The 4.7-litre HO (High Output) engine is a V8 engine. Chrysler produced it for use in several of its vehicles, including the Jeep Grand Cherokee. This engine provides increased power and performance compared to the standard 4.7-litre engine. However, there are several Jeep 4.7 Ho engine problems arised over the course of years
The 4.7-litre HO engine produces a power output of 305 horsepower and 334 lb-ft of torque. It features a DOHC (Double Overhead Cam) design and utilizes a VVT (Variable Valve Timing) system to optimize performance. Additionally, it uses a 32-valve design with a 10.5:1 compression ratio. It was available on the Jeep Grand Cherokee from 2005-2010.
The 4.7-litre HO engine was popular for its durability and reliability. But like any engine, regular maintenance is important to keep it running smoothly.
Otherwise, some issues may arise including oil consumption, Crankshaft sensor failure, oil leak, poor spark, noise etc.
In this article, we’ll discuss the most common Jeep 4.7 Ho engine problems and solutions.
Jeep 4.7 Ho Engine Overview
The 4.7L PowerTech has a cast-iron cylinder block with a bore spacing of 4.09 inches (104 mm), a deck height of 9.09 inches (231 mm), and an angle of 90 degrees between the cylinder banks, making it ideal for using one crankpin journal for two connecting rods. All dimensions of the engine block have been redesigned from scratch.
In the debut engine, a nodular cast-iron crankshaft was mounted on the block instead of five individual main bearing caps using a single bedplate. Vibration and noise are reduced by the compacted graphite iron bedplate.
The connecting rods are fracture-split and made of powder-forged metal. The pistons are cast aluminum with moly coated skirts. A stamped steel oil pan seals the crankcase from underneath. A balancing shaft is needed for the 3.7L V6, but not for the 4.7L.
How Good Is the Jeep 4.7 Engine?
It features a cast-iron cylinder block with a bore spacing of 4.09 inches (104 mm), as well as a deck height of 9.09 inches (231 mm) and a 90-degree angle. A new engine block was created for this engine based on all dimensions being new. “High-Output” versions of Chrysler’s 4.7L PowerTech engine were introduced in 2002.
In addition to standard Jeep Grand Cherokee Overland models, this version was used in several Jeep Grand Cherokee Limited vehicles. Also included are two knock sensors, new camshafts, high-compression domed pistons, and a tuned intake on the 4.7L V8 High Output engine. The 5.7L V8 Hemi engine was then replaced with a high output version with 30 horsepower and 35 lb-ft of torque. There were some minor changes to the standard version in 2005, including two knock sensors. A huge change was made to the 4.7L PowerTech engine in 2008.
For the 2008 model year, PowerTech’s 4.7L V8 engine featured two spark plugs per cylinder and all-new cylinder heads. A brand-new and lightweight piston and forged steel combination were installed at the bottom of the engine. Furthermore, the compression ratio was increased from 9.0:1 to 9.8:1.
How Much Horsepower Does A 4.7 Liter V8 Engine Have?
The Ram has a 4.7-liter V8 engine that offers 310 horsepower and 330 pounds-feet of torque, which serves as the middle engine. Despite its impressive power, this engine’s poor gas mileage leads many to recommend the 5.7-liter Hemi V8, which delivers 390 horsepower and 407 pounds-feet of torque.
Most Common Jeep 4.7 Ho Engine Problems & Solutions!
The most common problems associated with the 4.7-litre HO (High Output) engine in the Jeep Grand Cherokee include:
- Timing chain issues
- Oil consumption
- Head gasket failure
- Crankshaft sensor failure
- Throttle body issues
- Fuel Injector Failure
1. Timing chain issues
The timing chain is a crucial component of the engine that synchronizes the movement of the camshaft and crankshaft. It is responsible for ensuring that the engine’s valves open and close at the correct time. In the 4.7-liter HO engine, the timing chain can stretch and wear out over time.
When this happens, it can cause the following problems:
- Engine misfire: If the timing chain stretches too far, it can cause the valves to open and close at the wrong time, leading to engine misfires and poor performance.
- Engine noise: A stretched timing chain can cause a rattling or ticking noise from the engine, indicating that the timing chain is loose.
- Reduced engine power: A stretched timing chain can cause the engine to lose power, as the valves are not opening and closing at the correct time.
- Engine damage: If the timing chain breaks, the engine’s valves can collide with the pistons, causing severe engine damage.
