Ignition Coil Failure From Water Ingress

[T Sport 1978]

Last night whilst driving and setting off from a set of traffic lights, I felt a slight kick and thought I had wheel spin (VSC kicking in feels the same) but this persisted and developed into a vibration and noise. I investigated and visually checked the wheels, suspensions and joints and all seems fine and it turns out that it only happens when the petrol engine kicks in. I thought 'here we go' a mechanical problem has developed but there were no EML light or any other symptoms at all, not likely to be the Hybrid drivetrain as EV driving is just fine. I suspected that I lost a cylinder as I have experienced this previously in a Renault, but I just couldn't be sure.

I called Club Toyota for assistance and promptly they sent me an AA man who agrees that it sounded like a cylinder misfire and went to investigate by checking out the ignition chambers one by one, lo and behold the below was what came out of chamber No.3

It should look like this:

It seems like there is water ingress into the chamber from the water drainage gullies directly above the cylinder heads, the seals did not do their job and by the look of it, it looks like it has been a problem for a while.

Worst thing is no Toyota near me can help quickly and I am stuck with a makeshift fix (insulation tape round the coil to stop it shorting) and it is going in on the 22nd May soonest to be fixed. I asked my local Jemca if the AA man could just come and get the part and fix it for me, but they said that this could be done but it would be outside of warranty and chargeable, which of course I didn't take up since the car is under warranty.

Not sure if anyone else has had this problem, but this will serve as a heads up to you all.

[timberwolf]

What model of hybrid do you have?

I recall reading that some Prius 2nd Gen owners have posted about this problem, although I couldn't work out by looking at my car how the problem might occur.

[T Sport 1978]

It is a 2010 Auris HSD.

Basically it appears that the drainage hole directly drains water over onto where the coils are which is shielded by just the flappy engine cover, the coils themselves has a seal but evidently they didn't do its job.

[timberwolf]

Thanks. If I've understood you correctly it doesn't sound like a clever design.

[T Sport 1978]

Well, after a bit of a gentle persuasion with my local Jemca, they have decided to take the car off of me as the part duly arrived this afternoon. Speaking to the mechanic, he said that there might be a modified gutter and drainage for the car but wasn't too sure.

It does appear to be a poor design on the drainage system.

[T Sport 1978]

It is a 2010 Auris HSD.

Basically it appears that the drainage hole directly drains water over onto where the coils are which is shielded by just the flappy engine cover, the coils themselves has a seal but evidently they didn't do its job.

Just spoken to Jemca and they have confirmed that there is a modification for the drainage part directly above the engine bay to stop water draining and collecting onto where the coils are.

Thankfully they are able to look into my car today.

Well done Jemca Croydon!