deekim

iTrader: (-1)

i got a 91 ls400 with over 325K. i would like to know which kind of oil is best to use? 5w or 10w and if synthetic is better for the life span of my engine?

vaughn37

you will get many different answers to this...just make sure you use a good oil filter. use 5w 30 and long as you keep the oil changed.any brand/type oil will do..if money isn't a big deal sure use synthetic

haulin79

Since you are in California, basically warm weather
0w30 - I use Castrol Synthic, the one made in Germany
5w30 - typically less expensive than a 0wXX

Any name brand synthetic of the above weights will be just fine.

3UZFTE

With 325k you will not notice any benefits from switching from conv to syn. If you have a "0w30" it is a two part oil an maintains the viscosity of 0 weight (very thin) when it's below 32*, and act likes a 30 weight oil (thicker) when it is above 32*.... Therefore if youare running a 20w-50.... It will act as a 20 weight (thick for winter) below 32*, and like a 50 weight (super thick) above 32*....

So if your car calls for 5w-30... and it never gets below 40*, then you can run straight 30 weight oil, (i.e. no 0w, 5w, or 10w) straight 30 weight .... However if you live in a climate that goes below 40*, it would be in your best interest to run a combination oil (i.e. 5w-30, 10w-30) in order to allow the oil to move more freely when it's colder.

Now that I said that..... I'm not sure why you would want to use 0w-30 as it would be super thin, even thinner than the original clearances that Toyota recommends, which they recommend 5w..... when it's below 40* and MIGHT cause some wear issues... I would think 10w would be a better choice, but since it rarely gets below 40* I wouldn't really worry about 0w, 5w, or 10w but what is relevant is the regular weight, not the winter weight.

As Larry David would said, with that being said... I would go with whatever's cheapest, the real key to engine longevity is the filter and frequency in which you do the changes.

haulin79

0w30 is always thicker at lower temperatures than at higher temperatures.
5w30 is always thicker at lower temperatures than at higher temperatures.
10w30 is always thicker at lower temperatures than at higher temperatures.

For example:
................. cST@40C ---- cST@100C
Mobil 1 10W30---- 62.0------ 10.0
Mobil 1 0W-30---- 63.1 ------ 11.0

AMSOIL 0W-30 is 57.3 cST @ 40 deg. C, & 11.3 cST @ 100 deg. C
AMSOIL 5W-30 is 59.5 cST @ 40 deg. C, & 11.7 cST @ 100 deg. C
AMSOIL 10W-30 is 66.1 cST @ 40 deg. C, & 11.7 cST @ 100 deg. C

Here is a generic oil viscosity graph from http://www.widman.biz/Seleccion/Visc...aph/graph.html :

3UZFTE

Yeah, that's my point though... They are all combination weight oils, the "w" is just the winter weight below a certain temperature, the second number is above a certain temp. Try taking a quart of 0w30, 10w30, and 30 weight and then do the viscosity test below 32*. The 0w will pour faster then the 10w, and they will obviously pour faster than the 30 weight, even though they are all 30 weight oils, they have different viscosities below 32*.... The reason why you have winter weights is because when the temp drops overnight, the molecules of the oil can still be sent through the clearances of the bearings, pump crank, cams, etc... If you have 30 weight oil in your car from Florida, and you drive up to Minnesota where it is 20*, your oil will not be thin enough to allow the starter to twist the motor over because the oil is too thick.... Does this make sense? The reason why I mention this is because SAE 30 weight oil is often cheaper then combination oils (5w30 or 10w30).

omarg

i use mobile 1 for my 93 ls400 (287k). Its makes for much quieter cold starts. My 95(114k) has had regular its whole life and is quiet when warm but kinda loud when cold(its all relative). I will be switching it over to syth when it needs an oil change in 2 months or so.

You really don't NEED synthetic, and if you switch over now at 325k it'll probably leak, or at least weep. Also the 1uzfe is so tough it doesn't need any babying. I dont think there has ever been an engine failure on one (neglect not included, and even ). nobody needs them, thats why they are worth more as aluminum scrap than they are as engines!

Now I use synthetic for these reasons
- i like knowing that my engine is being fully protected sooner, especially since i crank and go to work 4 miles away
- extended drain periods (i change my own oil)
-quieter cold starts
- $10-15 extra an oil change( every 6 mos or so) is worth it to me.

i feel the same way about premium fuel. The benefit is small, but so is the cost... so why not??

to me the benefits outweigh the cost.

sik96ls400

i'm in the same boat..my synthetic oil changes cost $55 dollars, and premium fuel is only 20 cents more than regular in most gas stations.....i mean a couple less trips to fast food restaurants and you'll have more than enough money needed to put better oil and gas in your car....

7schulz

What is the recomendation for engine oil.
5w-30 is what is recomended for our enigine right? I was thinking 10w30 for the summer.
The Land Cruiser guys say Shell Rotella T 5w-30 Syn has the best wear characteristics. What does everyone here use. My car has been converted from Dino to Syn blend and to full syn over the last few oil changes at the dealer. So I want Syn in there. So what do you guys use?

Legionofon

Switch from regular to syn is a MYTH! trust me I not only went to tech school but worked at a quick lube... basicly all you did when you put synthetic blend in was put half and half in... Now back to the question... Oil is personal preference... put whatever you want in, I'm cheap and run Valvoline regular, In my old accord that I drove like a race car I ran only Mobile 1 Full Synthetic...

7schulz

I didn't do the conversion the PO did at the Lexus dealership, I went through all the old receipts and found the change over going on and the last couple were full syn. That was what the dealership did as their lexus thing. I would like to run the same syn in both my rigs. I want the best protection so when I open her up I don't have any wear. I have 154K on her and would like to get 300K. I don't drive her hard but do like to get on the V8 once in a while. PS I have an ME degree and have worked in valvetrain/piston design. I know how important oil as and how bad high RPM's are for an engine. Saying that, I don't know tons about this engine except for the enormous ammount of engineering and design that went into it. Would the thicker oil affect the tolerances in the engine and oil flow? I would really like to run a 15-30 but don't know how sensitive the oil flow is.

paulo57509

I use Pennzoil Platinum 5w-30 with a Bosch oil filter.

j stuff

iTrader: (5)

Toyota Fluid and Filter 5w30

Legionofon

I run 10w40, you want the 1st number to be 5 or 10 for easy flow at start up hell you could even run some of the new 0 weight oils, 30-40 is fine for the warm number... we run 15w40 Rotella diesel oil in our LS3s and LS7s at work. If you run your engine hard I would recommend a European 5-40 full synthetic from Mobile 1. The heavier weight allows for more support inside the bearings.

willhickey

iTrader: (1)

i truly believe in my opinion 10w30 in the summertime is fine as its only a little thicker upon startup and in hot summer climates both are thin. but why do you want to run 10w30? do you have a leak? if not dont run it because there is no point or difference. ... as far as synthetic goes there is nothing bad about it and everything good such as less friction , less wear , longer intervals, better gas mileage, higher ability to withstand heat. With that being said why wouldnt you switch right? I think that any synthetic is better than regular honestly but they do say STICK with whatever brand you choose since they all have different additives and could have a negative affect on your engine. Is it true? no clue im not an engineer but i would switch and i try to run castrol syntec or edge and valvoline synpower only but do settle for whatever synthetic is on sale.