REMOVAL OF INTAKE PLENUM TO ACCESS REAR PLUGS ON 09 RX350

Could be either, you have 1 coil for each cylinder (6 total). The problem is #3 is the rear middle cylinder. You have to remove intake plenum to gain access to rear bank. #4 is front center. What you can do, is swap #4 coil with the one next to it and see if the misfire migrates to that cylinder, then you know it's a coil problem. If you do have to remove plenum, you should replace rear plugs at the same time.

you do need to remove the upper intake plenum to replace the rear plugs. haven't found a easy way or special tool for the job.

you have to remove the intake plenum to access the rear plugs on the engine. it sounds rough but it is not that hard .just be sure to disconnect the sensors before pulling up on the plenum so not to damage them.

You have to remove the intake plenum to access the spark plugs. That's the piece that sticks up and completely covers the back side when looking from the front. If you have fairly average car repair skills, it isn't all that hard but does take a lot longer than a normal spark plug change-out. If you remove the plenum and do this job yourself, you MUST replace the intake plenum gasket or you will end up with a bad vacuum leak. I strongly recommend you refer to a maintenance manual if you attempt this procedure. There is a lot of stuff attached to the plenum that has to be removed.

You have to remove the intake plenum, the plugs are under it...Just take you time and watch what you are doing.. If needed, go to library and look in a repair manual for the vehicle as to how to R&R intake plenum.. Is this a 2.5 liter or 2.7 liter?

The 2.5 liter is the one with the plenum removal necessary...2.7 liter just has the plugs in the rear head but up under the windshield cowl.

2.5 liter, Remove the air plenum on that one to get to the back plugs,and when you do you,ll need to replace the gasket for it,those are hard to get to,use a really good socket because those are close and if the socket slips there's plenty of things to bust a knuckle on ,it takes a while to do those ,but be sure and don't hit the plug on anything when your installing it,that will throw the gap off and it wont run right,take your time with it,good luck.

2.7 liter, you do not have to remove the plenum. If you look under the wiper cowl area on the back head you will see the 3 coils just like on the Front bank. Remove the coils and the plugs are underneath. you will need a spark plug socket, 3 in extension, and a 1 in extension to get these out because of the clearance. Your car is the same as any 2.7 from 2001 until 2006.

Good luck

the upper intake plenum...you will have to remove the plenum to access the spark plugs...usually you are able to unbolt the plenum only and disconnect the front connectors and/or vacuum lines. and tilt the plenum up and out of the way to access the plugs... take care when doing this you can damage the engine if not careful. make sure you get a new intake plenum gasket...as well as the valve cover gaskets...the rubber rings that seal the spark plug tubes from oil tend to leak causing a misfire. you already have to pull the plenum might as well do the valve cover gasket while you are so far in it.

My 2002 Land Rover Freelander V6 thermostat crapped out as well and I decided to replace it myself.

The plenum is deceptive, but after 3 hours of looking and trying I finally got it off. Of course there are many hoses and electrical connections that need to be removed, but that's the easy part because you can see them all. The bolts that hold on the plenum are what your worried about and I will now tell you where they are. Read this and you should take about 30min to remove the plenum.

There are a total of 6 bolts to be removed that secure the intake plenum to the intake manifolds.

First remove the 4, 10mm large and obvious bolts at the top of the plenum. Now here is the tricky part, there are 2 bolts that are at the back of the plenum near the fire wall. As you are looking at the intake plenum from the front of the car, they are on the back side of the plenum near the fire wall on the passenger and driver side of the intake plenum.

Both bolts your looking for are 8mm bolts. If you remove a 10mm bolt, your removing the bolts that secure the rear spark plug coils.

The driver side rear intake plenum 8mm bolt is secured to the plenum itself. Fell with your hand about the back of the plenum on the right side for a lone bolt that is in the plenum with a metal tab that goes down to the back of the rear cylinder head. Remove the bolt that is attached to the intake plenum, not on the rear cylinder head

The passenger side one is a bit different. Feel on the back of the intake plenum about the passenger side for a metal support tab that comes down from the intake plenum and secures to the rear cylinder head. Where the support tab attaches to the head is a 8mm bolt that you remove.

Now here come the leap of faith. If you have the 4, 10mm obvious bolts removed and the 2, 8mm from the rear of the plenum removed, and if you can rock the plenum up and down about 2-3 inches,but it still feels like its attached to the intake manifolds in the middle of the engine, then you have removed all the bolts that secure the intake plenum to the engine. This is good.

