Lawnmower
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| posted on 30/12/05 at 11:44 PM |
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Help!!! Mazda MX5 Eunos....
Hi all!
Have just returned today from my weeks christmas holiday up to Cumbria.
On the way back in my (wifes) mx5, whilst doing 70mph on the M6, all (i think) the lights on the dah flicked on and off, and the battery and heater
lights stayed on.
Thinking the batery alternator was playing up, i switched all they non essential electrics off (radio, fan, heaflights) and sloewed down. Whilst
changing lanes a loud bang was observed, as well as los of steam, and I propmtly stopped on the hard shoulder, luckily next to a telephone.
Inspection of the engine bay revealed mucky brown water everwhere, and a 1inch by 6 inch hole in the top of the radiator!
when the AA man (actually a subby) eventually arived, he had a look and pulled out a bit of 'fan' belt.
after thinking about this all day, after trips on 3 diffenernt lorries, I think the following happened....
The water pump has packed in for an nknown reason....this resulted in the belt snapping and causing the alternator to stop working, hence a possible
power surge/drop and the battery light coming on. The car has 2 fans, which i think are both electric, loss of alternaor dropped power to cooling
fans, and the engine cllant built up enough pressure to blow up the radiator.
Recovery guy said it could have caused the head gasket to die as well......
The car still runs though, and can drive (onto a towing dolly)...
Have only had the car 2 weeks, and havent been able to get hold of a manual for it (Haynes dont do a standard manual for it according to
halfords...)
It a 1991 import, 1.6 automatic. with Air Con.
Have found the following parts site which seems reasnable...
www.mx5parts.co.uk
hopefully it is just the water pump radiotor and service belt i need to replace...
Any pitfalls help and advice are most welcome please.
[Edited on 30/12/05 by Lawnmower]
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Lawnmower
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| posted on 31/12/05 at 12:02 AM |
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The above parts cost about £180 all in...
have done some looking on ebay, and a pump is for sale their. however it sugests that changing the water pump is a cambelt off job, in which case, how
hard is this.
(I am slowly, but very definatly getting in over my head 
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MikeR
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| posted on 31/12/05 at 12:11 AM |
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try and get hold of IrvineD - he's got one and muggins helped him change the water pump and cam belt by the side of the road one evening this
summer ...... (don't ask).
the manaual you want is by chilterns or something. its a full workshop manual and very good. great little cars.
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Bo
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| posted on 31/12/05 at 08:21 AM |
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Miata
Otherwise there is one website you need : miata.net all the information you need is there.
Changing cambelt takes time, but is not any more difficult than on any other car, and since you are on a Locost forum, my guess is that this
shouldn't be a problem
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steve_gus
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| posted on 31/12/05 at 04:30 PM |
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i seriously doubt that the alternator failing caused the electric fan to run slower and overheat the engine..... very seriously doubt it.
Most fans only run on a warm day in traffic - In Decmeber with motorway speed ram air thro the bonnet, you were probably overcooled and the
'stat' may have been doing some work to keep the temp up.
My beemer 318 used to have a stone cold radiator after a 70mile motorway run at this time of year.
Any chance the fan belt just broke and lashed the rad on the way out?
atb
steve
[Edited on 31/12/05 by steve_gus]
http://www.locostbuilder.co.uk
Just knock off the 's'!
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JoelP
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| posted on 31/12/05 at 04:58 PM |
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surely if the pump failed it would overheat anyway? It does seem a bizarre place for it to pop though, id of expected a hose joint to go first.
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Lawnmower
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| posted on 31/12/05 at 08:27 PM |
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Thanks for all the help off of everyone.
(MX5 owners club forum, and the miata.net sites are both very good)
The pulley on the water pump still moves, indicating the pump isn't siezed, so i think the alternator/water pump belt must have snapped on its
own (did coincide shortly after acellerating from 50 to 70 ish with the overdrive turned off).
The belt snapping i think must have caused the dash lights to come on (interupting the power supply) and the lack of a water pump caused the engine to
get hot, and reduced power to the twin cooling fans (as no alternaor) which the radiator promptly built up pressure and exploded. (the rads plastic
btw)
If this theory is right, then i wont have to dismantle have the engine, and can leave the cambelt and water pump well alone!
