Hey Gang
Quick question on a L98/TPI and Mobil 1.


I picked up the car at Christmas (145, 000mi) and changed the oil to Mobil 1 full synthetic. I changed the oil again last week at 5,000miles (150,000mi).


My question is should I continue oil/filter changes at 5,000miles or is 7,500mile more in line with full synthetic?




Jonathan.....

 

What does the oil analysis say? That is what your question should be. Spend a little money and see if there are issues, whether the oil change is justified, etc, etc. It might be 5000 or 15000 but without analysis, it is hard to say. Also, if something is wearing out, it could show up in the oil.

http://www.blackstone-labs.com/

They are a decent one. Did it with them and they told me that 7500 was too much for the oil I was using in the diesel truck. Recommended was 5000 and there was nothing foreign in the oil in weird quantities.

 

Nothing wrong with a 5000 mile oil change interval and you could easily go to 6000 miles intervals if you so choose.

At that odometer mileage, you may want to consider using the Mobil-1 5W-30 High Mileage oil. Definitely use a good quality oil filter at each change.

 

If it bugs you change just the filter mid way
Oil is cheap do whats comfortable for you

These days I use whatever oil is cheap and a good filter esp on a high mile motor dont think it matters at a point.

 

Fundamentally - Oil is pretty darn cheap ! The cost for 5 quarts of M1 and a good filter is less than $37, To my way of thinking - trying to extend the oil change interval to 7,500 miles is just not a reasonable way to save money.

If you really feel that you must save money - I would think that there are other things that you could / should cut out first. Just my $0.02.

 

Well, you are correct from that standpoint. However, what you failed to consider is how many miles he MIGHT drive which dictates how often he has to change oil. I drive quite a bit as soon as I can and even in winter when there is no snow on the ground. Therefore, the difference between 7500 and 3000 or 5000 is significant in BOTH cost AND my time. Oil change means I have to jack up the car, drain the oil (comfort depends on weather conditions) clean up, install filter and fill oil and dispose the oil. You can dump the filter in the garbage but I wouldn't just dump the oil down the drain. So, what is your time worth? At 15000 miles, it is the difference between 3 or 2 oil changes. Time and money again.

OTOH, if all he does is putz around for a few miles on the weekend, you are correct. One oil change more or less in a season isn't too bad.

Kinda why I also suggested a UOA to really see how far he can stretch it. Or he can guess based on good hopes and our guessing.

 

I certainly understand that time has a value, and yes, disposing of old oil can be somewhat of a pain (where I live - if a retailer sells new oil - they have to accept used oil - so pretty much all the parts stores and Wal Mart do accept used oil). I do a lot of oil changes every year (10+) on a number of vehicles - so I typically wait until I have 4 - 5 gallons of used oil, and drop it off at a parts store that I use.

One other thing to consider though is that when you're under the car - you probably look at a few things and tend to notice things like small leaks, damaged rubber boots on ball joints & tie rod ends, torn CV boots (obviously not on a Vette) etc. etc. etc., and there is a value to doing that as well.

Many of the car makers and oil companies have gone to oil change intervals of 10K - 15K miles. Unfortunately - IMO while filtration and oil formulation technology have certainly improved over time - the big driver for the oil change interval increase certainly seems to be more sales pressure related than technology related. Most car makers are now offering some variant of free maintenance for the first so-many miles, and by raising the oil drain interval - that service costs them less. Since so many cars today are leased - there is a value to the dealer to be able to say that the off lease car they're now trying to sell, has been regularly serviced by the dealer....

Most of us who turn our own wrenches have had the opportunity to open up an engine that has been well maintained, and it is amazing how clean an engine that has had frequent oil changes looks. On the other hand - if you have opened up an engine that has not been maintained, the amount of sludge and crud on the parts can be amazing. While I won't say that 7,500 mile change intervals with synthetic is stupid long, I do not think that saving a less than 40 dollars in oil changes every 15,000 miles makes much sense from a financial perspective. Then again - I don't think that using "Jiffy Lube" or any of the fast oil change services makes sense from either a time perspective or financial perspective. The OP wanted opinions (oil analysis would give him the best opinion, as it will be completely fact based - but very very few individuals do that) so I presented mine, to do with as he wishes.

 

Good point.

Yep. IF they had to go with the old 3000 mile change, they might lose a lot of money with the "free service for 3 years", etc. At this rate, they still get you in.

I have seen a lot of sludge and crud on the parts but never inside except on a motor in a junkyard so IDK what the story was. I have gone as far as valve covers and intake manifold and head but thankfully, mine don't have sludge. Milky stuff when the gasket leaks, yes. Other than that, I often use Engine Degreaser when I do something that spills oil around, clean it and then put dye to be sure.

