Screaming coolant pump

[ddd]

I may be the first one to report this problem. I have had my 04 Seaside since 10.2003. As the mileage was 35,500 and getting to the end of waranty period, I took it to Downtown Toyota in Oakland to check the loud coolant pump.

Since day 1 I have been very careful with my car and get rewarded with a consistent 58 mpg( 90% freeway/10% local ). Since 8 months ago, I noticed that when I turn off the engine when I get home at night, the coolant pump has been getting louder and louder, to the point of screaming. I wonder if it is because I live on the top of a small hill, so when I go up the hill, I stress the engine and it runs hotter. The speed limit is 40 mph uphill and I drive around 30 mph. (By the way, I set cruise control at 59 mph on the freeway)

Going to work means driving downhill and then on a long stretch of flat highway, with 1/3 of the time on battery power. So when I get to work in the morning, I do not hear the screaming coolant pump when I turn off the engine. Could this be because the engine is cooler?

The sound definitely has gotten louder over the last 8 months. The technician said there are actually 2 coolant pumps and had a hard time figuring out which one. Eventually he narrowed down to 1 and has ordered the replacement, to be put in tomorrow.

If the coolant pump would malfunction at 1 1/2 year of use, I wonder how long the replacement would last and when the other coolant pump might give out?

I love the car, even though for 7 times within the first 3 months of owernership the car wouldn't start - "stuck" in no power, then there was the gas tank/tube recall and mileage dropped afterwards. Took car in for the rattles then had to go back 2 more times for them to remove the ugly black adhesive sticking out the speedometer window. After the 3 rattle fix I actually felt the instrument display board shifting on large bumps. I have given up on the rattle business.

Since the 15,000 oil change I have been changing the oil using synthetic myself. Just need someone to balance the tires (Downtown Toyota charges $60 to do the rotation). By the way, the kick panel right passenger side came off and I will ask them to replace it.

[aka007ii]

I have learned not to buy anything right when it first comes to market. I hate to say it but I'm thinking that some of the early '04s may just have some small problems. I'm just crossing my fingers that my late '05 Prius will not have a single issue for at least 5 years like my Civic (I'm sad to say I sold it today). Let's hope your replacement pump is built better and that it's not a different problem all together.

[efusco]

There was some discussion of this on one of the other forums. I think the concensus was that this is probably a part covered under the 100/8 emissions warranty since that's the main job of the coolant--to reduce emissions.

There are a lot of us getting into those 30-50k mile range and we may see a crop of minor problems such as this start to rear thier heads. I suspect Toyota will "do right by us" and fix the problems as they come up.

[jeromep]

ddd, I hope you post back, because this thread is of great interest to me.

First off, I'm confused as to what pump you are hearing. It sounds like it is the hot coolant transfer pump, and not the belt driven main pump. If it were the belt driven pump it would be noisy anytime the ICE is running. I'm not sure which pump you are referring to, however it sure sounds like the hot coolant transfer pump.

I have a hot coolant transfer pump which is progressively getting louder when it does the coolant transfer in the morning at first start up and whenever the engine block is cool. My car is garaged at home and at work, so it ambient temperature even in the dead of winter is no lower than about 50 degrees. The sound isn't a screaming sound, however it sounds sandy, like one of the bearings on the pump is going out. It however doesn't make this sound when I get to work after my car has warmed up. My local dealer had it overnight and said nothing is wrong, however they messed around with my tire pressures. So, an obvious change in the operation of the car is something you can't determine but you sure can mess with things that are unrelated to that pump.

Anyway, I have just been letting it go for now. I'm waiting for my letter from Toyota for the SSC50p recall, and I will go to my selling dealer 100 miles away and let them do the recall work and I also hope they will believe me regarding the transfer pump noise. I do not trust the local dealer to competently work on this car if they cannot believe what I tell them and then take appropriate action.

[efusco]

Jeromep,
How many miles/how old is your Prius?

Here's the PriusOnline thread on this subject that I think you'll both be interested in:
http://www.priusonline.com/viewtopic.php?t...ht=coolant+pump

[Paul R. Haller]

ddd, I hope you get your pump fixed the first time around. With regard to downtowns prices... you might consider Walnut Creek Toyota. I took my car in for the 5000 mile service last week to make an appointment for the near future. It was at night. <10:30 PM> They are open for service until midnight. This service includes tire rotation and an oil change + checking all fluids and topping them off if necessary and a quick vacuuming of the interior. They did the service while I waited, saying that no appointment was necesssary, for 29$ + tax and guaranteed to be finished in 45 minutes or less or the service is free. It's called the lube express service program. Good luck with the pump,
-Paul R. Haller-

[jeromep]

Originally posted by efusco@Oct 27 2005, 11:55 AM
Jeromep,
How many miles/how old is your Prius?

