The 4 Most Common Ford 5.8 Engine Problems

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An engine breakdown is not avoidable but you can prevent it through timely intervention. While this is common to all engines, the Ford 5.8L engines are not left out.

Some most common problems with Ford 5.8L engines include:

  1. Overheating
  2. Thermostat Failure
  3. Worn Valve Guides
  4. Oil Leaks

These problems need swift actions to resolve them to keep the engines in good health and extend their longevity. Ignoring the symptoms can lead to further issues in the engine in the long run. That will cost you some bucks.

What Are The Most Common Ford 5.8 Liter (351 Windsor) Engine Issues?

1. Overheating

The Ford 5.8L often referred to as the 351 Windsor, is prone to this specific problem. If proper attention is not given, it may excessively overheat, resulting in complex engine damage. Overheating in your engine may lead to other issues, deteriorating it faster, including the engine’s general performance.

The engine cooling system keeps the engine and its components under a standard operating heat and temperature. The system pulls heat away from the engine by ensuring coolant, oil, and antifreeze pass through the engine and get to the radiator.

If your Ford 5.8L is excessively overheating, it will also lead to the malfunctioning of the circuit system. Certain factors can be responsible for the excessive heat in your engine.

Why Your Ford 5.8L Engine Overheats

There are many reasons a car engine can overheat.

Here’s a highlight of a few of them:

  • Low Coolant Level: If you drive with a coolant level lower than the recommended coolant, coolant level, or without coolant can be dangerous to the health of the engine. Typically, a 50-50 mixture of coolant/antifreeze and water is recommended to refill the empty reservoir.
    However, when the coolant system fails due to the low level of the coolant reservoir, the engine starts to overheat, causing the temperature on the dash to rise above the standard level. You can easily top the coolant. Make sure you follow the proper method for refilling.
  • Coolant Leaks: Another reason your engine will experience this is when the coolant leaks away from its pipe. You’ll notice some puddles on the floor of your garage where you park the car. Depending on the brand of coolant you’re using, the coolant color ranges from orange, blue, or green usually with a sweet smell.
  • Defective Water Pump: A broken water pump can be the reason you’re experiencing the Ford 5.8l engine overheating problem. The water pump is essentially designed to send the coolant around the engine. However, a dirty coolant causes a build-up of deposits, resulting in the coolant not circulating.

Other reasons your car engine can overheat include:

  • Plugged-up or clogged heat exchanger.
  • Worn or Ruptured belts.
  • Leaky or clogged hoses.
  • Thermostat failure.
  • Defective radiators or radiator caps.
  • Low oil levels.

What To Watch Out For

  • Tickling Noise: This can result from oil failure to lubricate every essential part of your engine correctly. When there is excessive heating of the oil, lubrication is not at its best.
  • Hot Smell: This sometimes is caused by excessive heat when rubber seals or plastic valves begin to melt, producing a burning smell. As often described by many people as a hot smell, this odor is not something you will want to perceive.
  • Reduced Engine Power: This symptom can reduce the overall function of your engine, including the required rates of acceleration. You may also notice a coolant leak in the engine.

What To Do

Should you notice any of the above symptoms, it is advisable to consult your mechanic to provide the needed solution quickly.

You can check the level of coolant as well as replacing the gasket as it may be responsible for overheating. Even when all these problems have been fixed, you should still check for a coolant leak in the engine to prevent further issues.

How To Prevent Engine Overheating

There are steps you can take to prevent your car engine from overheating:

  1. Regularly inspect the car’s coolant levels.
  2. Use recommended coolant or antifreeze.
  3. Keep an extra bottle of sealed antifreeze and a gallon of water in your car booth.
  4. Monitor the rise and fall movement of the temperature gauge on the dash.
  5. Reduce the use of the car’s AC during an extremely hot or sunny day.
  6. Ensure regular maintenance and scheduled servicing.

2. Thermostat Failure

Thermostat failure is one of the common Ford 5.8L engine problems. This problem is in a way related to and caused by overheating. A thermostat is a component of the car that’s dedicated to and responsible for cooling, monitoring, regulating, and controlling the engine’s temperature, including coolant flow.

The thermostat is located between the engine and the radiator. The thermostat closes when the engine is not working; it circulates coolant again through the engine while preventing its entry into the radiator for quick engine heating.

