Mitsubishi 3.0L V6 SOHC and GenI Montero/Raider FAQ:
Valve Cover GasketsQ: Why are my vlave covers leaking?
A1: Possibly because the blowby ports (one of those being the PCV valve) have become clogged allowing a buildup of pressure undereath the valve covers eventually expelling the pressure through the seal created by the valve cover gasket. Oil will be expelled with the pressure release.
A2: Age.
A3: If your vehicle has recently experienced an overheat condition, it can harden the valve cover gaskets to the point where they no longer adequately seal.
A4: The valve cover bolts are too tight
A5: The valve cover bolts are too loose.
Q: How easy/difficult is it to change my valve cover gaskets?
A: Remove the ignition coil bracket. Remove the intake plenum. 2 bolts of varying length hold each valve cover down; remove them and work the valve covers until they are removed. Scrape out the old valve cover gaskets.
Place high-temp gasket maker at the elbows for the half-circle cutout at each end to seal the gasket and install the new gasket. Tighten the valve cover bolts to 6-7ft-lbs (8-10Nm). Installation is the reverse of disassembly. Make sure to replace the intake plenum gasket as well.
While you're at it: Replace/clean the PCV valve, clean the baffles of your valve covers, clean out your intake plenum.
Links:
Huge oil leak (06/21/04)
90 V6 Valve cover gasket leaking (09/08/03)
Valve cover gasket question (12/16/02)
Plenum Removal (06/04/04)
PCV valveQ: Where is the PCV valve located?
A: The PCV valve is located on the driver's side valve cover underneath the intake plenum.
Q: How easy/difficult is it to change the PCV valve?
A: On most early 3.0L engines, the intake plenum will have to be removed in order to get to the PCV valve. Some models without EGR systems make the PCV vavle more accessible and possible to change without removing the plenum. Replace the PCV hose and the hose on the passenger's side vavle cover while you're at it. You will also have to replace the gasket for the intake plenum if it is removed.
Q: Can I reuse the PCV valve?
A: YES. The PCV valve on this vehicle is very durable and can easily be salvaged with a few spritzes of carb cleaner.
While you're at it: Clean your valve cover baffles, replace your valve cover gaskets, clean your intake plenum.
Links:
Wheres the PCV valve? (12/26/04)
PCV Valve Question (02/29/04)
PCV Valve...Removal trouble!! (01/27/03)
ThermostatQ: Where is the thermostat located?
A: Follow the upper radiator hose back to the nozzle on the intake manifold. The thermostat is located under the nozzle.
Q: How easy/difficult is it to replace the thermostat?
A: Remove the 3 bolts for the ignition coil bracket and set it off to the side. Disconnect any crowding wires. Remove the upper hose from the nozzle. Remove the 2 bolts for the upper hose nozzle and pull it off (you may have to pull hard). The thermostat is plainly visible once the nozzle has been removed. Pry out the old thermostat and scrape off the old gasket with a razor. Install the new gasket and thermostat. The thermostat must be installed correctly to insure proper operation. Draw an imaginary line across the verticle supports on the thermostat. This line should parallel the front of the vehicle, i.e. the imaginary line should extend perpendicular to either side of the vehicle. Due to the offset design of the thermostat and the thermostat block, it is difficult to install the thermostat in the wrong postion.
While you're at it: Replace the U-shaped bypass hose on the thermostat block.
Q: At what temperature does the thermostat operate?
A: The stock thermostat will start opening at 190?(88?C) and will fully open at 212?F (100?C).
Links:
Replacing Thermostat in an 89 LS....where and how? (12/28/04)
Automatic Free-Wheeling HubsQ: My auto hubs lock/unlock when they're not supposed to. What can I do about this?
A: GET A SET OF AISIN or SUPERWINCH or WARN MANUAL LOCKING HUBS! Preference is in that order.
Q: Where can I find Aisin manual locking hubs?
A: Junkyards. Look at model years from '88 and prior.
Q: Why is preference given to Aisin manuals?
A: Simplicity. Durability. Reliability. Ease of service.
Rough IdleQ: Why is my idle rough?
A1: Most likely it is because your Idle Air Control (IAC; read also Idle Speed Control or ISC) servo is dirty.
