Grumble noise before and after gas motor runs

eddie27970 · 12-20-2007, 09:37 AM

I have 2-Prius (Pris), an 04 and 05. Recently, when shutting down, there was an intermittent grumble noise, as if a bearing going bad in a motor turning. Now it happens just before the gas motor comes on, and also immediately after the shutting down the gas motor. It is not the coolant pump that runs 30 to 40 seconds after turning off the car. This motor is down low by the driver's side tire. And it seems to be related to the gas motor coming on or shutting off. Once the car is warm, and I shut down without the gas motor on, the grumble does not happen. ....only when gas motor first comes on from cold start, or shutting down with gas motor running, is the noise heard. My guess was maybe an gas fume evaporative motor?

Whenever I make it to the mechanic, I am on electric power in the sales lot, and the noise will not happen. His comment was that if it is driving fine, and no check engine light, then keep on driving. It is now worse, and I worry that whatever motor is failing will eventually stop and then gas motor will not come on.

If one can listen real close to this front driver side tire area when first starting a Prius, you can hear a faint motor run 4 or 5 seconds before the gas motor cuts on. And again, if you are stopping the car while the gas motor is on, you can hear it for a few seconds. What motor is this? Thanks

firepa63 · 12-20-2007, 10:10 AM

Have you checked the oil level to make sure it was not overfilled?

eddie27970 · 12-20-2007, 12:09 PM

Yes. I try to put oil level in between full and low. Long ago, from people who race cars, the lower the level in the oil pan, the less friction as the crank turns and plashes through the oil.

But this grumble noise is prior to the gas motor coming on. ...as if a fuel pump building pressure before you start motor. ....only, the first I heard it was always after shutting off motor. So that would not be fuel pump. And now that it is worse, it happens when first starting up and again when shutting down. And it is always in relation to the gas motor, only happening when gas motor first comes on, and immediately when cutting off.

eddie27970 · 12-21-2007, 06:24 AM

Used to only hear this grumble after shutting down and getting out of car. Now, it happens when starting also. And it is down by front driver tire. I've read about the brake bark. Mine happens without foot on brake, happening after I've gotten out of the car (and it is not the usual water pump the comes one 30 to 45 seconds after car is off).

I have 2-Prii. an 04 and an 05. It's the 05, with 65k miles recently making this grumble sound, as if a bearing is bad in an electric motor. It was intermittent when it first started. I can press the start button, jump out of car, with hood up, and put head down by front tire and hear this motor running a few seconds before the gas motor comes on. Same thing after shutdown. And, it always has to do with the gas motor, either coming on, or stopping. If I press the stop button when the gas motor is already off, the noise does not occur. I can only hear the grumble just before and just after the gas motor runs. When I go to the dealership, I am on electric power through the car lot to the back, and cannot make the noise happen for them to hear it. I guess I will have to leave the car overnight. Hoping someone on hear can give me an idea as to what to tell mechanic. Thanks

bwilson4web · 12-21-2007, 10:44 PM

Quote:

Originally Posted by eddie27970

Used to only hear this grumble after shutting down and getting out of car. Now, it happens when starting also. And it is down by front driver tire. I've read about the brake bark. Mine happens without foot on brake, happening after I've gotten out of the car (and it is not the usual water pump the comes one 30 to 45 seconds after car is off).

I have 2-Prii. an 04 and an 05. It's the 05, with 65k miles recently making this grumble sound, as if a bearing is bad in an electric motor. It was intermittent when it first started. I can press the start button, jump out of car, with hood up, and put head down by front tire and hear this motor running a few seconds before the gas motor comes on. Same thing after shutdown. And, it always has to do with the gas motor, either coming on, or stopping. If I press the stop button when the gas motor is already off, the noise does not occur. I can only hear the grumble just before and just after the gas motor runs. When I go to the dealership, I am on electric power through the car lot to the back, and cannot make the noise happen for them to hear it. I guess I will have to leave the car overnight. Hoping someone on hear can give me an idea as to what to tell mechanic. Thanks

Upon further reflection, it is likely another electric motor. There is a possible problem with MG1 but the problem would be there anytime the car is running or if in EV mode. But if the noise is heard without the ICE turning over, it suggests another electrical motor including in the front thermos.

