A complete guide to replacing SPARE PARTS for SINOTRUK with your own hands 

Why DIY HOWO Parts Replacement Requires Precision, Not Just Tools

ReplacementSPARE PARTS for HOWODoing it yourself is not just a mechanical job of unscrewing bolts, but a complex engineering process, where the cost of an error is measured in fleet downtime in days, not hours. In our practice, we have repeatedly encountered situations where an attempt to save money on qualified service led to damage to the cylinder block seats or a critical violation of the suspension geometry. Sinotruk trucks, especially the HOWO A7 and T7H models, are designed to withstand the high loads typical of Russian operating conditions, and any deviation from the factory tolerances when installing components can be fatal to the unit as a whole. This article is a complete technical guide, based on real-life experience servicing thousands of pieces of equipment, and is designed to give you a clear procedure that eliminates intuitive guesswork.

We will not use abstract advice like “tread carefully.” Instead, you will receive specific tightening torque parameters, requirements for surface cleanliness and a sequence of operations tested in workshops and on routes from Chelyabinsk to Vladivostok. Whether you manage your own fleet or repair commercial equipment, understanding these nuances will be your main asset in the fight for business profitability. Remember: correct installation of a part is often more important than the brand of the part itself.

Preparation of the workplace and diagnostics before starting work

The beginning of any serious work with heavy equipment determines 80% of the success of the entire event. A mistake during the preparation phase, such as using a dirty tool or misidentifying an engine modification, renders all subsequent efforts pointless. Before lifting the hood or climbing under the cab, it is necessary to conduct a complete diagnosis of the vehicle's condition. We recommend starting with a visual inspection of all adjacent nodes. For example, if you are planning to replace your water pump, be sure to check the condition of the drive belts and tensioner pulleys. In 40% of the cases we worked with, the failure of one component was only a consequence of wear of an adjacent element that was missed during the initial inspection.

Organizing the space around your truck is critical. To work with Sinotruk equipment, a free zone with a radius of at least 3 meters is required. Make sure you have a stable platform or inspection pit that can support the weight of the technician and the necessary equipment. Lighting should be at least 500 Lux in the work area - dim garage lights are a common reason for tradesmen missing cracks in blocks or installing O-rings incorrectly. Prepare a container for collecting technical fluids with a volume of at least 10 liters, since HOWO cooling and lubrication systems can hold significant volumes of antifreeze and oil.

Vehicle identification is a step that many people ignore and this is their biggest mistake. The HOWO model has many modifications of engines (WD615, D10, D12) and gearboxes (Fuller, ZF, Fast Gear). Parts that appear visually identical may have differences in spline length, number of mounting holes, or valve actuation pressure. Find the VIN plate and check the engine code against the parts catalog. If you do not have access to the original Sinotruk catalog, turn to specialists such as the team at Jinan Metalled Auto LLC, who specialize in exporting original and compatible parts and can quickly confirm component compatibility by VIN, minimizing the risk of ordering the wrong part.

Necessary tools and special accessories for HOWO repair

The tool set for servicing Chinese heavy trucks differs from the set for European equipment in the presence of specific heads and torque wrenches with a high upper limit. A standard set “for all occasions” will not work here. You will need at least three torque wrenches: small (20–100 Nm) for attachments, medium (100–500 Nm) for wheels and hubs, and powerful (up to 1000 Nm and above) for the main engine and gearbox mounting bolts. The use of an “impact wrench” for final tightening of critical connections is strictly prohibited - this is a direct path to breaking the studs or deforming the gaskets.

Pay special attention to cleanliness. In common rail systems, which are equipped with modern HOWO engines (for example, the D10 series), the ingress of dust larger than 5 microns can damage the injector instantly. You will need lint-free wipes, special brake cleaner, and high-strength thread locking compound. Also an indispensable tool will be a bore gauge for checking the diameter of the cylinders and a micrometer for measuring the thickness of the liners. We have seen cases where installing new piston rings into a cylinder with an ellipse of more than 0.05 mm led to gas breakthrough and ring coking after only 5,000 km.

Special mandrels and pullers are another critical element. To replace crankshaft or camshaft oil seals, conical mandrels are required, which allow you to install the seal strictly perpendicular to the shaft without damaging the working edge. Trying to hammer the seal through a wooden spacer, as is sometimes done in the field, is guaranteed to cause an oil leak in the near future. To work with the Wabco or Knorr-Bremse pneumatic system installed on the HOWO, you will need gauges to check the stroke of the brake chamber rods. Ignoring this tool makes it impossible to properly adjust the brakes, which directly affects driving safety.

