Any guidance on replacing the Plugs in my Jag?

 

Jaguar X Type Bank 1 Sparkplug change

 

With the age of the vehicle and the amount of labour involved, it may also be wise to replace the cam cover gaskets and spark plug boss seals with Jaguar parts.

If there is any oil evident in the spark plug wells, thoroughly clean the coil units prior to reinstalling them.

 

JC: If your X-type has 100+K miles and the IMT O-rings and Bank 1 upstream Oxygen sensor are old / original, then consider replacing them when the intake manifold is off the engine:

1) IMT O-rings: The lower O-ring is more accessible.
2) Bank 1 Upstream O2 sensor: The firewall-side catalytic converter is more accessible.

There are plenty of threads in this forum describing how to replace these, because they are a common maintenance need on our high mileage X-Types. Ask if you have questions how or why to replace them.

 

dw, 2004 X Type 3.0, 139,966 miles on her. I had an engine service light and received following codes; P301, 303, 305, 306, 0181 (Fuel Temp sensor) and P1251 (throttle relay).
Since I am unsure what service of this nature has been done since I bought it used last year.
Are there 2 upstream O2 sensors?
I would also assume since I am replacing all spark plugs, Intake gaskets, IMT O-rings it would be advisable to replace both valve covers and boss seals?
How concerned should I be with the coils?

 

I just did that job on my X a few weeks ago. It's a very simple process and took me about an hour and a half from start to finish. The coils may or may not need replacing, mine did not. If the plug boot shows signs of decay or electrical burn-through, then by all means replace that coil while it's off the car. Otherwise, I wouldn't worry much about it. A coil either works or it doesn't. If you think it's something to worry about, then go ahead and change all six while you have it apart and be done with it.

The coils are available at any autoparts chain- that is if you don't want the Jaguar name on them. I made sure my local Advance Auto had some in stock just in case I needed them. The last thing you want to do is tear into the engine and realize you need a coil, but nobody locally has one.

 

JC: Your initial query about replacing spark plugs had me thinking you were doing routine, preventative maintenance. Hence I suggest that while the intake manifold is removed (to access Bank 1 / Firewall-side spark plugs), you also replace the Bank 1 upstream O2 sensor and the lower IMT O-ring, if they're old / original.

The error codes P0301, P0303, P0305 & P0306 indicate misfiring in cylinders 1,3,5 (all on the firewall side) and 6 (radiator side, closest to the battery). You didn't describe how the engine runs, but I assume with 4 cylinders misfiring, it runs rough and lacks power. When you change the spark plugs, chances are you'll find some engine oil in the spark plug wells, causing the misfiring. That would be "good", because it's relatively easy to fix. After you remove the intake manifold, remove the valve covers and replace the gaskets, which prevents oil from seeping into the spark plug wells. I'd also inspect the rubber boots on the coils. If they're degraded by oil or arcing, or if the spring inside the boot is damaged, replace those coils. Otherwise, clean any residual oil from inside the boot with isopropyl alcohol or similar.

I'm not familiar with the other 2 error codes P0181 (Fuel Temp sensor) and P1251 (throttle relay).

Regarding the O2 sensors, our X-Types have 4. Each bank has it's own catalytic converter with one upstream and one downstream sensor. The upstream sensors have an electric heating element that burns out with age, causing an error code. This link has details and pictures of all 4 O2 sensors:
https://www.jaguarforums.com/forum/x...-where-129374/

 

is there any place to find the torque specs for bolts?

 

JC: Torque specs are in the workshop manual. Here's a link:

http://www.mediafire.com/download/xp...Manual.pdf.zip

It's at the bottom of the X-Type How To / Quick Links page, here:
https://www.jaguarforums.com/forum/x...essories-5915/