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Discussion Starter · #1 ·
Hi, 2 days ago I purchased a '09 Mx5 from a dealer. When I test drove it around the block, all seemed fine. On driving home on the motorway, I was a bit alarmed to see that the oil pressure needle went up to 3 increments from H, then when slowing down, went to 3 increments above L. When my Mk2 did that once, it needed oil. It seems to fluctate quite a bit between these two points. I phoned the dealer and another local MX5 dealer and they thought it was normal due to the pump working harder at higher revs. Sounds plausible but can anyone tell me why does this car does that and no other car I know of does please? It also goes to H when I first start off at very slow speed. Does anyone else's do that??
 

· Blithering Idiot
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Oil pressure will vary depending on engine revs and throttle use...

If you hammer the throttle, you'll have higher oil pressure than if you drive like an old lady.....constant on/off throttle will obviously show a rapidly fluctuating pressure. It shouldn't be anything to worry about unless the pressure is getting abnormaly low/high.....which I'm sure someone with a MK3 will be able to tell you

Otherwise, Welcome to the forum!
 

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Discussion Starter · #3 ·
Thanks for your reply......and welcome. Feel a bit happier now! Hopefully all is as it should be then. It's just that my previous Mk.2's needle barely moved from the centre of the guage in ten years, whatever speed I was doing (as long as it had enough oil), so would be interested to hear from any Mk3 owners too.
thanks again.
 

· Blithering Idiot
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The MK2 is the same as 1.8 mk1's which is basically a warning switch, which will only change under lack of pressure (as it was controlled by the pressure....i.e pressure=fine, would stay in centre all the time, no pressure = shows down and stays there) whereas the early engines gave a true reading of oil pressure measured by a sender inside the engine.

By what you're explaining I'd assume the MK3 has gone back to using a proper oil pressure gauge, which is only a good thing as it gives a better reading of what's going on in your engine


EDIT!!: After a quick look, this is what I can find, The only device fitted to a MK3 which knows about oil pressure is an oil pressure switch (you know the on off type). The gauge readout is based on a signal from the CPU, which calculated from the engine speed, temperature and the oil pressure switch. The gauge is then made to move in a way that simulates what a real oil pressure gauge would do.

So yes, it will move. But it's still using the same idea as the old 1.8, just with some new fangled electrical stuff involved.
 

· Advanced Nutzer
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The oil pressure gauge in a mk3 is a completely useless toy, mine whips around the dial (with no scale) like a vacuum gauge.. mine goes from near L to near H and everywhere in between very quickly when revving through the gears, it won't be your oil level.

My first mk1 had the best gauge, i.e. a real one, with a scale that actually meant something..

It doesn't help that the dipstick is very hard to read as well.. come on Mazda..
 

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My mk3 goes to 1 bar from h when its at 7,000ish rpm..

It moves about even more now its got the k&n oil filter and millers race oil.
 

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Discussion Starter · #7 ·
Hey, great to see all the informative replies/feedback from you all, Many thanks. I am very happy now I know it is actually normal and other people do experience it. Having owned MGs for many years and then a 1999 Mx5, these new cars take a bit of getting used to! Thanks again and if I get any other queries, I will be back!
 

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Sometimes, twice so far, I noticed that, ONLY when idling the pressure gauge indicator (1998 mk1 1.8 = so "stupid" gauge) just moves left and right like the oil pressure is not constant.

It usually stays still, always in the same position as it should and it goes back to "its place" as I give it some revs.

I noticed that if I leave the car overnight for example, it gets cold and then the "issue" does not occur anymore for a while.

Besides, while the oil pressure indicator moves about, the engine sounds normally and you would not even notice something is not right. Opinions?

Thanks in advance.
 

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The main problem with the mickey mouse gauges is that should they ever drop significantly while driving the engine will be finished by the time you bring it to a halt. That is why I have fitted the original - proper - gauge to both my 1996 Mk 1s. It moves as it should from 30psi to 70 depending on the temperature of the oil and the rpm. It keeps me mindful of the oil and reminds me to check and change it regularly. But then I started on old BMC motors.
 

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While driving my pressure is stable, as soon as I stop and car idles, after 10 seconds the indicator starts shaking/moving about up and down. If it was the sender it would play up no matter if I'm stationary or moving am I right? I changed my oil about 1 week ago. This happened once before the oil change, and twice after it. Yesterday after a trackday and today, when I got back home from work. Opinions or past experiences with this?
 
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