4. 2 vs 5.o . I read that article and honestly scared me about the 5.0 . Im in the market for a xk and dont know which engine to go with so if anyone can please advise me ,thanks

 

Find an example of both to drive so you can decide which one is best for your needs. Only consider a vehicle that has a complete service history.

 

As many others have said in this thread the 4.2 is a more reliable motor hands down. I have taken apart many 5.0 and 3.0 sc motors that have spun crank bearings. Very rarely do I ever hear about 4.2 s prematurely locking up. The ultimate proof of this theory(observation) is in the price of used engines. A decent used 5.0 with moderate mileage(80K or less) will be 3-5 times the cost of a similar 4.2. That tells you everything you need to know.

 

LOL! Not only do I remember, but in the early '70's I owned a '37 120 Sedan briefly and I also had a '37 LaSalle. Sold the Packard, kept the V8 LaSalle because it handled better and was more fun to drive. The ad slogan for the LaSalle was a simple "suggestion" (more like a command!). "Look at LaSalle!". They sold a ton. Wait...why am I telling you this?.

 

i have the same problem!! I rhink im gonna get the black xkr and just wrap it white

 

what is a ecu remap?

 

Google is your friend.

Give a hungry man a fish and he won't be hungry tonight.
Teach him how to fish, and he'll spend all day in a boat drinking beer!

 

Build a man a fire, he'll be warm until he can't figure how to keep it going.
Set a man on fire, he'll be warm for the rest of his life.

 

Set a hungry man on fire in a boat and ...

 

;-)

 

The 5.0 XK is a smooth, quiet version of my C4 Corvette without the annoying rattles. It has a much better albeit subtle exhaust tone. Besides the obvious advantage of the added horsepower, I love the styling upgrades that came with the 2012 redesign (headlights, grill, trunk leaper, dash, etc). But those do come at a cost - seems the market made us pay $$'s to find a low mileage XK post '12 model. There are tons of '07's at good prices. As for the reliability of the '12, so far it has been fine, as would be expected from a lower mileage vehicle. Just a water pump and the 2 batteries - I've read it among other owners and have had the first-hand experience with a battery that died (and then its faulty replacement, too!). I'm meticulous about upkeep and oil changes, so hoping for as pleasant a tenure as possible!

 

I’ve owned both.
The 5.0 has more power and a better sound.
Ive seen no difference in reliability. I owned the XK8 for 9 years and it ran fine up until I sold it.
I’ve had the XK for 5 years. No issues.
i keep up all maintenance and neither were/are daily drivers.

 

Engine sound's really personal, there're many members here who find the 4.2 engine sound to be more refined compared to the 5.0. The new AJ series motors, mostly due to DI, are extremely noisy at idle. And the 3.0 and 5.0 litre engines require more frequent and more expensive maintenance compared to the 4.2. I've had 7 of the 4.2 and 4.4 engines and 3 of the 5.0 litre and 3.0 litre and done hundreds of thousands of miles cumulatively on all and can say the older versions have had ZERO parts wear issues and only inexpensive fluids maintenance, the newer engines have all had the same failures adding up to tens of thousands in maintenance costs including the well know common failure parts.

 

Irrespectively I think they are both better then the aj126 (V8 block with rear bores blanked off)

 

@steve_k_xk , couldn’t agree more. I have the aj126 in the LR4 and I find myself paying acute attention to it. Not so with the aj34s.

Besides, what idiot came up with “blanking out the cylinders” when there was 6 cylinder ecoboosts (based on duratec blocks) around 2009…. or was it the case of false economy…. a bulk buy of the v-8 to which a downsizing effort was applied.

But back to the topic of the thread. Sure, the 4.2, older technology. The 5.0, newer technology. And the spreadsheet of accolades and detriments differs by the author. There’s just something “old school”, raw and tough about the 4.2 as opposed to the modern”ish” 5.0. And that’s what interests me for my toy…. I drive the sh*&$#+ out of her (not to be misinterpreted as she is not properly cared for), on all the winding roads, in all the weather… (Jeremy, on the Top Gear episode featuring this car has nothing on me) and she seems to love it as much as I do.

Cheers!

 

Thank u for the insight jahummer thats is why im in the market for the 4.2 . Was going to buy a 08 xkr but guy whats way more than true condition of car

 

I'm a bit obsessive when it comes to engine note. I had the 4.2XF and thought the sound was beautiful. I added a paramount back box which gave a fantastic improvement, super loud but throbby, sounded like a race car at higher revs. When I got the 5.0 I really didnt like the sound, it lost the throbbiness and it had a metallic edge to it that kind of grated on me and putting the paramount back box on that didnt improve it, it just made it louder. Then I got the XKR which was a lot better but also howly rather than throbby, also no supercharger whine in it, but sounded pretty good. I had the X pipe done to that which made it a lot more aggressive in sound, especially over about 3000rpm (?) when the valves opened up and I loved it, though the 4.2 is still my favorite.

I thought the 5.0 was a lot more responsive but the 4.2 sounded heaps better. The 4.2SC would be my pick if the cars all looked the same, unfortunately I also much prefer the post '11 headlight shape.

Funnily enough, after 7 years out of the XKR and in the F Type (and Mustang) it has been crossing my mind to trade the Mustang in on an XKR, as it is probably out of all of my past cars the one I remember the most fondly.