that makes real synthetic that I'm aware of. This kind of synthetic isn't suppose to be mixed with conventional, or even conventional based synthetics. This type of oil is built in a lab from scratch. Its 100% man made, where as your normal synthetics are just modified conventional oils.

 

Now the reason behind the thoughts of not switching between the two is because when you drain the oil, there is still some leftover inside the engine. The only way to get ALL of the oil out is to do a complete flush.

 

With that being said, if you switch from Pennzoil, Castrol, Mobile, Quakerstate, etc synthetics to convention (or the other way around), you will be just fine.

 

A lot of automotive sales people use the line "Well you ran synthetic last time, so you have to use it every time now." to get more sales. They rope you in the first time, and make you feel like you're trapped into using it afterwards

[Gire]

I decided to go synthetic after my first year of ownership.

 

Then after 3 years of oil changes at the dealer as needed, their oil changer made a mistake and switched me back to regular. I didn't complain too much as they were covering a transmission problem at the same time that I thought I'd have to pay for.

 

I've been back to regular oil for the last couple years. No worries.

 

I just don't think I will switch back to synthetic even though I love the loner intervals between changes.

[Baddog]

I just feel as if I am getting better protection from using a Synthetic. A good brand at that. My engine feels smoother with RP. I was running Shell and Mobil-1 before.

 

I also USE my car. I don't just daily drive it. I abuse it. So I make sure I spend that little extra in oils for added protection.

[thefultonhow]

There is a lot of misinformation in this thread, and it's not even that long yet.

 

First of all, to the OP, the reason people say not to use synthetic after using conventional oil is that, theoretically speaking, the additive pack in the synthetic will dissolve the deposits of dino oil around seals. With the deposits gone, there is more room around the seals for the new oil to leak out. I'm not sure I buy this argument, though. Plenty of people switch without having any problems, and if you have oil leaks, you should replace the seals, not pray that the deposits keeping the leaks manageable stay there.

 

The other kind of synthetic oil is REAL synthetic oil. There isn't much around, and what is around is VERY expensive. Amsoil is the only company that makes real synthetic that I'm aware of.

 

Shell Rotella T6, German Castrol Syntec, and I beleive Pennzoil Platinum are also true synthetics (i.e. PAO base stocks rather than refined dino base).

 

This kind of synthetic isn't suppose to be mixed with conventional, or even conventional based synthetics. This type of oil is built in a lab from scratch. Its 100% man made, where as your normal synthetics are just modified conventional oils.

 

Where did you hear that? They are all oil. The advantage of synthetic is that it breaks down more slowly and (usually) has a better additive pack. Normally, you don't have to change true synthetics as often as dino oil. Some are reporting 7500-10000 mi. between changes on EJ255s (notoriously hard on oil) with Rotella T6, and the UOAs say the oils even have a bit more life in them. But, if you were to mix Rotella T6 with Quaker State (widely considered to be crappy oil), as long as you keep an appropriately short OCI, there is no way you can damage your engine.

 

I just feel as if I am getting better protection from using a Synthetic. A good brand at that. My engine feels smoother with RP. I was running Shell and Mobil-1 before.

 

Too bad Royal Purple does not have any oil industry certifications. If you want to talk about selling "snake oil," Royal Purple does it. Maybe they are good, but they have no proof.

[broknindarkagain]

Pennzoil Platinum is dino oil

[thefultonhow]

After doing some research, you are partially correct. It is synthesized from a blend of Group III and Group IV base stocks. It is not fully Group IV. However, it is not "dino oil" in the traditional sense. It still qualifies as a "full synthetic" and is up there with full-Group-IV oils in terms of the UOAs.

[broknindarkagain]

I've heard (don't have proof though) that a lot of the "synthetic" oils on the market are just conventional oil with additives in them. Wouldn't surprise me if this is the case.

[thefultonhow]

I've heard (don't have proof though) that a lot of the "synthetic" oils on the market are just conventional oil with additives in them. Wouldn't surprise me if this is the case.

 

Most of them are synthesized from a combination of Group III and Group IV base stocks, like PP is. As a thread I read on Bob Is the Oil Guy said, though, the base stock matters less than the UOAs. If an oil gets good UOAs, who cares what the base stock is?

[Baddog]

The RP did cure a halt in the engine. Not sure what it was but around 4k RPM's it felt like the engine fell flat on its face. I put in RP and it even feels smoother in the low end and doesn't fall flat on its face anymore.

 

I will give AMSoil a try next time. I haven't read many problems with RP and it really has helped my engine out. So I will stand by it for that fact.

