Follow-up on second service and dealer oil recommendation
 

As posted yesterday, I took my car in for its second service yesterday. I had also brougt along a six-pack of Mobil 1 15W-50 but was told by my service advisor that use of such a heavy oil wasn't recommended as it could lead to a hard starting condition. I asked if they had other synthetic oil of a lighter weight that they could substitute (at my cost of course) but was told that they didn't stock synthetic at all. In the end I told them to use their recommended oil, which I later found out was 5W-30. <p> I'm a little concerned about the use of such a light oil, especially since this will be in the car through most of the summer (I live out on Long Island and we certainly see temps in the 90's) and slightly confused about just what I should do. I'm definitely leaning toward replacing the dino oil with synthetic (previous fill was Mobil 1 10W-30 that I supplied at my first service back in December) but now I'm unsure just what weight I should stick with. I know that this subject has been beaten to death around here but even a search through the archives hasn't provided any firm direction. Should I simply dump the dino 5W-30 and go with my original choice of Mobil 1 15W-50 or would I truely be better off running something lighter ... and if so what? <p>Charlie<br>98.5 1.8TQMS (10,000 miles)<br>

Have you checked with other dealers?
 

I just switched to Mobil 1 15W50...I have 3000 miles on it and no problems. Before switching I contacted the service department to ask what wieght they were using...Joe Pecheles Audi/VW in Greenville, NC, they said they used 20W50 and the 15W50 would be fine. The manual says it's fine, and at least one dealer says it's fine. And NC isn't that much hotter than coastal MA where I used to live, so you should be fine. I'd call a few other dealers in your area and ask their service folks what they're using and what they think. But if the manual says it's ok, I wouldn't worry too much.<p>Regards,<br>Rodney<p>'99 A4 1.8tqms

Re: I know a little about motor oil... (long)
 

You should be fine using 5W-30 for your car, even in Long Island. One of the benefits of synthetic oils is that they maintain their proper viscosity at very low and very high temperatures. If you look on either the Castrol Syntec or Mobil1 websites (technical specs), you'll see that you're covered - even in a lightweight oil - up to 475degrees F and down to -50 degrees F. Manufacturers recommend lighter weight oils for a couple of reasons: (1) they produce better fuel economy, and (2) because today's engines are engineered with tighter tolerances, thicker viscosity oils are no longer needed to prevent metal-to-metal contact, etc. In addition, synthetics do a better job at controlling engine wear (since they "trap" dirt particles and carry them to your filter), preventing sludge and piston deposits, and a whole host of other nifty things.<p>Personally, I wouldn't go with something as heavy as 15W-50 unless you're moving to Arizona or have knocking problems. But 10W-30 will do fine for you as well (its the most popular grade for good reason!) The manual really is the best source of info, because auto manufacturers test these things extensively. Who do you think makes up the "specs" for motor oil manufacturers?!<br>

this is nonsense...
 

first, synthetic 15W50 has the same pour and viscosity characteristics as a nonsynthetic 10W30, so it's not that heavy. Second, the owner's manual, I am almost sure, OKs 15W50 for hot weather use.<p>I'd especially want 15W50 with a turbo. I use it in my 2.8 in the summer. My service advisor, who I know from pre-Audi ownership from our time at the track with the Porsche Club [his 914 track car, my '73 911] said he recommends 15W50 for a turbo year 'round.

Re: this is nonsense... p.s., we're in No. Va. in case geography is relevant to your oil weight choice...

You certainly do! (more on oil specs)
 

I agree completely. Audi advises dino 5w30 in the manual up to 90+F. As you mention, synthetic is so vastly better than dino that it can cover any reasonable temp range encountered on THIS planet.<p>I think it is fine if people want to be conservative in their spec (it's your car), but there is no technical reason to go that way. In fact, I find a discernable difference in turbo spoolup between viscosities. <p>We do have an oil cooler (exchanger) on the 1.8, and we have a properly sized radiator. So peoples history with old overheating V8's isn't quite relevant here.

Tend to agree; need for heavier weight oil largely carryover from Dino days when needed heavier oil for high temps to tmper the oil breakdown. Not true w/ synth. oil

Thanks for all the advise! I'm going with 10W-30 Mobil 1.
 

Thanks for all the comments. Based on what has been said and a brief visit to the Mobil 1 web site, I think that I'll stick with 10W-30 Mobil 1 for my application (geography and intended use). I'll drain the dino 5W-30 that the dealer used in a month or so and put in the synthetic by the time the really warmer weather rolls in. <p>Regards,<p>Charlie (98.5 1.8TQMS)

clarification
 

15W-50 synthetic does not have the same viscosity characteristics as 10W-30. The 10W and 30 refer to viscosity values at specific temperatures - it's independent of whether its synthetic or not.<p>Tom<br>1.8TQMS Silver/Ecur

T2 is correct and Jon C has no idea what's he's talking about. I work for a motor oil company, so I know!
 

<br>nt