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Lawnmower
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| posted on 31/12/05 at 08:43 PM |
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quote:
Originally posted by steve_gus
i seriously doubt that the alternator failing caused the electric fan to run slower and overheat the engine..... very seriously doubt it.
Most fans only run on a warm day in traffic - In Decmeber with motorway speed ram air thro the bonnet, you were probably overcooled and the
'stat' may have been doing some work to keep the temp up.
--
Any chance the fan belt just broke and lashed the rad on the way out?
[Edited on 31/12/05 by steve_gus]
good point, it was the day when all the forcasts were saying only travel if you have to! due to the snow! so the fans perhaps weren't
working?
the tow truck man pulled a bit of belt out of the engine bay, and thee are loads of gubbins and another belt to get past before hitting the rad.
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steve_gus
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| posted on 31/12/05 at 11:19 PM |
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I think you can discount the fans. Take any car on a run this time of year, stop it at the side of the road for a min or two and see if the fan
runs...... if you wait long enougth it might, but with 5 degree air going thro the rad, i think fans are optional this time of year 
Your battery is more than capable of powering the car for an hour or so without the alternator - i think you can discount the alternator stopping
causing a problem.
sounds like you had a simple overheat due to a snapped belt....
atb
steve
[Edited on 31/12/05 by steve_gus]
http://www.locostbuilder.co.uk
Just knock off the 's'!
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blueshift
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| posted on 1/1/06 at 04:36 AM |
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I have the veloce miata 1.6 enthusiast's manual for mine (1992). It's pretty good, covers some things in more depth than haynes, but is
conspicuously lacking wiring diagrams.
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irvined
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| posted on 6/1/06 at 09:21 PM |
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Hiya,
My theory, is that the fan belt snapped, there are 2 on mine, one for the power steering and air con, and another for water pump and alternator, both
are driven of the crank. I had one snap, and it pulled the other off, but anyway.
What I suspect may have hapenned, is that your belt snapped, this would cause some wierdness, and hopefully a red light, i think its the top left or
bottom left of the centre four to come on. In the mean time, your water pump isnt spinning, and subsequently nothing is circulating in the engine, as
a result the water temp is getting higher and higher.
Unfortunately it can be relatively isolated to the block, and probably didnt show up immediately on the temp guage. The result was the pressure build
up which blew your rad.
This is potentially good news. What I suggest you do, is pull out the thermostat and seal it all back up, put a new belt on, and start up the engine,
open the radiator cap and you should see a good gush of water coming in at fast idle, if this is the case the pump is probably ok, if otoh there is no
water flowing, then its probably a nackered pump, they do disintigrate over time, but usually they start to leak first, then you end up on the m1
fscking around marking your cam belts whilst miker stands around laughing....
I've cooked mine big time at least twice and so far the head hasnt let me down, so you may be lucky there. Have a check there are no leaks in
the system though as the pressure may have cracked other bits and bobs.
If you do need to change the water pump, do the cam belt, and idler pullies at the same time. It will take about 2-3 hours in a nice non-motorway
environment. What to do, is get a nice white tip-ex pen and mark up everything really carefully, make sure you label the belt front/back, intake,
exhaust, and crank, mark all the pullies and belt so that in order to line it up again, you just need to match the marks on the belt with the marks on
pullies, if you don't get it wet and lose the marks, it makes putting it on a doddle, but just in case, make sure you can see the marks on the
pullies and that you understand how it aligns as it isnt obvious.
The book[1] outlines how to mark with a scribe which is also a good idea.
Once its marked up and your happy you can get it back together rip out the belt, and pump, put the new pump on the gasket is a bit of a pain, but
probably a lot easier when its not dark.
Once the pumps in, change the idler and tensioner, then put the old belt on using the alignment marks, once its aligned, cut the belt length ways so
that its half as wide as it normally is, slide the new belt on the bare half of the pully, cut the old belt off completely, slide the new belt on and
bobs your fathers brother.
Its not as complicated as it looks, and believe me, when its dark, wet, and you can't see the marks you made with a black pen on a black oily
belt, it looks complicated. Hopefully you wont need to do this though.
