power steering fluid

If the level has dropped, it has leaked out. Probably very slowly, or you would notice the pool of fluid where you park.

The first thing you would notice if the level drops to a critical point is a groaning noise as you turn. This is caused by cavitation at the pump. The second would be a grinding noise as the pump runs dry, and the bearings and other parts are no longer lubricated.

It lasts a very long time, you don't have to get it changed because at some point the rack will need replacing and that will involve new fluid. It differs from other oils according to the requirements of the system, ie it is not subject to extreme temperature variations like engine oil. We trust the engineers got it right.

Steve

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A very full and accurate answer, to which I would just add that unlike brake fluid, it doesn't adsorb moisture from the air so doesn't self- contaminate.

Chris

If the fluid drops too far you lose the assistance. Won't do any damage provided you top it up immediately. But don't drive it like this or run the engine. You'll normally get a warning of the fluid being dangerously low by groaning noises or a slightly rough feel to the steering caused by cavitation in the pump. Before it stops working totally.

If the level is dropping quickly, you have a leak somewhere. A tiny amount of leakage is normal - such that it only needs a small amount at service times.

The fluid is normally automatic transmission stuff. Make sure you use the correct one as there are several and mustn't be mixed. Check the handbook for the correct one.

Most/all use ATF fluid I think.

It should be changed about every 3-5 years / 60-100K miles. Along with transmission oil. There should be "hot" and "cold" marks on dip stick as fluid will expand when hot.

As with any ATF fluid, if it isn't clear, clean and pink, it needs changing. Some cars may use other oils.

[...]

Neither of those things have been on the service schedule of any car I've owned that's had power steering. Equally, none of them have had a dipstick for either PS fluid level, or for the transmission oil.

Chris

My 2003 Focus (auto) had both a transmission fluid level dipstick, and a PAS fluid dipstick. The PAS dipstick was incorporated into the resovoir cap. In fact, I've never (AFAIR) had a car with PAS that did not have a dipstick, and I've had around 45 cars. The vast majority were bangers without PAS though.

[...]

Neither my '99 or '03 Focuses have a dipstick for PAS. (They went out of fashion when translucent plastic was invented!)

Of the half dozen or so Focuses within my family that I've serviced, none has had a PAS dipstick. In fact, I repeat, I've not seen a PAS dipstick on anything tolerably modern.

The owner's handbook only makes reference to checking the minimum and maximum levels marked on the reservoir, as does Haynes. So does this:

You can just about make out the level lines on the outside of the reservoir here:

Are you sure you had a Focus that had a PAS reservoir dipstick? Perhaps with 45 to choose from, you might be mistaken?

Either way, there is no scheduled change for the fluid...

Chris

Lots of cars still have dipsticks on PAS lids. A few even still have dipsticks for manual gearbox oil. It is still mercifully rare for autos to NOT have a dipstick, although there are some. Quite a few have dipsticks for washer fluid, although they never seem very successful, and of course older vehicles had dipsticks for fuel tanks.

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I obviously don't see as many cars as you, but what about a Focus?

Blimey Mr C, you're going back a bit now!

Early Beetle?

Chris

With the possible exception of the Focus, all (that I can remember) of the cars I've had with PAS in the last ten years (5 BMW, 2 Audi, 1 Daewoo, 2 Peugeot have PAS dipsticks in the caps.

Now you have me wondering... But I'm sure it had one, that ebay picture is not familiar. I don't have the car now.

Unfortunately, neither of my current cars (both automatics) have transmission fluid dipsticks.

My BMW is 14 years old and never needed one. It doesn't leak unlike my other auto.

I was thinking MG ?

Not sure what you have but the dipsticks are the speedo drive.

Later cars have a "sealed gearbox" which you get the auto fluid up to temperature and pull the plug to drain excess.

some cars have sealed for life auto boxes, some must have dealer equipment to check or top up level.

I have never come across one, but the tanks of all of the recent cars I've had, have been quite large / hidden in the wing and have had a low fluid level warning light on the dash. My current one turns of headlight washers, when the level becomes critical.

They can have a fill plug on the side which also gives the level. All that's missing is the drain plug.

Still standard on generator sets, nobody ever trusts the guage :-)