After some spirited driving yesterday (on track, I hasten to add), I lost a fair bit of PAS fluid out the top of the reservoir. Is there a certain spec of fluid I need to top it up with?
 Power steering fluid is the same as Auto gearbox oil, red in colour
You should be be able to pick some up at your local auto factors, or petrol station, most oil Co make it.
M-m
Hi Mazda Mender,
will the above power steering fluid work on my mk2? Manual says I need dexron-II or equivalent ATF M-III spec, and Halfords has suggested the following -
Iâve had my MX5 2 weeks and donât really know much about cars!
Cheers,
G
You shouldnât really be losing any fluid, so the cause ought to be investigated by the supplying garage.
 Thats the stuff, but like AT as said if you are loosing fluid, a lot? then she does need to be looked at.
M-m
my experience of driving an MX5 on track is that loss of power steering fluid is very common.  Iâve seen it on many MK1s after a hard session. With two of the 5s Iâve spent time driving on track and also on spiritted road driving I have never seen it happen on the road, however hard you drive.  I guess it just over heats and boils when run proper hard as you do off the public highway. Top it up and move on is all Iâve done.Â
I suspect âgd201â hasnât been on a track with their MX5 yet. Power steering fluid is unlikely to boil; you are referring to what are now elderly cars, still using original seals (cheap, made to a cost), that are now failing. Power steering fluid can overheat, and cook, and loose some of its viscosity, I guess through heat cycling. If a MX5 has ever been that driven hard that its âboiling awayâ (I say its leaking away), maybe you ought to consider upgrading your PS fluid to one more suited. Redline and others do suitable products. If power steering fluid is boiled, its pretty much wrecked, and needs changing. The most likely scenario for the fluid to actually boil is if its low to start with. If evaporative losses were to blame, I suspect Mazda wouldnât use the kind of dipstick/lid that it does, and/or theyâll be using a PAS cooler. If its low, you might also have a foaming issue, which might cause a mess, but thats not boiling. Iâm not convinced that 20 minutes on a track, with a few corners interspersed with straights will cause boiling of the power steering fluid.
On my 91, I did start to experience very small losses, after a long drive; I traced it to a failing seal. I decided to take a chance with STP power steering Stop Leak; nothing to lose, as if it didnât work, I would be tearing down the rack anyhow. Worked like a dream.
 Well i have to agree with AT that if it boils???then there is something else wrong, and i think the mistake is coming from the fact that it would be more frothing up (tiny little air bubbles), either from the fluid being low in the first place or being drove wrong? then boiling over.
M-m
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It is pretty common for power steering fluid to boil on an MX5 Mk1 or Eunos during hard competion such as autotesting, my own V-Spec did the same on an autotest last year as can be seen when the PAS stopped working effectively around the third cone in the centre row shown in this video
The answer to your problem Steve is to fit a larger aluminium PAS resevoir (have seen them advertised via TR Lane here)  or introduce cooling finning to your existing or install a cooler in the fluid return pipe
Or just stop driving like a hooligan!!!
Dr. Eunos
Thanks for the link Dr Eunos. If I continue to have problems I may invest it one of those.
Iâve only experienced PAS fluid leak after some hard track driving; never on just road driving. It was fine after the first 20min session and only âboiled overâ after 3 or 4 such sessions. It looked quite bad in the engine bay but it must spread very thinly because the fluid level had hardly dropped when I check later that day. It was just below full, so I didnât even bother topping up.
Cheers for the advice everyone,
back studying on the other side of the country from the supplying garage now 
Took my mazda to a local specialist, new hoses required apparently as mine are leaking - hopefully covered under the warranty I got from the supplying garage!
Again, fairly common, especially on Mk2s the lowest pipe tends to corrode through where it joins the rubber hose on the return to tank, have done several of these pipe replacements for Mk2 owners, pipe should be around £30 + Vat from Mazda Dealer, fitting is about an hours` labour plus a refil of new fluidâŚ
Dr. Eunos
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Yup, checking the boiling temp of common garden variety power steering fluid; 425F. If the PAS oil is really getting to this temperature constantly and repetitively, then it is degrading (oxidizing), and needs to be changed; the fluid not only provides for the hydraulic action (if viscosity changes, the assistance changes), but also maintains the pliability of the seals. If drivers really are checking the PAS level EVERY time they hit the track (they donât, that I know), and that their PAS fluid is always to the MAX, then I suspect they are seeing foaming, because the story I am gettingis that once things have cooled down, everything is fine, and on they go. Of colurse, on they go, using the same cheapo fluid, probably never ever changing it, and then they whine when the seals starting failing. Get the right fluid for the right job; if you spend all your waking hours on the track, prepare the car appropriately, with the same effort as people go through endlessly choosing the right oil or the right pads. Most people, myself included, donât really pay all that much attention to exactly whats in that PAS reservoir.
(drifters may well get boiling fluid, but then, that sort of motorsport really rags the steering, unlike other forms)
 Sorry to bump this one up again - but Iâve found some ATF Type G in the garage, just enough to top up. Will this be OK. I donât want to mix up the fluids.
89 Eunos.
Â