Potential faults on the Toyota Hilux 2.5 D4D

Commonly Experienced Problems

The Toyota Hilux 2.5 D4D may pull a few tricks from its hat during its time in your care as an owner. The following commonly experienced problems need some attention:

Injector Issues

The D4D system commonly presents itself with injector problems and the main reason for this is dirty diesel being used. In order to comply with legislation, additives are being added to diesel (apart from the Sulphur already in fuel). This is being done to reduce harmful emissions. These additives create sticky deposits in the fuel system and whenever these deposits (even in miniature quantities) find their way into the injector, you are in for some trouble. Faulty injectors need to be replaced if you don’t want to end up with engine failure and engine replacement.

To prevent this from happening, you can stay clear from the biggest killer of injection systems, namely dirty diesel, such as bio-diesel. Bring your vehicle to your nearest Steves Auto Clinic and have the injectors tested. At SAC we will apply a reputable injector cleaner and also replace your vehicle’s diesel injector filter (these should be done at least every 10 000 km if you want to reduce/prevent injector failure). The cost of having these done will far outweigh the costs of replacing broken injectors.

Owners sometimes fit an extra inline diesel filter and a water trap – connected in series to the already present filter – to protect the sensitive injectors. Steves Auto Clinic, at the request of vehicle owners, can assist in this regard.

Suction Control Valve

Some owners mentioned that their 2.5 D4D Hilux vehicles, when at cruising speed, all of a sudden lose power, which is then accompanied by a tremendous noise as if a bearing broke inside the engine! This may be cause for much concern and you may wonder what the problem is and what you are to do! If you had injectors replaced, then you have to make sure that the suction control valve (SCV) is also replaced. The SCV gets clogged, no thanks to dirty diesel being used. As mentioned in the previous point, it may be wise to install a second (additional) filter in order to minimize the risk of particles that may have slipped through the original filter, to enter the SCV. Professional and friendly technicians at Steves Auto Clinic may assist you in both of these aspects.

Low Grade Oil Being Used

This is a common problem, and this tendency should at all costs be avoided. A Hilux 2.5 D4D will meet a painful death if it follows a diet of low grade motor oil. Using low grade oil will result in an excess of heat building up due to poor friction. This in turn will result in carbonization and supply blockages (as seen in the oil pick up below). If this ever happens, be sure to embrace yourself for an engine change because sludging to this extent can never fully and properly be cleared from the oil galleries.

Low Grade Oil


It is good practice, if ever you want to prevent the occurrence of this, to take your vehicle to a reputable workshop – such as Steves Auto Clinic – and have the injectors and diesel pump flow and pressure characteristics checked. To be on the safe side have this done every 60 000 km.

Little Performance In Low Gears

There are complaints that the Hilux 2.5 seems very sluggish when pulling. There is nonetheless also a solution, and this is to install a Unichip into your Hilux. Doing this will not only increase your vehicle’s torque with 15% but it will also improve fuel consumption to as much as 2 km per liter. Steves Auto Clinic excels in helping you to get more torque from your Toyota Hilux.

Visit an SAC branch near you if you experience any of the issues discussed.

Related Articles:
My Toyota Hilux 3.0 D4D and the setbacks I may encounter as its owner!
Toyota Hilux & Fortuner 3.0 D4D Performance Upgrades
Unichip Plug & Play | Toyota Hilux 2.5 & 3.0 D4D Uni chip Performance chips

Within the above article, potential problems, causes and fixes have been identified as founded on the experience of vehicle owners and repairers, online sources such as discussion blogs, technical service bulletins and SAC experience. This information is provided solely for reference purposes. SAC strictly instruct readers that only properly qualified individuals should carry out repairs and/or modifications on your vehicles. It should also be made clear that the number of times an item is identified within this discussion should by no way be seen as an indicator of a model’s reliability or the frequency with which they may occur. Two of the exact same vehicles, owned by tow entirely different owners, driven in entirely different ways and on different terrains, and looked after in their own unique ways, will each behave differently. As mentioned, this information is provided solely for reference purposes but we hope – in the process of doing so – to empower you with relevant information which may enable you to make informative decisions whenever you experience any of the mentioned setbacks.