UnknownJinX

Going bad means absorbing water in this case.

It's based on time, not mileage. Leaving the car in storage is the same as driving it 100 miles everyday. Both need to be done every 2~3 years. If you want to squeeze more life out of them without sacrificing performance, you can get the tester and see when to replace the fluid.

I'd imagine the corrosion and boiling point effects aren't very apparent to street-driven cars.

There was some green algae-like stuff in the brake lines of my old Accord, and it felt kinda spongey, so it definitely does go bad eventually. I have no idea how long it was in there, by the way.

wannawankel

UnknownJinX is correct - brake fluid has a high propensity to absorb moisture from the air [brake fluid plastic bottle and the reservoirs used are semi permeable too]. Time and rate are the factors. I have never seen a BMW brake line rust out from the inside out nor have calipers fail - this is because BMW service replaces the fluid then bleeds the braking system every two years. The fluid in the reservoir uses DOT 4 .SL6 grade (low viscosity - unless you're tracking it) fluid but it still requires the reservoir fluid to be replaced 2 years independent of the bleed schedule.

I follow this same procedure on all my vehicles and motorcycles - but I replace the brake fluid in the reservoir every year when I change my filters.

REDRX3RX8

UnknownJinX,

Ok, I see you live in wettest rain forest of the world, so maybe brake fluid would absorb water.

I live on high plains of West Texas desert where it sometimes gets 5% humidity.

We drove several 2.5 ton fuel trucks for 25 years each; we never lost or changed brake fluid on anything, and almost never had a brake job where it could be bleed.

We had and sold cases of brake fluid inside warehouse.

Only brake troubles we had were from faulty design GM vacuum boost.

UnknownJinX

Actually, where I live is pretty moist, especially in winter.

Unopened brake fluid bottles can last a while. They are packaged with brake fluid's hydrophilic property in mind.

Also, heavy commerical vehicles don't use brake fluid outside of the clutch system. They use air brakes, so air is your brake fluid.

REDRX3RX8

Medium duty trucks still use brake fluid.

Lots of them out there in GMC, F250, etc. work trucks.

Might have only 6 wheels; big duallies.

Over the road semis are mostly air brakes.

We sold lots of fuel and oil products for vehicles and machinery.

When I was young in 70's I obsessed over changing everything, and lots of things broke like fan belts, but almost no vehicles I ran had any brake seal leaks or spongy pedal.

wannawankel

For reference those same PE and PP bottles that hold liquid medicines - unopened - typically lose about 4.5 g of water to the environment over their 2 year shelf life expiry dating. For solids, we typically see about 2.5 to 7.3g water ingress into the bottle for solid dose medicines. The solid dosage depends on the what hygroscopic materials are used. That drive for moisture in is much more for a anhydrous liquid that is highly (water loving) or hydrophilic in nature. I remember seeing that unopened bottles of DOT3 and DOT4 have about 1-2 years of shelf life depending on conditions stored.

UnknownJinX

So I lost a tire because I didn't catch it in time, and even worse, I have to replace the whole set(or at least 2) since the ones I had are no longer available.

I thought for the longest time that my RX-8 have the TPMS system, but as I looked at the instrument gauge cluster more closely, I didn't see it illuminate with all the other warning lights when I turn the key to ON.

So my question is, is there a sure way to see if I have TPMS? I have read that any malfunction or attempt to bypass it will cause it to flash, but mine isn't flashing. Also, it will supposedly beep when the tire pressure is low, but I never heard one so it doesn't sound like the light is broken.

Looked at FSM and wiring diagrams and tried my best. Just need some inputs and see if I will have to buy an aftermarket TPMS system. Thanks!

200.mph

iTrader: (9)

tpms sensors have a metal valve stem cars without are usually rubber. i think all rx8s have tpms

UnknownJinX

Thanks for the input 200. I have the metal ones, and the tire shop informed me I have sensors, but if I don't need them, then I may as well save some money next time or get an aftermarket unit.

Did a little more reading on my end as well. Supposedly, if you have a car sold in the US market after 2007, it will have to have TPMS, but since it's not required by law in Canada/Snow Mexico, some cars don't have them. Hmmm...

200.mph

iTrader: (9)

ive seen a lot of sensors (working in my bros shop) damaged by idiots changing tires. if you dont know what you are doing when dismounting/mounting a tire you can break them easily, it just happened to my boss a few days ago. also where i live the salt/brine used to treat roads in winter will rust the metal stem and cause a flat tire. you can put tpms in aftermarket wheels fyi

UnknownJinX

I don't think I have ever damaged one, but good to know since I do my own summer/winter tire changes.

The thing I am really curious about is if my particular Canadian market RX-8 has a TPMS receiver built-in. I do not see the light illuminate during startup, and it doesn't look to me that the light is broken.

REDRX3RX8

I bought new my 07 RX8 GT, and some dealer had installed Enkei GF-1 7.5 x18 et38 wheels on it.

I liked the car, and the light wheels, but TPMS light has always been on.

I don't even care.

It now has some very grippy 215/40r18 Michelin PPS.

