Melted pistons :(

Fingle · Post by **Fingle** » 14 Oct 2008, 16:58

Ok Looks like my number 3 or 4 cylinder has died.
Cracked cylinder head too.

This is on a recon Aircooled 2.0l engine (fitted in 1999), and which from the records has has this happen to it before in 2002.

(get the feeling it was a bit abused by Aussie backpackers for a few years before coming to us)

Should I call it a day?
Fit new engine ? Looks like it will be about 2k !?
Persevere with the old block and get new pistons etc ? How much will this cost est ?

"pooh" day, esp after me and the miussus put so much time and effort into her

Post by **VWCamperfan** » 14 Oct 2008, 18:08

If you have the know-how, (or some spare time!) give repairing a go but I would check that your timing isn't too far advanced and your fuel mixture isn't too lean, both can lead to overheating and melted pistons!

Fingle · Post by **Fingle** » 14 Oct 2008, 18:18

It still drives, does that mean the pistons arent melted ? Could it just be the rings ?

Just feels like 3 cylinders, about 10% loss of power.

Im guessing that a melted piston would seize the engine no ?

Post by **VWCamperfan** » 14 Oct 2008, 18:46

Ohhh, you would know it if you had a melted piston! You would be chucking out oil everywhere and the engine would be just a tad noisey!
I would say it could possibly be valves or rings but if you have a cracked head that could also be a cause of the problem, depends really where it's cracked.
A compression test would reveal a bit more.
If it is idling a bit rough then it could indicate a loss of compression on one or more cylinders. A simple test for this is to start engine and allow to warm up, then hold hand over exhaust. If the exhaust gasses come out erratically then that would indicate a misfire.
Check all the usual stuff first though eg. plugs, air leaks, timing and mixture settings.

Fingle · Post by **Fingle** » 14 Oct 2008, 18:54

Yes the garage are doing a compression test tomorrow.

Its certainly not as bad as that first scenario, and deffo sounds like the second.
I almost hardly noticed it, at first (i thought it was the cold weather), but last weekend was warm and it carried on all the way back from Essex.

Sounds like it did well to do that !

Only have myself to blame for not getting the timing done earlier.

How much is a fix ? I see Justkampers do heads for about 350 quid

Post by **VWCamperfan** » 14 Oct 2008, 18:57

A lot less usually with a 'wanted' post in the wanted forum!
Where is the head cracked? Some cracks have no effect on performance and can generally be left without worry.

Fingle · Post by **Fingle** » 14 Oct 2008, 19:11

No idea, I do think there is a mild oil leak however

Post by **VWCamperfan** » 14 Oct 2008, 19:22

Only a mild oil leak?!! Blimey, thats lucky!
It may be an idea to check that the cylinder head bolts are tight as well. The engine has had work done to it in the past as you stated and sometimes the bolts can work loose. I know this because it happened to me and I'm quite thorough with engine reassembly! You may get a knocking sound when cold if this was the case though.
Hopefully the compression test will give a few more clues tomorrow though.

Post by **Mr Bean** » 14 Oct 2008, 19:33

Fingle wrote:No idea, I do think there is a mild oil leak however

Blimey man you are making a lot of bold and costly assumptions seeing you aint exactly Mr Spannerhands diagnostic expert 2008!

You need an expert to do your diagnosing and a knowledgable friend to stop you getting stitched up.
Cheers
Smiffy

Post by **HarryMann** » 14 Oct 2008, 19:36

Only have myself to blame for not getting the timing done earlier.

Who said it was timing related problem... ?

In fact, who said it had melted a piston.. or was this just to get our attention??

Perhaps a proper analysis before asking open ended questions, have we yet heard what actually happened, or is the whole thinga windup...

Fingle · Post by **Fingle** » 14 Oct 2008, 19:45

Jeez fellas ease off, im no expert, and I was told it could be that.

Thanks to people here, I am finding its not that bad.

Im a bloke that bought a van, not a mechanic that spends his life tinkering with them. Im sorry if I have wasted anyones time

Thanks to those who have helped

Fingle · Post by **Fingle** » 14 Oct 2008, 19:48

Oh, and I was also told on another site, that poor timing and lean running can overheat an engine quickly, hence my regrets at not timing it earlier.

Its with an expert anyway, im just panicing as im not made of money.

Post by **HarryMann** » 14 Oct 2008, 19:55

Sorry Fingle, but...

For accurate responses here though, a straight description of the 'symptons' is No. 1 on the list.. if you get my drift.

What you have heard elswehere can come later, but so far we haven't heard of one simple fault... just what you've been told elsewhere... maybe.

What actually happened???

Fingle · Post by **Fingle** » 14 Oct 2008, 20:06

Sorry yes, i guess that was my fault.

Its an Aircooled 2.0 l CU recon.
The symptoms are a loss of power, not great but noticable, ie 4th gear doesnt so much pull (not that it was ever warp drive), just kind of slows down gradually over a mile or so. Which gives 3rd gear a break, but isnt much use for a long trip.
Also this weekend the oil pressure light intermittently came on.
Its leaking oil but certainly not peeing it out.
It was never great, and it did need its timing done. (Altho I know its never going to be a race car being 2.4 tonnes).

The only catalyst I can tell was me dinking the back into a lamppost on the rear drivers side, naroowly missing the exhaust, altho I sepculate the exhaust may have suffered a knock (could this have knocked something else, like a heat exchanger ?)

It did backfire down a big hill in Dorset which gave us all a shock, but it ran same as ever for the rest of the journey.

Post by **VWCamperfan** » 14 Oct 2008, 20:11

Ahh, could be a lack of back pressure due to a leaking exhaust system somewhere. If the exhaust is more noisy than usual then this could be the problem. It could also explain the cracked head. Look for signs of carbon deposits around exhaust system espicially near heads.