Free UK car question library — MOT advisories, warning lights, fault codes, servicing intervals and buying advice, explained in plain English by a qualified UK mechanic.
You can ask a UK mechanic about your own car for £14.99, or £29.99 for a full diagnostic write-up, and get a written reply within six hours. Free mechanic advice on warning lights, MOT failures, fault codes, noises and DIY jobs is published in this library at no cost.
Answered by Bob — 32 years on the tools, DVSA-approved MOT centre, Birnam, Perthshire.
A real mechanic's answer, not a forum guess
Describe the fault and Bob answers personally: what is most likely causing it, how to confirm it before spending money, whether the car is safe to drive, and what the repair should cost in the UK. Thirty-two years on the tools rather than a search result reworded.
It is most useful in two situations: you have a quote and want to know whether it is fair, or you have a symptom and do not want to pay for a diagnosis that turns out to be obvious.
What to include in your question
Make, model, engine, year, mileage and the registration if you have it. Then the symptom: when it happens, what makes it better or worse, any warning lights, and anything that was done to the car just before it started — that last one solves more faults than any scanner.
If you already have a garage quote, include it. Knowing the parts and labour split is what lets us tell you whether the price is reasonable for that job on that car.
What it costs and what you get
Answers are £14.99 for a straightforward question and £29.99 for a detailed diagnostic write-up where the fault needs working through step by step. One payment, no subscription.
You get a written answer you can take to any garage. It is not a substitute for physically inspecting the car, and anything safety-critical will always come with an honest 'get this looked at properly' rather than a guess.
The free reading first
Before you pay, the free guides on this site cover warning lights, MOT failures, common symptoms by make and typical repair costs. A great many questions are already answered there in more detail than a paid reply could fit.
If your question turns out to be covered by a free page, we will say so rather than take the money.
Free mechanic advice, and when it is worth paying
Most of the mechanic advice on this site is free to read: warning light meanings, MOT failure categories, fault code explanations, symptom guides by make, and typical UK repair costs. That is deliberate. If a free page answers the question, nobody should be paying £14.99 to be told the same thing.
Paying makes sense when the answer has to be about your car specifically — your registration, your mileage, your fault code, your garage quote. General advice cannot tell you whether the £780 quote on a 2014 Qashqai is fair or whether the rattle you can hear is the heat shield or the timing chain. A written reply from Bob can.
Ask a Mechanic is a one-off payment of £14.99, or £29.99 for a detailed diagnostic write-up. There is no subscription, no call centre and no chatbot — the reply is typed by a working mechanic with 32 years on the tools.
DIY mechanic help — doing the job yourself on the drive
A big share of the questions that come in are from home mechanics part-way through a job: which part actually fits this build, whether the cheap one is the same casting as the dealer part, what the torque figure is, which bolts are one-time-use, and whether the job needs coding with a scan tool afterwards.
The advice a DIY mechanic needs most is the order of checks. Testing the cheap, quick thing first — a wiring plug, an earth strap, a vacuum hose, a fuse — saves more money than any tool purchase. Plenty of sensors get changed every week in this country when the fault was the connector behind them.
Send the fault code, the registration and what you have already tried, and you get told what to check next rather than what to buy next. If the job genuinely needs a ramp, live data or a smoke test, that gets said plainly instead of sold as a part.
Where to start if you are not sure what to ask
Work through the free tools first: the fault code lookup for a P-number, the warning light guide for a dash symbol, the symptom pages for a noise or a smell, the MOT history check for a car you are buying, and the recall checker for anything safety-related.
Then write the question down in three parts — what the car does, when it does it, and what changed just before it started. Those three lines are what turn a vague answer into a specific one, whether the answer is free or paid.
Frequently asked questions
How much does it cost to ask a mechanic?
£14.99 for a straightforward question and £29.99 for a detailed diagnostic write-up. One payment, no subscription.
Who answers?
Bob, a working mechanic with 32 years in the trade, running his own workshop in Perthshire.
Can you tell me if a garage quote is fair?
Yes — that is one of the most common questions. Include the parts and labour split and the vehicle details.
Is there free advice?
Yes, plenty. The warning light, MOT failure, symptom and repair cost guides on this site are all free.
Where can I get free mechanic advice in the UK?
The warning light, fault code, MOT failure, symptom and repair cost guides in this library are free to read and written by a working UK mechanic.
Can I get DIY mechanic help with a job I am doing myself?
Yes. Send the code, the registration and what you have already checked, and you get the right order of checks, the correct part for that build and any model-specific catches.
Is online mechanic advice reliable?
It is if it comes from a named, qualified mechanic in a real workshop. Every answer here is written by Bob, not generated, and anything needing physical inspection is flagged as such.
How quickly do I get an answer?
Paid questions are answered in writing within six hours, day or night apart from 10pm to 7am. The library pages are there to read instantly.
Ask a mechanic about your own car — from £14.99, written reply within six hours