Bob Wilson

Bill Lumbergh · 12-23-2007, 06:03 PM

Sounds like the hot coolant storage pump running. It may be a little louder when cold.

Mine sounded as if it had a very bad bearing while I was in AK when it was cold. Now that I'm in CA, I never hear the bearing noise anymore.

To hear the pump running is normal.

hobbit · 12-24-2007, 12:13 AM

The throttle control motor also makes a bit of noise, since it's
pulsewidth-modulated. That's probably the loudest underhood
sound when you're powered up, engine off, and the brake accumulator
pump isn't chuggin'.
.
_H*

patsparks · 12-24-2007, 05:50 AM

My old car had a grumbling noise before and after I filled up with gas.

Came from the guy paying for the gas.

fruzzetti · 12-27-2007, 02:01 PM

Actually, that grumbling sound before and after your engine runs is me. It's getting really cramped living under your hood and having to tolerate the constant temperature change and vibration when I'm trying to sleep during the day.

~ dan ~

PS - in my 2001 I once had a mouse chew out my windshield squirter hose (thank god it wasn't the brake line). I would pull the lever for a squirt and I'd get the pretty "Prius" lid dirty, with no squirt. How sad!

eddie27970 · 12-28-2007, 09:49 AM

Thanks for the replys. I've been awawy from the computer a few days. I'm about convinced it is this coolant heat transfer pump making the grumbling bad bearing sound. Read several other threads about this. But no one seems to answer the question of wether or not it is covered under the 70k emissions federal mandated warranty. If any sensor goes out in 70k, causing check enging light, federal law requires manufacturer to fix this. I am thinking this coolant pump is part of the low emissions system on the Prius.

Anyone ever talk to the dealer, or Toyota about this pump being covered under the emissions controls warranty?

Anyone ever try to lubricate this pump?

Read all about replacing it. Not to hard. But getting all the bubbles out of the coolant when refilling seems a little involved.

12-20-2007, 09:37 AM	#1
eddie27970 Junior Member Join Date: Mar 2005 Posts: 18 My Car: 2005 Prius Package: #7 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Grumble noise before and after gas motor runs I have 2-Prius (Pris), an 04 and 05. Recently, when shutting down, there was an intermittent grumble noise, as if a bearing going bad in a motor turning. Now it happens just before the gas motor comes on, and also immediately after the shutting down the gas motor. It is not the coolant pump that runs 30 to 40 seconds after turning off the car. This motor is down low by the driver's side tire. And it seems to be related to the gas motor coming on or shutting off. Once the car is warm, and I shut down without the gas motor on, the grumble does not happen. ....only when gas motor first comes on from cold start, or shutting down with gas motor running, is the noise heard. My guess was maybe an gas fume evaporative motor? Whenever I make it to the mechanic, I am on electric power in the sales lot, and the noise will not happen. His comment was that if it is driving fine, and no check engine light, then keep on driving. It is now worse, and I worry that whatever motor is failing will eventually stop and then gas motor will not come on. If one can listen real close to this front driver side tire area when first starting a Prius, you can hear a faint motor run 4 or 5 seconds before the gas motor cuts on. And again, if you are stopping the car while the gas motor is on, you can hear it for a few seconds. What motor is this? Thanks

12-20-2007, 10:10 AM	#2
firepa63 Senior Member Join Date: Jul 2005 Location: SE Pennsylvania Posts: 296 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Re: Grumble noise before and after gas motor runs Have you checked the oil level to make sure it was not overfilled?

12-20-2007, 12:09 PM	#3
eddie27970 Junior Member Join Date: Mar 2005 Posts: 18 My Car: 2005 Prius Package: #7 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Re: Grumble noise before and after gas motor runs Yes. I try to put oil level in between full and low. Long ago, from people who race cars, the lower the level in the oil pan, the less friction as the crank turns and plashes through the oil. But this grumble noise is prior to the gas motor coming on. ...as if a fuel pump building pressure before you start motor. ....only, the first I heard it was always after shutting off motor. So that would not be fuel pump. And now that it is worse, it happens when first starting up and again when shutting down. And it is always in relation to the gas motor, only happening when gas motor first comes on, and immediately when cutting off.