Once its back together you want to reset the ECU, run the car and check for any diagnostic errors, which you do with an LED and some voodoo magic, I
also recommend you get the book on that stuff[2] which for a fiver is quite handy, although not absolutely needed.
If you've got the time, set your timing to 14degrees, check the idle, and enjoy your five, apparently, they are dead reliable, i had a nightmare
with mine at first, but its been great fun ever since, and i've just driven 5000km in it over the last week, with my house inside, and my bike
and snowboard on the back.
Good luck
David
[1] http://www.mx5parts.co.uk/product_info.php/products_id/28
[2]http://www.mx5parts.co.uk/product_info.php/products_id/35
for a mk1 1.6 you want:
http://www.mx5parts.co.uk/product_info.php/products_id/245
and http://www.mx5parts.co.uk/product_info.php/products_id/216
you can probably get them a bit cheaper from your local factors, but these guys will sell you the right bit first time round and my experiences have
been fairly good.
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jack trolley
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 posted on 7/1/06 at 04:22 PM |
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US version available
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Keith Tanner
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| posted on 10/1/06 at 08:47 PM |
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You're putting too much emphasis on the fans. You lost your alternator/water pump belt. This would trigger a warning light on the dash and your
engine temperatures would start to rise extremely quickly, fans or no fans. I've had this happen on an MX5 that was well instrumented, and it
took less than a mile (granted, I was at the top of a 10,000 pass) for the temperature to spike up to a point that had me concerned. I've seen
them get surprisingly hot without lasting damage though. Your rad is 14 years old and made of plastic, the overheat must have raised the pressure to
the point that it failed. At least you know your radiator cap is holding pressure
On the part of manuals, the best are the ones sold by Mazda. They're the only ones with real wiring diagrams.
Second best complete manual is one called the "Enthusiast's Manual", published by Veloce. It was written in the UK and should be
easy to find. I have a certain interest in one called "Miata MX5 Performance Projects" as I wrote it, but it does have a good reputation
for covering a number of jobs extremely well. It just doesn't cover them all. A cambelt/water pump change is included though.
I wouldn't recommend the Haynes manual to someone unless I didn't like them very much. It does burn easily, though.
While you're doing the work, replace your power steering belt. Sounds as if there's some deferred maintenance on that car.
Keith
www.slowcarfast.com
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Lawnmower
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| posted on 21/3/06 at 11:13 PM |
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Thanks for the replies, have been so busy the last few months that I havent visited this site hardly at all recently
shortly after the incident, the tax ran out and the car was declarded sorn. a few weeks later it finally got fixed! replaced the radiator and service
belts, and replaced a missing bracket and bolt that tension the alternator!, and the car drove fine, for about 4 days!!!
Then the cambelt promptly snappped! stranding my wife a few miles from home. AA said about 90mins to get to her, so towed her back with the astra.
Car then spent a few more weeks been fixed by myself! Luckily it was a later 91 model with the supposedly long nose crank shaft, although how your
supposed to undo the 21mm olt without breaking somthing on an auto i don't know...
However, now i have a car that has had recent waterpump, cambelt and pulleys, service belt, oil change radiator and water changed!
car must have spent 75% of first 3 months of ownership out of action!
Will changes plugs leads and fuel filter when funds will allow, and assuming nothing else goes wrong....
On the plus side, head gasket seems fine (runs to touch wood!)....
A big thanks to all the help i have had, from here and especially the guides on miata.net and mx5ocforum.co.uk (of which we have now joined).
and also mx5parts.co.uk, where i bought a decent book!
(In my limited experiance, the haynes manuals are usually generic rubbish, with occasional useful tips. the best manual i have is an official workshop
repair manual for the land rover, the green bible as its somtimes called. breaks everthing down nto step by step drawins, and actually shows you what
special tools are!)
[Edited on 21/3/06 by Lawnmower]
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Keith Tanner
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| posted on 22/3/06 at 12:20 AM |
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The best thing about the Green Bible is that it's by appointment to her Majesty Fantastic manual. I have a 1967 IIa 88" myself to keep
the Seven company.
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