Hi All
We have a 1993 Mk 1 in the family and it is only used a few times a week sometimes less.
On 2 occasions now In 12 months I have had to remove the coil pack assembly and clean out quite a lot of green corrosion from the plug lead connections due to misfire problems.
I have replaced the leads and the plugs and there doesn’t seem to be much water ingress.
Does anyone know why this happens?
Maybe some dielectric grease may help?
Thanks in advance.
Quite a common problem.
You say green deposit, so I am guessing MK1 1.6? These have a couple of copper HT ports whereas others are aluminium so more grey/black oxidation with water.
Essentially the problem is proximity of water and the HT lead sleeves not fitting adequately. Expansion/contraction creates a vacuum that sucks any water into the ports.
The 1.6 coils are usually quite easy to shine up but I suggest you fit a set of standard mazda leads that will seal better or perhaps flex less.
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Yes sorry it’s a 1.6 import.
Thanks for the info, I may try a little grease around the boots to start with and see how it goes.
Use some Servisol 10 contact cleaner on the bits tarnishing. This will help clean them and minimise future tarnish.
Then for once I can recommend the original WD40, and this is for its original purpose - waterproofing. After you have reassembled the leads still with hints of Servisol, then spray the WD40 on the outsides and maybe allow it to run into the seals around the leads. The WD40 then turns to a gluey sticky residue over a few hours, ideal for keeping out water, and useless for anything else such as lubrication.
Don’t use WD40 on the contacts as it is quite a good insulator and causes no end of trouble in plugs and sockets and switches. It can even gum up a car door lock sufficiently well to render it jammed solid on a cold morning.
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I’ve never used anything in the coil ports but dielectric grease may help as long as it does not attack the rubber sleeves.
The secret is getting a good sleeve seal such that any vacuum that develops is insufficient to draw in water.
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I could try pulling the boots back, inserting the lead connection in, and then adding some grease/Vaseline before sliding the boot back over.
May be a better option.
The leads I fitted were from MX-5 parts and although it didn’t specify they were oem they look reasonable quality wise.
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