A2: You have a vacuum leak.
A3: Your EGR system (if equipped) is not operating properly.
A4: The wiring harness for the Airflow Sensor is disconnected (reconnect the wiring harness).
Q: Where is the IAC/ISC located?
A: The IAC/ISC is located on the front of the throttle body, to the bottom right, and has a wiring harness connected to it.
Q: How easy/difficult is it to clean the IAC/ISC?
A: Disconnect the negative battery terminal. Remove the connector for the IAC/ISC. Remove the 2 bolts that hold it in. Wiggle it free. Clean the IAC/ISC with a clean shop towel and a small spritz of carb cleaner if necessary. Do the same for the mating port on the throttle body. Be sure not to get any cleaners deep inside the throttle body or on any gasket surfaces. Replace the IAC/ISC.
Q: What are the possible sources of a vacuum leak?
A1: Vacuum lines for the Emissions Control System.
A2: Breech of the ducting between the airbox and the throttle body.
A3: Bad gasket seal between throttle body and intake plenum.
A4: Bad gasket seal between the intake plenum and intake manifold.
A5: Bad gasket seal between the intake manifold and cylinder heads.
A6: Bad gasket seal between EGR (if equipped) valve and/or pipe and the intake plenum and/or exhaust manifold.
Engine HesitationQ: My engine hesitates when I step on the gas. What is causing this problem?
A1: Your IAC/ISC is dirty.
A1: You have a clogged fuel filter.
A2: You have dirty fuel injectors and/or intake valves.
A3: Your Fuel Pump and/or Fuel Pump Relay switch are malfunctioning
A4: Your EGR system (if equipped) is not functioning properly.
Automatic TransmissionQ: My A/T will not downshift or downshifts very late in the gear cycle. Why is this?
A: There is a problem with your Throttle Control Cable (read also Detent or Kickdown cable). The cable has most likely rusted enough to prevent easy movement through the sleeve.
Q: What/where is my Throttle Control Cable?
A: The throttle control cable helps to control shift points depending on the position of the throttle blade. It is located on the top of the throttle cam. The cable itself runs across the top of the intake plenum, curves down and disappears underneath the driver's side footwell, and connects to the valve body on your A/T underneath the vehicle.
Q: How easy/difficult is it to replace the Throttle Control Cable?
A: Replacing the Throttle Control Cable is generally beyond most people's experience level. It involves dropping a valve body inside A/T oil pan. Find a good transmission shop that you trust, bring them the new cable, and ask them to install it. Generally, this operation costs ~$150. Ask for the old cable to make sure the work has been done. Drive the vehicle to make sure the work has been done correctly.
Q: Can I adjust the shift points from the Throttle Control Cable and if so, how do I go about doing so?
A: Yes, but do so using caution; the Throttle Control Cable controls the actuation of particular valves in the valve body and maladjustment can cause other problems. Using the 2 14mm bolts on the bracket located on the top of the intake plenum just behind the throttle cam, you can adjust the tension on the Throttle Control Cable. Adjust the cable until shift points are smooth and predictable. Retighten the 2 14mm bolts in that position.
While you're at it: Drip a few drops of ATF down the Throttle Control Cable.
Q: My A/T Temp light comes on while I'm driving. Why is this?
A1: YOUR AUTOMATIC TRANSMISSION IS OVERHEATING. DO NOT DRIVE THE TRUCK WITH THIS LIGHT ON. THERE ARE SPECIFIC INSTRUCTIONS INSIDE THE VEHICLE ON WHAT TO DO IF THIS LIGHT ILLUMINATES. FOLLOW THEM OR RISK MAJOR DAMAGE TO YOUR TRANSMISSION!
A2: Your ATF level is too low.
A3: Your ATF level is too high.
A4: Your A/T filter is clogged.
A5: Your A/T oil cooler is obstructed or not functioning properly.
Q: What can I do to keep my A/T from overheating?
A1: Make sure the A/T oil cooler on the front of your vehicle is not blocked or caked with debris. Also, check to make sure none of the cooler lines running from the transmission to the oil cooler are bent or kinked.
