sealant for leaks

Technical Area Body, Interior & Styling
2

Im new to both the MX5 and this club. I bought a Mk3 for my wife, (on her bucket list!), I guess I should have read more of this information before buying, but its what she wanted. Now Im faced with numerous short commings of the car. Seems to me its just like the WW2 japanese mitsubishi Zero fighter, Nimble but fagile and fraught with design faults.

Anyway, Ive been solving leak problems or should I say TRYING to solve leak problems. During the process I have used bath sealant caulk to replace the very poor thin foam washers on the rear high level brake light, in fact I made a gasket of the material all around the periphery of the light…No leaks there now. Ive used this stuff before, it sticks like sh*t to a blanket and is ultra flexible, its never let me down. For smaller leaks like those around and through plastic inserts for screw fasteners, ive used “Captain Tolleys creeping leak sealer” Brilliant stuff, works using capiliary action to seek out and seal minor fissures. Again, its never let me down.

So, I think Ive got the leaks sorted, cleaned out the various drains etc, now Ive got to sort out the non retracting seat belts and the hunting tickover, any suggestions on the seat belts would be welcome, particularly proven ones.

3

There is a known leak on the bulkhead, which is quite common.

The screw which holds the plastic trim in front of the windscreen, allows water through and in to the fuse box, causing potential electrical problems, wet carpets and wet passenger legs.

You have to remove the wiper arms and whole front plastic trim to seal the plastic screw plug.

In all likelyhood, the blanking caps covering the screws will snap.

 

 

The seat belts can be improved with replacement seatbelt guides, from about 2008 onwards, the guides on the top of the seats were redesigned.

It improves it a little, but doesn’t resolve the issue.

Recently, I removed the top caps where the seatbelt enters the bodywork behind the seat, I modified this with a rotary tool, giving a little more clearance.

I did initial think that it improved it yet again, but i’m now not convinced.

There is talk about ensuring the belt is spotlessly clean and using slilcone spray, under the top cap.

I’ve tried this also and found that any improvement was short lived.

 

I’ve investigated how the webbing is attached to the reel, and I think that it may be possible to remove the webbing, without any damage or structural intergrity, then rotate the reel one more turn before refitting the webbing. This would in effect put a little extra tension on the spring.

However, I’m not really willing to try this on my own belts, so I’m on the lookout for a really cheap test belt.

 

 

Regards the hunting tickover… if the battery has been disconnected, then the ECU needs to relearn, 10-20 miles will usually cure that.

4

Thanks Keat63

I used Captain Tolleys creeping crack cure on the bulkhead leaks and have cured them so far. Used trombone brush through the hood drains, we’ll see how that works next downpour! (there was a lot of crud in them so I’m hopeful!) The high level brake light seems leak free now, so i’m getting there. Its less like a pond now.

The seat belts are a real pain, it seems every body suffers this to one degree or another. If you do hear of any solution or indeed do have sucess with retensioning, please let me know. I was speaking to our local Mazda service dept about it and even they could only come up with the modded seat belt guides and cleaning the belts. In fact we were overheard by a young lady receptionist who still had the problem with her MX5 despite working at the place!

The tickover issue is strange, it only occurs when the car has covered a distance and thoroughly warmed up. the every two or three seconds there is an audible click and the revs increase by around 200rpm, two or three seconds later, click, and theyve dropped back…???

 

5

The tickover issue is strange, it only occurs when the car has covered a distance and thoroughly warmed up. the every two or three seconds there is an audible click and the revs increase by around 200rpm, two or three seconds later, click, and theyve dropped back…???

 

Sounds like your air con is doing it’s job, try turning it off (if you have it) and see what happens.

6

Thanks safetymatch, didnt think of that, sounds like a good plan, i’ll give it a try.

7

I’d concur on the aircon, I’ve heard this mentioned before, although mine doesn’t have it, so I don’t suffer.

8

Thanks to all those who helped. As I said, I’m new to this marque, so there will be more probably naive questions. Here’s the first: the car is the two litre version, are there any quirks or pitfalls I should be aware of?

regards to all

bob

9

Notchy gearbox in low gears, an oil change does improve it slightly.

I spotted corrosion starting on the last 6 inches of the chassis, directly in line with the exhaust, after I mentioned it, one or two other folks have since said they’ve looked and spotted the same.

Get under and fettle it now.

 

Alloy boot lid (quite common near the number plate lights), under the bonnet bonnet and bonnet shut panel can suffer some aluminium corrosion.

 

10

I take it that the engine and general mechanicals are pretty sound?