How To Solve This Issue
The best way to solve timing chain issues in a 4.7-liter HO engine is to have the timing chain and related components inspected and replaced as needed by a professional mechanic. The following are some steps that can help solve timing chain issues:
- Regular Maintenance: Keep up with regular maintenance and inspections as recommended by the vehicle’s manufacturer to ensure that the timing chain is in good condition.
- Listen for unusual noises: If you hear a rattling or ticking noise from the engine, it could be an indication of a stretched timing chain and it’s best to have it checked by a professional.
- Check for engine misfires: If the engine is misfiring, it could be an indication of a stretched timing chain, and it’s best to have it checked by a professional.
- Replace the timing chain and related components: If the timing chain is stretched or damaged, it will need to be replaced along with other components such as the tensioner and guides.
- Timing chain tensioner replacement: If the tensioner of the timing chain is the root cause of the problem, replace it.
2. Oil Consumptions
Oil consumption in the 4.7-liter HO engine can cause several problems:
- Reduced engine performance: If the engine is low on oil, it can lead to a decrease in performance and power.
- Engine damage: If the engine runs low on oil, it can cause damage to the internal components such as the pistons, bearings, and crankshaft.
- High oil consumption: Excessive oil consumption is a sign of an internal problem, such as worn piston rings, which can lead to poor engine compression and oil leaks.
- Warning light illumination: If the oil level is low, it can trigger the oil pressure warning light on the dashboard, indicating that the engine is low on oil and you need to check it.
- Decreased fuel efficiency: Oil consumption can lead to poor fuel efficiency as the engine has to work harder to compensate for the lack of lubrication.
How To Solve This Issue
To solve this issue, the mechanic must identify the precise cause of the problem before replacing any worn-out or damaged components. An engine overhaul may be required in specific circumstances. It’s crucial to have a reliable mechanic identify the issue, then adhere to the suggested service intervals from the manufacturer and apply the right type and weight of oil.
In addition, it’s also a good practice to regularly check the oil level and top it off as needed to ensure that the engine is running with the correct amount of oil at all times. This will help prevent damage to the engine and prolong its lifespan.
3. Head Gasket Failure
A head gasket failure in a 4.7-liter HO engine can cause several problems, including:
- Coolant leaks: If the head gasket fails, coolant can leak into the combustion chamber, which can cause a loss of coolant, overheating and damage to the engine.
- Oil leaks: A blown head gasket can leak oil into the combustion chamber and coolant passages, causing an engine to lose oil pressure and die. Read More Why Is My Jeep Wrangler Leaking Oil? Reasons Explained!
- Compression loss: A leaking head gasket causes the combustion chamber gasses to leak out, which reduces engine power and causes a loss of compression.
- Mixing of oil and coolant: If the head gasket fails and oil and coolant mix together, it can lead to sludge and clogging of passages, causing damage to the engine.
- Overheating: A head gasket failure can cause coolant to mix with the oil, which can cause a reduction in the engine’s cooling ability, leading to overheating.
How To Solve It
To solve a head gasket failure in a 4.7-liter HO engine, a mechanic should diagnose the issue through a compression test, a leak-down test, and a visual inspection of the engine. Replace the head gasket to fix the problem. It’s important to address head gasket failure as soon as possible to prevent damage to the engine.
4. Crankshaft Sensor Failure
A crankshaft sensor failure in a 4.7-liter HO engine can cause several problems, including:
- Difficulty starting: The crankshaft sensor is responsible for sending information about the engine’s speed and position to the engine control module (ECM). If the sensor fails, the ECM may not receive the correct information and may not be able to start the engine.
- Stalling or misfiring: If the crankshaft sensor fails, the engine may stall or misfire, as the ECM may not be able to receive the correct information about the engine’s speed and position.
- Poor fuel economy: A faulty crankshaft sensor can cause the engine to run rich or lean, which can result in poor fuel economy.
- Check engine light: In many cases, a crankshaft sensor failure will trigger the check engine light to come on, which will alert the driver that there is a problem with the engine.
How To Solve It
To solve a crankshaft sensor failure in a 4.7-liter HO engine, a mechanic should diagnose the issue by using a diagnostic tool to check the sensor’s signal and comparing it to the factory specifications.
If the sensor seems faulty, replace it to fix the problem. In some cases, it can happen because of other issues, such as wiring or connector problems. These issues should be inspected and repaired if necessary.
