How much for an engine replacement?

I’m interested in getting a good working engine in my xj6 because it has a blown head/gasket and a bad valve and I was wondering how much it costs to get an engine replaced on an s3 xj6 4.2. Or if it would be a better idea to get it rebuilt

If the engine is in good condition and low mileage I would go for a rebuilt.
Like this you know what you have, plus a reconditioned head and valves and whatever else it needs, rather than an unknown replacement engine that might have unknown problems.
My 2$…

The engine has 212k miles and seems to be in poor condition

Unless something is seriously wrong with the bottom end of your engine (low oil pressure, pistons, cylinder walls, crankshaft, bearings or ring problems) you may only need to remove and replace the cylinder head to get the valve fixed and then install a new head gasket. Call a local machine shop for a rough estimate of the machine shop work but they will want to see the cylinder head first before providing a quote. It could be $1-2K.

I have removed and replaced several cylinder heads and a few Jaguar engines. IMHO removing and replacing an engine is 10 times the work of removing and replacing a cylinder head. I can imagine that having an engine professionally removed, rebuilt, and reinstalled may cost $10K or more depending on the work required.


Jabraan, rebuilding will almost always be more expensive than buying second hand - but you will be getting a “known quantity”. As Paul suggests it might be best to determine the condition of the block and all it contains - despite the mileage it might be a sound basis for a refresh: hone, bearings, new pistons and rings etc.
As a data point my cylinder head overhaul cost AUD$780 (three years ago) and included: a strip and tank clean; crack testing; a skim; two new exhaust valves; and valve shimming to spec. I did the remove and refit. Paul

Looks like a new engine is called for. Good advice given above. Cost depends on how much of the work you can do yourself. You are never too old to learn. Having someone else do all the work would leave you upside down. The 4.2 engines seem to be in good supply so shop around and find a rebuilt that comes with a warranty.
Good luck,

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there are always two sides of every equation and it is still your decision in favor of which unknown you want to solve it.

I’d fully support Paul and Frank: “the devil you know …” would support a clean and limited repair of what is broken. Things are even easier as you already have a quite clear picture of the present damage at your hands. For even more peace of mind you might check the condition of the lower part of the engine with the engine in situ. It is possible to remove the oil pan if you swing down the crossbeam by the anti roll bar:

Then it is quite easy to assess the crankshaft and the main bearings

(My PO did that and took the pics before I got the car many years ago - the engine’s still running strong … touch wood).

A used exchange engine would be a clear option for me only if I had seen the engine running well before I pulled it - or someone I really, really trust - and I wanted to use the car for the time it takes to treat a matching numbers original engine to a full overhaul or the not so matching engine to a certain degree of performance and reliability. Either way may take some extra time …

Whichever way you’ll take - good luck!


75 XJ6L 4.2 auto (UK spec)

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So it seem the cheaper option would be to replace the head gasket and valves so I started watching some videos. On Honda 4cyls it seems like something I could do but I’m wondering if it’d be similar on the xk engine

The Jag engine is a pretty simple engine: it’s big, but it’s WAY easier to rebuild properly than an old Bug engine, and probably so, the Honda.

There is a series of YT videos on how to rebuild an XK engine, plus you will not find a better and more comprehensive source of info than this website.

What did the oil pressure read when this engine was running?


It still runs. And the oil pressure is usually around 40. Maybe just under but it hasn’t had an oil change in forever because it doesn’t get driven much. I will be doing one soon since now ther water was mixed and it’s milkshake

The car had hg sealer that has been running in there for who knows how long but I think the car sitting for like 8 months caused the seal to break so I’m planning on adding more and doing an oil change for now till I can take the head apart

If it has 40 psi, that suggests the bottom end may be in pretty decent shape.

Just beware of using the Rolon timing chain tensioner (only use Renolds), and if possible, use the OE timing chain guides, over some of the crappier repops out here.