Step-by-step instructions: Replacing cooling system components

The HOWO truck's cooling system operates under high pressure and temperature, so sealing connections is the number one priority. Let's start with the procedure for replacing the water pump, as this is one of the most common operations. The first step is always to completely remove the coolant. Open the drain valve on the radiator and cylinder block. Important: the drained liquid must not be poured onto the ground; it must be disposed of in accordance with environmental standards. After draining, remove the pipes going to the pump. They often stick to metal fittings. Do not try to tear them off by force - use a hair dryer to locally heat the pipe, this will expand the rubber and make removal easier.

Removing the old pump requires care. Unscrew the mounting bolts. Pay attention to their length: in some modifications of WD615 engines, the bolts have different lengths in different holes. Remember or draw a diagram of their location. Installing a long bolt into a short hole can result in a hole in the cylinder block wall—a catastrophic failure that cannot be repaired without replacing the block. After removing the pump, thoroughly clean the mating surface on the block. Use a scraper made of soft metal or plastic to avoid leaving scratches. Any unevenness on this surface will become a channel for leakage of antifreeze under pressure.

Installation of a new pump begins with checking the contents. Make sure the new gasket matches the old one in thickness and hole pattern. We recommend using a high-quality gasket sealant even if the gasket is included, applying it in a thin layer on both sides. This compensates for casting microdefects. When installing the pump, follow the tightening order of the bolts: crosswise, starting from the center to the edges. The tightening torque must strictly comply with the specification (usually 40-50 Nm for M10, but always check the manual). Over-tightening will lead to deformation of the pump housing and bearing jamming; under-tightening will lead to leakage.

After installation, fill the system with coolant. Here lies another common mistake - the formation of an air lock. Fill the system slowly, periodically squeezing the upper radiator hose with your hand to expel air. Start the engine and let it idle with the expansion tank cap open until the thermostat opens. If the fluid level drops, top it up. Only then can you close the lid. Check for pressure leaks by slightly increasing the engine speed to 1500 rpm. If you notice even drops of moisture at the joint, stop the engine immediately and repair the problem.

Technology for replacing transmission and chassis components

Working with the HOWO transmission and chassis requires an understanding of how heavy components operate under load. Let's consider replacing brake pads and adjusting the brake system, since the life of the driver and the safety of the cargo depend on it. HOWO trucks most often use drum brakes with automatic slack adjustment. Remove the wheel and brake drum. This may require a puller, as the drum often sticks to the hub. Inspect the inner surface of the drum: the presence of deep grooves or changes in geometry (tapering, ovality) of more than 0.3 mm require replacement or grooving of the drum. Installing new pads on a worn drum will reduce their service life by 3 times.

When installing new brake pads, be sure to lubricate the guide pins and the contact points between the pads and the expansion cam with a special high-temperature grease. The use of ordinary lithol or solid oil is unacceptable - they will burn out at the first intense braking, and the mechanism will jam. After assembling the mechanism, it is necessary to manually adjust the gap between the shoes and the drum. Turn the adjusting screw until the drum begins to rotate with slight resistance, then release it 3-4 clicks (teeth). This is a basic setting that will then be adjusted by the machine.

A critical step is to check the operation of the automatic slack adjuster. Ask an assistant to press the brake pedal several times with force simulating emergency braking. After each press, a characteristic click of the machine is heard. The brake chamber rod stroke should not exceed 40 mm for standard 24/30 type chambers. If the stroke is greater, it means that the machine cannot cope or the linings are worn out. Driving with improperly adjusted brakes leads to overheating of the hubs and fire of the wheels - this is not a theoretical threat, but a real statistics of truck accidents.

In the context of the supply of chassis components, it is important to note the role of reliable partners. Jinan Metallid Auto Co., Ltd., based in Jinan, provides a full cycle of supply of spare parts for trucks, including suspension parts, axles and brake systems. Their experience working with clients in the Southern Urals and Central Siberia allowed them to develop strict quality control standards adapted to the harsh Russian winters. When ordering critical components such as axle gearboxes or leaf spring suspension components, the personalized “butler-style” service offered by the company allows you to obtain detailed technical documentation and ensure compliance with the markings before shipment, which eliminates equipment downtime due to defects.

