At 94000 this now needs to be changed, but I thought perhaps this is a sensible time to deal with other things in the vicinity?
Your advice much appreciated
Paul
I would do the water pump at the same time.
Change other belts - power steering and alternator. Crankshaft oil seal. Cas o ring while cam cover is off - easier to replace because you can see the slot in the camshaft. Coolant hoses if ropey.
I replaced the idler wheel, tensioner wheel, camshaft oil seals (2Nr not surprisingly) cam cover gasket and accessory belts. If mileage is high and it hasn’t been done before the water pump too should be changed. Often when you see a keen price at a garage for changing the timing belt it is just that - the belt only.
All of the above makes a lot of sense
Dr. Eunos
There is a school of thought that you are better leaving the original Mazda idler, tensioner and water pump rather than replacing with inferior aftermarket parts. Be interested to hear what others have to say about this ?
It isnt a school of thought worth considering
the general consensus is that the water-pump will probably last about 120,000miles on average or approx 2 cambelt changes, trouble is that its getting very marginal as to whether it will last until the second change. Tensioner and idler bearings certainly do not last forever, they wear out and also require replacement if you want to keep your reliability…
Dr. Eunos
This sort of decision has to take into consideration annual mileage. Say, at the time of cambelt change, that the water pump is only going to last another 40k (rather than 60k). For me that is 8 to 10 years use. I do not want to change the water pump 8 or more years before I need to. For me, I would not even change the pump at the second cambelt change, unless it was showing signs of distress, but then I do all my own work on the car so no labour charges to worry about. If it fails while I’m out and about I have breakdown recovery to home, and I’m retired so haven’t got to be anywhere by a particular time. That is a breakdown isn’t going to be much of an inconvenience. Its horses for courses.
Alan
Hi Alan, in a way you do have a point but the problem is that unless you have owned the car from new, or the previous owners have documented milages against previous work on the car, you really don`t know what state everything is in on the car.
Personally I like to have full reliability in my car (replaced the engine and box a couple of months back, before they gave a problem) it is very well having breakdown assistance to call on and the luxury of not needing to get anywhere at a particular time but the problem is that too many people will run a car into the groundby not keeping on top of everything and then expect to travel long distances one special weekend or even to nipaccross the channel` only to have thier trip ruined by something that should have been replaced at service time.
I have just bought European Breakdown Cover at £92.00 for a year and my car probably represents a pretty low risk to the likelihood of needing recovery back to home from our forthcoming Nurburgring on a Budget trip, because it is regularly serviced correctly. Cant help thinking I may be subsidising the owners of cars who skip replacing parts when needed at service time in an attempt to save a few pounds, and that is annoying.
See what I mean?
Dr. Eunos
I would tend to agree but posted my comment as several well know MX5 professionals disagree. I look forward to further comment on this as it really is what this thread is all about.
As the engine in non interference, so will not self destruct if the timing belt snaps, a lot of owners do not bother with the expensive belt changes and associated work. I imagine that belt, tensioner, idler, water pump change is going to cost over £300 - expensive work on a car worth £600 - 800.
Hi Taff
I was just putting the other point of view, in many ways I do agree with you, especially if one is paying for labour. In fact, arguing against myself, when my clutch hydraulics failed I replaced the master as well as the slave to save messing about later. I also take your point about subsidising the breakdown cover of those folk who do not service their cars. Mine are serviced and the MX-5 has not stranded me in 5 years ownership and my other car only once in the last 10 or so years with a faulty crank sensor. Its replacement recently showed the early signs of failure again (I now know what they are), so that has now been changed as a precaution. See, in essence I really do agree with you.
Regards
Alan
Don’t take that for granted, you can still get damage, I agree with taff, makes no sense to just change the cambelt only and hope and rely that it’s ok because i have read it’s an non-interference engine on the forums, the number of times owners have been here and not listened to what i had said when it comes to this change and penny pinching, so you do the cambelt and 20,000 miles later the old water pump gives up and then double the charge again, one of the worst things that can happen to these rock hard engines is over heating, for the sake of penny pinching, you can end up with a bigger bill than just changing a water pump at the same time, try towing in and a new engine, i am with Taff…piece of mind and as for after market parts, thats all down to which parts and maker you use, some are just rubbish where as others are the same and some are even better than mazda parts.
Who are the several that say this???
Most of the info in this thread is correct in my eyes about what needs to be changed at the same time, penny pinching does not work, but as for Mazda or after Market parts, mazda parts are not made by Mazda, but are bought from outside of the Co, so these makers can sell the same parts under their own name a lot cheaper than having mazda printed on the box, which I do not see a problem with, if owners wish to pay over the odds for their parts, then that is up to them, but owners like myself, Andrew at Autolink and Carl at CBS Autos will always give the right info to help other owners to keep them fixed and on the road/track at the correct cost, so the owners do not end up with empty pockets and with the right parts, if we would not fit them to our Roadsters, then we will not fit them to other owners Roadsters, if we do not like a part an owner has brought to us for fitting, WE WILL SAY SO, like Raceland coilovers for one.
But at the end of the day it is down to the owner and what they want, we can only advise and point them in the right direction.
rhino666…bring your roadster to me that is after market stuff free???and I bet I can show you some that is on her, 95% of the Mk 1’s (more so) and 2’s have on them after market parts now, unless some one as been sad enough to have bought one from new,goes to a Mazda dealership every year for service/look over and is not used and stays in the garage as a show piece.
