Heys,

Anyone know where is the coolant temperature sensor located? Have an issue of temperature rise during turn on of headlights, LMST 4 bar (Normally 3 bar). Haynes noted its "underside of inlet manifold casing".

Some webpage mentioned add grounding to headlights, and also ensure headlight not sharing same power source/leads with the sensor. If that does not solve suspect instrument cluster.

But I guess i'll have a look at the temperature gauge first and perhaps add more grounding to it before proceed to adding grounding specifically for headlamp.

Also note that prior to this I had retarded timing, which equates to probably higher running temperature as well. Coolant drain off and fins cleaning had been done prior to retarding timing too.

Perhaps the engine might already run slightly overheated already prior to retard timing, retarding makes it overheated. Maybe the situation is: (From my logic and AlbertB mentioned about high working temp of engine after retarding)
Before retarding timing, headlamp off: 3.5 bar (Meter display 3 bars)
Before retarding timing, headlamp on: 3.8 bar due to aged grounding issue (Meter display 3 bars)
After retarding timing, headlamp off: 3.8 bar (Meter display 3 bars)
After retarding timing, headlamp on: 4.1 bar due to aged grounding issue (Meter display 4 bars)

Currently no solution to it from my side yet.

Forum sources mentioned connectivity between battery and battery ring not good, result in lower voltage and under charge situation. This situation is also true as I just installed a new battery not long ago and the charge doesn't seems to be good, have a voltmeter reading, looks like this new battery cant be fully charged, resulting errors in readings? But I doubt it from testing.

First run the engine with headlamps on a short trip, when see 4 bar a few times. Park at a safe place, leave headlights on, wait it 4 bar, or if already 4 bar, then quickly turn key to ACC, then to ON. You'll see the temp reading is 3 bar again. Test means the undervoltage is irrelevant here as the sensor works through out all battery voltage range, including just 12V. You can also straight start back the car, the temp will also display 3 bar.

Since forum also quoted it might be sensor grounding issue. I also tried to take jump start cable and connect to the grounding wire from engine to firewall, at the engine side grounding nut near the starter. Wait temp till 4 bar, then clamp the engine ground to negative terminal of battery. The fault does not clear immediately. I tried already, with car idling condition and headlamp on, it'll take 1min+ to cool back from 4 bar to 3 bar, regardless of with and without jumper cable aka extra ground direct to battery. So i dismiss the statement of bad grounding too.

Itenary that is related and can further troubleshoot:
Temp sensor resistivity test, values at haynes manual, to check faulty temp sensor (Requires unscrew thermostat)
Additional Groundings from headlight to ground (Not sure if they share the same power cable on lights and temp sensor)
Faulty instrument cluster voltage regulation (forum quoted for foreign cars)

But it should be solved easily by "work around" of the problem. New cooling systems or change either of the components. I believe its the combined issue of slight inefficient radiator, aged fan, or other inefficincy of the cooling system. So maybe the meter interpret around "3.5 bar" already normally, then at night with slight voltage drop, and some other electronic issues, the meter interprets "3.8 bar" which show 4 bar. However, a quick off engine and restart engine will show 3 bars again, which is rather

Add on for DIY:
Identify by jacking up the car, leaving suspected wheel suspended. Then, turn the wheel and place hand at absorber. If there's vibration/shaking from absorber while wheels is rotating, bearing is suspect. If not sure, try a few wheels and sure you can tell the difference.

wheel bearing sound nothing to do with alignment
consider changing workshop

if he insist alignment/chassis repair, tell him to print out your alignment reading and show it to us.

also do enlighten us why the absorber/brakes need to be changed.
pictures and detailed description would help

that's tire issue then, not wheel bearing.

that's referring to the suspensions or more particularly, the lower arms or axles.

kayaba (KYB more specifically) are under UMW in malaysia, although the parent company is basically Japanese and being a long time huge manufacturer of suspensions and is oem for many car make/models.
no complaint on them since among cheapest price/comfortable stock ride.

bushes/mounting etc are sold separately.