Q: Engine overheating replacing thermostat

asked by on July 25, 2016

I own a 3500 express van with a 5.3 votex engine. I replaced the water pump a year ago and put in a new thermostat 2 times. 2 weeks ago my engine started to overheat again. So I replaced the thermostat, and it was OK for a few days. Then it started to overheat again. I checked the water and it was low, so I added some. The van drove OK for a few days, but now it’s overheating again. So I decided to completely take out the thermostat to see how the van would run without it. I drove down the road a few miles and ENGINE flashed on the screen display. This time it wasn’t boiling over, and it didn’t reduce the power like it did before. Is it OK to run the van like this without the thermostat? I don’t want to ruin my engine What are you thoughts and ideas? Thank you.

Thermostat Replacement $157.20 - $759.78 Get a Quote
Car is overheating Inspection $94.99 - $114.99 Get a Quote

Hello. Let me start off by saying that it is just as bad, if not worse, to run an engine with no thermostat as it is to run it with a bad one. It will also cause engine damage. It sounds like there is a head gasket issue with the engine.

If it primarily overheats under load then it has combustion pressure getting into the cooling system which will ultimately causes this to occur. I usually look for bubbles in the cooling system when the engine is running and do a block test to verify this.

If you need to have this looked at, consider YourMechanic, as a certified mechanic can come to you home or office to diagnose your overheating issue and repair this.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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


Experienced Mechanic?

Earn up to $70/hr

What others are asking

Car alarm won't turn off.
If the alarm is an aftermarket alarm then if may just be defective. I have found that most alarms made aftermarket do not last long and are made of cheap relays and circuits. If you have a factory alarm then...
Driver airbag off light appear on start and tire issue
Your tire pressure light is simply telling you to check the tire pressure. The reason it comes and goes is because the pressure is directly related to the temperature. While you are driving, the temperature fluctuates and the tire pressure...
Air bubbling in coolant reservoir when car is starting /running.
When the radiator hose was broken, did the vehicle overheat and did it overheat bad enough to cause a failure of the cylinder head gasket? When the new hose is replaced, air must be purged from the system and you...
My check engine light came on and my car was diagnosed as needing a catalytic converter. Now, my car won't start.
Hello, thank you for writing in. The catalytic converter can cause a vehicle not to start. This would be an extreme situation where part of the catalyst inside has broken off and is clogging the entire exhaust pipe. Tap on...
My negative battery cable start smoking when the car is running.
There is a faulty, high resistance (often due to corrosion, wire defect or break or loose mechanical connection) connection at the battery post and/or at the vehicle ground(s) at the frame. The recommended and safest practice is to replace the...
Car vibration
Your car has some of the most sophisticated Motor Mounts in the business. It may even have a variable motor mount that has a vacuum line going to it. When the car is idling, the engine vacuum opens a valve...
How do you know if the ignition needs to be replaced when you replace the plugs on dodge 5.7 hemi?
Hi there. To determine if the ignition coils need to be replaced, remove one park plug wire at a time and hook it up to a spark tester gauge and set the gauge to 10 thousands gap and increase it...
My car wont start after driving it for an hour, it will just crank and then start after 30 mins
The engine is very common to have an intermittent cam or crankshaft sensor. You can have the computer scanned for codes to one of the sensors and replace them as codes are stored. If you have codes for both then...
I have a 2012 ram 1500. From a stop at a light or stop sign when i give it gas i feel and hear a grinding sound from the pedal.
It sounds like you may have a problem with the traction control system, which may include a number of things. The traction control system (https://www.yourmechanic.com/services/traction-control-light-is-on-inspection) monitors the steering and stability of the vehicle and engages when loss of traction has...

Related articles

What Do the Belts on the Front of an Engine Do?
Car serpentine belts power multiple parts like the power steering pump and air conditioning. A broken engine belt can cause damage to components.
Top 10 Bad Driving Habits That Damage Your Car
Even the best drivers are guilty of bad driving habits. Riding the brakes, not warming up the engine, and ignoring warning signs will damage your car.
How to Get a Used Engine
The engine (https://www.yourmechanic.com/article/how-a-modern-engine-works) under the hood is the most important component of a vehicle. Without the engine, your car cannot run and is of little value to you. If you have been in an accident, or neglected your engine to...