GMC Rally Wagon 2500 Vacuum Pump Replacement Cost
How Much Does a Vacuum Pump Replacement Cost?
Vacuum Pump Replacement Service and Cost
Vacuum pumps are the secondary source of engine vacuum for gasoline vehicles, and the primary source for diesel powered engines. As you'll read, they perform the same functions, and several components rely on them.
Most vehicles use vacuum for several things, the most common of which are brake boosters, evaporative controls, engine controls, and air conditioning functions. Gasoline engines use a closed intake system, which allows the engine to maintain vacuum on its own. Smaller engines and vehicles which use engine vacuum to actuate many features may need a vacuum pump to keep up with the demand for vacuum pressure. Diesel vehicles fall into the latter category, but because they have an open intake system, so the engine will never create vacuum pressure. The vacuum pump in diesel vehicles, then, is a closed system, with only the vacuum pump, vacuum lines, and vacuum components attached.
Since vacuum pressure is one of the necessary conditions for many components in the vehicle to work properly, those systems will not function properly when the vacuum pump fails. This may include, but is not limited to the brake power assist, air conditioning features, engine control systems, or even turbocharger and supercharger wastegate systems. Only for gasoline engines, exhaust gas temperatures will rise from lean running conditions, the engine will have misfires, the engine may surge then lose power, and fuel mileage can be significantly impacted. Aside from these symptoms, the check engine light will illuminate to inform you the vehicle is having problems. When the on-board diagnostic (OBD) trouble codes are read, they will likely reference the mass airflow sensor, throttle position sensor, manifold absolute pressure sensor, fuel delivery system, exhaust system, engine misfires, the vacuum pump, and intake air volume. These codes illustrate how vital it is to ensure a proper seal on all vacuum connections and components, and to test the vacuum pump periodically.
Erratic engine performance, power surging, stalling, hesitation, misfires, and very poor gas mileage may result when driving a vehicle with a vacuum leak. Also, the vehicle may stall randomly, and may not restart. It is better to avoid these issues, and wear and tear to the vehicle, by using a towing service instead of driving. If the vacuum leak is small, or the check engine light is on, but no symptoms are present, the vehicle can be safely driven in most cases. Diesel vehicles with vacuum assisted brakes should not be driven with poor vacuum. As diesel vehicles tend to be large by nature, the weight of the vehicle can quickly overcome the force available when pressing the brakes without assistance.
Vacuum pumps tend to last at least 75,000 miles in gasoline engines, but for diesel engines, 150,000 - 200,000 miles is very common. Since most vacuum pumps are lubricated by the engine oil, changing the engine oil according the manufacturer's specifications should increase the life of the vacuum pump, and allow it to work as efficiently as possible. However, especially on turbo diesel models, failing to change the oil on time can result in damage to the vacuum pump, as well as numerous components in the engine, and in the fuel delivery system. Some manufacturers are beginning specify an interval for changing the vacuum pump on late model diesel powered vehicles.
Vacuum Pump Replacement Repair Information
Any of the mentioned symptoms are going to point to the vacuum pump, and vacuum leaks at some point, and if failure has occurred, the technician will find it through hands-on inspection, or diagnostic aids. The entire vacuum system will be tested in an observable manner that will provide the technician with evidence that some component is faulty. If the engine is able to start and run, a vacuum gauge can be connected at various points in the vacuum system, and pressures will indicate where failure has occurred. Many technicians will use a smoke machine if the vacuum leak cannot be detected otherwise. It will be connected to a vacuum line with the engine off, and pressure from the machine will push smoke out of the smallest of leaks.
Replacing a vacuum pump is normally a straightforward procedure, but can become complicated with manufacturer specific connectors, obstructions to removal, age of connected components, and location of the vacuum pump. For engine camshaft or balance shaft driven vacuum pumps, the pump must be disconnected from electrical and vacuum lines, unfastened, and replaced in reverse order. Note that there is a gasket and mating surface that must be prepared before remounting the new vacuum pump, and removing several components may be necessary for access to the vacuum pump. This procedure is much the same for accessory belt-driven vacuum pumps. Timing chain-driven vacuum pumps are much more in depth, and require the removal of, at least, accessory components, timing cover, timing components, and relevant seals and gaskets. Motor mounts, valve covers, and crankshaft pulley may require removal in many vehicles. Once the vehicle is reconstructed, the system will be tested once again for vacuum, and the results will identify if additional leaks exist.
Using a certified shop with the proper training and equipment to accurately diagnose the vacuum pump as a faulty component prior to replacement may save cost. If the pump is changed on a hunch, instead of diagnosis, and the technician says something else is leaking, there must be empirical proof that the vacuum pump has failed. This proof of failure is what certified and trained technicians are taught to provide to the customer.
Not all vehicles need a vacuum pump. They are almost always needed on diesel powered vehicles, and smaller engines need them commonly. Large V6 and V8 engines do not typically need them, as they tend to create enough vacuum to operate anything equipped from the factory with the throttle open or closed. Many high-end European vehicles use V10 and V12 gasoline engine and vacuum pumps. This is to compensate for several luxury systems that require vacuum to operate. In some instances, the extra need for vacuum has led exotic vehicle manufacturers to integrate additional, electrical vacuum pumps.
Vacuum pump replacement should be attempted by the experienced DIYer, with a good understanding of sealing an engine against oil leaks, and the proper tools and techniques to diagnose a vacuum issue. If the vacuum pump has failed, and it is located in the timing cover, this job should be left to a professional technician, as damage is likely without excellent knowledge and skill.
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