[thefultonhow]

The RP did cure a halt in the engine. Not sure what it was but around 4k RPM's it felt like the engine fell flat on its face. I put in RP and it even feels smoother in the low end and doesn't fall flat on its face anymore.

 

I'm not convinced that's not just a coincidence. On my brother's 2001 Forester, a hesitation at 3000-4000ish was caused by a bad front O2 sensor. It's possible your O2 sensor was temporarily acting up and stopped at around the same time as you put in new oil. Unless you keep oil in way past when you should have changed it, or you use too heavy of a weight, there's no way brand of oil would affect a hesitation problem.

[Baddog]

Alright. Well this is gonna turn into an awesome debate. I will try amsoil next. So far my engine feels smoother is all I am saying.

 

I ran a 5-40 and ran it for about 5k miles. Rotella T6.

[broknindarkagain]

The original poster only has 1 post. Maybe someone just registered to strike up the never ending oil debate lol

[cbt299]

The RP did cure a halt in the engine. Not sure what it was but around 4k RPM's it felt like the engine fell flat on its face. I put in RP and it even feels smoother in the low end and doesn't fall flat on its face anymore.

 

I will give AMSoil a try next time. I haven't read many problems with RP and it really has helped my engine out. So I will stand by it for that fact.

 

how often do you change with RP?

[Baddog]

Usually around 4-5k miles depending how hard I drive it.

[broknindarkagain]

Hell, I do 4 - 5K on conventional oil. Nearly 10K on synthetics

[BAC5.2]

Hell, I do 4 - 5K on conventional oil. Nearly 10K on synthetics

 

I don't think I could do that.

[broknindarkagain]

Oil last considerably longer then 3000 miles.

 

GM suggest oil changes on conventional oil every 7500 miles

ford is every 5k miles

etc

[BAC5.2]

But they stand to benefit from long OCI's, and don't care much about longevity beyond warrantable limits.

[stevenva]

Here is a list of true synthetic oils and what defines a true synthetic oil.

 

http://answers.yahoo.com/question/index?qid=20090103173207AA710Ro

[0Tyrael0]

I use Mobil 1 0w20. Engine runs great with it.

 

As long as your not mixing two different oils at the same time you should be fine.

[broknindarkagain]

You can mix oils and be just fine.

 

And WHY do you run 0w20? Your engine probably HATES it

[0Tyrael0]

I dont mean changing to a different oil. I mean mixing them. For example putting in half 5w30 from brand x and half 5w30 from brand y. Or even worse putting in 0w30 from brand x and 10w40 brand y. Different companies use different chemicals in their products so naturally if you mix them you increase the chance of having a chemical reaction. There is a probably a good chance nothing would happen but you still shouldnt do it. There is no reason to.

 

As far as my choice in oil I dont really know why my engine would hate it. My legacy is my winter car so typically I put 0w20 in it. During the summer though it runs 0w30 if I need to use it. I guess my response to that is why wouldnt I use 0w20?

[broknindarkagain]

Different companies use different chemicals in their products so naturally if you mix them you increase the chance of having a chemical reaction.

 

A chemical reaction? I don't think so.

 

The reason you're not suppose to mix oils is because it changes the viscosity, but if you're within a certain range you will be fine.

 

As far as my choice in oil I dont really know why my engine would hate it. My legacy is my winter car so typically I put 0w20 in it. During the summer though it runs 0w30 if I need to use it. I guess my response to that is why wouldnt I use 0w20?

 

There are a couple of reasons why you shouldn't be running 0w.

 

#1 being oil temperature. You're oil cools the engine (about 30% of cool while coolant is 70%). 0w oil runs MUCH hotter then thicker weights. So while everything seems find and dandy, you're actually running on overheated oil. Yeah, its going to do its job lubricating for awhile...but it likely breaks down and does not perform how it should sonner then you even think about changing the oil.

 

#2 design. Your car was designed for a thicker weight of oil. Do you think you're smarter then the engineers that designed that engine? There are several things to take into account when picking a weight for engine oil in an engine. Oil passage sizes, oil pump volume, total capacity, oil cooling system, etc. I'm sure you didn't even consider any of this when you decided to run 0w.

 

#3 benefits. You get no benefit from running 0w, except for the pleasure of spending more money on it. Its not some magic juice that will protect your engine on cold starts.

 

Continue running 0w if you want. Its not my engine your going to destroy

[0Tyrael0]

You made some pretty big assumtions with not much evedence. You also make me sound pretty stupid.

 

A chemical reaction? I don't think so.

 

The reason you're not suppose to mix oils is because it changes the viscosity, but if you're within a certain range you will be fine.

 

 

 

There are a couple of reasons why you shouldn't be running 0w.

