How often do you change your GC?

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Jan 9, 2004
Portland, Or
I spoke to an engine builder today who said M1 oil is commonly ran for up to 20k. Then he showed me a bottle of Amsoil that said it's ok to run up to 35,000 (with new oil filters every 12k). That totally blew me away that companies would actually advertise that. Even M1 is advertising that their extended performance synthetic is guaranteed uo to 15,000 right on the front of the bottle. I knew modern synthetics lasted a long time, but not that long. I change my vw 1.8T w/ GC and M1 filters every 5k and I'm beginning to think that is way to often in order for it to be that cost effective. If I could run it for 12k, that would be awesome. Maybe I could do that then run a UOA and see how it's working out. I really hate changing my oil. What would you do?
What are your driving habits? (Drive it hard? Freeway/City? Dusty Areas? etc.) 12k intervals would be insane for my driving style... I'll probably end up with 5k OCIs. Maybe 7.5k. Then again, I'm more of a "play it safe" guy, not a "live on the edge" or "maximize my penny" guy. [Big Grin] I'd have a real hard time changing oil PAST the factory recommended intervals. A UOA is a good idea, but I wouldn't push your engine to use an oil for 12k right away.
I drive hard with a lot of stop and go traffic and short trips.I'm in the Northwest, so there's very little dust. That's why I used the best oil and filters that I know of. Just for the sake of this discussion, what makes you think your oil is toast at 5k?
It's a mix of things. I'll admit, I can probably use the oil longer than 5k. I change it mainly for peace of mind. 1. I drive my car relatively hard. I didn't get my car to drive it like an econo-box. 2. Lots of short city trips. Most of which are less than 10 miles. 3. Subaru recommends 7.5K OCIs for typical driving. I don't consider (1) and (2) "typical". 4. 5k OCIs are a nice compromise between the Factory Recommendation and the traditional 3k OCI. 5. I like to change my oil! Just FYI, the longest I've used my oil is 4k. I'm changing it frequently for the first 20k miles. That's a whole other can o' worms. I'll be increasing my OCIs to 5k soon.
Due to the fact that... 1) You drive it hard 2) Lots of stop and go traffic with short trips 3) It's a turbo ...I would think 5K is just about right. Better to have that piece of mind. If you didn't have a turbo and/or had all the short trips in traffic, then I think you'd be able to extend your OCI further. 5K is about all I'd do if I were in your situation...FWIW [Cheers!]
I agree with BH. If you want to extend your OCI I think it would be wise to do the UOA on the next drain and then get Terry Dyson involved to evaluate your sample. My last/first UOA revealed good results with GC and LC-20 after 7500 miles. I've been directed by Terry to make changes and to take it to 10,000 miles which I am doing now on my little ECHO. With you turbo I wouldn't chance a long drain, more than the 5K that you are doing now without Terry's input. I would also be doing the LC-20 and FP-60 treatments to take advantage of those chemistries. I'm a rookie, but that would be how I would approach the situation. I hope those with better knowledge will correct me if I've suggested something improper. John
Am using a huge Napa Gold filter and GC on my 1.8T. Oil is GC. Engine is consuming no oil to speak of with annual oil changes. Have not had a UOA done as of yet but the colour of the oil stays relatively consistent (I know, doesn't tell much of anything). The oil capacity is around six litres now with the barely-fitting filter (never leaks - no problems). The vehicle works really well, smooth & quiet at idle, & fuel economy is consistently great. The vehicle has anywhere from eight to ten thousand kilometres of use per oil chage annually. John.
I have done some UOAs on my 1.8 T and you can find them on the Vortex and here. Both of them were at 5K and the TBN was 6.3, 6.4, with Mobil 1 and GC. Both of them are with VW OEM filters. I usually drive 90% highway, but Reno, NV is pretty dusty anyways. I will try 7.5K and see what the results are. I dont think it is really saving you any money, espcialy if you send it for an UOA. I know that in Germany most people will go 20000km before they change oil. If you look at the VW filter, it says Langzeit filter, 2 years 20000km if I remember correctly. Also a quart of Castrol Longlife 3 is about 20 EU, which expalins the savings you would have there. If you are concernd about the sump capacity, you can get the bigger VW filter (this is if you have a transverse mounted engine). VW and Audi did this "quick" fix ot prevent the sludging on the front-back mounted engines.
I've been running 10k service intervals with Amsoil in my 2002 Audi TT turbo. I don't see any reason for changing oil every 5k in this application. If you have a Golf or Jetta with the 150 Hp or 180 Hp engine, I think that 10k is conservative. TS
