Hi,
My mk3 has engine issues, I don’t think it has long left on the road.
I’ve heard after 2009 the engine comes with a forged crank so the big end bearing issues don’t occur anymore.
I’m wanting another mx5 but I’m not wanting to walk into the same issues I’ve had, I’ve aged 10 years in the last year just trying to keep mine going.
Cheers for any advice.
What are the symptoms ?
How long have you owned it ?
How has the maintenance schedule been ?
What’s the mileage figures in your ownership ?
Mk3 2006 2.0ltr
Had It 2.5 years
97k on the clock.
When I bought it, first thing I did was change all filters and plugs and oil and diff and gear box oil.
Then an oil change 1 year after I got it, then the beginning of this year its been none stop repairs.
Engine very loud under load and throttle pedal has a lot of vibration through it, sounds fine reving it up, just under load.
Also sounds like a dry bearing noise coming from the engine bay.
New valves and valve stem oil seals (burning oil and smoking badly), now cured.
New Big end bearings, (cured the rod knock , or what ever people call it these days).
Timing chain and head skimmed.
Piston rings
Auxiliary belt and tensioner
Battery
2 hub bearings
2nd hand cat converter.
Power steering pump
Injector.
Crank case breather pipe.
Etc etc
Cheers
Michael
Where are you based Michael ?
When changing serpentine belt, did you change idler pulley as well as tensioner 
Yeah it came as a kit. I didn’t change the water pump but I’ve span that and it sounds okay.
Based in Sunderland, good old North East.
Gosh, I feel for you.
All that work done and still the engine isn’t right…
Nope, I’ve got a feeling its crank shaft related which is why it’s the end of the line.
Not including radiator, calipers brakes.
It now needs a thermostat and a spring before it’s mot at the end of January.
I read on a miata forum that after 2009 the crank is different so this doesn’t happen.
Don’t think the “forged” crank makes too much difference. Oil level and quality and being thrashed from cold/short journeys usually start the rot.
Probably worth giving Paul Roddison a call as he knows the car inside out
Are you saying you had big end shells replaced?
The problem is when some people re build these engines they do not replace the crank (if required) and it’s common to see con-rods out of shape due to the knocking prior to re build.
If done right there is no reason a rebuilt engine will not do another 100k
I’ve done plenty
I replaced big end bearings or con rod bearings , I now know I should of changed the crank as cylinder 1 had a very light scaring mark on it, felt smooth to the touch but was slightly visible, ran out of money and took a chance, it back fired.
Lot of lessons learned I guess.
Thank you for the help.
I feel upset for you just reading this 
I have to say, if I found myself in your position right now I’d be considering getting another engine entirely, or getting rid of the car altogether and starting again with something else entirely, how much more money can you throw at it before something else goes wrong and even then, you have to ask yourself how much faith you have left in it. I ended up in a similar (though not as dire) position with my first MK3 and I cut my losses before getting too involved, it just wasn’t worth it for me… Hats off to you for going this far… I’d have run a mile a long time ago.
However, the MK3 engines are known to be troublesome if they’ve ever been neglected at all… @mk375 is absolutely right: good oil, changed regularly and kept at maximum, in addition to high levels of mechanical sympathy is the only way to keep these engines going.
The above is the reason why finding a good used lump is also not an easy thing to do… Most people who find themselves replacing a duratec will have them overhauled before install… Yet more money unfortunately.
Good luck and keep us posted as to how you get on 
I honestly just love driving my little car, I kept thinking, must be nothing left to fix now and it just kept going and going and going.
I should of walked away but I guess I was thinking with my heart not my head, just didn’t want it being crushed.
I now know I’m done and out of energy, when it dies it will stay dead and head to the scrap yard.
Not sure what to do now, finding a rust free mk2 is impossible so not sure where to turn next.
Thank you for the reply and advice.
It’s nothing to do with crank material.
‘A man’s got to know his limitations’ Dirty Harry, 1973.
Think with your head, not your wallet. Stick it on a pallet and send it to someone who knows what they’re doing.
Thanks for the tip, I’ve ran out of money and patients and luck, once the engine dies it is going to the crusher once I’ve taken a few parts off that are fairly new.
Seems a bit drastic, you’ll only get about £100 there.
I know but I’m not passing the issues onto someone else, its just not fair.
Hopefully it will last till I can get another one.
Your article was very helpful, there was a lot I didn’t know.