Gen 3 Timing Belt job + spark plugs check list (3.8L)

SampaGuy

Member
I am getting ready for my timing belt job next week on my 2004 Limited, probably starting on Monday or Tuesday and going to work on it all day, hoping I can get it done in 3 days at the most. It will be my first timing belt in any car. I will also do spark plugs and the secondary butterfly removal while I'm in there. I would appreciate if you have any feedback on my plan:

High Level Plan:
Day 1: Spark plug change, removal of secondary butterfly valves, put intake back together, drain coolant, disassembly of timing belt
Day 2: Install new timing belt and put everything back together
Day 3 and hopefully not 4: allocated extra time for the above since this will be my first time



Here are PARTS what I have so far:

  • Aisin Timing Belt kit with Water Pump
  • Mitsubishi MD362861 Engine Timing Belt Tensioner
  • Crankshaft pulley bolt and washer
  • Crankshaft seal
  • 2 camshaft seals
  • new drive belt
  • new radiator upper and lower hoses
  • new thermostat
  • new spark plugs and plug wire set



1. Do I need intake plenum gaskets? Upper or lower, both? Do I need spark plug tube seals? Anything else?

2. Chemicals: I will buy spark plug anti-seize, WD40, and new coolant. Anything else I need? Locktite? Anti-seize? Grease?

Thank you!
 

SampaGuy

Member
Also, I will try to build the homemade tool to hold the pulley before I start, or at least have the metal and screws for it ready.
 

ChrisCosta416

Well-known member
Do your Crankshaft position sensor, and valve cover gaskets. There is a Gen3 maintenance write-up with all the required parts
 

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RyanY

Adventurer
Why do you need WD40?

Have you looked into replacing the butterfly valves rather than removing them and suffering the low-end torque loss that will create? The lower intake from a Kia Sorento with the 6G74 can be adapted by welding and redrilling one mounting hole, and they're inexpensively available.

It wouldn't hurt to do the spark plug tube seals and valve cover gaskets while you've got the intake off.
 

SampaGuy

Member
I will add the valve cover gaskets, crankshaft position sensor, spark plug tubes. Do I need to buy RTV? I have never done a valve cover gasket or any similar gaskets. I will look for some videos.

Some have reported no impact from removing the secondary butterfly valves, we'll see. It is not that hard to get back in there if needed. I don't want to add any more complexity to this job, but don't want my motor to grenade itself. WD40 is to remove tight bolts of course :)

nwoods, I am in California but I am originally from Brazil.
 

Michael Brown

You followed me, so now we're both lost
I ordered the DNJ Intake Manifold/Plenum gasket kit. They have worked great on my 05. Some people have reported issues with the Fel-Pro valve cover gaskets, but I cannot confirm this.
 

jlocster

Explorer
This is my copy/paste response for Gen 2/2.5:

"In your case, think of what you're doing as 2 separate jobs.
1--Front of the engine includes: timing belt, water pump, front cam seals, crank seal/bolt
2--Top of the engine includes: valve cover gaskets, spark plugs/wires, spark plug tube grommets, rear cam seals

Now, since the top of the engine will be apart/accessible, I'd also strongly recommend you replace both rubber heater hoses and the rubber coolant crossover hose at the rear of the engine.

In that same vein, while the front of the engine is apart, I'd strongly recommend you replace your upper/lower radiator hoses, accessory drive belts, and thermostat. You may also want to consider the cam and crank sensors."

I'm assuming the Gen 3 is similar...

Chemicals: I like Permatex #2 on paper gaskets (water pump), sensor safe RTV on rubber gaskets and around the sealing surfaces of the cam/crank seals, dialectric grease on electical conections/spark plug boots, antiseize on all spark plugs/bolts...on my Gen 2.5 I used a light coat of motor oil to seal the valve covers...not sure if the Gen 3 has same valve cover design or gasket material as the Gen 2.5...hopefully someone else can chime in.
 
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RyanY

Adventurer
Some have reported no impact from removing the secondary butterfly valves, we'll see. It is not that hard to get back in there if needed. I don't want to add any more complexity to this job, but don't want my motor to grenade itself. WD40 is to remove tight bolts of course :)
You WILL lose some low end torque - regardless of how some people "feel" their engine to be after removing the butterfly valves, it's a matter of physics.

WD40 is not a penetrating oil - the WD stands for "water dispersant" - virtually anything it does can be done better with another product and it's really only useful if you don't have anything else available. Use a proper penetrating oil like PB Blaster or Kroil and you will have far better results.
 

SampaGuy

Member
Thank you guys, I start the tear down today.

I'm thinking maybe I should just red threadlock the secondary butterfly valves instead? I didn't know red threadlock existed.
 

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RyanY

Adventurer
Typically when the shaft bushings wear and allow the shaft to move, it develops a vacuum leak at the front end of the shaft. Using threadlocker on the screws will prevent them from coming apart but won't do anything to help solve the vacuum leak.
 

SampaGuy

Member
Typically when the shaft bushings wear and allow the shaft to move, it develops a vacuum leak at the front end of the shaft. Using threadlocker on the screws will prevent them from coming apart but won't do anything to help solve the vacuum leak.

Good to know. I will use the red threadlocker.
 
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