Pajero Owners Club of South Africa

Been hearing what sounds like an exhaust leak and had it checked out today. The guys reckon there is a crack in the exhaust manifold and recommended fitting a branch. Is this advisable? Any other alternatives?

Personally I would keep it standard.

They start mucking with the exhaust manifold and then perhaps the turbo gets relocated and then they hack pipes from the airbox and to the cold side of the turbo intercooler and ...

Maybe more to the point is to find out why the exhaust manifold cracked. Are you perhaps experiencing high EGTs? And if so, why etc etc.? Because maybe there is something underlying this that may be an indicator of worse damage to come if the root cause is not removed.

Don't just fix the symptom - find and fix the cause.

Hi Andrew, I fully agree with you. To be honest I'm not too sure if that really is the case - is it possible to diagnose this without physically seeing the manifold?

The car performs well and apart from consumption that's bit heavy (average around 12.5/100) there isn't anything that shouts "big problem" at me.

What would tell-tale signs be of a cracked manifold? And is the culprit perhaps the manifold gasket?

Andrew,

Both the manifolds on my Pajero cracked. The left was first to go and then about 10k-km later the right hand side manifold decided to go. My car never overheated, the exhaust system is still original and in good (excellent) condition, has not been bumped, etc. The cracks were welded and the faces (exhaust - cylinder head faces) machined flat by a friend of mine and for the last 3000 km been "normal" - no leaks. Would you care to venture a guess as to the reason for them cracking?

Cloyd

Hi cloyd.
If I may add M2CW. Where did the manifolds crack? Are the heat Shields still in place?

I have read that the heat shields protect the manifolds from water splashes, the thermal shock of the red hot manifolds being quickly quenched by cold water can possibly cause them to crack.

My previous Gen 3 6g74 Pajero's manifolds also cracked. I had them welded, lasted less than a year, doubt if they were done as carefully as yours by the indie I used. I had a set of branches made up for the same price as one manifold from the agents from noise boys.

Sent from somewhere in a galaxy far, far away...

cloyd wrote:Andrew,

Both the manifolds on my Pajero cracked. The left was first to go and then about 10k-km later the right hand side manifold decided to go. My car never overheated, the exhaust system is still original and in good (excellent) condition, has not been bumped, etc. The cracks were welded and the faces (exhaust - cylinder head faces) machined flat by a friend of mine and for the last 3000 km been "normal" - no leaks. Would you care to venture a guess as to the reason for them cracking?

Cloyd

Cloyd,

The OP was not me, it was fr4nn4.
His engine is Di-D. I think yours is a petrol V?
I wonder what sort of EGTs you experience?

If you Google this you will see quite a few reports of the Pajero / Colt / Triton V-engines (petrol, of course) developing cracked exhaust manifolds. I think mitsu may even have later changed from cast iron to pressed steel exhaust manifolds on the Vs in recognition of this problem.

It also looks in some cases Mitsubishi came to the party in accepting responsibility for the failed manifolds.

Generally, when owners have experienced this problem, they have replaced with correctly dimensioned custom branched manifolds, not requiring relocation of any components on the V engines. And have claimed a slight improvement in performance.

AFAIK this is not a common fault on Di-D engine.

fr4nn4 wrote:Hi Andrew, I fully agree with you. To be honest I'm not too sure if that really is the case - is it possible to diagnose this without physically seeing the manifold?

...

What would tell-tale signs be of a cracked manifold? And is the culprit perhaps the manifold gasket?

@fr4nn4,

When the car is cold, you could get someone to hold a cloth over the outlet end of the exhaust and then see if you can detect blowing in the engine compartment around the exhaust manifold.

Also look for signs of soot on the manifold / near the gasket face.

If you look at this thread: https://www.pajeroclub.co.za/forum/viewtopic.php?t=4154 you can see that one cause of cracked manifold on Di-D engine is lost / broken / stripped exhaust manifold nuts / studs. Then it seems that the weight of the turbo hanging can cause cracking.

Has anyone worked on your turbo / exhaust side previously?

Nick,

My Pajero 3.8 engine and exhaust system is still like the day it was "born". Heat shields on top as well as those lower down are all in place and in 100% condition. Both cracks were between the second and third port. After the welding both manifolds pulled with a gap of about 5mm at one end when measured lengthwise. Both were machined flat on a milling machine to get the mating surfaces absolutely flat. If they should crack again (and I am waiting for it) tubular manifolds will be fitted.

Cloyd