Javelin SuperDork
Jan. 5, 2012 3:48 p.m.

Every once in awhile the Mazda5 will hesitate a little to start. It's classic signs of worn/dirty plugs to me, but the manual says they are some sort of Iridium somethings that I don't change for another 50K miles (getting ready to roll over 75K miles now).

Should I change them anyways? Can they be cleaned? Should I switch to convetionals or will the high-voltage COP ignition eat them up?

I'd like to address this and keep her in tip-top shape, so any advice would be great, thanks.

Jan. 5, 2012 4:35 p.m.

My Mazda3 did that. I took the wires off, put some dielectric grease on the contacts and problem solved.

It wouldn't hurt to check your plugs, either.

Javelin SuperDork
Jan. 5, 2012 5:01 p.m.

No wires on mine, coil-on-plug (COP) ignition.

I see no harm in checking them and greasing the boots anyways though. I'll do that while changing the oil this weekend.

Jan. 5, 2012 8:54 p.m.

Are you saying that you don't have wires going to your coils? What witchcraft is this?

I should have been more clear, sorry.

I've seen the dealer I got mine from pressure washing engines at the used lot. I suspect one of them got a little happy under there or something wasn't seated right; regardless, putting a bit of dielectric on the connections and re-seating everything fixed the problem

CGLockRacer HalfDork
Jan. 5, 2012 8:56 p.m.

My old 3 did that. It was corrosion on the wires going to the starter. There was a TSB about it for the 3. Not sure if it affected the 5 or not.

The other thing my 3 did was flood. If i cranked it over and it didn't catch, it would flood the engine the next time i tried to start. The dealer never tried to figure it out.

Jan. 7, 2012 8:50 p.m.

So what was it? Starter? Coil Wires? Something else?

KATYB HalfDork
Jan. 7, 2012 11:52 p.m.

bs on the plugs. 70k is max.... also dont be surprised if that doesnt solve long crank. im guessing it uses the same purge valve that mazda3's had which those would go bad causeing extended cranking, also

GTwannaB Reader
Jan. 8, 2012 12:30 p.m.

On this subject. Where are you supposed to apply the dielectric grease? Is it supposed to be around the boot, used like a sealant? Or is it supposed to be applied to the metal contacts, ie the grease is conductive?

Travis_K SuperDork
Jan. 8, 2012 2:50 p.m.

Yeah... the plugs might be good for another 10k, i find 50k hard to believe as well.

Jan. 9, 2012 10:17 a.m.

I put dielectric grease into the connectors whenever I have them apart, mainly to keep them from sticking together, make them a bit more waterproof and prevent corrosion of the terminals.

Now is where I wait to get told this is a terrible idea.

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