Is my understanding correct?

[badduxx]

I do ridesharing. I do about 3,000/ month of mixed driving with average speeds of 21-28 mph depending on the trips I get. I believe that puts this in the category of severe service. My owners manual states that in severe conditions oil should be changed at 3,000 miles using regular API, etc 5w-20 conventional oil.

Lurking on this forum and reading the articles on Blackstone's site my understanding is that as long as the oil is changed at the correct interval based on service type, protection benefits between oils are minimal at best.

I just don't want to change my oil that much especially in the winter. I created a spreadsheet to comparison shop the $/mile for several products, both conventional and synthetic. My research shows me that it appears to be actually somewhat cheaper to use synthetics over the course of the mileage they state. Even Amsoil, with it's tremendous cost difference comes in about equal with just doing SuperTech Conventional with a basic filter.

Therefore, it seems like it is a no-brainer to just buy the synthetic oil and not have to do the changes so that I can drive and make money instead for the same or less cost. But it seems to good to be true. Am I missing something here? Why are there so many people that do not go that route? Are there factors that I am not considering?

 

[PimTac]

Which make and model of car are you driving?

 

[KCJeep]

You are correct, synthetics at their appropriate use intervals are more cost effective than conventionals at their shorter OCI's. At 3k a month I question whether you are really at severe service, that certainly isn't short tripping!

You didn't say but let me guess, it's a Hyundai or KIA right? If you read their manual virtually all owners fall into severe service ha ha. On the other hand, shorter intervals may help prevent LSPI carbon build up.

 

[badduxx]

Kia Sedona

 

[WyrTwister]

I have often read that cold start ups in a cold climate puts more bad things in the oil than cold start ups in the summer .

Remember , oil / filter changes are cheap insurance .

 

[KCJeep]

Originally Posted by badduxx
Kia Sedona


What year Sedona? Ours is a 12 and it's not even direct injection, so no LSPI concerns for us. We do 10k OCI's on name brand full synthetic no problem.

 

[ARCOgraphite]

3 month interval quality oil.

The motor will let you know if you have garbage in there.

 

[bullwinkle]

Any warranty? If so, use Kia/Hyundai OEM filters, go by the book, document EVERYTHING. There's been a few horror stories lately with Kia/Hyundai engine warranties.

 

[ka9mnx]

Is your 3,000 miles stop and go? That's severe. If trips are about 10 miles or longer at <30 miles an hour I don't think that's severe.

 

[maxdustington]

Originally Posted by badduxx
Therefore, it seems like it is a no-brainer to just buy the synthetic oil and not have to do the changes so that I can drive and make money instead for the same or less cost. But it seems to good to be true. Am I missing something here? Why are there so many people that do not go that route? Are there factors that I am not considering?
Because people are old fashioned, drive old heaps that were made before extended drains became more popular or are given bad advice by those who want to sell them services. However:
1. Some engines have timing chain wear when doing long OCIs and should be kept shorter (GM 3.6)
2. Turbocharged engine with direct injection have fuel dilution issues and should be kept shorter (like 5k)
3. Some engines are hard on oil, some are not. No one really knows without doing UOAs. The engine in my car has a rep for being hard on oil but I saw a UOA on here that showed that it's not so bad. I extended my OCI to 10k km from 5 or 6 because of that.

If you're racking up high miles and want to reduce downtime to a minimum, pick an oil and do a UOA. It would probably be worthwhile in your situation. I'd be running a Fram Ultra with that amount of use, you could max one out in 8 months!

 

[blupupher]

Hyundai/Kia OCI is 7500 miles regular, 3750 miles severe.

Rideshare is another word for Taxi, and if you look, pretty much all manufacturers put taxi service in severe.

Now realistically, if you are running 5-6 hours at a time, even with the low speed average, you would probably be fine with 7500 miles with synthetic, but only a UOA could tell you for sure.
Also, not sure if the engine is a direct injection motor or not, but those could have issues if not using SN+ oil.