Engine maintenance: replacing filters and timing belts

The engine is the heart of a HOWO truck, and its maintenance requires meticulousness. Replacing the oil and fuel filters seems like a simple operation, but this is where most mistakes are made that lead to major repairs. When replacing the oil filter, be sure to lubricate the rubber O-ring of the new filter with fresh oil. When first started, dry rubber may rotate or tear, which will lead to an instant drop in oil pressure and rotation of the liners. Tighten the filter only by hand, without using a wrench, until it touches the gasket, then tighten it 3/4 of a turn. Excessive tightening will deform the filter housing and make it difficult to remove next time.

The fuel system of HOWO diesel engines is extremely sensitive to the quality of diesel fuel and the presence of water. When replacing the fuel filter separator, it is necessary to completely remove water from the sump. After installing a new filter, be sure to pump the system manually using the booster pump on the filter housing or injection pump until resistance disappears and fuel flows without air bubbles. Air entering the Common Rail system can damage the expensive high-pressure pump. We strongly recommend that after replacing the filters, check the system for leaks under pressure by starting the engine and inspecting the connections.

Replacing accessory drive belts and timing belts (if applicable to a specific model) requires following the marks. On engines of the WD615 series, the timing drive is carried out by gears, which is more reliable, but requires checking the engagement. On more modern belt-driven models, using the old marks is not acceptable - apply your bright marks with a marker before removing the old belt. The belt tension is checked with a special device - a strain gauge. Tension “by eye” or by sound (“so that it rings like a string”) is an unprofessional approach. An overtightened belt destroys the bearings of the generator and pump, while a loose belt slips and overheats.

Common mistakes when doing DIY repairs and how to avoid them

Experience shows that 90% of repeated requests for service are caused not by the quality of spare parts, but by violations of installation technology. The first and most dangerous mistake is ignoring the tightening torques of threaded connections. Many craftsmen rely on their sense of proportion, which is unacceptable for a truck weighing 30 tons. A cylinder head bolt that is tightened below the specified torque will cause the gasket to burn out and gases to enter the cooling system. A bolt that is overtightened stretches beyond its yield point and breaks under vibration load after a couple of thousand kilometers. Always use a torque wrench and check the torque charts for your specific engine.

The second common mistake is mixing technical fluids from different manufacturers and types. This is especially true for antifreeze. Mixing carboxylate and traditional silicate antifreezes leads to sediment, which clogs the thin passages of the radiator and thermostat. We have recorded cases of HOWO engines overheating for this very reason when the owner added “any red antifreeze” to the system. Before replacing the fluid, the system must be flushed with distilled water or a special flushing compound. The same applies to gear oils: mixing oils with different additive packages can lead to foaming and loss of lubricating properties.

The third mistake is the use of non-original or cheap analogues of sealing elements. Gaskets, seals and cuffs for HOWO operate in aggressive environments at high temperatures. Cheap analogues made from low-grade rubber harden in the cold and leak when heated. Saving $5 on an oil seal can result in a loss of $500 in unit repairs and machine downtime. In our practice, there was a case when a client used substandard cylinder head gaskets, which led to water hammer and destruction of the piston group after 200 km of travel. The quality of the seals directly affects the tightness and durability of the entire assembly.

Quality control of work performed and testing

Completion of installation is not the end of the work, but the beginning of the verification phase. Before starting the engine for the first time after major intervention, it is necessary to pre-crank the starter without fuel supply (for diesel engines) or by turning off the ignition (for gasoline engines, although this is less important for HOWO). This is necessary so that the oil pump creates pressure in the system and lubricates all rubbing pairs before starting to work under load. Monitor the oil pressure light on the dashboard - it should go out within the first 3-5 seconds of starter operation. If the lamp stays on longer, immediately stop trying to start and look for the reason for the lack of pressure.

After starting the engine, carry out a visual inspection of all areas where intervention was performed. Use a flashlight and mirror to inspect hard-to-reach areas. Listen to the engine: any unusual knocks, whistles or hisses should be investigated immediately. Allow the engine to warm up to operating temperature and check the operation of the cooling fan. Make sure it turns on within the specified temperature range. Check all fluid levels again after warming up, as volume may change due to expansion and filling of lines.

