After a minor problem last night, the efforts and labours from a very committed RAC man, an overheated engine, split radiator, broken belts, two coffees, and a recovery truck, it seems we have a head gasket problem.
Coolant is pressurising, and it seems pretty conclusive, so time to do some work.
I’ve had a look and can’t see a good online guide anywhere - is there one? Any pointers for someone who has done head gaskets before, but never on a Mazda, and never on a OHC engine.
Finally anything I really need in order to be able to do the job? Oil and filter, coolant, other gaskets that will need to be changed? Naturally the Haynes manual is pretty much no use whatsoever.
Thanks Geoff, but I was planning to do the strip down this afternoon.
I can get the book ordered, but won’t have it until later this week - don’t want to miss any important steps in the strip-down before the book gets here!
No-one? No hints and tips on ways to make life easier with this job?
Managed yesterday to get the ehaust manifold and inlet manifold off with the help of the Haynes “remove the inlet manifold” - seriously? I turned to section 5, and the instructions for removing the inlet manifold could have been written on the back of a fag packet. Just the head to go now, hopefully not too tough. Putting it back together is going to be fun, all kinds of wires, connectors and hoses to remember - should be ok but might have a few more questions this week
Any suggestions on a source for a new radiator? The plastic topped jobbie split nicely when the head gasket pressure got at it - rad cap didn’t blow off (or the plastic is really very weak!) so we have another job on the list once the head gasket is done. Happy to upgrade to an all-metal jobbie, but not sure the best source for these things. If anyone has got a good condition secondhand rad they want to sell for cheap then just shout.
I’ve just picked up the new head gasket, and we’re going to be starting the job of changing it this evening. If anyone does have links to any online guides (I’ve had a look but can’t see any) we’d be very grateful. Equally, if there is anyone near the Watford or Hemel area who has a copy of the workshop guide that I could borrow for a few days we’d be grateful (in form of beer / workshop labour / chocolate as suits!).
I’ve changed head gaskets on plenty of cars, but not on a MX5 and it’s always useful to know the tricks…
Nobody with any opinion, advice, contribution at all on this?
Guess we’ll just plough on through and get it done, would be good to have some advice from the forum. There must be others who have done this?
Tips appreciated on how on earth a person gets to the exhaust manifold bolts that secure it to the block - managed to get the head off without removing this, but replacing it will be more difficult without damaging the gasket as we do it.
Honestly? Apologies for my bluntness, and frankly I am pretty tired after 2 full evenings spent on this after work, as well as a Sunday afternoon spent just getting things sorted to do the job, but on the basis the response to our request was very very limited from other club members, I think the chances of us taking several hours to write this up, with the photos it needs as a club resource are almost nil. Sorry to say this is a two way street, and so far nobody has ventured any more than a relevant thread that doesn’t have a lot of detail, and instruction to buy a book that has arrived 2 days after we really needed most of the info. Perhaps someone local could have offered to lend us their copy until ours arrived, and they could have had the sparkly new one for the favour.
The book has now turned up. It is clearly going to be useful, and will probably get us through, but first hand tips and experience on here would have been great.
I am a bit surprised that more club members haven’t done this job, and those that have must have encountered the very familiar problem of how to get around the exhaust manifold being well and truly bolted to the block in an almost inaccessible location, and found a way around it, and how to depressurise the fuel rail so it doesn’t pee petrol all over the side of the engine. Which it did. For those that have done this before (assume in a club of several thousand members, many of which are online, there must be at least a few hundred people who have done a head gasket change on the exact engine we have in front of us) why not take the time to help some people with a quick tip on some of this stuff?
Suggestions welcomed on how to get the cambelt back on without undoing half of the front of the engine or losing a finger. Partly because I’ve not got to that bit in the book yet, and because in the garage after a few hours it was beyond me to work it out without any info at all in the Haynes manual or on here. It is marked up to put it back exactly as it came off, good thing I thought of that - the kind of thing someone could have suggested was a good idea…
Well, that’s a very fair comment ! I’ll probably be doing the same job myself, so I’m as keen as you are to have that very same information. Tips and tricks are what forums are for, are they not?
Do be carefull when taking the cylinder head off … lift it , do NOT drag it to one side of the engine before lifting it … you might bend some valves.
Replace the thermostat
Replace the timing belt while its in bits… and depending on the mileage replace the water pump too
When laying the cylinder head on the bench place it block face up … saves bending those valaves again
Check the surface of the cylinder head with a straight edge ( you dont want to put a warped head back and have to do it again
When reassembling the head to the block lightly oil the threads on the head bolts … and the underside of the bolt heads
After its all finished … dont forget to put the correct coolant/ anti freeze in it … run up till normal operateing temp … then change oil and filter
do NOT use engine flush…
Use a genuine Mazda cam cover gasket…dont be tempted to try a cheap one…
I use a contact adhesive to hold cam cover gaskets to the cam cover… use it sparingly… place a “dab” of silicon sealant at the corners of the cam caps at front and rear of the head ( the size of a match head is fine)…and more than that and you risk it oozing out into the engine and blocking your oil pick up pipe
I,m sure you,l get more MX5 specific tips from the guys on here that are used to the MX5
It wasn’t directed at you - it was very much more directed at all those people out there who have done this job before and haven’t pitched in with advice or even support.
