According to the owners manual it's too thin for our cars, but I don't know anything else besides that.

I know it says in that article that doesn't matter, but I'm always hesitant to believe something just posted online without sources over the owners manual.

 

^^ obviously you did not read the article.

 

Well I skimmed though it, but no I did not have time to read the entire thing yet. It's rather lengthy.

 

Good lord that is way too long... My attention span does not allow for that kind of th

 

How about yes.. Unless it stays at the 20w during it's entire run. In other words use 5w30 or 5w40 and call it a day. I didn't have to read the art

 

20w doesn't get thinner at high temps. 20 is the high temp rating. It would over the life of the oil change get a bit thicker more than likely.

 

Remember where he says that ALL available pulls are too thick at startup? At operating temperature, it does thin out. It's at operating temperature that the first number doesn't matter.

Fixed, can't spell thick correctly.

Sent from my Nexus One using AutoGuide App

 

Have you ever see how thin 30 is at operating temp? They also state it is not the fact oil thins out when heated but the real problem is oil thickens when it cools down.

 

I'll be running 0-20W Pennzoil Ultra during the winter for certain.

Anyone check oil pressure and if so share RPMs vs. oil pressure vs. the oil you were running?

 

IMO, the 20 or 30 weight oils make no difference in engine performance/reliability since engine oil runs at mostly the same temperature (usually around 200*F) unless you live in pretty EXTREME hot or cold environments. I always just stick to the recommended weight and be done with it.

I don't have a gencoupe yet, but does the manual recommend 5w20 for generally average yearly temperatures? As far as I know, allot of newer cars are running 5w20 oils due to tighter tolerances (and some due to CAFE standards)

 

I would think the 20 would give you a few hp over 30.

 

................................. :gc-Popcorn_Smiley_b
Just curious >> what makes you "think" such a silly idea?
At "normal" operating temp. the viscosity is the ~ same in both.
20 is good in winter cause it never gets to thick.
30 is good in summer cause it never gets to thin.
The W signifies winter and is the oil’s low temperature characteristics, while the higher number gives the oil’s high temperature viscosity properties.
A 10W-30 oil behaves as 10-weight oil at low temperatures but gives the protection of 30-weight oil at the high engine operating temperatures.
:gc-drool1::door:

 

The 20 weight oil would save hp due to less pumping losses over the 30 weight. At operating temps the 20 weight acts like a 20 weight and a 30 weight acts like a 30 weight. There is a difference in viscosity as that is where their viscosity is rated. If they were near the same then there would not be a 20 and a 30 rating.

The W is for the number in front of it, not the number after it.

 

The 3.8 requests 5W-20 so you don't want to go over a 20. A 30 would only be a good idea if you needed it to maintain oil pressure on a really hot track day. For instance if I was hitting TX track days in July I'd run a 5W-30.

Since during my next oil change it will be cooler outside I'll be going to a 0W-20. For miniscule hp, mpg, and improved wear characteristics.

The paper that was referenced in the OP said to look at oil pressure to determine the high number of your oil. The idea is to get 10psi of oil pressure per 1000 RPM. If you run more oil pressure than that you need a thinner high # on the oil bottle to bring it down. But w/ 20 being the practical lower limit for now. If you run less oil pressure than that you need to run a thicker oil. This could easily happen on a 100 degree track day.

The lower number just means cold flow. And the lower the better, even on a 90 degree TX day at start up. You are preventing wear by getting oil to internal engine parts quicker at cold start up, which is when 90% of engine wear occurs.

The reality is that a 0W-20 should have slightly less oil pressure when warm than a 5W-20 due to the addtional viscocity spread. Which is the reason that you would want to run the 5W-20 in some cases.

But 0W is the future.

I'm going to use the oil pressure method to determine if it is safe to run 0W-20 for my next oil change. I'll use my little bluetooth OBDII & Smartphone to view oil pressure under different operating conditions.

 

Running AMSOIL 0W20 right now with no issues. AMSOIL recommended it, not that what they say is law but I thought I would try it.

Offtopic -

Suns - What OBDII bluetooth did you buy and did you like it? I'm thinking about this one

Amazon.com: OBDLink Bluetooth OBDII Scan Tool Interface Adapter & Software (425103): Automotive

 

Running AMSOIL 0W20 right now with no issues. AMSOIL recommended it, not that what they say is law but I thought I would try it.

Offtopic -

Suns - What OBDII bluetooth did you buy and did you like it? I'm thinking about this one

Amazon.com: OBDLink Bluetooth OBDII Scan Tool Interface Adapter & Software (425103): Automotive

Where did you get it? I'm interested. Thanks

 

From what I've seen so far this summer 75 psi is the limit. A relief valve must open at that point. At 7k the oil was at 75 lbs and when cold it is easy to see the 75 lbs. This is on Mobil 1 5w30.