It all boils down to warranty. If you want it to stay in effect, then you should do it every 3750 miles, or you could just lie and say you drive all highway miles.
First thing though is if your worried about warranty, never let them know you are using it for commercial purposes, that can invalidate the warranty, so it may be a moot point anyway.
If not worried about warranty, then just use any SN+ synthetic oil every 7500 miles and don't worry about it.

 

[BrocLuno]

It's all about direct injection (DI), or not. If it's a DI engine - change the oil and pay attention to brand/chemistry. If not, DI do what you want.

 

[badduxx]

Thanks for the replies. This vehicle was manufactured in 2009 and no longer has the warranty as it was not purchased new or as certified used. It has the 3.8L Lambda engine in it. It is naturally aspirated, port fuel injected and only has VVT on the intake side. Currently, about 0.5 qts needed to top up 7500 change intervals I had done prior to ridesharing the vehicle starting in September. This seems to indicate that oil consumption is not currently an issue although the clock reads 120,000 miles.

From most of the suggestions, it sounds like putting a synthetic in and running it under the normal maintenance schedule, followed by a UOA to determine if the OCI needs to be shortened or could be extended is a conservative way to proceed.

 

[69Torino]

That vintage of Lambda V-6 has been known to develop chain slap on startup. Err on the side of caution with that engine, as I do. I also have a Lambda V-6 in the driveway. It's just turned 200k, and my wife beats the stuffing out of it. (She pulls a small horse trailer).

On a side note, I was a Kia Master Elite tech for 5 years. I've had a few of those engines torn down for chains, guides and tensioners. Always the neglected ones that got noisy though.

 

[d00df00d]

Originally Posted by badduxx
I do ridesharing. I do about 3,000/ month of mixed driving with average speeds of 21-28 mph depending on the trips I get. I believe that puts this in the category of severe service. My owners manual states that in severe conditions oil should be changed at 3,000 miles using regular API, etc 5w-20 conventional oil.

Lurking on this forum and reading the articles on Blackstone's site my understanding is that as long as the oil is changed at the correct interval based on service type, protection benefits between oils are minimal at best.

I just don't want to change my oil that much especially in the winter. I created a spreadsheet to comparison shop the $/mile for several products, both conventional and synthetic. My research shows me that it appears to be actually somewhat cheaper to use synthetics over the course of the mileage they state. Even Amsoil, with it's tremendous cost difference comes in about equal with just doing SuperTech Conventional with a basic filter.

Therefore, it seems like it is a no-brainer to just buy the synthetic oil and not have to do the changes so that I can drive and make money instead for the same or less cost. But it seems to good to be true. Am I missing something here? Why are there so many people that do not go that route? Are there factors that I am not considering?

I did a much more complicated version of that spreadsheet: mine calculates (based on a bunch of assumptions) how long the engine would have to last to justify the cost of the oil. But I think cost per mile probably gets you 80% there for 20% the effort. :]

Just remember, you're assuming that the engine will last equally long with SuperTech every 3k as with Amsoil at 20k or whatever. That's not implausible; just something that has to be considered.

Your best bet is probably something like Mobil 1 Extended Performance or Annual Protection. Whatever you can get for ~$5/qt in big jugs.

 

[StevieC]

Use a quality synthetic and keep the first couple of changes conservative and then run a UOA to confirm based on your application and driving pattern. That is the safe way to determine if the lubricant is spent or can go further.

 

[badduxx]

Quote
Just remember, you're assuming that the engine will last equally long with SuperTech every 3k as with Amsoil at 20k or whatever. That's not implausible; just something that has to be considered.


I think you have hit the heart of what I meant to ask but didn't know how -- is it safe to assume an oil that claims a 20k interval protecting the engine at the same level as a conventional oil changed 4-6 times? This vast difference is what led me to post at all. If this is generally sound it seems crazy that people would choose anything but the synthetic for convenience alone. I suppose there are a lot of owners out there who probably don't check their oil though so at least at 3k it would be filled to the proper level though.