i was looking at Mobil 1 oils the other day!
and it seems they don't have 5W 30 anymore! as the vette requires!
Would 5W 50 be too thick!
also i have heard that full synthetic is not good, but semi is ok!
hope this doesn't start a big debate! just curious as to what others are using?

 

Where I live the local auto zone has 5-30,make sure you're car had full syn. in it before,mine didn't and I put in full syn. and developed alot of leaks

 

Yes ,they still have it, the Walmarts here still carry 5w- 30w..I wouldn't use anything higher then 10w-30w unless your having a problem with your oil pressure being to low or you are running in tempertures above 100 degrees constantly, then maybe 10w- 40w but nothing higher. Synthetic oil is better because it can handle the higher temps that our engines sometimes see but like the guy above said, if you haven't been running synthetic in your car and it has a lot of miles on it you could develop leaks...WW

 

Ok then, my car has 80K odd miles, but don't know the history of the oil!
i thought that a 10W 40W, or 10W 50W is better for older engines as it is a thicker oil?
Isn't the 5W or 10W(first part) depicting how cold the temp can be, for the engine to be safe during warmup?


anyway i think i will be going for 5W 30W semi syn!
thanks

 

The first number is the cold startup viscosity, the 2nd is when its warm.

Depending on the average temps where you live, its perfectly ok to go to 10w30, and if the car has higher mileage then 10w40 is also just fine.

Dont worry about the weight so much as changing it on schedule with a good filter.

 

It's possible that 5W-30 is not a popular viscosity in Australia or at least where you live (Western Australia??) . Mobil-1 in 5W-30 is still available and is the standard viscosity for 1992 and later Corvettes. Full synthetic Mobil-1 5W-30 was the factory fill beginning with the 1992 LT1 motor and is still used today. The L98 motors got regular "dino" oil but still in a 5W-30 weight.

Ambient air temps play a part in selection a proper weight and a 10W-30 will work fine for high air temps.

As far as the full-vs-semi synthetic arguments, your L98 motor will run fine with either type. Just get a good quality oil and a good filter.

 

Where I live the local auto zone has 5-30,make sure you're car had full syn. in it before,mine didn't and I put in full syn. and developed alot of leaks

I had the same problem when I switched to Mobil 1 - several seals started leaking

 

The different molecular structure of the full synthetic allows the oil to get through places standard oil doesn't. You should have seen the smoke cloud when I put synthetic blend in my S-10 Blazer. Most leak at the valve covers when you switch over.

 

We are running our L98 (89) on GM brand (it is mostly Shell or Mobil lubricant relabeled) 10W40 semi synthetic in Europe. It is less expensive than any other brand name semi synthetic oil. It is equivalent to Shell Helix Plus (4 liter GM bottle) or Mobil Synth S (5 liter GM bottle). In general, the lower number is representative of the base stock used. The higher this number is the better. Mercedes Benz did a variety of tests back in the 70s, and found out that lowest wear is with 10W or higher base oils.


The oil thins down considerably at higher temperatures (viscosity). The viscosity of a 40W oil at 100C is less than 1/5 of 10W oil at 0C. The main advantage of synthetics is to make it possible to make oils with low viscosity like 5W50, 0W40 etc. This is great if you have to drive a car operated in the winter time.

L98 can run dino oil because it has oil cooler, and thus lower oil temperatures. Supposedly, synthetic oil can sustain higher temperatures and with LT1 engines both the engine runs hotter and the oil cooler was deleted...Therefore, the Mobil 1 suggestion. In the USA, I would rather use Quaker State 10W30 Horsepower Full Synthetic Oil as it is cheaper, comes with a generous rebate until recently (like $10 on $18 five liter bottle) and is actually Shell Helix Ultra in Europe and other places.


Since the poster is from Australia, check out the following comparo, it claims some of the semi synthetic actually perform better on the scar test than the full synthetic.



http://www.animegame.com/cars/Oil%20Tests.pdf


C4ZF6nut "running Kumho MX"

 

well most of the winter in Western Australia would never get below 0degrees C, so far this winter it has been 3 degrees C a few times! so i think a 5W 30W weight should be fine, no need for 0W 40W!

the reason i asked the diff about Full and Semi syn is because i have heard from a few mechanics that Full syn can actually harm an engine! something to do with the properties the oil is made from! don't know how true this is? but i have always liked semi syn, and seeing as the L98 is getting on now, it doesn't need Full syn.

Well thank you everyone for the detailed info on the different oils, i definately don't want my rocker cover seals to leak! i checked them today and they are fine, so i will keep them that way i hope

Over in WA we have a wide range of oils and viscosities, from memory 0W 40W, 5W 50W, 10W 30W, 10W 40W, 15W 40W, 20W 50W, 20W 60W and so on.... actually i think Mobil has 5W 30W! here! but it is Full Syn, i might check out Castrol and a few other with semi syn!
We have a brand called Royal Purple too, is this on par with Mobil?
Have you guys heard of Penzoil, Penrite, and valvoline? they all do semi's and at the correct viscosity!

 

I work at O'Reilly's and we are still carrying Mobil 1 5w-30... I couldnt see them getting rid of it. It's one of the most popular sold oils from them!

 

damn!
Mobil 1 do a 5W 30W supersyn oil and it costs $30AUD more than Mobil 1 5W 50W
thats crazy!
5W 30W is $100AUD and it is Full Syn
think i will go with Castrol Sports around the $50 or even Valvoline synguard!

 

I've always used 10w30

 

me to

 

Me too. It is not driven in the winter , here in PA. Too much salt and crap on the roads. I know a Vett mechanic still working (He is around 70 ) , and he prefers 10W-30 in the LT1 .
Ted

 

ok then so 10W 30W is ok, what about 10W 40W, thats what we have mostly over here!
and this is for an L98 engine too!

 

The only reason I could see for using 10w-40w in a street car is if you were running real low oil pressure, older engines sometimes have lower pressure because of engine wear,,,Like mine has ...WW

 

Just my $.02. I run Amsoil in my 85. no problems at all. it has the extra additives needed for flat tappet engines.

 

Still very available.

https://www.mobiloil.com/USA-English...l_1_5W-30.aspx

 

ok thats the oil i want, but where i am the Mobil 1 5W 30 is Full Syn, and i i don't want that!