Some 4m40 questions from a diesel newbie.

[roddersp]

Hi all,

Have owned a 4m40 (NL) 180000 kms for a few months now and have a few questions that I hope someone can help me with:

1. I have an ongoing oil leak from the rear end of the motor that I am trying to track down. Not serious - motor uses negligible oil over 5000kms. But over time it sprays a film of oil over the exhaust manifold heat guard and areas of the firewall. It looks like it is coming from the head gasket on the exhaust manifold side at the rear of the block - but very hard to see. It is not from the rocker cover. Has anyone had a similar experience?

2. Have some smoking issues. Blew some serious black smoke under load at low rpm. Had injectors and valve clearances serviced. This has improved it alot but I still get some smoking. Looks more grey than black - and most noticable at higher rpm (above 3500rpm - not that I go there very often). Also smokes when I pulse the throttle from idle. Will this motor always blow a little smoke - or should I expect it to run perfectly smoke free?

3. Has anyone had experience with a diesel service centre/mechanic in Adelaide that knows the 4M40 well? Prefer somewhere down south - but happy to travel for piece of mind.

Many thanks,

Rodders.

[robz]

Hi Rodders.
The leak could be coming from the back of the rocker cover.
There is a half moon robber seal there at the back near the cam.
A little bit of sealent over it before you tighten down the cover should seal it.
Is the black smoke while under load or accellerating?
I fixed mine by turning down the fuel load and increasing the pressure on the boost compensator.
Hope this helps.
Cheers Rob.

[dolphin]

you should give the engine ect a good degreasing so then you will find the oil leek alot easier.

[Jaydee]

Hi all,

Have owned a 4m40 (NL) 180000 kms for a few months now and have a few questions that I hope someone can help me with:

1. I have an ongoing oil leak from the rear end of the motor that I am trying to track down. Not serious - motor uses negligible oil over 5000kms. But over time it sprays a film of oil over the exhaust manifold heat guard and areas of the firewall. It looks like it is coming from the head gasket on the exhaust manifold side at the rear of the block - but very hard to see. It is not from the rocker cover. Has anyone had a similar experience?

Yep.... turbo oil feed pipe splits at a little bracket just behind the turbo exhaust... mine did it... not hard to replace... another one costs about $47 from Mitsubishi and about 15mins if you do it yourself. Just make sure you use new washers.

[roddersp]

Hi Rodders.
The leak could be coming from the back of the rocker cover.
There is a half moon robber seal there at the back near the cam.
A little bit of sealent over it before you tighten down the cover should seal it.
Is the black smoke while under load or accellerating?
I fixed mine by turning down the fuel load and increasing the pressure on the boost compensator.
Hope this helps.
Cheers Rob.

Thanks Rob.

I will check out the rocker cover. Had a look at this before and it looked pretty clean - but will have another look.

The smoke is under acceleration. I am probably not confident enough to adjust the fuel and boost settings. I take it these are set on the injector pump? I assume this is something I could get the diesel mechanic to do?

Cheers,

Rodders

[roddersp]

Thanks Gents for all your suggestions.

I will follow up and see what I find.

Cheers,


Rodders.

[Muzza]

Hi all,

Have owned a 4m40 (NL) 180000 kms for a few months now and have a few questions that I hope someone can help me with:


2. Have some smoking issues. Blew some serious black smoke under load at low rpm. Had injectors and valve clearances serviced. This has improved it alot but I still get some smoking. Looks more grey than black - and most noticable at higher rpm (above 3500rpm - not that I go there very often). Also smokes when I pulse the throttle from idle. Will this motor always blow a little smoke - or should I expect it to run perfectly smoke free?


Rodders.

Smoke at high end RPM can be be caused by,
1 Blocked or low fuel flow ( grey /black)
2 Max fuel setting on pump has been altered and boost not adjusted ( tends to be black)
3 Injection set wrong ( needs to set using a dial gauge) ( grey/ black)
Cheers
muzza

[Hill]

Rodder
I also have a poverty pack and live in Adelaide.
RE the Injectors: Having had my injectors changed at a 4WD specialist and not being happy with the result I took my pajero to Adelaide Fuel Injection ( page 837 of yellow pages) and had it dyno tuned and the diesel pump reset. These guys are great and reset the pump to original specs. Around $170 I think. Fuel economy is up and power is slightly down as it had been over fueling. I think they mentioned that some "CLOWNS" had opened up the diesel pump without really knowing what they were doing.
Re servicing: I have always lubed, changed oil fiter and oil every 5K and all other oils at 45K. Coolant is changed at 2 year intervals using Mitsubishi coolant. All rubber hoses were changes at 8 years. ( I dont believe in EVER mixing coolants) Air filters are changed on a needs basis and I have just added a Baldwin fuel filter that runs in series with the original filter. I will only change the BAldwin filter at 20K intervals from now on. Previously I used a CAV filter which is now surplus. The BAldwin filter is all metal exterior, self venting and is finer than original.

