which synthetic to use

trife86

Registered User
well i just recently rebuilt my motor (1000miles) and doing great so far, i want to start running synthetic i know alot of people say mobil1 but i dont know which weight i should use, i live in NYC, hot summers up to 95degrees or so and cold winters down to maybe 20 - 30f.

i was thinking get some 5-30? and where is the cheapest place to buy full synth oil?
 
XR7 Dave said:
Run 15w50 in the summer and 10w30 in the winter. Mobil 1 from Walmart.


I've seen you state this many times, but the only 15w50 I see always says for disel...

Is this the kind you are taking about???

I read somewhere else, can;t remember where, that someone used some disel oil and his car smoked because the rings couldn't scrape it off the walls good enough???

Just curious...

Thanks!
 
I use Mobil1 10w-30 all year. Although the temperatures here range from about 55-80 year round, so it's almost never really hot or cold. :p
 
I just switched to 15w-50 Mobil 1 ... Didn't see much if any difference from conventional 10w-30. ... Just price. .. Supposedly it'll hold up the beatings better without breakdown.

Anthony
 
I use 10w-30 Valvoline Synpower full synthetic motor oil. I dont care to much for mobil 1. I dont have anything against them I just have always been a Valvoline man so I stick with what works for me.

Shane
 
This is why I prefer not to answer or get involved in questions of this nature. Everyone has an opinion and usually no facts to back them up.

I make my recomendation from a) objective testing which has shown the oil specified to be superior or at least as good as any other, 2) from the advice of both engine builders and engineers, but primarily because 3) it has worked for me under extreme conditions which according to the "experts" out there should have done my motor in long ago.

If any one out there who runs 10w30 or 5w30 in their SC's knows WHY they run that specific weight oil I'd like to hear the reasons. :)
 
Last edited:
XR7 Dave said:
I use diesel oil. :p

Maybe that's my HP secret. :D

As it turns out, I just changed the oil this morning. I also used the Mobile1 15w-50 with the diesel option and I can absolutely feel the extra HP!! :D

Ira
 
The reason I use Mobil1 15W-50, is not only can it still provide great lubrication under the extra heat, but the 50 weight keeps me from leaking a lot of oil. :D
 
I used both

I have used both Mobil 1 and Royal Purple and prefer the Royal Purple feels alot smoother and the car seems to like it, no dyno numbers tho. Weight I am not getting involved with. Use what you like.


Drew
 
What Oil???

I have always used Penzoil 10w30 or 40. I have seen many engines torn down using Valvoline and they where sludged... Have torn down engines with Penzoil and they have looked clean... Guess it could also be how often they change it... My cousin is a manager at the oil change place and Mobil 1 is supposed to be top of the line. That is according to test that he showed me. Guess I may switch out to the synthetic on my new engine this next change.

I guess it is just personal preference though with most people. Kind of "My dad and his dad used it for years!!!"
 
ScrapSC said:
I guess it is just personal preference though with most people. Kind of "My dad and his dad used it for years!!!"

This is very true and that is why I tend not to make recommendations or claims about anything. The only reason I even spoke up on this thread is because by all rights my motor should have given up the ghost long ago. The fact that it continues to run (and it's spotlessly clean inside too) at the HP levels it does and stands up to the abuse it does with nearly 200,000miles on it has to stand for something.
 
I think I know the reasons dave!

I'm pretty sure I know the reasons.

I run Mobil 1 5w-30 Year Round! The reason why I run 5w-30 is because that is what the factory owners manual tells me to! ;)

But seriously though, I ran 10w-30 one time in my car and when the temperature started getting below 25degrees F, when I started the car in the morning, there was a lot of lifter tapping.

After about 2 mornings of that, I changed over to 5w-30. It works great. I've started my car at -15 Degrees F with 5w-30 in the crankcase. The engine is noisy for the first couple of minutes, but there isn't loud lifter tapping.

I would imagine that running a 15w-50 oil would only be worse in cold weather.

Another thing too, I know for a fact that Mobil 1 is Fully Synthetic. What I mean by that is every single molecule in mobil 1 is man-made Olefin/polymer base. This is not true for other fully synthetic oils that still use purified petroleum base stock with synthetic detergents and fiction modifiers and pass them off as being "fully synthetic".

I remember reading by Dr.Fred 4.3 that when it comes to oil grade selection, you want to use the viscosity index that is most appropriate for the temperature the engine will be operating at and then be sure to use the most NARROW range possible for the best in oil efficiency.

It's one of the reasons why 5w-30 will carry a "energy conserving" seal on it's label, but 15w-50 won't.

It's another reason too why some cars these days are requiring the usage of 0w-20 and 5w-20 oils Which is recommended for newer honda and ford engines. Because they are so thin to work into the even tighter tolerances of the engine. I've also seen 0w-40 which is recommended for BMW and Mercedes engines.

Lastly, I'm seeing Fully synthetic "endurance" oil which can go an astonishing 15,000miles between changes. Which IMHO is crazy talk!

With all of the different grades to choose from and since I still drive on the street, I'll stick with what the factory recommends, use synthetic and change it every 3000 miles just to be a fastidious nut-job.
 
Lastly, I'm seeing Fully synthetic "endurance" oil which can go an astonishing 15,000miles between changes. Which IMHO is crazy talk!

I agree. .. The oil may hold up. But let's not forget the filter. .. 3k sounds about right for any oil.

Anthony
 
happy with conventional

I have used convential oil (changed every 3-4K miles) exclusively and currently have 319,000 on my '90 SC. Used Quaker State 10W-40 then 5W-40 for the first 160,000 then switched to Valvoline 5W-30 after learning about some indepentent lab data comparing oxidation resistance. It's not that I don't believe in synthetic, I use it in another vehicle I bought new. I'm just afraid to change at this point.
 
Walmart Super Tech

Super tech full synthetic is made by quakerstate for walmart. Good stuff and only $3.00 per qt. add a $2.00 supertech oil filter made by champion and you can do a full syn oil change for only $17.00. Better than spending $60 at jiffy lube. 3 syn oil changes for the price of 1. If your not afraid of getting your hands dirty, but who here is.
 
Back
Top