Overheating/rough idle

20THCENTBOY

MEMBER
2005 CHEVROLET TAHOE
4.8L
V8
2WD
AUTOMATIC
300,000 MILES

On a hot day pulling a new camper (3,500 lbs with load) and the A/C running the SUV runs supper rough while parked. Shut if off for a few minutes and then made a step climb up a short hill with the xamper and coolant leaked from the overflow tub. Now the Tahoe has been having a rough idle off and on for a few years but when I rev the motor it stops. Also has a slight squeal/noise from what looks like the water pump. I'm thinking the water pump needs replacement but is there something else that could be involved in the problem?

3 Replies

JACOBANDNICKOLAS

MECHANIC
108,268 POSTS

Hi,

Has the check engine light ever stayed on while the engine is running? Also, have you ever checked for engine vacuum leaks that can cause a rough idle?

As far as the water pump, it could be going bad. A squeal usually indicates the belt is loose or contaminated. Have you noticed any leaking coolant? Is the noise loud enough for you to record and upload for me to hear?

What I would suggest is this. Since it has a rough idle, first check to see if there are any engine vacuum leaks. Here is a link that shows how it's done:

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

Try that first. Also, let me know if the mileage is accurate for this engine, if the check engine light stays on, and if possible, upload the sound from the water pump.

Take care,

Joe

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Sunday, August 1st, 2021 AT 6:57 PM

20THCENTBOY

MEMBER
19 POSTS

Sorry for the delayed response. So my neighbor who has better gear skills than me listened to my motor and determined no issue is visible on the water pump, but I need to flush my radiator and replace the loose tensioner pulley. The sound and vibration is from the pulley and the alternator whining (normal) a little together making it sound worse to me, but are normal sounds, he has a similar engine to mine. The vacuum line looks very good. So we are going with the band aid approach for my overheating issue and see what happens. Thanks for the insight.

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Thursday, August 5th, 2021 AT 5:40 PM