Many thanks for your patience, I am pleased to be able to continue assisting with your query now. First of all, I am sorry to hear about the issues he has experienced in his situation.
When a consumer enters into a contract for services, the Consumer Rights Act 2015 says that such services must be:
- Carried out with reasonable care and skill (to the same standard as any reasonably competent person in that trade or profession)
In the event of substandard work, the trader should either redo the parts of the work which are inadequate or perform the whole service again at no extra cost to the customer. This must be done within a reasonable time and without causing significant inconvenience. If this is not possible, the consumer can claim a price reduction, based on the severity of the issues. That is something which should be negotiated between the two parties. Similarly, they will still be liable for any issues caused by their negligence, even if it falls outside of the warranty terms.
As replacing the engine is unlikely to be considered reasonable at this stage, purely on a ‘what if’ basis, he should know that they would be reposnsible if anything happens to the engine as a result of their failure to put the coolant in.