By the signs and reports the dealer ( which serviced the car just 2500km prior to the failure ) overfilled the engine oil causing the excessive oil to be blown into the PCV ( positive crankcase ventilation ) hose that feeds back into the intake.
The extra oil in the combustion chamber led to excessive EGT's causing the head to crack.
This is how I see it from the evidence, results and feedback at hand.
Oil in the combustion chamber is normal.
The engine has, like most other, a positive crankcase ventilation system. The crankcase pressure is relieved by passing the gasses into the inlet of the turbo, where the pressure is low.
These gasses contain oil and the oil settles in the inlet tract as well as the inter cooler. It is normally burnt with the diesel in the combustion process.
Unless it becomes a very significant amount, due to a increased crank case pressure, it does no harm, except reducing the effectiveness of the inter cooler.
Back to the cracked head.
Until the cause is found, the blame cannot be apportioned.
I have heard of very few Di-Ds cracking a head.
A head cracks due to overheating, which can occur due to reasons:
This can be caused by one or more of the following:
This is caused by running a to rich mixture (over-fuelling), which in turn can be caused by one or more of the following:
The engine has, like most other, a positive crankcase ventilation system. The crankcase pressure is relieved by passing the gasses into the inlet of the turbo, where the pressure is low.
These gasses contain oil and the oil settles in the inlet tract as well as the inter cooler. It is normally burnt with the diesel in the combustion process.
Unless it becomes a very significant amount, due to a increased crank case pressure, it does no harm, except reducing the effectiveness of the inter cooler.
Back to the cracked head.
Until the cause is found, the blame cannot be apportioned.
I have heard of very few Di-Ds cracking a head.
A head cracks due to overheating, which can occur due to reasons:
- insufficient cooling of the head by means of the coolant
- excessive EGTs
- defective manufacturing
This can be caused by one or more of the following:
- loss of coolant (burst pipe, lack of maintenance, etc)
- blocked coolant passages
- sticky thermostat
- broken / inefficient water pump (no circulation)
- blocked radiator
- reduced air flow over radiator
- inefficient / broken viscous fan coupling
- broken V-belt
- excessive use of power (towing/hills etc)
- extended runs at high EGTs
This is caused by running a to rich mixture (over-fuelling), which in turn can be caused by one or more of the following:
- incorrect pump settings
- broken injector
- ECU malfunctions
- reduced air intake (blocked pipes / filters)
Gerhard Fourie
If you want to shoot somebody, make sure you aim at his head, not your own foot.
Me
If you want to shoot somebody, make sure you aim at his head, not your own foot.
Me
Affiliate Member
This brings up a topic that concerns me regarding the report.
Can excessive oil cause high EGT? ( As diesel is an oil anyway and as 4ePajero mentioned that oil in small quantities is part of the combustion process )
Or is the excessive oil just causing a rich mixture causing high EGT?
Can excessive oil cause high EGT? ( As diesel is an oil anyway and as 4ePajero mentioned that oil in small quantities is part of the combustion process )
Or is the excessive oil just causing a rich mixture causing high EGT?
I am not a pro or mechanic. For that reason I am servicing my pajero at the agents. They must see red lights if something is going wrong. This damage didn't happen overnight. They should've notice something with the previous service. They always fix what is broken, not the cause of it.
My Pajero is paid in full, but I've got an emty garage, not even a loan vehicle from Mitsubishi.
My Pajero is paid in full, but I've got an emty garage, not even a loan vehicle from Mitsubishi.
Site Admin
Can someone post the report here? Perhaps we should invite the dealer response here before we start apportioning blame.
Simon Bloomer
Affiliate Member
See attached
Attachments:
Techrep LJ04-0110Mr. Morne Nel.pdf- (2.45 MiB) Downloaded 124 times
With all due respect,
a Technical Specialist acting on Mitsubishi's behalf will shoot that report full of holes.
My opinion:
The engine lost coolant, overheated and blew the gasket.
The head will invariably suffer under those circumstances.
a Technical Specialist acting on Mitsubishi's behalf will shoot that report full of holes.
My opinion:
- the engine overheated (at some stage) due to a cooling system failure. It could have been some time before the weekend of the 'incident'
- no mention of a search for evidence of a cooling system failure is made, such as looking for evidence of replaced hoses and coolant stains in the engine bay. It is as if nobody wanted to even entertain that possibility. "Can you, without a shadow of a doubt, state that the engine did not suffer a cooling system failure?" I think not.
- the reference to 'clogging' of the radiator looks like dodging. Why was the radiator not sent to a specialist for an opinion?
- the oil in the inlet tract is not responsible
- There is a major discrepancy between Ferdi's report and Alan Black's regarding the condition of the pump and the injectors. Including contradicting reports does not do your case any good (par 1.1.10 & 1.1.11).
- This paragraph 2.3 ("The cylinder bores all exhibit evidence of abnormally high combustion chamber temperature
conditions having prevailed in this engine. This is in the form a “checker pattern”
concentrated in the combustion chamber environment where a “heat soak” in the structure of
the engine block has thermally discoloured as a result of significant heat dissipation through
these surfaces. (See photo plate 4). The cylinder bores exhibit evidence of vertical piston to
bore seizure damage commencing from the combustion chamber environment extending down
the cylinder bores along the major thrust/ anti-thrust axis. (See photo plate 4).") is not technically very good and contradicts itself, referring combustion chamber, bore, block etc in a dis-functional way. - EGT related overheating does not cause seizure failures AFAIK
- par 3 conveniently assumes that the problem lies in the crankcase ventilation system, without comparing it to a 'normal' engine. It basically says that the design is at fault. Most TD engines' inlet tract look like that (if they have Positive Crankcase Venilation.
- It was never proven or even suggested that the blow-by is 'excessive'. What is excessive IAC?
The engine lost coolant, overheated and blew the gasket.
The head will invariably suffer under those circumstances.
Gerhard Fourie
If you want to shoot somebody, make sure you aim at his head, not your own foot.
Me
If you want to shoot somebody, make sure you aim at his head, not your own foot.
Me
If Mitsubishi had spesialists, why did I pay a forencics team to find out what is going on.
Yes, the water went thru the cylinder head (pressure test by Mitsubishi)
Sorry, never did my pajero ever run over its normal temp. Never even done a 4x4 trail. I've got a Willys for that purpose.
I wish I could take my Pajero to Pinetown Mitsubishi. They previosly sort out a problem Midrand couldn't, before I went on vacation in April 2
Yes, the water went thru the cylinder head (pressure test by Mitsubishi)
Sorry, never did my pajero ever run over its normal temp. Never even done a 4x4 trail. I've got a Willys for that purpose.
I wish I could take my Pajero to Pinetown Mitsubishi. They previosly sort out a problem Midrand couldn't, before I went on vacation in April 2
Thanx for all youre replies. Unitrans extended Waranty desided to pay for a new engine and a very helpfull Paul @ Midrand Mitsubishi went out of his way to give me a courtesy car. Yesterday he told me he will make a plan and today i've got a Lancer till my Pajero is ready. THATS GOOD SERVICE.