I'm old school from owing 73 RX3, and could feel deflating tire at 100 mph.

That tire had wrong core on it, and was maybe 20 psi so pulled over at night, and changed pretty quick.

Aired it up later, and used till worn out.

UnknownJinX

It's the kind of thing like oil level and coolant low light: having an idiot light doesn't mean you don't need to check it, but at the same time, it can turn into an expensive mistake if you just accidentally let it slip and didn't catch it until it was too late.

Greasyman

Yup. I was at Laguna Seca a few weeks ago and my friend, who has a Lotus Elise, experienced a spongy pedal all of a sudden during his first session, while he had me for a passenger. Yikes. He asked around for people's opinions about what was happening, and the consensus was water in the fluid. When the brakes get hot at race track speeds, the water boils off and leaves gas, which can compress, unlike water, and voila, extra pedal travel. He thought he'd have to leave, but he found that if he didn't carry a 200 lb passenger like me, plus changed his braking technique a little, he was ok for the rest of the day.

In a daily driver that doesn't see that kind of hard usage like on a track, where you might go from 100 to 50 lap after lap, you might be able to get away with a little water in the lines for a long time, but why chance it, you never know when you might decide to take a road trip to the mountains.

jimteslarx8

ticking noise post oil change from dealer

went to Tri Point and they suggest changing oil again and going to a different weight from oem because of age of car

what are your thoughts on oil weight?

Is this the cause?

car passed smog check

Previous Oil change from dealer was 5 months ago

went and had oil change after purchase

car has 93000 miles, 60000 on new engine replaced under warranty from mazda

factory specs on oil for every oil change

new recommendation is go to 20-50

Thoughts?

IamFodi

iTrader: (1)

Did they say why? If not, ask them. My bet: either they have no idea ("it just works for some cars" or something), or they'll say it helps keep the valvetrain quiet. Rotary engines don't have valetrains.

In fact, I'm having a hard time imagining what in a rotary engine could possibly tick or not depending on oil. Maybe someone better informed can chime in.

What oil did they put in?

jimteslarx8

factory spec 5-20

had the compression checked 107 105 104

ticking sound when car gets warm, not on start up

little hesitation on getting going, high end really goes

spark plugs were still good, but they dont think coils have ever been changed or wires

they said car need those replaced, auto tranny serviced, replace overflow tank because of coolant light coming on and off

Rear shocks are shot, sits real low in back, showed the shocks to me on the lift

the said I should replace all the shocks at the same time

it passed smog so they dont think its a exhaust leak after looking at car underneath

jimteslarx8

reason to change oil weight was they think its too thin when warm with this weight. This is what they use on older rx7 and rx8 cars

NotAPreppie

I can't think of anything that oil viscosity would change that would cause a ticking noise (it's not like we have hydraulic lifters in our cylinder heads).

It could just be a coincidence that the VDI or SSV actuators started ticking at the same time. They get noisy as they age but it doesn't really impact performance that much.

Simi Valley... that's LA/Oxnard area, right? If so, 20-50 is fine as long as you don't take the '8 up to Big Bear or Yosemite in the winter.

UnknownJinX

My take on things:

Oil: 5W-20 is perfectly fine if you live in an area with a cooler climate and the most you do is AutoX(~1 minute of high RPM driving, then quite a few minutes for you to rest). My car has only ever seen 5W-20 conventional oil and it works fine. UOA shows no excessive wear. I change it every 3k miles, which is a somewhat reasonable rate.

You could go higher if you live in a hotter climate or if you track your car with 0/5W-30 or 0/5W-40 since thermal breakdown will make the 5W-20 perform a lot worse, but generally, 20W-50 is way too high and should be reserved for track cars. In fact, I think a lot of manuals recommend against it if you ever see temperatures below freezing since your cold starting and lubrication can be compromised.

Here is a useful link. A lot to learn but quite helpful: https://540ratblog.wordpress.com/

Ticking sound: if it's present at idle, can you identify where it's coming from? A long stick could help you pinpoint it.

Shock: these things don't have a static service interval. You could use this opportunity to change the whole set and upgrade to something aftermarket.

Coils: service or at least check ASAP especially if you have the cat intact. You don't want it to get blocked with all the unburnt fuel.

New Yorker

UnknownJinX

If you drive like I do(spirited DD with a touch of AutoX), it's fine.

On a track, however, I have had an FD guy inform me that he has seen a lot more bearing wear with 5W-20 than XW-40 or XW-50 oils with extended track driving. Some of 8s using 5W-20 actually failed on the track.

IamFodi

iTrader: (1)

Agree with all of this except the 540rat blog. There's some decent info there, but there's also a whole lot of BS that looks valid to the untrained eye.

UnknownJinX

Such as?

IamFodi

iTrader: (1)

It's been discussed at length on BITOG. I don't want to attempt a full summary with my thumbs. But the biggest problem is his test method. He has taken the details off his site since I last saw it, but basically it's a homegrown extreme pressure tester -- poor repeatability and almost no relevance to what happens inside an engine.

If anyone cares, I'll type more when I have time and a computer.