Restore oil treatment blows head gasket
 

What a week, and it's only Tuesday.
I replaced the the valve (cam) cover gaskets to solve an oil leak that was getting worse.
That led to a broken part load breather tube that had broken.
That led to taking the throttle body off to get to the connection.
That led to rebuilding the EGR valve.
So got everything back together, ran the engine no codes YAAHH.
I had read on the forum that the oil additive RESTORE would help renew a tired engine, so I added a can of Restore with an oil change.
Took the car out to get gas, and gave it the beans, WOW what a difference,
great pickup fast, just like new I was ecstatic.
Just as I pulled into the drive way it started to hesitate and run rough, but no codes, got it in the garage and opened the hood, rough idle.
Turned off the engine, let it sit for a few minutes while I got a beer and scratched my head.
Tried to restart and it locked solid and made a very ominous thud, PANIC !! OH Sh*t what had I done, did I leave a rag in there, what did I do.
After a few minutes I thought it through and pulled all the plugs, driver side were all OK. Passenger side back 3 OK front plug was wet, with a great deal of trepidation I got my flashlight and looked down the hole.
Green water !!! I am pretty sure the RESTORE raised the compression back to like new and the 203,000 mile head gaskets asked what the hell it was going to do and let go.
HELP GUYS !! do I need special tools to pull the heads, I looked for a thread on head gaskets and did not find any that helped.
I'm pretty mechanical and feel that I can do this but I need guidance. Do I have to pull the front cover?
Oh yeah my old mechanic said he updated the tensioners at 120,000 miles, guess what Plastic, so I'm going to do the tensioners as well. and change the oil in the supercharger, anything else.
I can't think straight I just about died...

While I'm no fan of cures in a can you can rest assured the oil treatment didn't cause your HG failure. More likely is a neglected cooling system and "giving the beans" to an admittedly tired(and boosted) engine.
Sorry for your woes but it was gonig to happen with or without the Restore.

I would have to agree with you, but the title sounds more intriguing

well, then perhaps a can of head gasket??

On a serious note I HAVE a "Heal a Seal" kit that a friend was about to use before I convinced him to properly repair his engine(Cadillac Northstar), he gifted this to me for Christmas, ball buster that he is.
I've been saving it for some dispose-a-car with a popped gasket that passes through here that I could experiment with. I'd not put it in my Jag but if you're game let me know.
Cheers

Sorry to hear about what happened to your cat :( I hope you'll be able to find a solution soon...

I just wanted to ask you - can you give a link to a web store with this additive or could you tell me what's its fuel name? I know it went wrong with you, but in my case it would give a little life back to the engine as my car is suffering from low compression. I don't trust such oil treatments but in my situation I would give it a try after your story.

It's Ametech Engine Restore. Best price I've found in the UK is on Ebay. Read the guide at their website first, I'm pretty sure you're not to use it with Magnetech and similar oils.

It calls for a head gasket, no special tools apart from the timing kit as you're doing the timing at the same time.
Yes the front cover has to come off. Put the bonnet in the service position (undo the struts at the top and lodge a broom in to hold the bonnet secure. Remove the top finisher and fan assembly, then the radiator to get at the front cover bolts.

I'd change the pulley bearings while at it. New belts too.

Maybe go with the orange coolant on fill, but run a flush additive and pure water for a few miles first. Also check the water pump bearing and impeller, if black bin it (but Jaguar should have done that on a 99' already) to later white impeller version.

If you get the gear together it should be a 1-2 day job no rushing, get the engine down first day, buttoned up on the sunday.

You're going to need a few new seals and gaskets, front cover pair, head gasket and Loctite ultra grey engine sealant, timing covers, water pump - the SC duct seals might be a good idea. These engines are good for double your mileage so well worth doing ;)

Head bolts can be re-used once, if they've got punch marks on them, bin them and buy new - I'll update this with torque settings, you will need a quality torque wrench - you do not want a bolt snapping in the block at all costs.....

Thanks Sean,
I owned the car from new so I do not believe the heads have been off before.
I was hoping the front cover did not have to come off, Oh well.
This is the most complicated job I've done so I'm hoping the forum will be my guide.
I had just filled and checked the car over including coolant. I am sure it was OK before driving it.
I assume the crank pulley is coming off I understand it's a bit of a tough job.
I did all the pulley bearings about 2 months ago.
I will be checking the water pump, I am going to go slowly and try to do all the maintenance my loved cat deserves. (Wife is not too happy HER car is not drive-able)
The more I think about it, the more I keep thinking OH CR*P I have to take this or that off. In for a penny in for a pound.

Sean usually mentions that the Land Rover head bolts are the same, but cheaper.

that's why we love sean, so new bolts, water pump, gaskets, spark plugs, oil coolant, I need a new credit card....

I've done one side and it is time consuming but not really difficult- just label everything with tape and put each set of nuts or bolts in ziplock baggies. I would remove the bonnet for ease of access though. After having the heads machined and a valve job, you will be shocked at the increase in performance I'll wager. Plus you will get another 200K miles out of it. (we can chalk this one up as a "recommended top end rebuild" mileage point.) Plus we are here to help.

Label the baggies :)

LOL Plums- spot on.

Sorry to hear your cat is now at the vet & I know the sinking feeling when head gaskets blow-it happened to my Bentley last year & I had to stop in a muddy farm entrance, trudge in the rain to a garage to get some water, then limp the car home & decide which limbs to sell for medical experiments :)

I did the job myself in 3 solid weeks of work, and once you've overcome the mental barrier & made a start on the job, it's not too bad if you progress steadily. It shouldn't take anything like that long for the Jag V8.

Trickiest part is likely to be the cam timing, front cover & crankshaft pulley. Taking cylinder heads off is not too bad & cleaning/decoking everything is quite threapeutic :)

I would suggest taking photgraphs as you progress the job, so you have a record of what it looked like before it was attacked with the spanners :)

I'm stood in my garage now doing the dis-assembly, feeling very lucky to have such good companions. I have my sharpie and bags, and my camera.
I've already broken a hose connection and I'm looking at it thinking which English Pr**k came up with that one.
When you take the covers off I think Sir William Lyons invented or had shares in the jubilee clip maker. Forgive me after 28 years in the states I still describe stuff using english terms.

Well begun is half done.

Good luck Roger.

Everything was already said. Labeling, documenting, plenty of beer,.... you got it all. The only thing I am nervous about is timing. I would put it all together, seal it tight, and take it to the Jag dealer to properly time it (in the case of MY Cat). While you're in there, check ALL the timing chain guides, and replace them. They are not expensive, and after all is done, your cat will have a new lease on life.

With an XJR there is not much you can do wrong with the timing, just needs to be flat across the cams with the flex plate plug in place.

flex plate plug?
Do you have one?
What does it look like
this is the bit I'm worried about

AHHHHH more beer, I can't get the bolts out of the thing that screws to the inlet elbow