The Oil Life Rule of Thumb

Yup, brake fluid is hygroscopic, it absorbs water from the atmosphere.

The thing is, unless yo uare constantly opening up your brake resovoir, where is it geting new moisture from? Most resovoirs these days have a screw on lid that seals pretty well. Yeah, my old Toy truck have a sort of pop-on rubber thning, I can see that not being air-tight. But the one on my car tightens enough that it almost takes a tool to get it open.

You know, we have a vacuum oven at work. I'd be really tempted to take in 2 bottles, one that is new, another that was opened a year ago. Pour some fluid into a jar, weigh it. Then bake it at 100 c for a few hours, and weigh again. That would tell how much water was in each one...
 
Also - power steering fluid is unquestionably the most overlooked and forgotten about fluid.
 
re: oil intervals - the stated rule makes a hella lot of sense.
However, it requires keeping up w/ your average mileage, and then doing oil at some unusual numbered interval. Great if your a record keeper. Terrible if you're a slacker like 90% of people.

For everything except my new car, we do oil changes and tire rotations on 5k intervals ending on 0 and 5. Why? Because I can look at the odomter and say, "Oh its time to change the oil by about next weekend".
Mathematicall this maybe costs be $30 more annually than doing it according to the stated rule here... and for $30 I'd rather do what's easy to ensure it's done.
The new car I actually keep meticulous records and for the first 75k or so I'll do the dealer schedule of 7,500. The nswitch to this rule.
 
RatLabGuy said:
Also - power steering fluid is unquestionably the most overlooked and forgotten about fluid.
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I had a 2003 chevy 2500hd that had a small power steering leak on the return side. For some reason, I took it to the dealer in Shallotte, NC while I was down at the beach and had them replace the line and bleed/flush the power steering system. I could not believe how much of a difference it made. The sharp turn whining was gone, and it just felt better throughout the entire range of motion.
 
RatLabGuy said:
Also - power steering fluid is unquestionably the most overlooked and forgotten about fluid.
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Also likely the hardest one to change. Flushing out the box could be a bear without taking it apart.
 
rcalexander105 said:
Sticking w/ my every 5k on the 5k
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RatLabGuy said:
For everything except my new car, we do oil changes and tire rotations on 5k intervals ending on 0 and 5. Why? Because I can look at the odomter and say, "Oh its time to change the oil by about next weekend".
Mathematically this maybe costs be $30 more annually than doing it according to the stated rule here... and for $30 I'd rather do what's easy to ensure it's done.
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Ya don't say...:cool:
 
paradisePWoffrd said:
Also likely the hardest one to change. Flushing out the box could be a bear without taking it apart.
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I've always wondered why it isn't typical to have a drain valve or some other easy way to flush PS Fluid. Every vehicle I've owned ypu have to either disconnect a hose or suck it out the reservoir.

Its like the engineers are begging people to not flush it.
 
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RatLabGuy said:
I've always wondered why it isn't typical to have a drain valve or some other easy way to flush PS Fluid. Every vehicle I've owned ypu have to either disconnect a hose or suck it out the reservoir.

Its like the engineers are begging people to not flush it.
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Along with cost, might be the reason why many cars are electric assist steering these days.
 
It's real easy if it has hydro boost. Pull the return line off the booster, run a line from the hose barb on the booster to a pan, crank it all the way left and pump the pedal, all the way right and pump the pedal, and repeat until the fluid coming out is clear. Obviously, keep the reservoir full during this process.
 
paulevans76 said:
I've got a '11 suburban 1500 and an '07 camry, both renowned oil disappearers. They each get topped off so often I never really need to drain it, just change the filter once or twice a year.
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That suburban still have AFM? My mom has an '07 that has 160k miles or so and was using a good but of oil. Turned off AFM in the tune and the oil consumption reduced dramatically.
 
LBarr2002 said:
That suburban still have AFM? My mom has an '07 that has 160k miles or so and was using a good but of oil. Turned off AFM in the tune and the oil consumption reduced dramatically.
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I haven't touched that yet - assume it would be part of a tune. First thing I did was buy the updated valve cover they made for these, and when I pulled off the existing cover, it was the same PN :rolleyes:. It typically consumes between 1/2 - 3/4 qt every 1k miles depending on driving. Not sure if it's worse doing highway miles or around town.
 
mbalbritton said:
no need to think about it when it’s a sealed system.
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Which of them isn't technically a sealed system?
Maybe oil, b/c the dipstick isn't really sealed?
 
None of them are sealed if they have a breather and open reservoir.
 
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