The most common issues as far as the noise you are describing are usually the balance shaft belt tensioner, as they fail very regularly. The drivebelt tensioner also has a tendency to fail in the pulley's bearing.
I would remove the drivebelt and start the vehicle, and verify if it is coming from the belt drive system or internal/timing belt system. If the noise goes away, remove the detachable pulleys (tensioner) and check them for wear, as well as the unit pulleys (alternator, power steering, etc). If the noise does not go away and you are certain it is in the front end, then it is time to think about doing a timing belt job.
I would strongly suggest you leave the timing belt on this vehicle to a professional. This is one of those belts that if you have to ask about it, you may be better off with a pro. Improper installation will destroy the cylinder head at best, XXXXX XXXXX create piston/rod damage in worst case scenarios.
As far as special tools, the only ones that you really *must* have are the timing belt tensioner adjuster (available from Mitsubishi), as improper tensioning without it will lead to belt failure, and a cam gear lock (available aftermarket). The cams are heavily tensioned when at TDC on this car and are impossible to hold in place without a lock tool.
One other thing to note, while it is not the norm, is that I have run into tensioner type noise when cold on these vehicles when they have had prolonged use with non-synthetic or low quality oil and insufficient oil changes. The noise is from the pump gears in the oil pump seizing intermittantly. I'm not sure what your maintenance history/standards are, but if they are lacking, this could be a possibility for you as well.
That's cool, I've actually spent the past several years at a Mitsu/Volvo only shop myself :)
Regarding the tensioner etc being OK. If you are going in for a belt just test each one, and replace as necessary. If it is your personally vehicle, I'd just do them all for piece of mind. For a customer, test and report to them; they often don't like it when they add $50+ per pulley to the job and skip them if they are tight/quiet.
The long rod you speak of is not the tool I meant.... I usually do not use that one honestly, it isn't really necessary. All it does is make it easier to put the grenade pin int he hydraulic tensioner if the belt had been done before and was not tensioned properly. The tool you need is MD989767 and is for settin gthe eccentric position of the main belt tensioner after removal. It is very small (smaller than gambling dice) and shaped like a horseshoe with two pins and a 1/4 drive hole.
Remove RF wheel
Remove the drivebelt
Remove drivebelt tensioner (14mm center bolt and 12mm offset bolt)
Loosen crankshaft center bolt but donot remove.
Remove four 12mm crankshaft pulley bolts and remove crankshaft pulley.
Remove drive belt idler pulley by removing center 14mm bolt
Remove power steering hose support via 12mm bolt
Choice of two: support engine with overtop engine support stand or remove exhaust downpipe and support engine from below with wood blocks on oil pan.
Remove engine front motor mount.
Remove four 10mm bolts from water pump pulley
Remove timing belt top cover
Remove lower belt cover
With the crank bolt snug, rotate engine clockwise until A) rear balance shaft belt XXXXX XXXXXnes up with block, B) crank reluctor plate notch lines up with block, C) both camshaft marks line up with valve cover marks, D) oil pump/front balance shaft XXXXX XXXXXnes up with raised arrow on oil pump.
This may take up to six revolutions due to the phasing of the oil pump.
Insert a grenade pin into the hydraulic tensioner, then remove the two 12mm bolts.
Slide the cam belt off.
Remove two 10mm crank position sensor bolts and set sensor aside to allow belt off.
Remove loosened crank bolt and slide crank sprocket off crankshaft.
Remove crank reluctor wheel, notating front/back orientation
Loosen center bolt on balance shaft belt; note orientation of eccentric
Remove center bolt and tensioner.
Check tensioner condition: Look for oil tracking out back of seal; spin next to your ear listening for loose, 'dirt in bearings' type noise.
Install new balance shaft belt
Install new tensioner, set eccentric to same position. Balance shaft belt should have 1/4"-3/8" of deflection at top side of belt when tightened correctly. If this belt is "drivebelt tight" you WILL have excessive noise and potentially a check engine light. 1/4"-3/8" deflection looks loose, but is normal.
Inspect belt tensioner pulley for same noises by spinning, replace if necessary. You can check the idler as well, I have never seen on fail ever though.
Install reluctor wheel in correct orientation and crank sprocket.
Install cam belt temporarily
Install crank bolt temporarily
Install crank position sensor and tighten two 10mm bolts
Align crank, both balance shafts, and both cams to previously noted marks and insall belt into position.
Reinstall hydraulic tensioner, with pin still installed.
Using MD998767 and a torque wrench (needle type) apply 31in/lbs tension to eccentric tensioner and tighten in position.
Release the grenade pin.
Rotate engine two rotations and verify tension is correct.
*if you do NOT remove the main belt tensioner, this leaving it in eccentric position, you can not fool with the previous step. If you need to replace the tensioner however, that step must be performed.
Once verified correct, torque the crank center bolt.
*Be sure you do NOT move the oil pump balance shaft sprocket from its location; there are 6 possible *correct* locations, but only ONE for each engine revolution. If it is incorrect, the engine will rattle/vibrate heavily and set a check engine light.
If you lose position, there is a set bolt behind the downpipe you can access in an emergency to reposition it.
Here is the special tool from mitsubishi (with torque wrench applied)
Here are the balance shaft and main belt timing positions:
Reassemble all parts in reverse order, checking drivebelt idler pulley and drivebelt tensioner pulley for noise by spinning near your ear. Replace as necessary. Both of these pulleys tend to fail after having driven through deep water.
If you have any questions, let me know. Please remember to click Accept when you are done, I do not receive credit for my answer until you do.
If you have any problems, let me know. I am very familiar with these :)