 

#1 being oil temperature. You're oil cools the engine (about 30% of cool while coolant is 70%). 0w oil runs MUCH hotter then thicker weights. So while everything seems find and dandy, you're actually running on overheated oil. Yeah, its going to do its job lubricating for awhile...but it likely breaks down and does not perform how it should sonner then you even think about changing the oil.

 

Lets break this down a bit... First of all the oil doesnt run hotter. It runs thinner. This might have been what you meant but just to be sure ill explain the whole thing as I see it. Your main problem seems to be with the 0 in 0w20 (or 0w30) so ill explain that first. The 0 indicates what weight the oil acts like at start up. In this case it acts as a 0w oil which means its thinner. Thinner is good. Thin oil is good because its easy for your pump to move through the car. Im sure you know how that works. If a pump is moving water instead of oil which is going to flow faster? The water of course. So it would be safe to say that thinner oil flows better. Now if thinner oil flows better we might start think "maybe it cools better too?". Perhaps but lets look at some other factors before we go so far as to say that.

 

Like I said 0w oil runs thinner not hotter. So you know that you have thin oil in your car the oil pressure is going to drop. Is this bad? In some cases yes but not in this one. Now you may know that your oil pump has a limited psi it can reach. Once that psi is reached it has reached its max flow. For example (the flow rate is just a made up number) 50psi at 4000rpm with a flow of 5 on a 10w oil. Now what if we put a thicker oil in? Now the oil pressure is going to go up. So we reach our max oil pressure at a lower rpm say 50psi at 3000rpm with a flow rate of 4. The pump has not been changed so how could it move the same amount of a thicker liquid? Thats not physically possible. Now we put a 0w oil in and: 50psi at 6000rpm flow of 6. See what I mean?

 

You might know that most of you engine wear occurs at startup. If the oil is thinner at startup the pump can get oil to the engine faster than it could with a thicker oil. This is the primary benefit of a 0w oil

Now having said all that lets address the second number... we will use 30 first. There is almost no difference between a 0w30 and a 10w30 oil once you reach running temp. How could there be? The 30 stand for 30w. Once the oil gets warm it acts like a 30w oil instead of a 0w or 10w. So in this case 0w30 is thin like a 0w at start up and doesnt get any thinner than a plain 30w oil would at running temp.

 

Now my reason for 0w20 should be obvious now based on what I have said. Oil gets thicker in the winter (its obviously much colder, colder = thicker oil) so I put in 0w20 to counter this effect.

 

 

#2 design. Your car was designed for a thicker weight of oil. Do you think you're smarter then the engineers that designed that engine? There are several things to take into account when picking a weight for engine oil in an engine. Oil passage sizes, oil pump volume, total capacity, oil cooling system, etc. I'm sure you didn't even consider any of this when you decided to run 0w.

 

Your wrong I did consider this. Our cars were made quite a few years ago and if you look now most manufacturers are going with thinner oils now. No I am not as knowledgeable as they are however I have done quite a lot of research on this.

 

#3 benefits. You get no benefit from running 0w, except for the pleasure of spending more money on it. Its not some magic juice that will protect your engine on cold starts.

 

I have already explained most of the benefits but lets review. 0w20 (and 0w30) is thinner at startup, flows more oil and in turn cools the engine better. Another benefit of thinner oils is it takes less mechanical energy to move. Not just energy from your pump but your engine as well. This means better gas mileage.

 

Here is a bit of real world evidence. I have been using 0w30 in my 78 Lincoln continental for over 4 years now. After switching it from 10w30 to 5w30 I got 1 more mpg (a lot in this car trust me) and after switching to 0w30 I got an additional 2mpg ( a huge amount in this car).

 

Continue running 0w if you want. Its not my engine your going to

destroy

 

If you disagree with me still I will turn you over to someone who is a true expert. He is also the person who educated me on this matter. I explained this quite crudely but my post was already going to be quite long so I cut it short.

 

On another note if your engine were extremely hot you might need a thicker oil to actually reach max oil pressure at high rpm (such as track use). In this case I would use a 0w40 oil. This oil would act like a 0w oil at startup and like a 40w oil at running temperature.

 

And a final thought I should mention just because it says say 0w40, 0w30, 0w20 doesnt mean the actual viscosity is going to be the same at say freezing level. Its just a geneal scale of the oil. In real world the 0w20 will still be a bit thinner than the 0w30 and quite a bit thinner than 0w40. Just keep that in mind.

 

There is no perfect oil. They all have their purpose or they wouldn't exist. I stand by my opinion that there is little reason to use an oil that doesnt begin with a 0w.