I'm presently holding the line at 7500 to avoid a possible wty fight. Once I've driven out of wty, based upon my present UOA, I think GC in my engine (N-I VQ35) will be good for up to 20k, though to maintain a safety margin, I'll probably settle in at 10-15k, depending upon how future UOAs look. My last interim UOA (posted here) at just under 5k miles almost looked like a VOA (ultra low wear metal, strong fluid condition including high TBN, and very clean particle counts). EDIT: Paul, are you staying with the relatively short OCI because your car is a turbo? I hope you and the elves haven't developed some unresolved trust issues! [Wink] [Razz] [Cheers!]
Originally posted by FordF150: Your suppose to change your oil?? Thats the first I have ever heard of this [Big Grin]
You laugh. There's a guy over on one of the 350Z boards who has concluded that the Nissan VQ35 is so solid that after a break-in and a couple "flush out" runs of synthetic, he does not need to change oil ever again. He says he's just going to top off as needed and maybe put on a new filter once a year! My thought on that:  -
I spoke to a BMW performance engine specialist. They expressed concern that while new BMW engines running BMW spec 5W-30 by the monitoring system will have no problem reaching 100K in good shape....they are not comfortable that these engines will reach 300K like many of the engines they service that are changed at shorter intervals using the same oil. They use BMW's 5w-30 OIL but at 5K intervals. I suspect the correct OCI is somewhere between the 5K and 15K intervals...and should take into account factors like how hot , how dusty, and how hard the vehicle is driven. I realize the BMW system probably takes into account variables such as: start temps, oil or coolant temps, short trips, rpm, and throttle posistion etc. But it still doesn't know if there is a coolant leak, or a defective oil filter, or contamination. The oil life monitoring system is probably correct, but I would rather change at 50% to 70% than at 100% of oil life. I also still believe in changing oil filters and/or oil even sooner when I have driven in tough conditions, such as on dusty roads, sustained high output [ like towing, mountain roads, full throttle ], extreme hot or cold, constant idling, short trips, or bumper to bumper traffic. The best oil and filters , IMHO, add an extra margin of protection... but I want all of our cars engines to last... and to me that means changing fluids and filters midway in their service life.
Simply insane. ^^ How do people come to conclusions like that?
Agreed, good question. I should see if I can find that old thread (it was maybe a year ago or so) and bring it over here. I briefly entertained the notion of getting into it with the guy, but decided not to. It was clear from his overbearing know-it-all arrogance that that would have been totally pointless. I'm also quite sure that when his engine does finally blow up, he will be 100% unable or unwilling to see/admit that lube failure (i.e. his own stupid decisions) might have had something to do with it. [Roll Eyes]
Originally posted by Volvohead:
Originally posted by ekpolk:
Originally posted by FordF150: Your suppose to change your oil?? Thats the first I have ever heard of this [Big Grin]
You laugh. There's a guy over on one of the 350Z boards who has concluded that the Nissan VQ35 is so solid . . .

Solid my ***. That VQ35 uses toothpicks for connecting rods, the way they snap with the slightest engine modification. The performance aftermarket is making a fortune selling replacement rods for this engine. That guy obviously needs to learn the hard way.

I agree 100% that this guy does need to, and probably will, learn the hard way. In fact, I kinda wish I could be there to see the look on his face. Now, in fairness to Nissan, VQ's don't snap rods if you use them as their engineers intended. Although I don't even intend to boost my VQ, I've prowled around the boards and sites of the outfits that offer the turbo kits, single and twin. The rods are a known thing, and as long as they're properly dealt with (I'd put beefier ones in if I were to do a kit), the engine's just fine. Remember, this is a very versatile powerplant that sees service in everything from turbo 350Zs to Quest minivans. Maybe they should put better rods all of them, but that would be a waste in the Quests. But I digress. This guy's engine isn't going to snap a rod, it's going to melt down when that first critical oil passage finally closes off from the accumulated grime and sludge. Yep, I'd pay some decent amount of $ for a photo of his face as he's informed of what happened to his engine. If only. . . [Roll Eyes] [Cheers!]
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