Question about Grundfos MQ3-45 1 HP Pressure Booster Pump

1 Answer

Waterpump not working

Pump does not pump, it just groans, I've been told its probably the startup capacitor

Posted by on


1 Answer

  • Level 1:

    An expert who has achieved level 1.


    An expert that hasĀ over 10 points.

    Problem Solver:

    An expert who has answered 5 questions.

  • Contributor
  • 17 Answers

Either the start cap, start switch or possibly not getting enough voltage. You need to check winding resistance to ground. The manufacturer should have instructions on this. If there is any reading below about 10meg, just replace the pump. If it ran dry it will have burned up the pump internals.
This pump is not rebuildable. I tried once. So many parts and they make them so expensive you can buy a new one.
There are other pumps that cost much less on the market. Walrus makes one that works well and you can get two for the price of one Grundfos.
I would avoid the ones that have a pressure tank and other stuff. They work, but take up a lot of space and have too many things to fail. You can replace the simpler pump only models for the price of repairing the them.

Posted on Dec 11, 2013


1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

a 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of.(from cars to computers, handyman, and even drones)
click here to download the app (for users in the US for now) and get all the help you need.

Posted on Jan 02, 2017


Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

I have a astra 2008vvti 1.8 engine done 41000 miles when does the cam belt need to be renewed do i have waterpump done same time

Replace belt about every 75000 miles.. and yes replace water pump and tensioner... for its a timing belt driven waterpump

Aug 27, 2016 | Vauxhall Cars & Trucks

1 Answer

What's your question? what is cause of overheating in toyota coaster bus diesel engine ve change the casket but still wont stop

water pump not working , does the coolant boilaway change waterpump , cracked head , check the cylinder compressions to check the head

Jun 01, 2015 | Toyota Cars & Trucks

1 Answer

Is a 97 2.4L GM motor capable of oval track racing performance. I've heard the oiling system and water pump can't handle it. Also been told that they work fine? What is what?

yes the 2.4 dual cam works well and fits great in most eco stock racing rules. I run one on a 3/8 mile high banked dirt track. The engines are light and so are the cavaliers. The waterpumps are not the easiest but i did not find it near as hard as everyone online cried about to change. Im not sure yet on the oil pump having a fualt to the bottom end issues, i lean more on the counter balance shafts airiating the oil at high rpms.

Feb 10, 2013 | Cars & Trucks

2 Answers

A few months ago i had to get the water pump replaced, my belt fell off and i was told it it was the tensioner pully, since the water pump and belt were replaced there was a groaning noise then my belt...

for starter i would start using a different shop simply because if they are not ripping you off they are incompentent. but to answer your question about and alternator falling apart i have never heard of it happening. now it is possible that the bearing for the pulley would lock up which it would make a groaning noise before it completely seized up. but normally it would groan for probably a few weeks or more before locking up. in short find a new shop the guys that work at the parts stores like autozone can usually recommend someone good.

Apr 18, 2011 | Buick LeSabre Cars & Trucks

1 Answer

Steering seems to groan when turning...sounds like a pump laboring. is there a way to tell whether it is the pump or something else making the pump over-work?

Most Ford Windstars the power steering pump is the groan - very rare it is anything else - replace pump and use factory fluid

Dec 01, 2009 | 1999 Ford Windstar

2 Answers

Steering is choppy / groans at startup

The first economical solution is to have a shop to change out the steering fluid and the filter to see if improved. If it os not then we can talk about the steering pump service. Good luck.

Jul 08, 2009 | 2005 Jeep Grand Cherokee

3 Answers

1999 Lexus ES300 Steering wheel make groaning noise

If the groaning sound is still happening, you are probably low on power steering fluid. I suggest starting there. Remove the cap and check the dipstick attached to the cap. The reason the sound would go away at high speeds is that you don't turn the wheel as sharply at higher speeds so the pump is not trying to pump air ( that's the groaning sound ).
If you are low on PS fluid, fill it but check for leaks for a while. Look under the car in the morning for fluid. If you spot a leak, take it back to whomever replaced the hose and have them fix it.

As far as the engine light goes, first make sure the gas cap is on properly, meaning all the way. Turn it till you hear it click several times. If that is all it was, the light should go off after 20-30 miles or so. If it stays on, try changing the gas cap. That is probably one of the cheapest routes to go.
Good luck

Apr 12, 2009 | 1999 Lexus ES 300

Not finding what you are looking for?
Grundfos MQ3-45  1 HP Pressure Booster Pump  Logo

110 people viewed this question

Ask a Question

Usually answered in minutes!

Top Grundfos Garden Experts

john h

Level 3 Expert

12650 Answers


Level 3 Expert

2237 Answers

Audrey Messer
Audrey Messer

Level 2 Expert

176 Answers

Are you a Grundfos Garden Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides