Mitsubishi Pajero Sport Engine Problems

The Mitsubishi 4N15 engine in your Pajero Sport has a timing chain rather than a toothed rubber belt. As such, the chain should be good for the life of the vehicle rather than requiring periodic replacement as a timing belt does. However, this does not make the valve-train maintenance-free, as this engine requires valve clearance adjustments every 60,000km.

Cracked cylinder heads and blown head gaskets are not completely unknown on this engine, but exactly how big a problem it is is the real question. There’s one theory that the cylinder heads crack when mechanics over-tighten the fuel-injector hardware or try to remove stuck injectors with too much force.

The good news is that replacement cylinder heads are readily available and can be had in bare form or in fully built-up form including all valves and springs.

This problem has occurred before and happens when the pulley rubs through the hose, which finds itself in the wrong position under full turbo-boost. From what I can gather, the problem is due to a running change in supplier of this hose. And even though the hose was a slightly different shape, the manufacturer used the original alignment marks from the previous hose. So, when the mechanic fits the new hose, it places it in the path of the fan pulley when the engine comes on boost.

Ideally, the hose needs to be fitted so that there's at least 25 or 30mm of clearance between itself and the pulley. Your twist-at-the-bottom method should work, because you're effectively altering the incorrect alignment marks to where they should be.

This type of problem can have any number of causes. The best option is to have the car scanned electronically to see what fault codes have been logged by the on-board computer.

You could be looking at a fuel issue, something purely mechanical (like the idle-speed set too low) a blocked air-filter, a computer issue or any number of sensors that are not playing ball. But until you interpret the fault codes, you’ll be flying blind and potentially replacing things that aren’t the cause of the stalling problem.

I’d certainly be taking the vehicle back to the workshop that serviced it and pointing out that the problem only occurred after they'd 'fixed' it.

By and large, a car should perform the same day in, day out without any huge (or even noticeable) changes in its performance. So I’d say, yes, something is wrong with your car. As for the cause, well, it could be anything from poor fuel to a faulty battery to a park-brake that is sticking on. It’s impossible to diagnose problems like this one remotely, so have it checked out at a workshop. Continuing to drive it with a fault is asking for more damage to be done.