1994-2004 Chevy S10 common problems include intermittent starting, an S10 that won’t start after sitting, an S10 that turns over but won’t start, and other issues like fuel pump problems. Find out their symptoms, causes and fixes as we explore the top problems on the 2nd generation of Chevy S10 trucks, also known as the Chevy S-10 or Chevy S-series.

Top Issues on the 2nd Generation Chevy S-10 (1994-2004)

1. Faulty Heater Core

Symptoms of a Faulty Heater Core

  • Cold air blows from the heater vents when the heat is on
  • Windshield fogs up while driving, sweet smell in the cabin, and/or coolant leaking on the passenger side floor

Causes of a Faulty Heater Core

  • If cold air blows from the vents when the heat is on, the heater core is clogged from old coolant or sediment. This can happen from not performing a regular coolant flush.
  • If coolant leaks on the passenger side floor, if there is a sweet smell in the cabin, or if the windshield fogs up when driving, the heater core is leaking.

How to Fix a Faulty Heater Core

  • If the heater core is clogged and not damaged, try flushing the heater core to extend its life. If the heater core is damaged, replace it. Replacing the heater core includes removing the dash, steering column, and heater box to access the heater core.
  • If the heater core is leaking, replace the heater core

2. Bad Intake Manifold Gaskets

Symptoms of Bad Intake Manifold Gaskets

  • High level of engine oil with a milky color
  • Low coolant
  • Coolant leak near or behind the water pump
  • Cross-contamination of engine oil and coolant in the coolant reservoir

Causes of Bad Intake Manifold Gaskets

On the 94-04 Chevy S10, coolant travels through the intake gasket, so it can look like the water pump is leaking, but on this pickup it’s usually the intake gaskets leaking

How to Fix Bad Intake Manifold Gaskets

  • An intake manifold gasket replacement on the 2nd gen S10 is a big, detailed job. It requires the removal of the upper engine parts like the fuel lines and the A/C compressor

3. Distributor Problems

Marked spark plug wires and their corresponding cylinder engraved on the distributor cap

Symptoms of Chevy S10 Distributor Problems

  • Engine misfires
  • Engine turns over but won’t start
  • Check engine light for misfire code P0300-P0306

Causes of Distributor Problems

Common problems with the distributor on the Chevy S10 are from a bad distributor cap and rotor, but sometimes it’s from worn internal parts

How to Fix Distributor Problems

The distributor is located near the firewall. To prevent distributor problems, routinely change the distributor cap and rotor. Check the owner’s manual for recommended intervals, which is usually around 60-100,000 miles.

  • Remove the screws on each side of the distributor cap
  • Replace the distributor cap or rotor if it has corrosion or carbon deposits
  • If replacing the distributor, for an easier install consider marking the cylinder number the spark plug wires lead to, which is written on the distributor cap, with a marker

4. Front Wheel Bearings

Symptoms of Bad Front Wheel Bearings on the 4th Gen Chevy S10

Growling sound at the front wheels at certain speeds, usually over 30 mph

How to Fix a Bad Front Wheel Bearing

  1. Jack up the front of the vehicle up and spin the wheel, listening for a growl or whirring sound
  2. Grab the tire from the 12 and 6 o’clock positions. If there is excessive “play” or looseness in the bearing, the S-10 could have a bad wheel bearing
  3. Purchase quality wheel bearings at and replace them yourself. To replace the wheel bearing yourself, check out the steps in this video.

5. Fuel Pump Problems

Symptoms of Fuel Pump Problems

  • Engine cranks but won’t start
  • Intermittent starting
  • Extended crank eventually starts the engine

Causes of a Fuel Pump Problems

A bad valve inside the fuel pump sends fuel back into the tank, leaving no fuel or fuel pressure in the fuel lines. Cranking the engine without readily available fuel will cause extended cranking. Turning the key on and off and on and starting the vehicle will prime the system, which is necessary if the S10 won’t start after sitting for a few hours or more.

How to Fix Fuel Pump Problems on the Chevy S10

  • If the S10 won’t start after sitting for a few hours or more, try turning the key to the ON position, and then turn the key to the OFF position. Turn the key back to the ON position, and crank the engine.
  • The fuel pump is located in the gas tank. If the fuel pump is defective, it needs to be replaced. Replacement requires lowering the gas tank. This can be done from underneath the vehicle by supporting the tank and removing the straps, or by removing the bed to the side to access the fuel pump. One method might be easier than the other depending on how old and rusted the truck is.
  • To prolong the life of a fuel pump, keep more than 1/4 of gas in the tank to keep the fuel pump cool and running efficiently.
  • Change the fuel filter about every 30,000 miles or less to keep a consistent flow of fuel and to reduce strain on the fuel pump

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