When I had to drain 4 gallons from the Powerstroke and the filter was a B1TCH to get off because of how tight it was and this was the middle of winter, I went there. And you can bet your last dollar I was watching each and every move they make. Lying on the cold floor with diesel oil spilling around isn't my idea of fun. The 2 and soon to be 3 MBs I have are fun. Topsider to suck out all the old oil, take the cap off, replace O-rings and filter. Reinstall, fill. Don't even have to get under the car for that. Very nice in winter when you are in a warm garage.

IIRC, my service manager friend from a Ford dealership told me that from a strictly financial transaction, and oil change, after all is said and done, will COST them $3. Where they make the money is in the upsell. Jiffy Lube wanted $10 to do my CHIMSL. 2 screws that are in the open and a bulb. Sure. Want my kidney and lung to go with that? I got 2 of those and can spare 1. Jiffy lube's target is about $80 with an oil change. Then they suggest air filters, oil filter, oil, trans service, radiator service, Wallet and my butt service, etc.

For my 4 gallon powerstroke, I just drain some of the oil out of the Fumoto valve, catch the mid stream stuff and seal in the container they give me. Get postage and they tell me how worn the oil is and how long it can last. Also, they give an indication if your bearings or something is wearing out from the analysis, IIRC, maybe $20 or so?

PS. I prefer the Fumoto valve simply because it is less likely to strip the pan threads. Now, at the shop I just say "DO NOT REMOVE THE DRAIN VALVE USE THE TAP TO DRAIN OIL." Even without, I make sure you don't do it by any air tools.

 

Hey Gang
I'm not worrying about the cost factor. If I was, I wouldn't be using the synthetic oil. I'm not looking to waste money either.


I'm looking at what is best for the car.




Jonathan.....

 

I change my oil every 10,000 miles

 

Do a check on the oil. If brand A is worn out by 6000 and brand b is worn out by 8000, buy brand B and change at a lower interval to be sure.

 

Here is another way to do it.

I was talking to my friend that owns a garage about this. He told me that a customer told him that he his brother, a janitor at a well known oil company was cleaning the men's room when he heard engineers talking about the Oil Change Interval. The general consensus was at 6398 miles, give or take 10 was the right answer. My friend tried it on his customers and was amazed at how clean and long lasting their cars were.

And to add truth to the anecdotal story: I tried it myself and have been doing that for the last 5 years with NO PROBLEMS, whatever that last part means.

 

Were they talking about conventional or synthetic oil?

 

Could be any fluid you want. Number is as good as any you hear. Until you have tested it, all you really have is a SWAG made by someone that is passed on and on and on.

 

i use quaker state defy. every 7000klm. which i think is 4396 miles. i buy it when its on sale and my oil filter changes cost me less than 25$ and 30 min.

 

Then you are fast and cheap. I get the K&N filter for $15 because of the nut that allows me to unscrew it easier and with that kind of oil is $32 around here. I can't even get that sort of time for my MBs which doesn't require the car to be lifted. With those, I have a cartridge style filter and a wrench takes the cap off, pull out cartridge and replace and screw it back on. After that, I have to fill it, run for a minute and let it settle down, check level and then wipe off any spills with brake cleaner. Oil removal is done by topside which sucks oil oil out but you spend time to get the air compressor up to pressure. Dump oil into cans and bring it to Autozone or something.

 

And I change mine once a year. Unless I've run over 5000 miles.
No reason to leave the contaminants in there for more than that.

0.02

 

used oil wise, im looking at these guys who have converted a woodstove to burn on used motor/trans/gear oil. ive got 4 cars and im **** about oil changes. i create alot of oil over the warm months which i could use to keep my shop warm. pretty amazing actually. to think ive thrown all this free heating oil away over the years and then turned around and payed for natural gas.

 

Depends on your situation. If you are a garage and do oil changes all day long, I agree. OTOH, I have 4 vehicles, soon to be 5 and planning for one of them to be finally dead at 480K. The powerstroke dumps about 3.5 gallons of oil but I don't use it very much. The Vette I use more in the summer and dump maybe 8 gallons, give or take. The other cars are about 6 or 7 gallons a year. So even at 40 gallons a year, I am not sure if I can make a oil furnace pay for itself. It costs what it costs and there is the time to install that I have to pay for plus the uncertainty of the oil supply.

 

To the OP, I think your L98 has an oil cooler which prolongs the life of your oil. Running conventional oil you should change it every 5,000 miles. But with good synthetic oil you can safely go 7500 miles, assuming your engine is in good shape and your driving conditions don't fall under "severe service."

I run Mobil 1 EP 5w30 oil and Mobil 1 EP oil filters in my 1995 LT1. With the annual oil rebate and the discount oil filters from Rock Auto ($3.25 each awhile back), I pay about $18 per oil change -- still feel like I'm robbing somebody.

I change annually or every 7500 miles, or sooner if the maintenance light comes on. So basically I follow the owner's manual. I drive it several times a week and the oil lives an easy life with my driving conditions -- no short trips or cold outside temps -- so I am fine going 7500 miles, plus the manufacturer says so :-)