 

Coupe, I bought a little bluetooth enabled OBDII device that transmits to my smart phone and then using an app I'm supposed to be able to monitor things.

It hasn't arrived from Tiawan yet. It was only $22, shipped.

 

I have one of those and its really slick.

As for oil pressure though,the interaction of bearings and oils are a little more complex than simple rules about oil pressure in the system. Heres a taste of what goes into the design of bearings and choice of viscosity of lubricants. http://www.faculty.fairfield.edu/wdornfeld/ME312/PlainBearingsLectureE.pdf

The engineers selected certain lubricants for certain situations. I am not willing to second guess them and decide that I know that a thinner viscosity than they recommend for instance can properly support the rods on the crank shaft under load,or support the crank shaft on the main bearing. Part of it is in fact the oil pressure (ok,flow,well,not even that but film thickness),but viscosity and load also factor in so just adjusting the viscosity to meet an oil pressure specification does not sound like its going to be enough.There is more than just one degree of freedom there and you dont know and cant adjust what the load is. Yes,oil "weights" are really not enough information,but the engineers design their cars not based on those numbers but based on the actual specifications. They then tell you the oil "weights" to use so you know what to go buy.

 

It is too thin because a lot of the people here use Mobil1 which is substandard for the gc. The car runs way rich which dilutes the oil with fuel. Also Mobil1 shears from 30w to 20w in 5K miles. Imagine if you were using 20W and it sheared down to 10w. That isn't enough to protect the motor.

If you want to run 5w20 change your oil <3000 miles.

 

The viscosity spread is wider on the 5-30 whch is why they shear done to a 20W.

It's well documented that the 5-20's don't shear done any lower than 20. They are considered a more stable viscosity oil.

My oil cap says to use 5W-20 but I think I saw where a 2010 model said 5W-30. Not sure what to make of that.

 

I recently read a really LONG thread on oil and I do not remember if it was linked off of this forum or not. In a nutshell: The first number is how well the oil flows when cold. The lower the better as far as start-up wear goes. If you are using say 10 - 30W you will be damaging your engine on start-up. It is too thick when cold. The second number is how thick it is when hot. Here you want probably 20 or 30. Some say for real racing go up to 40+. I am using 5 -30W in the summer and will use 5 - 20W in the winter. I would use 0 - xxW if it were available in a synthetic blend. Full synthetic is too pricey with 3k oil changes required on the turbo per Hyundai TSB. The manual states 5 - 20W or 5 -30W for typical applications.

 

I had my 5w30 Mobil one tested at 3500 miles when I changed it and it showed very little shear (cst was at 9.4) and minor fuel dilution.

 

Bump from back pages of forgotten.

Something I found interesting . . .the AMSOIL site USED to recommend 0W20 for the Genesis Coupe back a couple months ago and I checked now and it's changed to 5W-20. Interesting . . . .


Thoughts?

 

I don't know why. IMO 20 weight oil is 20 weight oil. Unless Hyundai wants a thicker oil when it's cold out for the cold start.

 

Mobil 1 and Amsoil both say 5W-20 is optimal for both the I4 and the V6. I'd say stick with that for 99% of the people on this forum.

 

i just ordered a years supply of 0w40 Mobil 1.

 

I was gonna come in here guns blazing to post that article.

I <3 Red Raspberry.

 

a question here... I use Eneos 5w40 and i live in central america, the temperature everyday is like 90-100F at night 77-85F and alot of humidity, I don't really knnow about oil viscocity or anything, just that 5w is temperature for winter and 40 is hot temp.. so my logic will be if i get a higher temp like from 30 to 40 would it be better?? because some people told me that 5w30 would be ideal to use here in panama but 5w40 wouldn't be better??

 

From Hyundai Service Website:

Selection Of Engine Oil
API classification : SL, SM or above
ILSAC classification : GF3, GF4 or above
SAE viscosity grade : 5W-20, 5W-30, 5W-40

Engine oil

Oil quantity
Total
6.0L (6.34US qt, 5.28lmp qt)
When replacing a short engine or a block assembly

Oil pan
5.5L (5.81US qt, 4.84lmp qt)

Drain and refill
5.2L (5.49US qt, 4.58lmp qt)
Including oil filter

Oil grade
Recommendation
5W-20/GF4&SM
If not available, refer to the recommended API or ILSAC classification and SAE viscosity number.

Classification
API SL, SM or above
ILSAC GF3, GF4 or above
Satisfy the requirement of the API or ILSAC classification.

SAE viscosity grade
Recommended SAE viscosity number
Refer to the "Lubrication System"