Paccar PX-9: Problems, Durability, and Specs

PACCAR is a name that you may not be familiar with. However, this is a household name for American semi-trailer lovers. Paccar is the name behind very successful brands such as DAF, Peterbilt, and, if you are in Australia, Kenworth. Paccar has been around for over 100 years, which means the company knows much about big-rig engines.

In our article today, we take a look at the PACCAR PX-9 engine. This is a phenomenal engine from Paccar that has been around since 2013. When Paccar introduced the introduction of the PX-9, the market got an opportunity to sample one of the highest power-to-weight ratio engines in the segment.

We will explore the Paccar PX-9 specifications that make this American engine stand out. We will peek at the engine's durability and whether you can rely on it. To better grasp what the Paccar Px-9 is all about, we will investigate the common problems that tend to trouble this engine. At the end of reading this article, you will have a clear understanding of why or not you should pick the Paccar PX-9 engine.

An overview of the PACCAR PX-9 engine

The Paccar PX-9 engine is regarded as one of the best big-rig engines in the industry. It is used on a wide range of Kenworth and Peterbilt semi-trailers. The 8.9-liter engine is prided to have a very high power-to-weight ratio in its category.

The Paccar PX-9, just like the Paccar PX-7 and Paccar MX-13, has been designed in strict observation of the EPA 2021 regulations. According to the manufacturer, this engine offers a low cost of ownership. The engine also affords the owner great fuel efficiency and high reliability, making it ideal for long-haul tasks.

The Paccar PX-9 1,250 ft-lb torque makes it stand out amongst the heavy-duty semi-trailers. Whether you opt for the lighter engine configurations of 260 or 450 horsepower at a governed speed of 2,200 RPM, you can rest easy knowing this is a capable engine. Because of these powerful and reliable features, it is possible to find it in big rigs such as Kenworth W900S, T470, and Peterbilt 348 and 382.

The Paccar PX-9 specs

• The Paccar is an inline 6-cylinder engine.
• The engine boasts an 8.9-liter displacement, and its peak torque ranges from 860 to 1,250 ft-lb. The engine's maximum horsepower ranges between 260 and 450 HP. At 1,250 ft-lb of torque at 1,400 RPM, the engine delivers a whopping 450 HP.
• The governed RPMs of the engine range between 2,000 and 2,200 RPM.
• The bore-x-stroke measures 114x145 millimeters. The piston enjoys targeted piston-cooling, which guarantees longevity for both the pistons and the engine.
• The engine is backed by a variable geometry turbocharger (VGT). The turbo adjusts seamlessly to ensure rapid and high-quality performance because of the precise boost delivery. The VGT turbo comes with an exhaust brake feature which allows the turbo to act as an exhaust brake by retarding the engine speed. This feature helps prolong the vehicle's brakes and also increases the vehicle's safety.
• The oil capacity of the PX-9 is 29 U.S. quarts or 27.4 liters. The engine comes with a bypass oil filtration system, which further serves to make the engine durable.
• The clutch engagement torque is 500 ft-lb at 700 RPM.
• As for engine maintenance, the Paccar PX-9 engine fuel filter should be replaced every 80,000 km. The oil and the oil filter should be replaced at 80,000 kms.
• The diesel exhaust fluid (DEF) and the DEF filter are supposed to be changed every 320,000 km.
• The Paccar PX-9 weighs 1,695 pounds. This allows the engine exceptional power in a smaller footprint to move more cargo as compared to its weight.

Common Paccar PX-9 problems

The Paccar PX-9 engine has its fair share of problems. Familiarizing yourself with these issues gives you an advantage because you will be better placed to resolve them when they arise. Knowing these problems will also help you take measures to prevent some issues from arising. Without further ado, here are the common problems with the Paccar PX-9 engine;

1) EGR failure

One of the most common issues affecting the PX-9 is EGR malfunction. Many people on online forums have come forward, reporting that the check engine light appears beside other warning lights on the dash. You may also notice reduced engine performance.

