Mitsubishi Montero Sport: Common issues and how to fix them 

Updated Jul 07, 2021 | Same topic: Handy Maintenance Tips

From gunky intake manifolds to bad alternators. 

Being a seven-seater midsize SUV, the Mitsubishi Montero Sport has maintained itself to be a popular model in the Philippine market. People like it for its exterior design, and of course the interior space it provides.  

A picture of the Mitsubishi Montero Sport

The Mitsubishi Montero Sport 

On top of that, the Mitsubishi Montero Sport has good reliability in general. The current one available on the local market is built on the proven Strada/Triton body-on-frame chassis and it also uses the robust 2.4-liter 4N15 MIVEC inline-4 turbodiesel. An engine from the 4N1 series, which in turn has been around since the early 2000s. 

Like any car however, the Mitsubishi Montero Sport will encounter issues in the long run. These issues of course are similar to other modern turbodiesel models. So what are these issues and how does one fix them?

A picture of the Montero Sport's Super Select II 4x4

Generally, the 4x4 system on the Montero Sport doesn't have much problems

Mitsubishi Montero Sport: Common Problems 

Gunk in the intake 

Being a modern diesel SUV, the Mitsubishi Montero Sport will eventually experience gunk build-up in its exhaust gas recirculation (EGR) valve and intake manifold. If left alone, this can incur more damage to the engine’s internals. 

A clogged up EGR valve.

A clogged up EGR valve. Yuck

To understand this, the 4N15’s EGR takes a small portion of the exhaust gasses to clean it up by burning it. This of course results in oily soot. Now the said soot is likely to combine with the oily gas coming out from the crankcase. Whenever this two mix, it results in a very sticky substance that will gunk up your Montero Sport’s intake manifold and EGR valve. 

With those clogged up, it will result in a check engine light, and acceleration problems. Moreover, your SUV might experience trouble reaching peak power as the gunk blocking it from receiving the necessary air to effectively burn its fuel. 

Loose valve clearances 

The 4N15 is a turbodiesel mill that uses a shim-over-bucket valve adjuster. To be specific, the upside-down “bucket” and shim are devices that set the height of the engine’s valve springs. Now the issue is, these valve shims will get loose over time and so they can no longer keep the right valve clearance. They get loose over time because the valve shim is in constant friction. As such it will get thinner and thinner every time you use your Montero. The same is also the case with other cylinder head components like the valve bucket. 

A picture of the the Montero Sport's 4N15 engine

The 4N15 is tough, but wear and tear will affect it eventually

If you insist on running an engine without the proper valve clearance, this may result in damaged valves, or worse, upper-cylinder damage. That of course involves an engine rebuilt, which will surely destroy your wallet. 

And yes, the 4N15 has variable valve timing. As such, this means that having the right valve clearances is crucial to its operation.  

Faulty alternators 

Like any vehicle, an aging Mitsubishi Montero Sport might get alternator problems. Common causes of a failing alternator include the wear and tear of parts, bearing failure, and wiring problems. Any of these issues can be detected by flickering lights, strange noises, stalling, or difficulty in starting. 

Mitsubishi Montero Sport: Troubleshooting 

How to fix intake clogging 

To fix a Montero Sport’s clogged intake, one has to manually clean it. To do this, you’ll need to disassemble the intake valve, and locate the EGR valve. Once done, you can use a commercially available cleaner spray that will get rid of the gunk. If the clog is bad enough that it has reached beyond the confines of the intake manifold, you might have to take your Montero to a diesel specialist.  

A picture of an aerosol valve cleaner spray

Valve cleaners like this one from Liqui Moly is enough

In the event that you decide to fix this problem yourself, please don’t forget to wear gloves and eye protection. And yes, diesel gunk is not something you’d want on your skin and eyes. 

How to fix loose valve clearances 

In the olden days, one can readjust an engine’s rocker arms to get the right valve clearances. This can be done by ear and minimal tools. The Montero Sport however, is a modern turbodiesel that uses common-rail injection. And yes, the 4N15’s variable valve timing only serves to complicate things. To this end, we recommend acquiring the help of a proper mechanic. One that’s thoroughly familiar with the 4N15. 

Luckily for you, Mitsubishi recommends that one should have his/her Montero Sport’s valve clearances checked every 30,000 km. So if you followed this to heart, you won’t be having valve clearance issues at all. 

How to fix a Montero Sport’s alternator problems 

If you want to save on money, one way to fix a Montero Sport’s alternator is to have it checked by an automotive electrician. In the local setting, the said electrician might be able to jury-rig a fix, aka “recondition” your alternator. This however, in most cases, is a temporary solution. Instead, we recommend ordering a new alternator, if the problem was indeed traced to the alternator’s interior parts in the first place. 

If the problem was merely caused by wiring problems, then an automotive electrician will do. 

A picture of the 4N1 engine

As a side note, do remember that you also have to maintain the Montero's belts 

Did this help you in any way? Are there other common Montero Sport issues you want us to talk about?  

For more car maintenance tips, as well as car buying tips, keep it here on

Know more about Mitsubishi Montero Sport 2021

Mitsubishi Montero Sport

One of the most known SUVs in the Philippines is the Mitsubishi Montero Sport. It continually hits the list of best-selling cars in the country every year. Its popularity continues to grow because it is a reliable, tough, midsize body-on-frame SUV on and off-road, and a family car. It is not just a symbol of social status. The Mitsubishi Montero Sport, as a third-generation model, displays its benchmark for the brand's contemporary lineup, which is the 'Dynamic Shield' grille that shows a completely redesigned front. The new Mitsubishi Montero Sport features chrome linings that cover the large air intakes and stretch forth to the fog lamps, complemented by a sleek tail and headlights. Inside the cabin, top-notch variants and additional sportier trims for GT variants get to have leather-wrapped seats. For entertainment and central control, it is equipped with an 8-inch touchscreen infotainment system. Powering the Mitsubishi Montero Sport is the all-new 2.4L Diesel Engine, 4 Cylinder 16 Valve DOHC. The task of the Mitsubishi Innovative Valve-timing Electronic Control system (MIVEC) is to achieve low fuel consumption and exhaust emissions but a high-power output. Similar to the model it replaced, the Mitsubishi Montero Sport is L200 or Strada pickup based. The chassis and half of its front body structure are the same as its pickup sibling. It still uses the three-link live axle coil spring for the rear suspension and the independent double-wishbone front suspension from the model it supersedes. It comes with drum-in-disc rear brakes and ventilated front disc brakes. It is a standard for all variants to have 18-inch alloy wheels. The Mitsubishi Montero Sport features standard airbags for both driver and passenger, three-point seat belts for all the seven occupants, ABS with EBD, and an ISOFIX child seat anchors on the second row. Additional features for the GT variant consist of Trailer Stability Assist, knee airbag for drivers, and curtain airbags.

From ₱1,568,000

Cesar G.B. Miguel

Cesar G.B. Miguel


Cesar is a graduate of AB English with previous experience working as a freelance writer for varied internet publications in-between his former stints in the Pharmaceutical Industry, and later as a First Aid Provider and Training Staff at the Iligan City Disaster Risk Reduction and Management Office.

Since childhood, Cesar has been keenly interested in cars. He has learned the ins and outs of these marvelous vehicles and is a competent amateur mechanic who is keen on sharing his knowledge.

Cesar is perceptive of car culture in general – not only in the Philippines but in global regard, as well. His knowledge ranges from the prevalent stories and trends among car enthusiasts around the world, to closely following the latest local and international developments in the automotive industry.

View more
Cash Value