Engine oil question

[wohnson89]

Couple of months ago I took my svx to get the oil changed, and they put 5w-30 in it at the time, and I didn't think anything of it. I got a owners manual recently and it says to put 10w-30 or 40 into it 0 degrees or higher and below 30 degrees put 5w-30 into it, but with a caution notice along with that which says "CAUTION: SAE 5W-30 is not recommended for sustained high speed driving." When I drive it it is usually on the highway and at 80mph or above for at least 30 min, so my question is have I been hurting my engine by doing this? Should I go Get another oil change? What type of oil and grade is the best for these engines?

I wish I had noticed this earlier...

[Blacky]

The diagram in my owners manual shows that 5w30 is prefered for any driving under 100°F.
If driving at 0°F and up and/or 100°F and over to use 10w30 or 10w40.
I'm sure this will turn into a thread about which grade and brand of oil is best etc. etc. etc. The bottom line is, your fine, don't worry

[wohnson89]

The diagram in my owners manual shows that 5w30 is prefered for any driving under 100°F.
If driving at 0°F and up and/or 100°F and over to use 10w30 or 10w40.
I'm sure this will turn into a thread about which grade and brand of oil is best etc. etc. etc. The bottom line is, your fine, don't worry

Ok, well in that case why would they put in the manual that "5W-30 is not recommended for sustained high speed driving"? maybe I am reading the graph and page wrong. I'm sure glad I haven't hurt my engine.

[svxcess]

My 96 polo came fom the factory with 5-30 and despite religious oil changes, YT built me a new engine at 120,000 miles.

I use Mobil 0W-40 year around. Based on my driving style, I want to make sure I get adeuate oil flow through the tight oil tolerences when the engine is cold and most vulnerable. There were at times 6 month intervals between startups with absolutley no problems.

See this post from Huskymaniac, he has a lot of experience in this.

http://www.subaru-svx.net/forum/showpost.php?p=687996&postcount=5

..

[92 SVX]

When oil heats up it thins down, So if your doing sustained high speed driving (100mph or more) 5w-30 can become too thin to adequately lubricate.
Or if you live where the outside temp is consistently over 100F such as death valley or many parts of the south west, az, nv, etc.
Oil such as mobil 0w-40 is thin enough while cold to lubricate yet does not get thinner with heat.
I have been using rotella's synthetic T6 5w-40 and have liked it so far.

[Huskymaniac]

They suggest not using 5w30 at high speed because it will not maintain a proper film on the bearings under the high stress, high temperature conditions. But oil that is too thick will not flow properly at low temperatures. I like high mileage oils because it keeps the seals flexible and it has more of the key additives than standard oils. What I do is 5 quarts of 5w30 high mileage and 2ish quarts of 0w40. The oil can handle the stresses of highway summer driving but still flow well at winter temperatures. Some people like the Rotella 5w40 but it doesn't have the seal conditioners I like so I do my own blend of M1 products. Tom checked out my engine when it was down there and he said it looked great.

By the way, he also opened up some port in the pump and I swear the engine is running 4 to 10 degrees cooler. It is a mod that makes total sense to me.

[SVX_MY_BABY]

When new and a number of years after that I always used 10w40 in summer and switched to 5w30 in winter. Now I only use 5w30 simply because it doesn't get that hot in my neck of the woods. That said If I was to travel to a central area of the continent or south in the summer I'd most definitely put in 10w40.

The 10w40 is designed to work better at not breaking down under high temperature. Extended driving at the speeds you mention in the heat of your summer would certainly call for it in my opinion. Conversely the 5w30 gives better results in the below freezing temperatures.

You might want to consider one of the newer "High Mileage" oils which combine conventional and synthetic. I think there are a few which claim 5w40, but don't hold me to that.

Then there is always the choice of 5w40 full synthetic. That of course opens up the whole debate about whether it's a good idea to switch to synthetic after using conventional for years and what it does to the seals etc.

Rough calculation tells me you have 8000 miles on your oil already. (80 miles/day x 20 days/month x 2) I'd go for an early change to "summer weight" oil if I were you. The cost of the oil is pretty cheap insurance.

[svxcess]

By the way, he also opened up some port in the pump and I swear the engine is running 4 to 10 degrees cooler. It is a mod that makes total sense to me.

OT developed this oil pump modification to improve oil flow. He enlarged the orifice a bit, not sure how much. He has been recommending his simple mod to those who come to him for timing belt/ water pump replacement.

He also has been porting the coolant thermostat cover to streamline coolant flow; another OT innovation.

.

[icingdeath88]

I have been using rotella's synthetic T6 5w-40 and have liked it so far.

I have been using it in both of mine for a while now and I'm very impressed. Takes a long time to get all blackened and nasty. Not sure I'd recommend it to someone who lives somewhere that cold startups are very cold.

[1986nate]

I have become a huge fan of Rotella, namely T6-5w40 over the past year plus. It's been going in my A4 since I have owned it at around 200k miles and now has 247k and counting. I offroad/mud it, tow with it through the PA mountains and drive the hell out of it. It still does not leak or burn a single drop and oil temps stay low, especially for a turbo engine being worked hard. The 1.8t engine is very picky about oils and will trip the oil light if not using one of about a handful of oils.(which actually did happen to me when I took it for the local dealer syn blend oil change special) Mobil 1 0-40 is what is recommended/required from the factory.

Due to this, I recommend Rotella to almost all of our customers due to the potential for sludge buildup of inferior oils in the turbocharged engines.