A sad day today

[chomerly]

How do i start with this?

Basically, my V40 T4 is fooked.

Myself and the family were off to Chester today for a family get together as it was the missus's grand fathers birthday.
On the way there, climbing up hill i put my foot down a little and then the car developed what seemed to be a misfire.
Being just under half way there i pulled over at the nearest convenient place and had a quick look under the bonnet.
There was nothing obvious to be seen so instead of tempting fate we decided it would be best to turn back.
The car was clearly misfiring but we got back home ok.

Getting the tool box out, the first thing i did was to plug in my OBD2 device and read the codes off the ECU.
Nothing.
Great i thought. so i know my coil packs and leads are all fine.

I then pulled out each of the spark plugs. All genuine Volvo plugs i might add.
Plugs 1,2 & 4 all looked fine but spark plug number 3 was wet with oil.
I then decided to do a compression test and again, 1,2 & 4, were all pushing about 4 bar (according to my gauge) but 3 had nothing at all.
I tried it across the other 3 cylinders just to be sure there was no issue with my gauge and then re-tried it on number 3.
Again there was no reading at all.

So, it looks like there is an issue with either the piston ring or the stem seals are shot on that cylinder.
I've been doing some reading on the net and the general consensus is that a total failure of a piston ring would do some serious damage to not only the bore, but to the engine as a whole leaving the car undriveable.
Most believe (not in my particular case) that stem seals are the likely culprit.
I can't comment on this myself as i'm no mechanic but either way, it looks highly likely that i will have to replace the car as i don't believe it is worth my time to repair.

I know, i know.
I love my T4 and its relentless power but i have been thinking of buying another motor anyway.
Mostly another T4 but a phase 3 variant.

Anyway, it looks like my car will be going up for sale as a result of today's incident so i will be advertising it shortly.

[Clan]

It is probably a burned exhaust valve for what ever reason , not the end of the world ..

[Magnumpi]

I've no experience with this model, but the symptoms sound the same as when the HG went on my 340 a few years ago, it was fine, put my foot down stuttered and missfired, limped it home.
Luckily the HG only had a small crack between two cylinder walls so no water/oil was lost or mixed it just lost compression.

Hope its an easy fix for you.

[skyship007]

Originally Posted by Clan

It is probably a burned exhaust valve for what ever reason , not the end of the world ..

I agree with that, as piston rings don't suddenly break too often, they give some advanced notice with smoke and oil consumption issues. If there was no rattle associated with the misfire, then it's probably a valve problem, BUT I would take a look at the seating of the injector, because that could cause a similar misfire and loss of compression.
If the injector is not loose, then Clan is probably right as a valve guide or ring failure results in whitish smoke and if you drove back and it was not smoking or rattling, then valve seating is top of the list.
Did the engine start smoking when the misfire developed? If it did emit some whitish smoke, then I suppose it could be a valve guide oil seal, but they don't normally fail suddenly, unless it's a non OEM one.

[chomerly]

No, there was no smoking when driving.
There were no obvious rattles that i could hear other than the kind you get when it revs irratically.

It did smoke a bit when i tried to restart the car after cleaning off the plugs but there was wet oil on the top of the piston that i could just about make out through the plug hole.

To be honest, i haven't a clue as to what the issue could be related to.
All i do know is that its an expense i could well do without right now.

[KBB]

How would an unseated petrol injector cause loss of compression?

[Dog_Book]

Originally Posted by KBB

How would an unseated petrol injector cause loss of compression?

Its Magic!

[960kg]

Here we go again i feel some discomfort on the way!!!!!!

Volvo pre 2000 engines are as strong as an ox especially the `99 model if run on the correct fuel!

As Clan says it will be a burnt exhaust valve.....unusual for No. 3 `cos usually No. 2 cylinder cops it.

You can bet your bottom dollar the engine has used it`s more than fair share of 95 octane instead of the recommended 98 ron for the 1855cc T4.

The dirtier fuel leaves carbon to form around the neck of the exhaust valve and then it cannot close properly so it burns and a bit burns off leaving No compression on that cylinder

All very common to mainly 95 ron fuel being used

[skyship007]

Originally Posted by Magnumpi

I've no experience with this model, but the symptoms sound the same as when the HG went on my 340 a few years ago, it was fine, put my foot down stuttered and missfired, limped it home.
Luckily the HG only had a small crack between two cylinder walls so no water/oil was lost or mixed it just lost compression.

Hope its an easy fix for you.

Yep, that's another possibility, although a sudden HG failure that did not result in a loss of coolant is fairly rare, most HG failures start slowly unless they are caused by an overheating incident. If the compression was zero from a HG failure I would have thought the coolant level would rise (Or bubbles would be visible) during the check if the header tank cap was off, also the spark plug was oily which does not sound right for a HG failure.
It would have to be a fairly obvious HG failure to give a zero reading from a compression check. Zero is the kind of figure get get from a broken valve or blown out oil seal, although I've known a badly fitted injector cause a zero, although it was obviously loose.

[stephend]

Originally Posted by 960kg

Here we go again i feel some discomfort on the way!!!!!!

Volvo pre 2000 engines are as strong as an ox especially the `99 model if run on the correct fuel!

As Clan says it will be a burnt exhaust valve.....unusual for No. 3 `cos usually No. 2 cylinder cops it.

You can bet your bottom dollar the engine has used it`s more than fair share of 95 octane instead of the recommended 98 ron for the 1855cc T4.

The dirtier fuel leaves carbon to form around the neck of the exhaust valve and then it cannot close properly so it burns and a bit burns off leaving No compression on that cylinder

All very common to mainly 95 ron fuel being used

I'm curious: what's the last photo off, since it appears to be an 8v engine?