Question about electric coolant pump .

Hi ! Does anybody know if electric coolant pump supposed to be silent, because I can hear it ( "rrrrrrrrrrrrrrrrrr " ) from the driver's seat while turning ignition on before engine starts. And when I shut the engine off the pump makes " rrrrrrrrrrrrrrrrrrrrrrr " sound for a 3-4 seconds. I beleive it wasn't like this before. Is the pump going bad ? For now it's still pumping
coolant, I can feel it by touching the pump. What's gonna happen if it stops completely, is it possible to overheat the engine or some coolant system pipes
can blow out ?
Help , please ! It's 2005 Sprinter 3500 , 45000 miles.

Gray,
Are you certain it's the coolant pump? I'm not saying it can't be because there is an electric coolant pump related to the auxiliary heater. If that pump quits it affects your aux heater, not the engine cooling.....as long as it doesn't start to leak.

My 2004 makes a whirring sound quite often, but everything I've determined is that it's related to my fuel pump valves. If you think that's a possibility for your vehicle it's been discussed before. You should find more detail if you search. Hope this does some good. AP/vic

It's definetly electric coolant pump. Yes , I can hear some humming noise too, but this one .... It's seems to me something's wrong. I found this on
manual CD for Sprinter :

OPERATION
The electric coolant pump is controlled by the ATC
A/C-heater control and is only operational when the
ignition switch is on under the following conditions:
(1) Vehicle speed below 27 Km/h (17 mph).
(2) Coolant temperature above 65° C (150° F) but
less than 110° C (230 ° F).
(3) Any blower motor speed setting.
(4) Temperature heat setting above the halfway
setting (60% heat).
(5) The pump will turn off at speeds above 48
Km/h (30 mph).
(6) The pump will turn off if the coolant temperature
rises above 110° C (230 ° F).

I did try to exclude all mentioned above, but I hear the noise before starting the engine and after shutting it off. With engine working I can't hear or feel anything because of vibration. Looks like pump works all the time , I don't know what to think, maybe fuse or relay is blown ?
Can anybody listen to the noises in their Sprinters, please ?

Gray said:

I did try to exclude all mentioned above, but I hear the noise before starting the engine and after shutting it off. With engine working I can't hear or feel anything because of vibration. Looks like pump works all the time , I don't know what to think, maybe fuse or relay is blown ?
Can anybody listen to the noises in their Sprinters, please ?

Click to expand...

On my '02 I always listen for the electric coolant circulating pump because I've had trouble with it over the years. For me, hearing it run before and after the engine is a good thing. As many others have posted, the OEM pump's brushes wore away and the pump stopped running. I then bought a pump from Europarts-sd and it lasted less than a year B4 the seal failed, resulting in a coolant leak. That one was replaced by Steve under warranty, but the replacement failed - again a coolant leak. No warranty coverage this time. In the meantime, I rebuilt the OEM pump (magnetic drive, so no seal to fail) by replacing the brushes, but it soon stopped too. I guessed something might be blocking that pump's rotation, so I disassembled the pump head and found magnetic particles sticking to the magnets. After cleaning, it ran again, but I may have to disassemble again and clean again because it sometimes still fails to run.

So, I don't worry if I hear it run, I worry if I DON'T hear it run.

PS - Mine has two kinds of sounds when it runs. When normal, it's a hum. Other times, it can almost be like a clicking, which I interpret to be when the driven magnet is sticking/slipping due to those magnetic particles getting in the way. For me, the clicking is bad, the hum is good.

Thanks for answers. So, if I understand this right, usually the pump is silent and when you hear noise, it's a sign of wearing of the pump and you have to be ready
for repair ? How to know for sure, that pump is dead, is it gonna throw out a code, check engine light, in other words what are the symptoms ? What will happen if it stop working while I'm driving, any harm to engine ?

Gray said:

Thanks for answers. So, if I understand this right, usually the pump is silent and when you hear noise, it's a sign of wearing of the pump and you have to be ready
for repair ? How to know for sure, that pump is dead, is it gonna throw out a code, check engine light, in other words what are the symptoms ? What will happen if it stop working while I'm driving, any harm to engine ?

Click to expand...

For my '02 no effect (other than the aux heater won't run for long) if the pump stops running. Again, if the pump on my '02 hums or whirs before and after the engine runs, all is OK.

Gray, did you ever figure this out? Today, while playing with my Sprinter, was the first time I heard a noise like you did including the clicking sound. I have heard the clicking before but it is normally too noisey to hear the coolant pump. Raising the hood I could put my hands on the hoses to the top rear and feel vibration.

I do not have an auxillary heater that uses coolant so I am confused by this. No one else hears a noise? It is not very loud and occurs when you switch the key to the pre-start position where all the lights come on.

Regards,

Keith

kmessinger said:

Gray, did you ever figure this out? Today, while playing with my Sprinter, was the first time I heard a noise like you did including the clicking sound. I have heard the clicking before but it is normally too noisey to hear the coolant pump. Raising the hood I could put my hands on the hoses to the top rear and feel vibration.

I do not have an auxillary heater that uses coolant so I am confused by this. No one else hears a noise? It is not very loud and occurs when you switch the key to the pre-start position where all the lights come on.

Regards,

Keith

Click to expand...

You may not have the auxiliary heater, but IIRC, all T1Ns have at least the heater booster. I did not notice the coolant pump noise until I started fooling with the heater booster stuff in preparation for running it off a battery bank. It is not loud and you would not hear it while the engine is running. The heater booster dosing pump makes a clicking sound but you normally would not hear it with the engine running, unless you were listening for it. But if the engine is off, it is quite obvious (and you should never hear it run with the engine is off in a normal T1N without the aux heater.) The sound comes from an area between and behind the front seats. It is the dosing pump priming the heater booster with fuel. It starts at a slow rate and gradually increases as the heater booster kicks in.

You would also hear the coolant pump with REST on, but it would be obscured by the noise of the blower fan.

(Anybody with more experience here, please correct any mistakes I've made.)

Thanks! I was posting this from a "search" and did not notice it was in the T1 section. I have a NCv3 and no booster or aux heater. My noise comes from the right side of the fire wall or behind it behind my dash. My clicking sound comes from the front. The auxillary fuel tap is not used in mine but I am going to use it for an Espar d2 heater later this year.

Thanks for replying!

Regards,

Keith