The guys at Agostino MItsubishi, Elizabeth do the odds and ends eg repack wheel bearings, machine front disks and the odd drivetrain oils when I can't be bothered. I've given up on my 4WD Specialist after their efforts with the injectors.

I'm still running my original 15X6 rims with Cooper tyres. These have always looked undertyred for the PAj. TYres are now getting low and I'm up for a change. What is yours like to drive with its 31X10.5? I have considered some 245X75X16 and will consider this if I can source some cheap rims

Hill

[roddersp]

Hi Hill,

Thanks for the tip. This sounds what I am after. At least with a dyno tune you know what you are getting.

Re: Rims. The 31x10.5's drive well, but I never really had the originals rims on long enough to notice much difference. Has done lots of work, pulling the camping trailer etc and always got me through, provided I am not in a screaming hurry. And yes the 31x10.5's look sooo much better. The other plus is this is a very common tyre size, if you ever get stuck somewhere remote in need of another tyre.

Thanks for your help.

Cheers,

Rodders.

[bilgeboy]

The oil at the back of you engine is probably from from the breather on your rocker cover. Common problem they get blocked with gunk. Plenty of threads how to either clean them out or use a catch can.

Check you intercooler and air hoses. You Will most probably have oil in them.
If you do, check the hoses as the rubber perishes and splits, that's how the oil can spray on you rocker cover with no obvious location, and air gets out when the engine is under load as the hoses swell with the increased pressure, meaning less air in you engine, meaning black smoke because the mixture is wrong.
Black smoke is not necessarily from too much fuel, not enough air might be your issue.
Upping the fuelmixture is the first thing inexperienced mechanic will do to get more power.
Find a good DIESEL mechanic, and stay away from dynos for the time being, they will flog the bejesus out of your engine, and if they blow it up they don't usually have insurance to cover it. There are better options.
Also test for Blowby, all diesels have it, too much and you might have a Valve or a compression problem like I did. I didn't find out until it blew out my radiator from the oil cooler.

[insaneearthling]

Hey Rodders,

Any old-ish turbodiesel will blow black smoke under acceleration - the fuel pump puts out more fuel when the throttle is buried but the turbo takes some time to spool up. Having said that, if you're just cruising and not really changing throttle position very much, it sounds like you've got the wrong fuel-air mixture. If the problem is exacerbated at high RPM, it sounds like your engine isn't breathing properly.

I'd check the air filter first - that's cheap and easy. Then maybe the turbo?

[roddersp]

Thanks for the feedback.

My original post was in 2008, I still have the Paj, and she has done me very well and still going strong.

The oil at the rear of the engine turned out to be the gasket on the inlet manifold. It seems the factory paper manifold gaskets degrade due to the blowby oil coming back through the turbo and intercooler. Have replaced with steel gasket - all good.

Have also had pump and injectors done at 250,000 kms and made a big difference.

So hopefully the old girl still has a few more years in her.

Thanks for following up on an old thread. Appreciate your comments.

Cheers.

Roddersp.

[cboastie]

Rodders thanks for following up with the diagnosis and final fix on your thread. I've also got an old 4m40, now with 285k on clock coming up for new injectors/pump. I'm wondering who you found to service your paj in the end and if you'd recommend them?

Thanks in advance,
Charlie

[Valiant81]

Some 4m40 questions from a diesel newbie.

Hi all;
I to have a NL Pajero and now has just over 208,000 Kms and a while back I had a problem with oil been blow back onto the intake/ exuast manifold and also a little bit on the fire wall of the pajero, looked real bad as mine is white and the stains were black, andy way the fix was to replace the maifold gaskits as there are 4 of them and are paper thin. Anyway i had them replaced and now all good.

[Hill]

JUst found my reply from 2007.

My NL moved to new owner last year. After 11 years of ownership and just under 200k it was as good mechanically as the day I bought it. Oil and filter were changed at 5k intervals and all fluids at 45k intervals. I changed the original brake pads at 135k or so, installed new shocks at 60k and injectors at 120k or so. Two set of coopers looked after they tyre department. It had a trailer/boat behind it for most of my last 5 years of ownership.
I checked the valve clearance at 190k and they were still in spec after being shimmed up at 60k.

Great reliable car however my NT is a lovely beast. It accelerates going uphill towing the boat!!!