Q: Truck won't start after it gets hot. What can cause this?

asked by on

When it's cold, it's fine but after I drive it for a while and it gets hot and won't start. It turns over but it won't start. After it cools down it starts again.

My car has 198000 miles.

This is a common sign of a faulty ignition coil. Ignition coils are coated with a varnish-like insulation that becomes brittle over time after being stretched then contracted repeated as the copper beneath them expands and contracts at a higher coefficient than the insulation. The insulation develops small fractures that open when heated and close when cooled. When open, they allow shorting of coil windings and decrease or eliminate the coil’s ability to function. This type of temperature cycling happens because every time you shut the engine off, the fan stops running, the coolant stops flowing and the temperature under the hood rises. Every time you start the engine again the coolant flows, the fans turn on, and the temperature drops. The areas in and around the tops of the combustion chambers, the exhaust manifolds, and the exhaust components are hundreds of degrees hotter than the outside temperature under the hood. When this heat dissipates and is absorbed under the hood, it is trapped causing this cycling effect. Components that contain heat sensitive materials include parts like coils, injectors, igniters, and some sensors. Any of these may be potentially subject to this same kind of heat problem which can be very difficult to trace. I would recommend having an expert from YourMechanic come to your location to take a look at your vehicle to properly diagnose your ignition system.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Truck won't start after it gets hot. What can cause this?

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Front alignment issues

You bent the spindle assembly at the least. You may of also bent the upper and lower control arms. Try to take off the tire and put the jack stand under the lower control arm to support the vehicle if...

Q: Truck will crank but will not start

The best way to approach a starting issue like this is to break it down and start with one system at a time. Keep it as simple as possible. If you have not already checked for spark, you will want...

Q: Can I continue to drive my car until I get the ignition coil fixed?

Hello Since the ignition coil is the component responsible for generating the engine spark, any problems with it can quickly lead to engine performance issues. Because of this fact, it's not really a good idea to drive the vehicle any...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...