dielectric Grease on spark plugs / leads

[Spare tyre]

Is it necessary or is it an old trick that was done when all this was fields

[cml24]

https://www.denso.com/global/en/products-and-servi...

I checked this when I installed new denso plugs a couple of weeks ago in a toyota. So I left the threads clean. To be fair the ones that came out were clean, and no issue coming out after four and a half years.

Or do you mean between the top of the plugs and the leads? Ive never put anything there, old minis to modern hybrids. All leads or coils have made a good connection without.

[Spare tyre]

cml24 said:

Or do you mean between the top of the plugs and the leads? Ive never put anything there, old minis to modern hybrids. All leads or coils have made a good connection without.

This, cheers

[Mroad]

It's a good practice that's still valid today much like 'greasing' battery terminals...I wouldn't class it as a necessity though as it will still work without, it's down to the individual.

[Chris32345]

Depends on how the car will be used
More important on something like an off roader that will get water splashed)sprayed into the bonnet

[Spare tyre]

Cheers all

It’s a 2005 Mazda 2.0 petrol

I don’t think I’ll bother but if I come across someone with some I’ll slop it on. Cheers

[Blaxlinde]

I've heard of this, waaay baaack...

It's no longer recommended as any grease will attract road grime and lead to arc tracking / cross fire.

As there is a lot of carbon in road grime (ground up "Carbon Black" from tyres) even the best dielectric grease will have the conductive powder stick to the outside creating a viable arc path & on top of all that it's just gonna get all messy and black.

Modern waterproofing is more than up to the task of protecting your spark, I once had an air cooled VW with vertex magneto and it had aircraft style metal braid covered leads with threaded plumbing fitting styled attachments on each end, it was super reliable even when partially submerged (handy on a beach buggy) but each plug & lead was in the $50 range I swapped it to the regular coil ignition and sold the Mag to an ultra/micro light pilot.