Here's the PriusOnline thread on this subject that I think you'll both be interested in:
http://www.priusonline.com/viewtopic.php?t...ht=coolant+pump

[snapback]146318[/snapback]

Purchased 12/11/05. It currently has 7400 miles.

Prior to the most recent data loss crash of Priuschat I believe I had a thread going here with somebody else about this issue. Danman also had commented about this issue along with Rick57 in that thread.

The thread link you posted is the one at Priusonline I had posted to about this issue. Seems to me like there are a smattering of us with this problem. I'd like to think I don't have to wait for the pump to get the squealing point before I can get it serviced.

[htmlspinnr]

If by screaming you mean squealing, I've noticed mine doing it for nearly a year. Only when colder outisde though, so when I had time to do something about it last summer, it wasn't reproducable. However, now that we're finally seeing temps ~60°F at night here, I'm beginning to notice it again. I think last time I mentioned it, I noted that it sounded like an RC car motor with a spun bearing, for lack of a better analogy.

I'm quickly approaching 46k miles on mine, and it's just a bit over 2 years old now to me (my time flies!). If it's covered either by powertrain or hybrid warranties, and especially if there's a TSB on it, I'd be more than happy to get it fixed.

I'm more concerned that it's something that could completely fail in the future.

[DanMan32]

As Jeromep said, I too have notice the heat storage coolant pump a bit noiser than when new, for about the last 8-10K miles. I thought the pump should be covered under emissions warranty, but in reviewing somewhat related TSBs, it may only be covered under the 3/36. I mentioned this issue to the dealer at 35K, but they didn't have time to look on a Saturday, and I didn't have time to take a day off just for this. I have an extended warranty so if it is going to give out, it should give out before the warranty does. As long as it doesn't leak, I can always disconnect the pump and continue to drive until it can be repaired. And if it does leak, I probably could disconnect the water valve servo, though if I do that I probably won't get heat either.

Yes, there are 2 electric coolant pump, and your tech should have been able to identify the difference. The other coolant pump is for the heater core, so that coolant can flow when ICE and its mechanical water pump are not running. There's also a coolant water valve operated by a servo motor. I MIGHT understand confusion betweent the valve and the CHS pump, but there is clearly a difference between the two.

[ddd]

Coolant pump replaced - when I got it home, I thought I got a NEW car - no noise at all for about a minute, then a VERY low pitched hum for another minute that I had to jog my memory to recall how it sounded when new. I had lived with it for almost a year!!! Should I now worry that it is TOO quiet? :-)

Comment from the invoice -"hot coolant transfer pump motor is noisy/binding. Replaced hot coolant transfer valve motor assembly. Bleed system and check system. Operation is normal at this time." I should thank the mechanic for confirming the problem during the day, because for me during the morning there is no noise, but only at night.

So, yes, it was the same problem reported in the PriusOnline thread.

The service manager said the part is covered under 3 y/36K waranty, not emission. I'm glad that I finally got it done. I try not to think when the problem may resurface with the replacement.

Something I want to ask the group: The part had to be ordered and was installed 2 days later. Between the first visit for diagnosis and the return for installation, the "scream" went away! There was absolutely NO pumping! When I got home the first night I did not hear the pump at all - just DEAD silence when I pushed the power button. I called the service manager the next day asking if the pump might have been disconnected. He said "no way". Since the "scream" only happens on returning home after going up a hill, I listened again the second night. Again, dead silence even after waiting for 10 minutes. I was really worried. I asked again after the installation why there was no noise at all after the diagnosis and he did not answer me.

Lessons I learned:
1. not to minimize problem - I thought the "scream" was normal - NOT in this case. Get it diagnosed before waranty period. The service manager was not aware of this problem when I took it in. I always seem to be the first one to report problems, as he was not aware of the "no power on" issue when I reported it in 7.2004.

2. try out another service department next time. I was just complacent as this shop is only a 8 minute walk from work. Even a nephrologist should take some time off to take care of things in his own life!

Lets continue to share our experience. We've only got ourselves to help and support each other.

ddd