“How do I fix my pulsing & leaking Karcher pressure washer?”

crafty_penguinI have found several complaints on-line by people who say their Karcher pressure washer pulses and leaks when the trigger is off. I have even found videos posted on YouTube demonstrating the problem, one of which is posted below.

The consensus of opinion seems to be that the problem lies in internal cracks. Some people have found hairline cracks in the plastic pump cylinder head Karcher fit to many of their power washers.

If you fancy stripping down your Karcher pressure washer to see if you can find the problem and fix it yourself the second video below should be useful. It shows a step by step guide to dismantling a Karcher washer.

Spares for pressure washers from Karcher and other manufacturers such as Nilfisk and Bosch are available by mail order from BuySpares.

Karcher Pressure Washer Pulsing and Leaking


How to Disassemble and Reassemble the Pump on a Karcher Electric Pressure Washer


17 comments on ““How do I fix my pulsing & leaking Karcher pressure washer?”

  1. A robertson

    Excellent video -really helpful. Do all karcher electric machines have the same cylinder head. I have the AA model which has water pouring out of the unit but the cost of cylinder head plus cover part is expensive.

  2. Mark

    No they don’t all use the same for the cylinder head, my k3.575 (sometimes called the jubilee) uses a different to most others and the part number is 9.001-693.0. I would suggest ordering parts for your specific model using the model number…google can be your friend!

  3. Ashley Baker

    Hi. Excellent video. I have a 411A k2(1.994-972) that only leaks and pulses when I use the trigger. I have taken the pump apart, to reveal the filters and the ‘guides’. All appears well but wonder if the seal are worn. The mating surfaces of the ‘guides’ are clean. Suggestions please…… In anticipation, Thank you

      1. Craig F

        Volt drop occurs because of the length of the cable. However, the drop would not be substantial enough to cause major issues.

        17th Ed Amendment 3 Qualified

  4. Myra

    Hi Mark I have just watched your excellent video -really helpful, will dismantle my karcher tomorrow with your hepl, thank you.
    Myra – UK

  5. Richard

    Hi, I have a 3.575 jubilee, that has just started doing exactly as in the first video, pulsing and leaking while the trigger is off, what is the cause no likely repair. Any help really welcome, as I don’t want bin the unit…

  6. christine murray

    hi I have a karcher k2.97mb it sprays water out of the front grill I think its because I used a hoselock auto stop connecter can it be fixed or should I buy another one many thanks

  7. Shaun Key

    Hi my K3.575 has blown the ‘O’ ring twice on the small detergent elbow, any reason why this happens. It leaks really bad and not sure weather to just fit another o ring or a new detergent valve, any ideas would be very appreciated

  8. eugene

    I have a Kercher KB9030.It started pulsing when you let go of the trigger. I have no visible water leaks. after watching various video clips I decided to replace the cylinder head but it made no difference. should there not be a water leak visible or what else might be causing the problem

  9. Peter

    What a waste of our time, not once did the idiot say why the machine pulsates or which bit to replace, typical of a yank, they still cant say tube, no its a toob lol & you route a pipe as in route 66 not a router as in a carpentry machine! oh dear what are we going to do with them lol.

  10. David

    My k3.99 has developed the same fault, just used the video to dismantle the plastic pump valve housing and inlet/outlet. The clue is in the pulsing, that’s a relief valve of some description faulty. Operate the lever and the pressure drops so it stops pulsing. I have not replaced it yet but have a valve assembly with a red plastic piston, steel bearing and plastic sealing face, both very indented by the ball….


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