Car had a failure today and it diagnosed itself and warned my that it was broken

[Davezj]

I was driving home from may parents 240 mile trip. After about 110 miles when I put my foot down I getting really bad knock showing up on the engine management light on the dash and a massive misfire from the sound of the engine . So I pulled into the next services. I opened the bonnet to see a jet of coolant spraying out of a small split in the coolant hose, I was not expecting to see that. Conveniently it was spraying over the number 6 cylinder coil pack which made it arc to the head. If the coolant hadn't sprayed on the coil pack I probably would have driver the other 130 miles home which would have probably made me loose most of the coolant n the engine and caused massive camage to the engine, but caught it in time.
the temp fix for the split was of course duct tape, never leave home without it.
the coolant spray also showed up that the coil pack was arcing from the main body of the coil pack and not from the lead connection point as you expect, so this has shown up that the coil pack is probably on it way out as well.
so I need to fix these issues tomorrow. But had the car not sprayed on the coil pack I would never have known of the other issues. My car wants to be saved and fix and loved.
I think I will spray all the ht leads and coil packs with a mist of water and see if any of it arcs to the heads as a test, I am hoping it is only the one coil pack that does, then I can replace it with a spare from the shed.

It knows I have a present for it to be installed soon which consists of a rear view camera and 2 front side facing cameras with a duel screen monitor. So I don't reverse into any more posts, lol.

My car is great.

[MarkSanne]

I've got that same top radiator hose split (well actually it got a pinhole leak) on me in both my VR2 a couple of years ago (ducttape to the rescue for the 60km drive back) and again 1.5 years ago in Italy with the Legnum (ducttape to the rescue for many hundred kms although ducttape will not hold with high outside & our usual high under bonnet temps for more than 100kms, so I kept refilling with water until I bought a somewhat similar radiator hose for some Italian car that happend to fit quite perfectly after cutting off an unneeded bend).

There top hoses are getting thin and wear out after all those years of service, so anyone who haven't changed it... It might be a good idea to replace it before you run into real trouble!

[Davezj]

Well I replaced my hose today and all is good with that no leaks.
I did a water spray test on the ht wires and oil packs, and there were no arcs or parks from any of it apart from the coil pack that had been sprays with coolant.
I had noticed before this trip that under really damp conditions that the cr seemed to misfire a little bit when it was from cold. But only very slightly and by the time I had got out ofthe car lifted the bonnet and had a look around the car was running correctly.

The point I could see the arcing from was on cylinder 6 (front right) and it was where the rubber boot of the lead joined the coil pack at the front towards the top of the coil pack.
The arc had punched through the outer casing of the coil pack and was tracking down the outside to GND.


So I would highly recommend spraying the coil packs and ht leads with water if you are having a misfire issue to diagnose where the issue is, it seems to work great.
I will reiterate this that a good working system will not arc at all if you spray it with water.

[Nick Mann]

That sounds like a lucky catch. The last time I had a coolant hose split on the motorway I had warped the head before I realised what was going on. Not a VR4, but I would imagine the same result is easy in a VR4 too.