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Why does my Tacoma Sound Like a Diesel? – A Troubleshooting Guide

Why does my Tacoma sound like a diesel? There could be one of several reasons behind this change in noise. Different things can cause your gasoline engine to sound like a diesel engine, from mechanical failure and incorrect adjustments to oil and fuel issues.

Adjustment issues often have to do with valve clearance and chain timing. Mechanical or parts failure can occur in the pistons, crankshaft, connecting rods, and fuel pump. Depending on the issue, you might experience different engine noises, such as ticking, rattling, popping, and hammering.

The diesel-like sound isn’t just annoying but can be downright dangerous! So why wait until it’s too late? In this article, I’ll go over those causes, including how to identify them and how to fix the underlying issues.

Why My Toyota Tacoma Engine Sounds Like A Diesel: Troubleshooting Chart

To help you narrow down the causes, I’ve created this handy troubleshooting chart to help you figure out what’s going on with your engine. The good news is there are some tell-tale signs of what might be going on with your truck. These will help you diagnose the problem and get moving again!

Type of SoundPossible CauseCorrective Action
Rattling & ticking as you accelerate● Wrong type of fuel
● Wrong camshaft timing
● Valvetrain issue (too much valve clearance)
● Low oil level
● Sludge buildup
● Use regular unleaded gasoline ( 87 octanes or higher)
● Adjust the tension of the camshaft timing belt to specifications
● Check valve clearance
● Observe Toyota Tacoma oil capacity (depends on model)
● Use high-mileage oil for sludge prevention
Popping & engine hesitation● Dirty spark plugs
● Clogged fuel filter
● Damaged or faulty fuel pump
● Clean or replace spark plugs
● Blow into your fuel filter. Replace if air doesn’t pass through
● Replace the fuel pump with a new one
Deep knocking sounds as you accelerate● Crankshaft damage
● Piston ring damage
● Crankshaft bearing failure or a connection rod failure
● Wrong or counterfeit oil
● Refurbish or replace the crankshaft
● Replace piston rings
● Replace the crankshaft bearing or the faulty connection rod
● Use 5W-20 or 0W-20 oil
Squealing or whining● Worn-out fan belt
● Worn-out engine camshaft timing belt
● Have the fan belt (serpentine belt) and the camshaft timing belt replaced immediately
HissingOverheating engine● Replace coolant fluid
● Replace the water pump gasket

Read More: Why Are Toyota Tacomas So Expensive?

How To Perform Engine Noise Diagnostics In Five Easy Steps

Engine noise diagnostics can be intimidating if you’re not sure what to listen for. From the rattle of the engine to squeaking, knocking, and ticking, you have to tell apart the numerous diesel-like engine sounds to pinpoint the problem.

Follow these steps when performing engine noise diagnostics:

● Step 1: Secure your truck for safe operation and open the hood.

● Step 2: Switch off the fuel pump or the ignition system. Start the truck and listen to the start sound.

● Step 3: Activate the fuel pump or ignition system after diagnosing the engine sound.

● Step 4: Start the truck and listen to engine operation at idle, stable partial, and full load. Also, listen to the engine operation at fast acceleration.

● Step 5: Locate the source with a stethoscope if you suspect or notice any diesel-like engine noise. For this, I recommend the EZ Travel Mechanics Engine Diagnostic Stethoscope.

Important Adjustments For Smooth Engine Sound Explained

As I’ve clearly outlined in the chart, it’s worth making some adjustments and changing some settings to get the best sound performance out of your Toyota Tacoma engine. The two most popular adjustments are for the valve clearance and the timing belt.

Checking and Adjusting Valve Clearance

The valve clearance refers to the space between the valves in your engine’s cylinder head and their rocker arms. Check the clearance by inserting the blade of a feeler gauge in the clearance between the rocker arm and the valve stem.

The clearance is correct if the blade is a close sliding fit. Slacken the locknut on the adjuster screw (at the camshaft end of the rocker) to adjust the clearance.

Camshaft Timing Belt Adjustment

This long, flat belt connects the crankshaft to the camshaft, which drives the valves in your car’s engine. Use a socket wrench to adjust the belt tensioner bolts. Tighten it to the specified torque setting, which is 20 ft-lbs (240 in-lbs) for Toyota Tacoma.

Key Takeaways:

Diesel engine-like sound in Tacoma isn’t very common; however, it can occur over time due to many reasons. Here are some key takeaways that we’ve had so far:

  • Diesel engine-like noise in your Tacoma can result from mechanical failure, incorrect tuning, dirt and clogs, engine overheating, low oil level, and using the wrong oil/fuel.
  • Tell-tale sounds include rattling, ticking, squealing, popping, hissing, and deep knocking or hammering sounds.
  • Regular servicing and maintenance checks are a smart way to prevent these sounds from occurring.

You Can Also Read:

How Much Does It Cost To Regear A Toyota Tacoma?

How to Tell if Ford F-150 Has Max Tow Package.

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