Q: Engine shakes when heat is on

asked by on

I have a 2001 PT Cruiser. Engine shakes/vibrates loudly for like 2-3 seconds at a time on cold start only when I turn on the heat and let the car idle in park position. Does this for a while until car is "warmed up". Doesn't do it if I leave the heat off while letting it idle in park position on cold start. What can be the cause of this? Thanks.

My car has 106000 miles.
My car has an automatic transmission.

Hi There, This may potentially be a result of the change in heat in the coolant that results when turning on the heater while the car is still warming up. As you may know, when the car is first started when cold, the coolant temperature sensor reads the temperature of the coolant and relays this information to the ECU. Te ECU uses this information to make adjustments to the air/fuel ratio (adding more fuel) to the fuel supply as the engine requires more fuel to run when the engine is cold due to the difference in air density at colder temperatures. I would suggest having a professional from YourMechanic come to your location to take a look at your vehicle.

Was this answer helpful?
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. Engine shakes when heat is on

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: Q: Rpm problem

Hi Ritchie. Thanks for contacting us today. The first thing you need to do is isolate the source of the RPM increase. It is possible that a vacuum hose was not correctly attached during the service, so I would recommend...

Q: My 2004 Chrysler PT Cruiser is overheating

Hi there - there are a couple of possibilities. The simplest and most likely possible case, based on the recent thermostat replacement, is that the cooling system was not properly bled of air pockets, and is boiling coolant inside the...

Q: Brake Pulsation

You may have a bent rotor hub. This can be checked with a dial indicator gage and if hub is bent more than 10 thousands of an inch it will cause the rotor to move back and forth and cause...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
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...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...