The first test drive should be carried out in a gentle manner. Avoid sudden acceleration, working at maximum speed and transporting heavy loads in the first 100-200 km. This is the period of running-in of new parts. Once back in the park, inspect the vehicle again for leaks and check the temperature of the wheel hubs and transmission components. Overheating of any component immediately after repair indicates an error in assembly or adjustment. Keep a log of the work performed, indicating the date, mileage and parts replaced - this will help in future diagnostics and increase the residual value of the car when selling.

Where to look for reliable spare parts and technical support

The success of self-repair depends half on the quality of the spare parts used. The market is filled with products of varying levels of quality, from original Sinotruk parts to cheap fakes that cannot withstand any load. For a professional approach to fleet maintenance, it is important to have a partner who guarantees authenticity and compliance with specifications. Jinan Metallic Auto Co., Ltd. offers a one-stop solution for distributors and repair shops, providing original and compatible spare parts for a wide range of Chinese brands, including HOWO, SITRAK, SHACMAN.

The advantage of working with such a company is deep expertise and strict quality control. Each batch undergoes individual testing for compliance with technical characteristics and labeling, which minimizes the risk of receiving defects. A professional team of engineers and purchasers with over 15 years of experience ensures accurate selection of components, eliminating situations of incompatibility. In addition, flexible customization of packaging and labeling to suit the partner’s needs simplifies logistics and warehouse accounting. This is especially important for fleet operators operating in remote regions where the ability to quickly resend a defective part is not possible.

The service is built on the principle of transparency and proactive information. You receive comprehensive technical data for every order, allowing your mechanics to work confidently and quickly. The company's vision is to create a sustainable ecosystem in the auto parts market through long-term partnerships. By choosing a reliable supplier, you are investing not just in metal and rubber, but in the uninterrupted operation of your business processes and the safety of drivers on the roads. Trust the maintenance of your equipment only to proven components and professionals.

Frequently Asked Questions

What torque is required for the WD615 engine cylinder head bolts?

For the WD615 engine, the process of tightening the cylinder head bolts is multi-stage and critical. The scheme is usually used: the first stage - 100 Nm, the second stage - an additional 90 degrees, the third stage - another 90 degrees (the exact values ​​may vary depending on the year of manufacture and the specific modification, always check the service book). The use of a torque wrench and an inclinometer is mandatory. Violation of this sequence leads to uneven pressing of the gasket and rapid failure of the unit.

Is it possible to use regular automobile oils instead of specialized ones for HOWO?

No, it's risky. HOWO heavy truck engines operate under high load conditions and long oil change intervals. The use of oils of at least CI-4 or CJ-4 class according to the API classification is required, with a viscosity appropriate to the climatic conditions (usually 15W-40 for moderate climates, 5W-40 for the north). Conventional passenger oils do not have the necessary additive package to protect against soot and wear in large-volume diesel engines, which will lead to accelerated wear of the liners and turbine.

How often should I change the air filter on a HOWO truck?

The regulations depend on the operating conditions. Under ideal conditions - every 40-50 thousand km. However, in Russian realities with dusty roads and construction equipment nearby, the interval should be reduced to 20-25 thousand km or visual inspection and purging (if the filter allows) should be carried out every 10 thousand km. Operating the engine with a dirty filter leads to abrasive entering the cylinders, which causes irreversible wear of the piston group. Saving on a filter that costs $20-$30 is unacceptable when you risk a major engine overhaul costing thousands of dollars.

What is the difference between original Sinotruk spare parts and analogues?

Original spare parts undergo strict quality control at the manufacturer and comply with all drawings and approvals. Analogues may differ in material of manufacture (for example, less heat-resistant rubber or metal with impurities), geometry and service life. For critical components (brakes, steering, engine), we strongly recommend using only original or top quality certified replacements from trusted suppliers such as Jinan Metallic Auto Co.,Ltd to ensure safety and reliability.

Repairing a HOWO truck yourself is a task for competent professionals armed with knowledge and the right tools. By following this guide and choosing quality components, you can keep your fleet in top condition, minimizing costs and maximizing time on the line. Don’t forget that prevention is always cheaper than repairs, and proper maintenance is the key to the long life of your equipment.

Buy HOWO spare parts with deliveryis an opportunity to provide your fleet with reliable components directly from the manufacturer. Contact us today for a consultation and order cost estimate.