XJ8 nikasil victim
 

So, I took just bought a mint XJ8 for £900, drove 70 miles home, no problems, got home to find oil blowing back out of breather, along with steam, my mechanic looked at it and confirmed worn piston rings/cylinders :icon_cry:

Rough repair costs? Whats involved? Any of the oil treatment stuff on the market any good? Its done 110000k with full service history.

Rest of car is superb.

First of all - what year is your XJ?
Was the engine replaced before? It's easy to check - replacement engines had green tag on them. Or you can find a build date, coded in an engine nr.

Please add vehicle details to your Signature. Your forum profile shows XJ6!

Graham

Its an early 1999. I cant see a tag and there is nothing in the histiry to say its been done.

ps, I've updated my signature.

If it's really a nikasil issue, then it's better to swap an engine. For economy reason a replacement engine must be the same model as yours (AJ26 or AJ27). But if you want a reliable car - do a valve job, swap a tensioners and so on, while an engine is out.

To make sure that you have a nikasil issue - do a compression test, check oil for metal shavings and do a visual inspection of a cylinders (with a endoscope through a spark plug holes).

Cheers MoscowLeaper. Sounds like its going to be quite costly. Lucky I only paid £900 for the car, but, its still £900. So, id there a short term fix? Some additive that can seal up the cylinders?

At the moment the oil is backing up out of the breather hose and into the air box and you can see steam/fumes coming out of it, and the dip stick if you pull it out, everything else seems fine. I wonder how long before it gets worse...

Sounds like it already may be 'worst' but it could be a head gasket since you invoke steam, rather than a failed cylinder issue. That's a lot more repairable. While a Nikasil problem could produce oil blow by it would not involve coolant.

Didn't describe it too well, I just saw a bit of steam when the mechanic unclipped the breather hose. He's not familiar with these v8's but what ever he checked he said its some sort of compression issue. So I think it is that rather than a he's gasket. Would restore or something similar help with the oil blowing back until i sell it? There's a fair bit in the filter housing now.

Nikasil was an issue when we had sulphur in fuel and those days are long gone. It's generally accepted that if a Nikasil coated cylinder bore was going to fail, it would have done so years ago and any still running are likely to be more resilient than a standard steel liner.

Steam is not a feature of cylinder bore wear. That is more likely to be a failed cylinder head gasket or a crack in the head.

A compression test and a check for oil in the coolant / coolant in the oil will give further indication of what could be wrong.

Graham

This may be a waste of time in your case because of the described severe conditions but a clogged part load breather tube will blow oil out the full load tube into the filter box. Check that and then do or have done a compression test and that will tell the tale.

As Graham said, we don't see many new Nikasil problems. All those happened 10 years ago, or more, and life has been good since.

Don't chase that rabbit until it is the only thing left. RESTORE might help or might not but it is a cheap effort and won't hurt anything.

There's no coolant in the oil and no oil in the coolant (although it is a bit brown so could do with changing)

I will check all the pipe again today for blockages. Is the hose below the full breather or part? Also, whats the hole people talk about clearing with a drill bit?

https://encrypted-tbn1.gstatic.com/i...2EAmezp5k4Ql4o

The picture shows full load breather. Part load breather procedure can be found in this forum, even with pictures :)

The best description of cleaning the orifice can be found in the 'how to' sticky above, where all valuable information is stored.

It is from another forum and courtesy of Mr. TexasDan but here is a direct link:

http://www.mediafire.com/download/43...Clean_MAFS.pdf

You will have to download a .pdf file but it is worth it.

The text mentions that the plastic can be brittle so care is required. The fitting is only held on by the 'squeeze to release' connector and the friction of an 'O' ring but be careful.

I am in full agreement here

I'll try again

The Jag V8 is designed to run on 5-30 but you can use a slightly thicker oil on higher mileage cars, mine has done 110K miles and I still use 5-30. The quantity of Restore must be included in the total fill quantity so treat it like it's a litre of oil. These cars like to be on or slightly above the full mark on the dipstick.

I use 10W 40 on both of my cars.

I used Mobil 1 10w40 last change with a pint of Slick 50 when the oil level reduced slightly. Slick 50 quieted the VVT tapping at cold start (tensioners are new metallics). car has just turned 66kmiles, but I suspect mostly in town driving which wears more than highway.

From what I've read so far on the forums, a little oil in the intake tube is common. A lot of XJR and XJ8 owners have made up catch cans to stop the oil from getting into the intake. I used to clean my intake tube once a week, before I installed a catch can in my XJR.

If your compression is good, you're not spewing blue smoke from the exhaust, and your oil consumption isn't terrible, I wouldn't be too concerned.