The ZMZ-409 engine cooling system is a critically important node that ensures the temperature of the UAZ Patriot power unit. The water pump, or in common, pump, circulates antifreeze in a large and small circle. The failure of this element often occurs suddenly and can lead to catastrophic consequences, such as overheating. GBCs Or even jamming a piston group.
Owners of SUVs face the need to replace the pump on average every 60-80 thousand kilometers, although the resource is highly dependent on the quality of the coolant used. Ignoring the primary signs of malfunction, such as foreign noise or slugs, inevitably leads to more expensive repairs. In this article, we will discuss in detail the process of diagnosis and replacement of the unit.
You don't need complex specialized equipment to do this, but having a basic set of tools and an observation pit will speed up the process. ZMZ-409 The design of the pump drive has its own specifications that distinguish it from the classic engines of GAZ or VAZ. The correct approach to the matter will allow you to conduct the procedure in one evening in garage conditions.
Symptoms of malfunction and diagnosis of water pump
The impending failure of a water pump can be detected long before it stops pumping the liquid completely. The first and surest sign of bearing wear is the characteristic hum or howl that increases with engine speed. Often this sound is confused with the noise of the generator or belt tension rollers, so primary diagnosis requires careful attention.
Visual inspection also gives you a lot of information about the state of the system, and if you notice traces of rosine under the car after parking, or wet spots on the pump body, it's a signal of leakage. plumbThe liquid can be sprayed with centrifugal force, so look for traces of dried antifreeze on the pulley and protective casing.
The backlash is checked with the engine shut down and cooled. Try swaying the pump pulley with your hands vertically and horizontally. The presence of a tangible backlash indicates the production of bearings, which requires immediate replacement of the assembly to avoid breaking the belt of the drive of the attachments.
⚠️ Warning: Operating a car with a buzzing pump is not only dangerous because of overheating. The destruction of the bearing can lead to a skewed pulley and a break in the belt, which in some versions of the UAZ Patriot causes the generator to stop and loss of battery power in transit.
Another indirect sign is the unstable operation of the cabin heater, and if the engine from the stove blows barely warm air with a warmer air, and the level of antifreeze is normal, it is possible that the impeller pump slips on the shaft or partially destroyed, in which case the circulation of fluid through the system is disturbed, leading to local overheating.
Selection of spare parts and preparation of tools
The auto parts market for UAZ Patriot is crowded with offers, but the quality of water pumps ranges from disgusting to acceptable. ZMZ Experienced mechanics recommend paying attention to the brands Luzar, TZA or Fenox, which specialize in cooling components.
When buying, be sure to inspect the packaging and the part itself. The body should be cast, without visible shells and chips. Pay special attention to the impeller: modern modifications of the 409 engine often install pumps with a plastic impeller, which is less susceptible to cavitation than metal, but requires careful installation.
To make the replacement, you will need a standard set of keys and heads. It is critical to have a dynamometer key on hand, since tightening the bolts of the pump body and crankshaft pulley requires the right moment to avoid deformation of parts.
Also, be sure to purchase a new set of gaskets or a quality sealant, as well as fresh antifreeze to replace, as some of the coolant will inevitably be lost during dismantling.
Metal or plastic impeller?
Some people think that metal impellers are more reliable, but they're not. Modern composite materials (plastic) are better at resisting corrosion and cavitation destruction. Metal impellers oxidize over time and change geometry, which reduces pump performance. Plant pumps with plastic impellers last longer if you use high-quality antifreeze.
Refrigeration of coolant and removal of attachment
The pump replacement work is done only on a cold engine. The cooling system pressure can reach several atmospheres, and opening the radiator cover on the hot engine will cause burns. Let the car cool naturally for at least 2-3 hours after stopping.
The process starts with the coolant draining, which requires turning the drain plug on the cylinder block (if it is available and not acidic), or simply removing the bottom pipe of the radiator. Be prepared for the liquid to pour quickly, so use a wide capacity of at least 10 liters.
Once the system is empty, the auxiliary powertrain belt must be removed. The ZMZ-409 engine uses an automatic belt tensioner. To ease tension, you need to turn the square protrusion on the tensioner with a clockwise key, which will free the belt, and it can be removed from the pulleys.
Then you have to remove the pulley of the crankshaft, which is also the pulley of the pump drive. The pulley mount bolt has a significant tightening moment and often clings. To unscrew it, you need to fix the crankshaft from the tilt, you can do this by turning on the fifth gear and braking the car, or carefully mounting the mount into the teeth of the flywheel through the crankcase view window.
☑️ Preparation for pump removal
Dismantling the old pump and cleaning the landing site
Once the pulley is removed, the crankshaft itself is accessed by the water pump, which is attached to the cylinder block with four bolts, and before twisting them, it is recommended that the outer surface of the pump and the surrounding area be carefully cleaned of dirt and oil so that the abrasive does not get inside the engine when removed.