There are several possible causes for this problem. During the earlier years of PX-9 production, some engines, specifically the CM2350 PX-9, were equipped with over-efficient EGRs. The problem with such an EGR is that it turns the exhaust gases into shellac, consequently blocking the passages. This issue causes the water to pass through the passages very slowly or become blocked. The answer to this problem is to use an EGR flush solution similar to that used on MX13 EPA13.

2) SCR issues

Even though the SCR is part of the EGR, many semi-trailer operators have discovered that a faulty SCR will make the whole EGR system fail. The SCR problem is usually closely associated with the DEF quality problem. A replacement has been made in some cases where the SCR catalyst has been found to be the culprit.

To confirm whether the SCR is the one at fault, you should perform an SCR test. You should start by checking the pump pressure with insite and confirm that there is no leakage. In ideal conditions, the pump pressure should be in the range of 120-130 psi. Incorrect pressure might be caused by clogging of the decomp tube.

The next thing to check is the quality of DEF fluid, which should be 32.5%. Once satisfied that the pressure is okay and the quality of DEF is good, perform a regen. During regen, you should be able to pick out spikes or other abnormal readings. An incorrect or faulty Nox sensor can cause abnormal readings. If there are abnormal spikes, the other place to check is the +/- VDC of the battery VDC. If this is found to be the cause of the issue, perform a forced regen again.

3) Crooked idler pulley

A crooked idler pulley is more a Paccar engine problem than a PX-9 issue. Many operators of Paccar semi-trailer-powered trucks have discovered a crooked idler pulley after spending some time on the road. This issue is likely to affect the older engines.

When the idler pulley becomes crooked, you might be warned by a squealing sound from the engine belt, or you may notice the pulley is slow or is not spinning. There might not be warning lights on the dashboard, but a close inspection of the engine before and after a trip should tell you when the pulley is starting to look crooked.

The solution to a crooked idler pulley is to replace it. A professional should do the job as tensioners, and the belts should be fixed correctly. If a crooked idler pulley is ignored, you may end up with an expensive mechanic bill. Considering this is a Paccar engine problem, many operators conduct regular checks to catch it before it becomes severe.

4) Oil leakage

Different operators of the Paccar PX-9 engine have reported oil leaks. The leakage is not from a single point but from different points and fixtures. Some report oil leaking from the oil-sending unit, while others say oil leaked from the brass fixture.

The oil leakage reported by different PX-9 operators seems to revolve around brass fixtures. In one instance, the brass fitting lacked the necessary o-rings, thus the leakage. In other cases, Paccar has changed the design of the fittings, hence cutting down on the risk of leakage.

It's easy to detect an oil leakage either by observing the undercarriage of the semi-trailer or after an oil-pressure warning light appears. If the oil leakage from the fixtures is detected and there is no related problem, such as a warped overhead, the repair cost should be low. In many instances, the cost will be below $50.

5) Paccar PX-9 durability

The Paccar PX-9 engine is touted as one of the best semi-trailer engines in the world. It is found on many made-in-America big rigs and sometimes in Australia, New Zealand, and Europe. Many Paccar PX-9 enthusiasts insist that the engine will easily reach a million miles with proper care and maintenance. A qualified mechanic is also something to consider when buying this engine.

Paccar markets the PX-9 as a power horse that will not disappoint you in the long run and that you should have one, if not many in your fleet. The manufacturer has backed the engine with a 2-year warranty or 250,000 miles, whichever comes first. Paccar has further offered PX-9 owners an extended warranty, which further serves to make your engine more durable.

Conclusion

The Paccar PX-9 engine is one of the best engines out there. You will find it in Peterbilt alongside Cummins and sometimes CAT. Given the remarkable features of this heavy-duty engine, you can rest easy knowing that your semi-trailer or other machinery will get ample power. The problems associated with this engine do not seem to hamper its popularity.