The engine warm-up facilitates the thermostat opening, transferring coolant into the radiator to cool before entering the engine again.

At this stage, there is a closure of the restrictor plate. This will lead to the flow of most of the coolants to the radiator to cool before recirculating. Overheating will be noticed if the restrictor bypass plate misses, and there will be a direct water flow to the pump in place of the radiator.

There is uniqueness in the thermostat itself, such that it seals the bypass valve the thermostat opens. There will be no blockage of bypass valves from the standard thermostat that is used in the engine. If you pull out the plate restrictor, even with installing a proper thermostat, it will still lead to overheating.

Why Your Car Thermostat Fails

  • Overheating: Heating is great for the optimum functionality of the car thermostat. By default, the thermostat receives the heat from the engine and uses it for open-and-close operations of the valve. Also, the thermostat is wired to handle the normal temperature.
    If however, an extreme increase in the temperature occurs, it will force the thermostat to behave abnormally, resulting in it breaking or failing.
  • Wrong Installation: Not getting the right installation procedure is one of the surest ways to see the thermostat break and malfunction after a short period. Normally, the jiggle or bleeder valve should be installed airtight and upside-down. This will prevent air from the cooling system to get into the thermostat.
    Alternatively, you can install do a reverse installation in which case you set up the thermostat backwards to keep the thermostat sensor facing the radiator rather than the engine. Doing this will keep the thermostat farther from the reach of the heat while closing and opening.
  • Sludge-Filled Coolant: The formation of sludge and the presence of debris in the coolant is a major threat to the optimum functionality of the thermostat. The coolant can clot into a sludge which in turn can find its way into the thermostat, causing a restriction in the flow of the coolant.
    Besides, the presence of the sludge is a threat to get accurate readings from the thermostat. This naturally causes an interruption in the opening and closing of the valve.
  • Age: It goes without saying that the older the thermostat of your car grows, the weaker it becomes in performing its functions. The thermostat is easily exposed to heat and cooling effects; this will cause it to easily wear out over time.
    Unfortunately, you may not notice this malfunctioning until it completely overheats, causing the thermostat to break eventually.
  • Defect In Design: A defect in the thermostat is another reason it can fail to work. a minor defect in the production and design of the thermostat can result in its early damage or complete malfunction.

What To Watch Out For

  • Continuous Temperature Rise: This symptom can be due to the thermostat being stuck closed. Once there is no proper opening of it, the engine tends to have a temperature rise.
  • Coolant Leak: If there are traces of coolant leak around the thermostat housing, it will overheat the engine.
  • Engine Overheating: This is also connected to coolant loss and can damage the engine if not solved quickly.

What To Do

The best solution to thermostat failure in the Ford 5.8L engine is to replace it with a compatible one. It is complicated for a standard thermostat to cut.

One precaution to note is not removing the plate restrictor while replacing the thermostat. The plate restrictor seems to block coolant flow, which is why many people remove it. Its removal will lead to severe overheating of the engine.

3. Worn Valve Guides

Each valve within the cylinder head is provided with a guide. These guides work in connection with valve springs to see proper contact between the valve and valve seat. The valve, made of cylindrical metal pieces, is pressed into the cylinder head, allowing an up and down movement in the valve guide.

Apart from the guides ensuring proper seat contact during intake strokes, it also prevents gases entry into the crankcase. It also avoids the entry of oil into combustion during the same process.

The valve guides are prone to wear and tear due to their stem being in contact all the time. Oils shortage is a familiar problem in the 5.8L engine, which may result in the supply of limited oil quantity, and therefore, become old quickly than it should.

Your 5.8L engine may have cracked valves if there is excessively worn, resulting in the valve getting off track, closing them against the seat at a slight angle.

Why Your Valve Guides Bend Or Wear

  • Clogging And Contamination: The valve guides of your car can become clogged with foreign particles, including gunk and carbon deposits. This abrasive wear of the guides causes other serious damage to the car, including stem scuffing at the port end of the valve guide.
  • Improper Lubrication: Proper functioning of the valve guides requires that your car is running on sufficient coolant, antifreeze, and oil. Low or lack of lubrication causes the valve guide to breaking down, resulting in stem scuffing and scoring.
  • Valve Timing Failure: If you notice a collision between the piston and valve or incorrect valve timing, the valve guides will bend. The collision is often due to over-speeding in valve bounce.

