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Oil changes: How often do you need them? (Marketplace)

Oil changes: How often do you need them? (Marketplace)

(…and the possibility of unintended consequences…?)

You need them at least as often as stated in your owners manual. At a minimum that will preserve your warranty. After the warranty expires you are free to do as you please. But I would still follow the manual or even more frequently.


The results of not following the guidelines results in premature engine failure.

Actually a pretty good report from our Canadian friends at the CBC. Proves yet once again people don’t actually read their owners manual.

Recent experiences with OLM’s in my cars. I drove the Mustang 10,000 miles in 12 months with 6 track days in that time. My OLM said 39% when I changed the 8 (eight!) quarts of oil. I was surprised it was still that high. Maybe because much of that was highway and it doesn’t freeze where I live.

Similar experience with my Chevy truck with fewer miles. I don’t think I’ve sen the OLM light (light only, no read-out) in 2 years and 6000 miles.

My wife’s departed Saab would throw the light at 12 months but it had a calendar built into the driver’s info system.


We’ve been down this road many times already. I don’t dispute any of this but I change my oil on both cars right around the 50% OLM point. It’s a $35 expense versus a $5-10,000 engine. And it really doesn’t bother me if I’m wasting money. I’ve never (outside of the diesel) had a major engine failure and my last one still used no oil at 530,000 miles. So who am I gonna believe, me or them?

I imagine I probably change my oil more than necessary. I do a 5k mile interval on a 2005 GM 4.8 and 3.8. The oil monitor tends to suggest closer to 10k. I also do a 5k mile interval on my wife’s Toyota 3.5 V6. It has no monitor, but the manual recommends 10k or 12 months. It’s always been strange to me that different manufacturers have different requirements- some have a algorithm that monitors engine speed, idle time, etc. Others have no such monitor, but more of a blanket recommendation. So driving style and driving conditions either matter or they don’t…it seems odd that Toyota’s recommendation doesn’t seem to factor it in at all, yet the oil change interval is pretty much the same as GM, per the monitor and my driving conditions.

The oil change interval is a debate that will never end. I imagine going by the oil life monitor (or Toyota’s 10k mile suggestion with synthetic) would be fine. I just fear the outlier engines. “Oh the recommendation would’ve been fine, unfortunately we found out this engine is prone to developing sludge.” Also odd that Ford seems to use the same oil life monitor on all F150’s. Surely the oil wear must be different for a twin turbo, direct injection V6 running 5w30 than it is for a 5 liter V8 with port (pre 2018) injection running 5w20? But I’d bet money the same algorithm is used across the board. So I’ve always been a bit skeptical.

The main consequence of people following the extended interval will be engine failure. Not necessarily because they folowed a longer interval, but because they assumed the oil level would remain constant over the 10k or so mile interval. And it didn’t.

Since we keep our vehicles on average over 300k miles I’m not a fan of the extended oil change intervals like my Highlander has. Too early to tell if 10k oil change intervals will allow me to reach 300k miles. I know 5k mile oil change interval will. Not enough evidence for 10k oil change intervals are good for long mile engines.

I agree. I suppose the best approach (if you cared to extend the interval), would be to extend the interval once, then send that oil off for analysis. I assume they can tell if the oil is still good rather than just measuring wear metals. But like you, I’m good with the 5k mile oil change. Gives me a margin of error.

I’ve got about 140K on my Pontiac now so I think I’ll do an oil analysis again just for the fun of it. I think I did one before at about 90K. I guess it would be interesting to not reset the OLM sometime and see what mileage the thing would actually go to before getting down there. I dare not do it on the one under warranty though since I suspect the cloud knows. I know OnStar knows but big deal, it’s all on my dime anyway now.

I’m not a big fan of the oil analysis because the results will change over time/mileage. So in order to get the best results you’ll have to constantly keep doing them to make sure the 10k oil change is still good. The cost then will exceed the cost of 5k oil change intervals

Yeah I think the cost is about the same as an oil change, somewhere around $30. I’d do it more of a check on the engine condition though rather than the condition of the oil. I wasn’t real thrilled with the information analysis last time though. Pretty much what I already knew.

On my previous Mustang (03 with an aftermarket supercharger), just out of curiosity I sent in a sample to Blackstone. It was Pennzoil Platinum with 5k miles on it. The results were about what I expected given the mileage of the car. The gist of it was that it would be safe to keep the oil in the car for another 1k-2k miles. I just kept changing the oil every 5k miles as it was easier to remember. On my current Mustang I haven’t had an analysis done yet, but with the coyote’s larger oil capacity (8 quarts vs. 6 quarts), and the fact that it’s N/A at the moment, and has a reputation for being easy on oil, I would guess that it could probably go 10k miles without issue. With that said, so far I’ve been doing 6k-7k oil changes, as I have something of a mental block about going 10k miles between oil changes.

I’m more interested in seeing how well oil holds up on my Ecoboost V6, between the D.I. and twin turbos, it’s bound to be harder on oil than the N/A V8 is.

Many of the replies so far involve owners who keep their vehicles for a long time (e.g. 300,000 miles).

But what about the average new car owner who only keeps a vehicle 6-7 years and drives 12-15K/year? (based on whatever stats you want to believe). Why shouldn’t they follow what the auto manufacturer recommends?

IMHO it is perfectly OK to follow manufacturer recommendations for the person expecting no more than 100-150K out of his vehicle

the trouble may come from “set and forget” attitude, where owner does not check the oil level and new/thin oils burn out more over than long change intervals

my daughter’s coworker recently drove her car literally to the ground, had engine seize from no oil on highway: she was 100% sure that she has to do nothing in that 10K miles until the next service, warning light was too late to give her any warning, which she ignored anyway as she wanted to address the issue “the other day”

I have seen reports (as you probably have also) that the EB motors can sometimes dilute the oil with fuel. I believe the new engines are all DI and port injection combined. Previously the EB was direct injection only, 5.0 port only.

If you planned on trading at or near 100k miles, I don’t think following an extended interval would be an issue. If I planned on trading before the warranty expired, I’d definitely follow the oil life monitor. Nothing to lose.

How do the results change, assuming you’re driving style and conditions are still similar? It seems like if at 10k miles, the oil still had life left in it this year, results would be the same 3 years later. Although it might be good to do one analysis in the dead of winter and one in the heat of the summer.

I’m just asking, not arguing. I know people do take oil samples on one or two extended drain intervals and consider the results to be a baseline for when they should set their oil change interval. Just curious why this would be incorrect.

I’m too lazy to send oil samples off, myself. I just change it at 5k to cover the bases. Plus 5k increments are easy to keep up with :+1:

What are you doing to your cars that one 10,000 mile oil change would be fine but the next one wouldn’t be?

I get that the engine will wear over time, and maybe it would be wise to change the oil more frequently when it does, but I don’t see how that manifests in a “constant” need to keep testing the oil.

I’ve never understood using an oil analysis to check on engine health in a passenger vehicle. If you have elevated iron levels, for example, what’s the next step? Tear into the engine? Seems like by that point you might as well run it until the problem becomes obvious. Then tear into it and repair it.

Not arguing that it’s a bad thing to do. Just curious what you do next, after you get the results.

I suppose it could be useful trying to diagnose a loss of coolant. You could at least see that it is getting into the oil, for example.

The only thing I’d use a used oil analysis for is to see if my oil change interval is too short or too long.