Unplug the pipes if they interfere with access to the fastening bolts. On some UAZ Patriot modifications, it may be necessary to remove the generator or shift it for easy access, although on the 409th engine it is usually enough to simply remove the belt. Unscrew the pump mount bolts and carefully remove the knot.
The most important step is to prepare the landing plane on the cylinder block. The old gasket often sticks dead and the residues must be removed. Use a sharp knife or a special scraper, but act extremely carefully. Scratches on the aluminum alloy block are unacceptable, as they will lead to leakage.
After mechanical cleaning, degrease the surface with solvent or Kalosha gasoline. The metal should be perfectly clean and dry. Check the state of the pump itself: sometimes the pump body is deformed from overheating, and a new gasket will not be able to ensure leakproofness even on a perfectly clean surface.
⚠️ Attention: When cleaning the landfill plane, it is strictly forbidden to use coarse abrasive materials or filets. Any irregularity will become a channel for leaking antifreeze under high pressure.
If you use a pad of cardboard or paronite, you don't need to apply a sealant on it, clean surfaces are enough, if the pad is rubber or absent (only an anaerobic sealant is used), the composition should be uniform and thin, and the excess sealant, when squeezed inside, can come off and clog the cooling system channels or the heater radiator.
Installation of a new pump and assembly of the unit
The new pump is installed in reverse order. Apply the pump to the block and evenly, cross-cross, tighten the fastening bolts. The timing of the bolts fastening pump is about 10-12 Nm. Do not drag them, as you can tear the thread in the aluminum block or crack the body of the pump itself.
If you use a sealant, allow it to be polymerized according to the tube instructions (usually 15 minutes to an hour) before pouring the liquid. However, modern gaskets allow you to start assembly immediately.
The bolt of the crankshaft pulley is a critical element, it needs to be tightened with great force (about 120-140 Nm), for reliability, the thread can be treated with a thread lock. Curl the bolt with a dynamometer key using the same method of fixing the crankshaft as when unscrewing.
When installing the pulley crankshaft, lubricate the central sleeve and inner surface of the hole with a thin layer of graphite lubricant. This will prevent the pulley from sticking to the shaft in the future and facilitate the next replacement.
Put the harness back in place, make sure it's properly placed in the streams of all pulleys, the tensioner will do its job automatically, but visual control won't hurt, the belt should sit tight, without skewing.
| Element | Moment of puffing (Nm) | Tool. | Note |
|---|---|---|---|
| Pump mount bolts | 10-12 | Head 12 mm | Tighten the cross |
| Bolt pulley kneel | 123-150 | Head 24 mm | Shaft fixation required |
| Block drain plug | 25-30 | Key 12 mm | Replace the copper washer |
| Expansion tank cover | Manually. | - | Before the valve flicks |
Filling the system and removing air traffic jams
Once all the units are assembled, you need to pour fresh coolant, use antifreeze of the same brand and color as before, or do a full wash of the system with distilled water before pouring the new composition, pour the liquid into the expansion tank to the mark MAX.
The key is removing the air traffic jams. The air in the cooling system creates local overheating zones where the temperature sensor can read data incorrectly and the pump can work idle.
Start the engine and let it warm up to operating temperature. Periodically press the radiator nozzles with your hands (caution may be hot), helping to expel the air. Open the expansion tank cover on the warmed engine (with caution) and add fluid if necessary.
Quality removal of the air plug is more important than the brand of antifreeze, the remaining air is guaranteed to overheat the engine and re-break the pump in the near future.
Check the system for leakage. Check the junction of the pump and the unit, and the connection of the pipes for leakage. If everything is dry, and the engine temperature is normal and the stove is blowing hot air, the procedure can be considered complete.
Frequently Asked Questions (FAQ)
Can I change the pump without removing the radiator to UAZ Patriot?
Yes, on the ZMZ-409 engine, the design of the underhood space allows you to replace the water pump without removing the radiator. It is enough to remove the fan with the viscous coupling (or electric fan) and the drive belt. You will only need to remove the radiator if you replace the radiator itself or if you seriously damage the pipes.
How often should I change the pump to UAZ Patriot?
The pump resource directly depends on the quality of antifreeze. When using high-quality rosine or antifreeze G12+/G12++ and its timely replacement (every 3 years or 60 thousand km), the pump runs 80-100 thousand kilometers. When using water or cheap tosol, the resource can be reduced to 20-30 thousand km due to corrosion.
Why is the new pump buzzing after installation?
The new pump can be humming by a belt pull, which puts an excessive load on the bearing, and the part itself can fail. In rare cases, it's not the pump that makes noise, but adjacent units (rollers, generators), and the sound source was mistakenly determined. Let the new bearing work 100-200 km if the noise does not increase.
Do I need to lubricate the pump gasket with sealant?
If the gasket is made of special cardboard or composite material, the application of a sealant is not required and even harmful, as it can violate the design thickness of the sealant. The sealant is used only if the gasket is rubber (for fixation) or if the planes have micro-strokes, but it is better to replace the gasket with a quality one.