What To Watch Out For

  • Oozing Smoke From The Exhaust: This happens when oil leaks into the combustion chamber, indicating worn valve guides. It can sometimes mean your engine is cold. Smoke from the exhaust is the first noticeable sign of a worn valve.
  • Oil Use Abnormality: Your 5.8L engine consumes excessive oil. When this happens, you may need to repair or change your worn valve guides.
  • Poor Performance: Worn valve guides will affect the overall performance of your engine, including acceleration.

What To Do

There are two options to solve the problem of worn valve guides. First, you can choose to replace your worn valve guides entirely through your mechanic. Alternatively, your worn valve guides can be repaired using a process known as reaming.

Compared to replacing your worn valve guides, reaming is cost-effective than purchasing new ones. The reaming process, however, requires a high skill of the mechanic to avoid tampering with other parts.

4. Oil Leaks

An oil leak can result from a broken gasket and the rear main seal, making it one of the most common Ford 5.8 Liter engine problems.

The gaskets are not too strong and can break or crack when there is excess heat. The rear main seal in old Ford 5.8L engines tends to break, crack, or even fail anytime. The seal is responsible for the prevention of oil from leaking to the engine’s rear.

Why Your Oil Leaks

An oil leak is one of the Ford 5.8L engine issues and the causes are not far-fetched.

Here’s a highlight of the causes of oil leak:

  • Damaged Gaskets: Primarily, the gaskets help to circulate fluids from their respective tanks, through the pipes to the different parts of the car for lubrication. When oil, gas, or coolant fails to get to their destination, the first suspect is the gaskets.
    These components degrade over a long period of time due to old age and mileage (up to100, 000 miles). Once the gaskets fail, the oil will start to leak.
  • Worn-Out Oil Filter: Your car filter starts to wear due to use. As the name implies, an oil filter helps to sieve contaminants from the fluids, including gas, oil, coolant. If these contaminants get to the engine, they can cause serious damage. Once the filter is worn, the oil begins to leak.
  • Loose Filler Cap: Oil leaks can also be due to a loose or broken oil tank filler seal. You’ll notice this when you see a pool of oil puddles under your car or around the engine.

What To Watch Out For

  • Excessive Oil Consumption: Once you notice your Ford 5.8L consumes excess oil, it indicates an oil leak. To detect this problem is relatively easy. Just observe the quantity of oil you turn into your engine and watch how long it takes to consume it.
  • Low-Oil Light Comes On: Once you start having oil shortage, the light will come up, indicating likely oil shortage due to leaks or excessive consumption.

What To Do

Replacing your gasket and seal is the solution. Replacing the gasket is not too hard, and it is cost-friendly. You may spend more money if you are replacing the seal. It is, however, advised to hire the service of a professional mechanic.


1. What Is The Reliability Of The Ford 5.8 Liter Engine?

Without a second thought, it is fair to say the Ford 5.8L engine is reliable. Many people have enjoyed this reliability for years, with some only requiring minor repairs on their parts.

It is so reliable that it can cover up to a 300k mile mark if regularly maintained. You may start to notice faults around the 15k mile mark if not maintained well.

2. What Happens If I Ignore Coolant Loss In My Ford 5.8 Liter Engine?

Ignoring coolant loss can be devastating to your engine. Coolant helps in resisting heat from the engine. Therefore, its shortage can lead to overheating. A swift intervention can prevent overheating, while a continual use of the engine without fixing it can lead to severe and total damage to the engine.

3. What Are The Specs Of The Ford 5.8L Engine?

Features: Specs:
Fuel Injection Type Carburetor
Displacement 5.8L
Torque 380 lb.-ft @3400rpm 325 lb.-ft @ 2800 rpm
Engine Ford 351W V-8 (5.8L)
Ignition Standard Distributor
Engine Family Windsor

Final Thoughts

Choosing the Ford 8.5 Liter engine can be one of the best choices to make due to many of its benefits, ranging from reliability to easy repair.

Fortunately, most common Ford 5.8L engine problems can easily be solved, especially with a DIY experience. However, this is not an indication that the engine cannot develop any faults as other engines are prone to defects.

To have the longevity of your Ford 5.8 Liter engine, scheduling adequate and timely maintenance will help keep your engine healthy and perfect.

If you notice any sudden changes in how your engine functions different from the usual way, find out what is responsible for the cause and fix it as quickly as possible.