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When it comes to truck and equipment setups, hydraulic and diesel tanks often sit side by side, but they do very different jobs. Because of that, they also need very different design considerations.

It’s easy to assume a tank is just a tank, but choosing the wrong setup, overlooking key specifications or trying to make a standard product “work well enough” can create expensive problems down the track. Whether you’re fitting out a new truck, replacing damaged equipment or building a custom setup, getting the details right matters.

Here are some of the most common mistakes we see with hydraulic and diesel tanks, and how to avoid them.

Mixing up hydraulic and diesel tank requirements

Hydraulic tanks and diesel tanks might look similar from the outside, but internally they’re built with completely different functions in mind.

A hydraulic tank is designed to manage oil flow, cooling, filtration and pressure changes within a hydraulic system. Diesel tanks, on the other hand, are focused on safe fuel storage, fuel delivery and managing fuel movement while the vehicle is in operation.

Trying to adapt one style of tank for another application can lead to poor system performance, contamination issues or premature wear on components.

Roadrunner manufactures both hydraulic and diesel tanks specifically for their intended purpose, with custom options available depending on your setup requirements.

Choosing the wrong tank size

One of the biggest mistakes is undersizing, or oversizing, the tank for the job.

With hydraulic systems, insufficient capacity can lead to overheating and poor oil circulation. Oversized tanks can create unnecessary weight and take up valuable chassis space.

For diesel tanks, capacity needs to balance operating range, payload and available mounting space. Bigger is not always better, especially if the tank location affects weight distribution or clearance.

The best approach is to work backwards from the application itself:

• What equipment is being run?
• How often is it operating?
• How much space is available?
• What are the weight considerations?
• Is future expansion likely?

Custom manufacturing is often the best option when standard sizes don’t quite suit the application. 

Ignoring mounting and placement

Tank placement matters more than many people realise.

Poor mounting locations can create vibration issues, reduce accessibility for servicing or expose the tank to unnecessary damage from road debris and general wear.

Hydraulic tanks also need correct positioning within the hydraulic system to ensure proper oil return and flow efficiency. Diesel tanks need appropriate breather placement and secure mounting to safely manage fuel movement.

At Roadrunner, mounting brackets and layouts are designed around the application rather than treated as an afterthought.

Not planning for fittings, filters and accessories

Another common issue is leaving fittings and accessories until the last minute.

Things like:

• Return line filters
• Sight glasses
• Breathers
• Sender units
• Drain points
• Pump and reel systems
• Access hatches

all need to be considered during the design stage.

Hydraulic tanks especially rely on properly matched filtration and return systems to protect pumps and components from contamination and overheating. 

The same goes for diesel tanks. Refueling systems, lockable caps, anti-roll protection and integrated accessories should be designed into the build from the beginning, not added later as compromises. 

Guessing instead of customising

Trying to force a standard tank into a setup it was never designed for usually creates headaches later on.

Every truck, machine and application is slightly different. Space constraints, chassis layouts, operating conditions and servicing access all affect the final design.

That’s why custom manufacturing is often the smarter long-term option, especially for hydraulic systems, refuelling units and specialised commercial applications.

Roadrunner regularly builds custom hydraulic tanks, diesel tanks and combination tanks to suit unique layouts, capacities and operating requirements.
 

The right tank setup can improve reliability, reduce maintenance issues and make servicing easier over the life of the vehicle or machine.

Whether you need a straightforward replacement tank or a fully custom solution, taking the time to get the details right early on will save time, money and frustration later. For hydraulic and diesel tanks alike, proper design always pays off.