The intake plenum is now being held on by the rear intake manifold by 3 O-ring gaskets. Push onto the back of the intake plenum near the firewall to expose a gap at the front of the intake plenum at the front intake manifold. Put 2-3 long flat screwdrivers into the gap or a small pry bar, and ever so gently but forcefully, apply prying force as to not damage the mating surface of the aluminum intake manifold, until the intake plenum pops off. It will just POP off.

Now that the intake plenum is popped off, take careful note of all the electrical plugs and hoses as to where they attach. You will not need any tools to disconnect the electrical plugs or hoses. To remove the hoses, push down the red ring with you fingers that the hose goes into and pull on the hose, it should come out very easily. The electrical connectors, push on the metal clip down and pull the connector loose. The electrical connectors only plug into their own plug, so you cant mess them up.

Tools you will need to replace the thermostat;

1. 8mm combo wrench. Make sure its not too long, shorter is better.
2. 10mm socket, shallow. 10mm combo wrench
3. 2-3 flat screwdrivers, for prying off the intake plenum
4. Ratchet wrench
5. 1 foot long worth of socket extensions. 2 6inch extensions will work as well
6. Universal socket joint
7. Angled needle nose pliers make it easier for hose clap removal, but straight needle nose pliers will work
8. Diagonal cutters to cut securing zip ties for the wiring harness

Take you time, once the plenum is off it goes pretty smooth after that. We removed just the forward intake manifold and that was more than enough clearance to remove the thermostat. You do not need to remove the fuel rail or spark plug coils from the manifold but you will need to disconnect the electrical connections to move the intake manifold out of the way.


Take pictures, there's a lot of hoses that go all over the place. The electrical connectors are only long enough to go where their supposed to go.

Then take that UK piece of **** to the dealer and trade it in for anything made in the USA or Japan. Changing a thermostat in any of those will only take 10 min and require 1 tool.

Repair provided by KPCYCLES.com of Honolulu, HI

Here's how I do it: -Pull the coils out on the front bank and change those first 'cause they're easy.
-Remove air box top and intake tube from throttle body as a unit by removing 10mm bolts in air box and 10mm clamp on throttle body (unplug MAF sensor too)
-Unbolt brackets from rear of upper intake (one of them actually has to come off...the one on the left, I think...). 
-Unplug all the assorted gizmo's on the plenum, and the wiper motor plug (it's sort of in the way...). The connectors are all different so there's no worry about mixing them up...
-Unbolt all of the visible 10mm bolts on top of the intake plenum that hold on ground wires and cable brackets, etc.
-Undo the plenum bolts (12mm), keeping care not to lose the lock washers from the two nuts on either end (warning, us a rag to cover the intake ports). 
-As far as I can remember, you should now be able to lift the plenum up and to your right enough to get at the rear plugs. You shouldn't need to remove anything from the throttle body (cable, connectors, coolant lines...). It can be held up with a bungee cord or something. Or perhaps an assistant...
-After changing plugs, assembly is reverse of removal. You can replace the gasket between the upper and lower intake if you wish, but it's metal and usually in quite good condition. Good luck and hope this helps. 

Depends on how MECHANICALLY INCLINED you are. Have you done any repair work on vehicle engines before? It's not that difficult to do if you know how to turn a wrench/ratchet and THINK about what you are doing and what you are dealing with... .attention to details. Ya think? On the 04 2.7 lit V6 Sonata, there are two nuts and 5 bolts (two long and three short) which hold the plenum to the RISER manifold. There are an additional 3 to 4 bolts at the rear (firewall side) which support the plenum (they're all 12mm bolts). You'll need to remove the intake air hose to lift the plenum out of the way to access the 3 plugs on the RH side (rear) of the engine. You'll want to replace the plenum gasket when you do this. When you reinstall the plenum, the tightening torque is 11-14 lb.ft. Do not tighten the REAR support bolts until after you torque the surge tank bolts to the intake (riser) manifold.

The best way to remove the rear valve cover is to remove the intake plenum. There is really no other way to do it. It is not a hard job, removing the intake plenum, but, trying to tackle the rear cover without taking off the plenum is almost impossible. If he does remove the plenum, make sure he replaces the plenum gasket. Hope this helps.
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