A good clean, some new shells, maybe just a ball hone, new rings, and a head fresh up, and gaskets, and you’ll likely have a serviceable engine, again.

The BIIIIG bugaboo can be the head studs: much has been written about them, and likely will need replacement. Pull all the core plugs, and check the bottoms of the studs.

Just checked and there are three XJ6 series 3 for sale on Hemmings site for $4,500. Do you really want to put a lot of money into your 212,000 mile car that is only worth $4,500? My advice, buy one of those,(add about $1,500 shipping) and, either keep it and part yours out, or, buy the lowest mileage one, pull the engine, install in yours and then part that one out.

Well, you are getting a lot of differing advice. :wink:

If I were in your situation here’s what I would do.

I would remove the cylinder head, take it into a machine shop and have the head reworked. In addition to fixing the bad valve, the machine shop will likely recommend other needed work.

While the head is in the machine shop change the oil and install a new oil filter. Then buy a head gasket kit, new belts and hoses (especially fuel injector hose) and have the fuel injectors professionally serviced. This would be a good time to inspect the cylinder walls and decoke the pistons.

Once you get the cylinder head back, put everything back together and start up the car. All of this will likely cost you about $2,000 and in the end you just might have a properly running engine.

You should also purchase right away a Jaguar Series III Service Manual, a Series III XJ6 Parts Catalogue, and an Series III XJ6 S57 Electrical Guide to help answer the many questions that will come up. In my opinion a cylinder head removal and replacement is way too complicated a job to be done through emails (and I have done more than a few). Many of the steps required are not intuitive and require specialized tools like a torque wrench, timing chain tensioner, cam shaft timing tool, etc.

Don’t be surprised if this takes you a few months or more to complete, especially if you decide to clean up the engine bay, repair rust damage, or rebuild heat damaged wiring harnesses.

Take lots of digital pictures (you can never take enough pictures) and keep a detailed notebook, you will need it. Oh yes, and have fun.




The main question is if you are prepared to work on the engine, Jabraan…

xj6 85 Sov Europe (UK/NZ)

If you feel competent to do it on a 4cyl Honda, you can do it on the XK. With a helper for the lifting part you can have the head off in a day. Just make sure to get all the wires. It has been a first for me and I forgot two things that then were in the way.
Snapped head bolts are a major issue but I used inserts into the block face and with 5 such modified studs it is still running strong thousands of miles later. It might be simpler to buy another engine for a few hundred and use the head. A full rebuild on that car would be too expensive and take too long in my view, but I‘d give it to a nearby shop if possible.

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Im in Georgia, and i had the exact same issue on my xtype. Rather than risk repair only, my mechanic i trust recommended a new engine. My cost on a used engine with 50k miles was $3200.00

212k miles is a lot for an XJ engine, from the ones I have dismantled it would almost certainly have bore wear, so need sleeving or boring, pistons, probably a crank grind, so you would be looking at over $10k

I got a rebuilt engine for mine very cheaply (from a wreck) and notice that rebuilt XJ engines are sometimes for sale on Ebay

buy a rusty one with an engine that runs is another way

If you can get the head off without snapping any corroded head studs, thats a good start

consider your capabilities too. A head is doable, an entire engine & trans R & R is not a job for the feint hearted


Was the $3,200 for just the engine or did $3,200 include the removal and replacement of the engine?

I know that the X-Type is a very different model, I’m just curious as to how much the total cost was.

A friend here is San Diego told me that he paid a local shop $10K to remove and replace the damaged 5.3L V12 in his XJ-S convertible due to an engine fire and that price included the price of the replacement engine.


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Paul, your right the V12 is surely more complicated to my xtype. But that was my total . Motors come basic pretty much block/heads etc, and all the accessorial parts from my old engine are put back on. I got a 12000 mi warranty, but that’s gone now. So far Ive been lucky with the actual motor. As you know with Jags, something always needs to be worked on. It takes finding the right shop, where you can leave it couple weeks, as its very labor intenstive.