Dear @xulfiqar!
I know most of my questions have been answered in a couple of older posts. However, I wish to discuss my vehicle in particular please.
I have bought a 1993 model LWB Gen II Pajero with 4D56 Engine. It has been with me for more than two months.
I want to get the engine inspected by someone who knows diesel engines. So far unable to find anyone in Lahore. Following are the symptoms of my engine:
PROS:
It sounds okay, starts in split second any time of the day with a minor puff of black smoke which vanishes immediately without any more smoke until accelerated aggressively. The temperature gauge stays normal with AC in urban traffic as well as long highway runs. The coolant level remains up to the mark. Haven't had to add a single drop of coolant for the last 3000 km, although I check levels regularly. There is no boiling of coolant in the reserve bottle as well as no no level drop. The vehicle accelerates fine. The fuel economy is outstanding. I get around 8.5-9 kmpl in urban traffic with AC. On highways, I get around 11 kmpl @ 95-100 kmph. The car does not give extraordinary exhaust smoke even when on high speeds and aggressive acceleration.
CONS:
My car reduces oil 
need to top up adding 1/2 to 3/4 litre every 1500 km. When hot and engine running, as I remove the oil filler cap, I get drops of oil flying in the air. The blow pipe (The one that goes into the air filter pipe) when removed give smoke on a hot running engine. I think this is called blow by and any mechanic who sees this, gives his verdict that the engine is WEAK. I also have an oil spillage from the back of the head chamber, what could be the cause of it? I am also not sure if the turbo is working fine as I never hear the whistle. The acceleration however is satisfactory. I cannot find the EGR, looks it has been removed.
I have done a road trip of about 1000 km (round) in which I took the car to Azad Kashmir. I faced some really steep climbs and rough terrain, the car came out of it fine.
To cut the story short, I am concerned about the following:
1) Reduction of Engine Oil as mentioned above
2) Spillage of oil from the back of the head chamber
3) Blow by
4) Inspect / service / diagnose the turbo
Please advise where to begin. Hope I don't sound too confused. I am planning a family trip up North from August 1 and want to get all the inspection and maintenance done before that for peace of mind.
Appreciate your reading so far and would highly appreciate your advice.
Other friends may also suggest some mechanic who thinks systematically, though a very rare breed to find in Lahore. Thanks
