OCI Suggestions

[92saturnsl2]

Just looking for some suggestions / opinions as to what a good OCI would be for my vehicle use and driving habits..

It is a '01 Jetta VR6 (2.8L 12 valve), with approx 85k, no noticable oil consumption, so no makeup oil is used. I've been doing 5K intervals using Mobil 1 0w40 in winter, and Mobil 1 Truck and SUV 5w40 in summer for the life of the car. But now Mobil 1 Truck and SUV is so **** hard to find, and 0w40 would likely shear out of grade in the summer heat in extended drain intervals.

I've since switched to GC Gold, and my driving habits have recently changed dramatically. Right now I'm using it for 85% highway at sustained ~85mph speeds @ 3200rpm. The other 15% is stop and go city traffic. I have no previous used oil analysis so I was thinking 7500mi and possibly test? Manufacturer recommends 10k intervals for this engine when using VW 502.00 approved oil.

Any opinions/suggestions are appreciated.

 

[GROUCHO MARX]

My opinion, 7.5k in your type of driving works. I'd bet a used oil analysis will confirm it.

 

[GoldenRod]

Is the GC Gold quieter, smoother, basically more yummier?

 

[OriginHacker21]

GC Gold is the best. I'm taking my GC Gold to 6,000 miles and I have a 4 hour daily 220 mile trip @ 70mph @ 2,600 RPMs.

I'm going to do a used oil analysis to see if it can go longer. That is the only way to tell bout an OCI - a Used Oil Analysis.

 

[TomJones76]

Only one UOA I could find for this engine:

http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=3;t=000492#000000

If you read that, Member segfault ran his '99 Jetta VR6 just over 10K on a blend of 3 different Mobil 1 varieties. He had a 5.5 TBN, a 380 flashpoint and what look like normal wear metals for his mileage.

Were I you, I'd be happy to run this thing 10K intervals on GC or any of the suitable Mobil 1 Extended Performance varieties.

 

[bighead]

3200 RPM at 85?? My Grand Am barely kisses 2400 RPM at 85. Sits comfortably at 2000 at 70

....but then again that's the difference between domestic and import transmissions... In any case, I'd think that 7500 on your OCI would be perfectly fine. I'm not sure I would go the full 10K with the amount that engine is turning on your highway trip...but then again that's just me. Probably wouldn't matter much to the engine..

 

[mshu7]

Could it be that the OHC design in the Jetta is just a higher revving engine than the pushrod design of the V6 in the Grand Am?

I have a Grand Am GT so I know what you're talking about. 70mph on the highway puts me around 2200 rpm's I believe.

*Note - I'm not trying to start a OHC vs. OHV debate, just pointing out a possible cause for the difference in rpms.

 

[92saturnsl2]

Thanks for the replies. I will likely run it out to 7500 miles on this run.. I've got about 40% city driving on this OCI, so if this UOA turns out okay, then I'm sure I'll have no problem with 7.5k with the amount of highway driving that I'm doing now.. I'm not too concerned about extending the drain, the cost isn't of huge importance to me, I just don't want to waste my money by changing it when it's not needed. Where is the best place to have the UOA done?

To clarify the above, the 12v (DOHC btw) version of the VR6 is a torque monster, making peak torque at 3200rpm, and 85% of peak torque at 1200rpm. A variable geometry intake helps maintain torque toward the higher RPM's, but this is by no means a high RPM engine.

So no reason they couldn't have used a taller 5th gear. But bear in mind this is a 5sp, and most, if not all manual transmissions made nowadays have too short a top gear IMO, especially in the case of the smaller displacement 4 cyl's, in which many are turning 4k or better at 85mph. One thing's for certain, it'll pull through just about anything in 5th gear with top notch acceleration at just about any highway speed without needing a downshift to 4th.

Plus the rod/stroke ratio is something crazy high like 1.87, so piston speeds and cylinder loading are a LOT lower than most engines, reducing wear at higher RPMs.

 

[TomJones76]

92saturnsl2,

With the the 7500 miles you've settled on and Syntec 0W30, there's not a doubt in my mind that you'll give us a good UOA. Happy motoring!
Saturns are neat little cars, but I'm 5'10" and 340 lbs, and... uhh... yeah. Last time I test drove one I made it half a mile before I pulled a u-turn and drove back to the dealer.