When do you need to do yours? You’re only in Reading - if you provide lunch then we’ll happily come down and give you a hand. We can even bring our shiny new manual with us, and Amy will no doubt want to show off with her new torque wrench - for anyone wanting a torque wrench, the Teng Tools one seems to be very good with loads of little features that make life really easy.
Tips and tricks are exactly what forums are for. Which is why I was confused that a club of this size managed to provide very little of either to a couple of people who really needed those tricks and tips! Hence my toys leaving the pram a bit above MikeyMX5 has provided as much as he can, which has been a useful checklist, we could still do with some specific info on replacing the cambelt with minimum fuss if anyone has any suggestions?
I have not down a mk1 head gasket so here goes drain coolant remove radiator, remove cam cover (plug leads) etc wiring you will need to to remove the c/shaft pulley bolt you will need a special tool to stop the c/shaft turning to crack off the bolt for oc members there is a tool shop to use. you will need to find the timing marks on the the cams and c/shaft line these up slacken the belt tensioner off slide the belt off you will need a new blet, belt tensioner, thermostat and a water pump it is recommended to change the water pump whilst you have the front of the engine down,change the thermostat as well whilst you have the top of the engine striped down change the cam angle sensor seal as well as the cam shaft oil seals. I am sure some one will come along and add some more details I have missed off so this will give you some time to collect your toys thrown out. Best of luck oh by the way look in the FQA for the NA engine for more imfo
Not done this either but I would resort to buying a decent manual before whipping the head off so I had some guidance to look at/leaf through while doing it. that could explaine the lack of replies.
As you said its a two way street, so if you fancy documenting what you do it would help others…
To be fair…out of 100 MX5 owners…maybe 1 of them would be brave/skilled enough to attempt a DIY head gasket change. The chances of that one person seeing this thread within a day of it being up, would be very slim indeed.
I’ve done a head gasket myself…but on a 600 bike engine which was on the bench at the time. I would rather throw a bit of cash at someone and let them take the risk of stripping a head bolt than try it myself on a big engine in a car that I love.
The only source of information on any forum comes from the members. I doubt that more than 4 or 5 forum members have done a head gasket themselves, and I’m pretty sure that those who did, didn’t take notes or take pictures. If you really want to help the forum database, then write up what you did and I’ll post it in the faq section. If you were to join the owners club, there is an illustrated guide to changing a cambelt, which is only viewable by members
I’ve got a pretty good cambelt replacement guide I can forward to you - it’s in a Word 97 document with lots of photo’s. Don’t know where I got it from, but I think it was an American site.
Update - instead of guessing at the timing, we decided to get the cambelt set correctly as per the manual. Took a while removing the various pulleys and belts, including one snapped bolt (why is it that garages manage to get three bolts out, and replace two of them, presumably because they snapped on removal, and then refit one rusty old bolt with the two new ones? Are those diddy little bolts that expensive???)
Good thing we did, as the cambelt had slipped significantly on the bottom cam, or at least by the time we’d removed all that stuff it had. Would have taken us ages to get that right once we’d put everything back. Belt is now back on, hopefully in the right place, with the Es and Is lined up how they should be. I think.
Radiator needed changing, so to give ourselves some more room that came out, though I didn’t realise the power steering fluid went through the bottom of the rad as well. More mess to add to the puddle on the garage floor, I should have thought about why there were two extra pipes on the bottom of the rad For anyone attempting radiator removal, take the undertray off the car - it is a few bolts, but you will not get the rad off without doing that. Snapped two fan bolts near the bottom hose, inevitably corroded, luckily our new rad should be here today (I hope!) for fitting to the car this weekend. A set of new bolts can be the special reward for the car not hurting me very much so far on this job.
Looking at the radiator, it seems possible to remove the plastic top from the rad? Anyone ever tried replacing just that part? A metal alternative strikes me as a chuffing good idea - the plastic is 20 years old on ours and has become very brittle with the constant heating, cooling and pressure. Might be something for the club to think about long term, as the plastic tops on everyones cars are going to become increasingly fragile over time, and our experience of trying to replace this rad is that £200 thanks very much is about the only option for automatic MK1 owners - and the replacement is a plastic top too.
The real question is what to do with the cam cover while it is off? Clean it up? Paint it? It’s ally, so we can make it shiny, but it won’t stay shiny for very long.
MikeyMX5 has provided as much as he can, which has been a useful checklist, we could still do with some specific info on replacing the cambelt with minimum fuss if anyone has any suggestions?
For anyone attempting radiator removal, take the undertray off the car - it is a few bolts, but you will not get the rad off without doing that. Snapped two fan bolts near the bottom hose, inevitably corroded, luckily our new rad should be here today (I hope!) for fitting to the car this weekend. A set of new bolts can be the special reward for the car not hurting me very much so far on this job.