A2: Change your transmission filter. It is located on the valve body in the oil pan under the transmission. You'll have to drop the large crossmember that supports the A/T and the shifter linkage in order to access the pan. If this is beyond your mechanical abilities, have a shop perform the operation for you.
A3: Drain and refill your ATF with a high-quality DexronIII at least every 20,000mi.
A4: Make sure your ATF level is correct. Too much or too little ATF can cause your A/T to overheat.
Q: How hot is my ATF when the A/T Temp light comes on?
A: The A/T temperature sensor will actuate at ~302?F (~150?C).
Q: My A/T Temp light comes on when I start the car and stays on. Why is this?
A: The A/T Temp sensor is broken. Replace the A/T Temp sensor.
Q: How do I drain and fill the A/T?
A: Briefly drive the truck around the block to allow the ATF to warm up. Open up the drain plug on the bottom of the pan and let the ATF drain out. Replace with a quality DexronIII ATF. With the truck running and your foot on the brake, shift through all gears to fill up the torque converter. Put the shifter in P and recheck the ATF level on the dipstick. Do this several times. The ATF level measured on the dipstick should never get above the "HOT" upper limit. If this happens, the A/T has been overfilled. Drain off some ATF in order to get the ATF to the proper level.
Q: How many quarts of ATF does my A/T take?
A: A drain and fill will require ~3-3.5qts. The entire A/T has a capacity for 7.5qts of ATF.
Oil & Oil PressureQ: I'm doing an oil change. How many quarts of oil does my engine take?
A: ~4.5qts on vehicles without an oil cooler. ~5qts on vehicles with an oil cooler.
Q: What items do I need for an oil change?
A: 5qts of oil, a high-quality oil filter, a gasket/crush ring for the oil pan drain plug, and a drain pan for the old oil.
Q: What kind of oil should I put in my engine?
A: Most SAE rated oils are acceptable. 10W-30 is the most common used.
Q: What kind of filter should I use when I change my oil?
A: Use a high quality oil filter. NAPA Gold filters and Mitsubishi OE filters are preferred, but others brands are available.
Q: The needle on my oil pressure gauge barely moves. Why is this?
A1: The oil pressure sending unit has gone bad.
A2: You have low oil pressure.
Q: How easy/difficult is it to fix the Oil Pressure Sending Unit?
A: The Oil Pressure Sending Unit is located on the front of the oil filter bracket. It is a small cylindrical metal object with a single wire lead connected to it. Disconnect the wire and unscrew the unit. Replace with a new Oil Pressure Sending Unit (available most anywhere). Reconnect the wire lead. If the the oil pressure still does not register on the guage then you may have more serious problems than can be solved in FAQ.
Q: What kind of oil pressure should I be getting?
A: The stock electronic gauge setup should display ~10psi/1000rpm. Expect higher readings at cold startup and lower readings at hot idle. At highway speeds, the gauge should be reading ~30psi.
Q: Is the stock Oil Pressure gauge accurate?
A: No, not really. It basically lets you know whether you still have oil pressure or not and is prone to failure.
Tire SizeQ: What size tires can I fit on my GenI Montero/Raider?
A: 31" up to 33" tires fit easily on stock 15x8" rims with little or no modifications. 32"-33" tire sizes may require some trimming of the bumper ends and possibly a moderate suspension lift and/or body lift.
SuspensionQ: How can I raise the suspension on my GenI Montero/Raider?
A: The easiest way is to crank the torsion bars which support the front suspension. A rear lift can be accomplished with add-a-leaf springs or different coil springs depending on suspension type.
Q: How do I crank my torsion bars?
A: Find the rear anchor of the torsion bar. There is a bolt running through each anchor. Place a 17mm box end wrench on the top nut of each anchor bolt and tighten the bolts until the desired lift is achieved.
Q: Is a torsion bar crank really that easy?
A: Yes and no. Yes, it's easy to do, but you'll need a front-end alignment after you do it. Most standard alignment shops will not service a suspension lifted vehicle because it's beyond their capability. Look for a frame alignment shop in the Yellow Pages. Be prepared to open your checkbook.
Q: I cranked my torsion bars and now it rides really rough. Why is this?
A: You cranked the torsion bars until the upper control arm is resting on it's bump stops. Trim the bump stops about half way and it should remedy the problem.
