VR6, sounds like a tractor and knocking?

[mikehiow 0]

Evening all, after a 10 minute spirited drive this evening, I noticed something strange, the engine/exhaust note went very deep (and "gurgley", almost tractor like) and the engine felt very sluggish. I crawled the extra mile home - and opened up the bonnet, there appears to be a slight knocking noise and the oil is down to about 4mm showing on the dip stick (it wasn't this low when I bought it a few days back) - edit: an after thought, that was immediately after stopping, a lot of oil would have still been around the engine - this may not be a cause for concern?

 

Now, it sounds a bit to me like not all cylinders are firing, but I've no experience of a V/VR engine - so not entirely sure - if it isn't firing on all 6, would this perhaps cause extra stress somewhere resulting in the knocking noise I'm hearing? Could it purely be a lack of oil, and a top up/change may fix?

 

My first thought was perhaps the big ends, but I'm not sure that'd give the "tractor" sound, would it? Plus, the knocking sounds very precise, and not rattley like I'd imagine big ends would?

 

Oil was reading at around 103c, water at around 90.

 

Any help/advice would be much appreciated!

[Supercharged 2]

Temps look fine and it may be something trivial but I wouldn't drive it until you have checked the upper chain tensioner...

 

These can fail around the 100k mark so if you have no history of the chains being done I would check this asap.

[mikehiow 0]

Could you kindly explain how that would cause the effects mentioned? If it was that, and what I'm looking for when checking it?

[mikehiow 0]

I've just been out to the car again to investigate.

 

The knocking, as far as I can tell certainly isn't top end, and sounds more like it's from the gearbox area.

 

Oil level has returned back to where it was previously (just a bit over minimum).

 

However, I tried unplugging each lead from the distributor/coilpack on the side of the engine.

 

The middle from both top and bottom rows makes no difference, where the rest, when unplugged cause the engine to almost stall (I plugged them back in before allowing this to happen). I didn't pull the leads off the plugs to test for spark, as I saw no easy way of getting them back in properly, is there a "method" to this?

 

The two middle leads from the coil appear to correspond with the top left, and bottom-middle cylinders (if standing at the front of the car).

[Roger Blassberg 0]

If you remove one plug lead, you will lose two cylinders because they work in pairs and both ends of the common cicuit have to be earthed to produce a spark. Maybe you have a faulty coil pack. Try swapping it with a known good one before buying a new one though; they are quite expensive although they come up on e-bay regularly. A faulty plug or plug lead lead may also be causing the same symptoms.

 

Be careful pulling off leads with the engine running - the ignition system produces at least 30 000 volts and will make you jump about a bit if you get a shock!!

 

You need a special tool to pull off and replace the leads at the plug end properly without damaging them.

 

Best wishes

 

RB

[coullstar 0]

What was the weather like when you were driving? If it was wet this may point to a coilpack issue as well.

[was8v 0]

I vote coilpack too, but pull the spark plugs of the middle cylinders after running to see if they are fouled or wet with fuel.

 

Could also be a faulty injector.

[mikehiow 0]

I think It's looking more like spark than fuel/injector, as the middle leads almost certainly are not sparking.

 

I'd had been snowing yesterday here, quite bad - I drove in it when it was really bad in the morning (on route to have tracking/4WA done), drove it back from this fine - it was later on in the night this happened - the ground was wet, but I'm not aware of any puddles I went through.

[Supercharged 2]

Ah sounds like a coil pack then, especially if it's 2 leads because of the design.

 

The plastic casing does not take the extreme temperatures very well and goes brittle with age too.

[mikehiow 0]

I did a bit more investigation this evening, I tried grounding each "faulty" lead with a screwdriver, and got nothing but the most miniscule spark when rubbed against a grounding point.

 

Down to VW tomorrow for a new coilpack :(

[KipVR 1]

Check it in the dark mate you'll see the coilpack terminals earthing out, you can see it easier by getting a squirty gun and spraying a mist of water over it.

[mikehiow 0]

Check it in the dark mate you'll see the coilpack terminals earthing out, you can see it easier by getting a squirty gun and spraying a mist of water over it.

 

Yes, I did it in the dark, the four good terminals had good sparks, the bad ones had none - being a shared/wasted spark setup, I tried grounding each lead individually (as well as trying with different leads) to rule out leads/plugs. As if one lead/plug of a pair can't ground, the other won't spark either.

[mikehiow 0]

All fixed, new coil pack fitted in about 10 minutes and sorted.

 

Although, I now need to find a new engine cover, after failing to see the bolt on the top left hand corner :(