Which pressure washer should I buy for car detailing in the UK?

At the midrange price point around 230 to 250 pounds, the Nilfisk Core 150 is the recommended choice: 10 m flexi hose on an integrated reel and a strong reliability record. The AVA P57 Easy is a close second with better serviceability and up to a 10-year warranty. Avoid the Karcher K5 UM at this tier: its 6 m hose is too short and it does not include a turbo nozzle. For a higher budget, the Nilfisk E170 is rated the best domestic pressure washer pound for pound.

Is higher bar pressure better when buying a pressure washer?

Not on its own. Cleaning power is pressure multiplied by flow rate, not pressure alone. A machine at lower bar with a higher flow rate moves more water across the surface per second and does more net cleaning work than a high-pressure low-flow machine. The max-pressure figure on any domestic pressure washer is also a peak reading at the pump with the trigger off, not the sustained pressure delivered during use. Compare flow rate in litres per hour alongside bar when choosing a machine.

What nozzles are safe to use on car paint?

Use a wide fan nozzle (40 degrees) for pre-wash and wheel rinsing, and a 25-degree nozzle for the rinse pass after a contact wash. Never use a zero-degree nozzle on paintwork: it concentrates pressure to a single point and will damage clear coat. Stock hard plastic nozzle tips also scratch paint if the gun is knocked or dropped. Swapping to rubber-tipped quick-connect nozzles eliminates this risk. Always do a test shot away from the vehicle first when fitting a new or unfamiliar nozzle.

Can I run detergent or snow foam through my pressure washer pump?

No. Running detergents, snow foam, or wheel cleaner through the main pump intake corrodes the pump seals and pistons, voids warranty, and shortens machine life. The correct method is a foam cannon attached downstream at the lance outlet so chemistry never enters the pump body. The one safe exception is machines with a chemical-injection barb at the very tip of the lance outlet, where the chemistry injects after the pump.

My pressure washer is underperforming. What is the most likely cause?

Hose length does not affect performance within normal domestic lengths. If a pressure washer starts underperforming, the most likely cause is a worn seal somewhere in the pump. Check whether a service kit is available for the model before replacing the whole machine. Budget pressure washers with universal brush motors can also overheat on long sustained patio sessions because they rely on water flow for cooling rather than active cooling.