M-m
Hi Wayne - interesting post - hope you are having a peaceful Sunday 
Would imagine that the Ma5da racing MK1s could sustain valve to piston damage but only because of the skimmed head lessening the clearance. Please find me an example of a MK1/Eunos, standard spec that has had engine damage as a result of a belt snapping. These are well know to be non-interference engines where by definition damage will not occur.
One of the several that do not automatically replace some or all of the components discussed are the establishment at Nuneaton, mentioned on one of my threads but there is another and possibly a third from memory, who is not too far from home.
No key aftermarket parts on my car apart from the coolant radiator and cat supplied by my own supplier at a fraction of the cost of Mazda but undoubtedly an inferior part as not type approved so not so much precious metals. Sure the aftemarket also supply OE - I sell bosch and Denso lambda sensors that are exactly the same as originals on some cars but most aftermarket spares are not OE. I wouldn’t take a chance on an aftermarket Coil, CAS, etc for the MX5 - would you ? Obviously a lot of the expense of changing the cam belt is labour so logistically it makes sense to change the other parts. That said a future problem could be a toss up between and high spec OE part finally needing replacement or an inferior part going pear shaped prematurely. If you can vouch for good aftermarket idler,tensioner and water pump please message me or reply to this thread with details.
Funny enough we have just finished a water pump and cambelt change for an owner on here,on a early short nose crank 1.6 with I.L Motorsport units,and i have no problem using them,nippon parts i am a bit cautious of to be honest,my Mk 1 was done some years ago with an after market pump and belt etc and she has never missed a beat ,she is due again simply because of age but not miles(another can of worms there then
)
As you have admitted you do have after market parts on your own Roadster as many other owners do, so what is the line???a rad is a major part to fit also ,so why did you fit an after market rad and cat ,and you have been honest which is all down to cost,as many others do,if an owner comes to me and asks me to fit a part i am not happy with i will tell them,be it a really cheap part or a second hand part that i see as dangerous, i have turned owners away if i am not happy with what they are asking me to do, as for stating that Mazda parts are the best,they do not make them and are made by outside Co’s for them, so they can sell the same part under their own names, mitsubishi made the alternators for one,and so on.
I also have never had a problem fitting some good second hand parts,but there is also a line to that,when an owner asks if i can fit a second hand water pump,that one always gives me a laugh.
Damage can happen at high rev’s/speed with a cam belt snap,they may drive again,but she will never be what she was on a standard engine.
If you ask honest people that fit and work on these little gems,they will tell you what to use and not what to,as i understand from your post you sell parts, would you turn an owner away because they can not afford a OE mazda part??or would you help them the best you can also telling them what you would recommend and use yourself??
M-m
The rad was very easy on my car as UK spec with no aircon and all bolts on fan, etc undid OK. I’m not a mchanic by trade but half an hour to change. I am interested in what you have to say about idler, tensioner and waterpump because at some time in the near future my car will need the cam belt replacing and this is a lot more work than changing a rad. The theories are not my own but mixed up information from professional sources. Given my recent experiences with professionals, I no longer underestimate my own abilites and knowledge but to be honest know nothing about the parts for this job, hence the questions.
Aftermarket spares either make sense or they don’t. I give genuine advice where I believe it to be correct and know what I am talking about - I have had too many people look me in the eye and spout rubbish about MX5s recently to automatically respect anyone.
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when a cam belt snaps, engine damage occurs in interference engines where the valves potentially impact the pistons. If with a non-interference engine (MX5/Eunos) there can be no impact between valves and pistons hence no damage possible.
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Parts are either reliable or not. On the MX5 genuine new parts are stupidly priced at Mazda, so who would want to afford them ? The best advice is usually to fit secondhand OE or good aftermarket. I can’t think of one instance where a new commonly required part from a dealer would be recommended. The line between secondhand parts/aftermarket parts is varied as you would no doubt agree. Some aftermarket spares simply don’t work well and others are not available. Getting back to the waterpump, idler and tensioner. Surely no-one would take a chance fitting secondhand spares and I imagine new Mazda OE parts are prohibitively expensive. The only realistic choices are therefore to leave well alone or buy aftermarket. If IL motorsports are your recommendation, I will look them up for prices/availability.
Short nosed crank - you mean there are still some short nosed crank engnes out there - oh dear !!
You have a PM buddy
I would also recommend the GMB pumps which are made the same as the OE Jap ones with metal impellers
M-m
GMB pumps are sometimes boxed as Nipparts or Blueprint. They have GMB in the casting and metal impellers.
Cheers Wayne/Andy
Thats another job I’ve got lined up now 
I have a Jan 1990 Enous roadster with a short nose engine and 163,000KM on the clock so yes they are still out there, and I intend to treat it to servicing etc till it shows some signs of serious problems otherwise why not leave it in service. If it works etc etc .
why would they not still exist. It had cam belt, water pump and idler replacement 2 years ago. Yes I could fret about what could happen, or I could just drive it.
Designing parts for OE supply to the automitive market I worry less about OE supply, more about the work practices of the supplier. Some non-OE parts are better than OE, I have test and real world experience of that.