After replacing the water pump and thermostat engine idles really high

2002 CHEVROLET IMPALA

112,322 MILES • 3.8L

BENJAMIN LUCAS

MEMBER
1 POST

i'm looking to purchase a car the guy i may get it through said that he changed the water pump and thermostat which he had to remove the throttle after he got done. the car now idles on the highest when car is on and does not stop. he said that antifreeze shot out from the bottom of the front of the motor and it starts smoking from the motor as well. what happened? please help.

Mar 14, 2021 at 5:48 AM

KASEKENNY

✓Experienced Mechanic
18,907 POSTS

We are missing a piece to the story because you do not need to remove the throttle body to do the water pump. I attached the process below.

The coolant coming out of the engine is most likely the pump is not sealing or was not installed properly which when hot would cause a lot of steam/smoke to come from the engine as well.

However, I would press them a little more on what the issue was when they removed the throttle body. At this point with high idle, I would suspect there is a vacuum leak.

Here are some guides that will help with this:

https://www.2carpros.com/articles/engine-idles-too-high

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Let me know about this info and we can go from there. Thanks

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