12-21-2007, 06:24 AM	#4
eddie27970 Junior Member Join Date: Mar 2005 Posts: 18 My Car: 2005 Prius Package: #7 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Grumble noise before and after gas motor runs Used to only hear this grumble after shutting down and getting out of car. Now, it happens when starting also. And it is down by front driver tire. I've read about the brake bark. Mine happens without foot on brake, happening after I've gotten out of the car (and it is not the usual water pump the comes one 30 to 45 seconds after car is off). I have 2-Prii. an 04 and an 05. It's the 05, with 65k miles recently making this grumble sound, as if a bearing is bad in an electric motor. It was intermittent when it first started. I can press the start button, jump out of car, with hood up, and put head down by front tire and hear this motor running a few seconds before the gas motor comes on. Same thing after shutdown. And, it always has to do with the gas motor, either coming on, or stopping. If I press the stop button when the gas motor is already off, the noise does not occur. I can only hear the grumble just before and just after the gas motor runs. When I go to the dealership, I am on electric power through the car lot to the back, and cannot make the noise happen for them to hear it. I guess I will have to leave the car overnight. Hoping someone on hear can give me an idea as to what to tell mechanic. Thanks

12-23-2007, 06:03 PM	#6
Bill Lumbergh OEF/OIF: "We Spy, They Die" Join Date: Jul 2005 Location: Persian Gulf Region Posts: 504 My Car: 2005 Prius Package: #1 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 1	Re: Grumble noise before and after gas motor runs Sounds like the hot coolant storage pump running. It may be a little louder when cold. Mine sounded as if it had a very bad bearing while I was in AK when it was cold. Now that I'm in CA, I never hear the bearing noise anymore. To hear the pump running is normal.

12-24-2007, 12:13 AM	#7
hobbit Senior Member Join Date: Mar 2005 Location: Bahstahn Posts: 2,820 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Re: Grumble noise before and after gas motor runs The throttle control motor also makes a bit of noise, since it's pulsewidth-modulated. That's probably the loudest underhood sound when you're powered up, engine off, and the brake accumulator pump isn't chuggin'. . _H*

12-24-2007, 05:50 AM	#8
patsparks Uneducated bird-brain Aussie Join Date: Jul 2007 Location: Adelaide South Australia Posts: 4,438 My Car: 2004 Prius Package: Base Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 12	Re: Grumble noise before and after gas motor runs My old car had a grumbling noise before and after I filled up with gas. Came from the guy paying for the gas.

12-27-2007, 02:01 PM	#9
fruzzetti Customization-Obsessed Join Date: Dec 2007 Location: Hayward, CA USA Posts: 295 My Car: 2006 Prius Package: #7 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Re: Grumble noise before and after gas motor runs Actually, that grumbling sound before and after your engine runs is me. It's getting really cramped living under your hood and having to tolerate the constant temperature change and vibration when I'm trying to sleep during the day. ~ dan ~ PS - in my 2001 I once had a mouse chew out my windshield squirter hose (thank god it wasn't the brake line). I would pull the lever for a squirt and I'd get the pretty "Prius" lid dirty, with no squirt. How sad!

12-28-2007, 09:49 AM	#10
eddie27970 Junior Member Join Date: Mar 2005 Posts: 18 My Car: 2005 Prius Package: #7 Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	Re: Grumble noise before and after gas motor runs Thanks for the replys. I've been awawy from the computer a few days. I'm about convinced it is this coolant heat transfer pump making the grumbling bad bearing sound. Read several other threads about this. But no one seems to answer the question of wether or not it is covered under the 70k emissions federal mandated warranty. If any sensor goes out in 70k, causing check enging light, federal law requires manufacturer to fix this. I am thinking this coolant pump is part of the low emissions system on the Prius. Anyone ever talk to the dealer, or Toyota about this pump being covered under the emissions controls warranty? Anyone ever try to lubricate this pump? Read all about replacing it. Not to hard. But getting all the bubbles out of the coolant when refilling seems a little involved.