4. Throttle Body Issues
Throttle body issues can cause problems in a 4.7-liter HO engine by affecting the airflow into the engine. Some possible symptoms of a throttle body issue include:
- Reduced engine power: If the throttle body is dirty or clogged, it can restrict the airflow into the engine, which can reduce engine power.
- Stalling: If the throttle body is sticking or not functioning well, it can cause the engine to stall, especially when coming to a stop or idling.
- Unusual engine noises: If the throttle body is dirty or clogged, it can cause unusual engine noises such as whistling or sucking sounds.
- Check engine light: A malfunctioning throttle body can cause the check engine light to come on as it will impact the engine performance.
- Reduced fuel economy: A dirty or clogged throttle body can cause the engine to run rich, which can reduce fuel economy.
How To Solve It
By completing a visual inspection of the throttle body and looking for indications of dirt, debris, or damage, a mechanic can identify throttle body problems. They can also check the sensor’s signal using a diagnostic instrument and compare it to the factory specs.
The throttle body should be cleaned. But if you find it dirty or clogged with debris, replace it.
5. Fuel injector failure in a 4.7-liter HO engine can cause several problems, including:
- Reduced engine power: If one or more fuel injectors are clogged or not functioning well, it can affect the engine’s ability to receive the correct amount of fuel. Which can reduce engine power.
- Rough idling: If one or more fuel injectors are clogged or not functioning well, it can cause the engine to idle roughly or stall.
- Poor fuel economy: It can cause the engine to run rich or lean, which can reduce fuel economy.
- Engine misfires: It can cause the engine to misfire or hesitate while accelerating.
- Check engine light: A malfunctioning fuel injector can cause the check engine light to come on as it will affect the engine performance.
How To Solve It
A mechanic can diagnose fuel injector failure by performing a visual inspection of the fuel injectors, looking for signs of leakage or damage.
How Much Reliable is the Jeep 4.7 V8 Ho Engine?
Regular maintenance can easily extend the life of this engine to 200,000 miles (300,000 km). It is important to keep in mind that the PowerTech engine family does not tolerate poor maintenance. Otherwise, the engine becomes very dirty from the inside, leading to more serious problems. Thin oils and short intervals between oil changes are required for the engine.
Maintenance Tips for Jeep 4.7 Ho Engine Problems
Here are a few tips to help you deal with the most common Jeep 4.7 engine problem.
- Before using a vehicle in a low-temperature area, heat it for at least 15 minutes.
- Ensure that the engine is free from cracks and damages by thoroughly inspecting it.
- Oil filters should be changed periodically.
- It is important to use high-quality oil and fuel
- A minimum of once a year, perform the required maintenance.
- Make sure that the cooling system is functioning properly.
- Engine components that are damaged should be replaced.
- If your engine is performing irregularly, don’t be late to take action.
- Saving money by following these tips will benefit you in the long run. As a result, periodic maintenance ensures a smooth and comfortable ride.
Final Thought
The 4.7-liter HO engine found in certain Jeep models is known for its power and durability. However, it may encounter problems such as oil consumption, head gasket failure, crankshaft sensor failure, throttle body issues, and fuel injector failure.
These issues can happen because of a variety of factors such as wear and tear, poor maintenance, or manufacturing defects. To prevent additional engine damage and keep the vehicle running smoothly, it’s important to address these issues as soon as possible.
Keep Reading Most Common Jeep 3.8 Engine Problems: Explained
FAQs
How reliable is the 4.7 HO engine?
The 4.7L’s reliability is generally mediocre. These engines won’t likely endure for 300,000+ miles, in my opinion. Nevertheless, there are many millions of them on the road, and they are quite simple to repair. & you can solve them at a reasonable cost.
Which cars were included with the 4.7 HO?
- 2002–2004 Grand Cherokee Jeep.
- Jeep Grand Cherokee, years 2007–2008.
- Dodge Dakota, models 2007–2008.
- Ram 1500 from 2007 to 2008.
What kind of power can the Jeep Grand Cherokee 4.7 produce?
The 4.7 L was improved, and it now generates 305 horsepower (227 kW; 309 PS) and 334 pound-feet (453 Nm). An upgraded 5.7 L Hemi engine with 360 horsepower (268 kW; 365 PS) and 390 lb-ft (529 Nm) of torque was offered for the 2009 Jeep Grand Cherokee.