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Hi there,
I have a Mazda 2.2L diesel. The car is 7 years old and has been serviced through Mazda it’s whole life.

We were driving the car and the master warning light came on. We took it to John Ford Mazda in Penrose to get this checked and they also gave the car its service and warrant (which it passed). To fix the master warning light issue we were told to replace the battery which we did.

5 days later I was driving the car and the warning light came back on again and shortly after the check oil light and check engine light. We pulled over and called AA Roadside Assistance who came and said the car needed 3L of coolant and had no oil. We went to the petroleum station and put a litre of oil in.

We took the car back to John Ford Mazda the next morning and have been told it has blown a head gasket and needs a new engine for $12,000.

The dealer is accepting no responsibility and said that the warning light coming back on is unrelated to the original master warning light which came on 5 days earlier. They are also claiming they did a proper job on the service and WOF.

My questions are as follows:
1. Would there have been signs that the head gasket was about to blow that they should have picked up in the service and WOF and check of the warning light when we originally went in?
2. What are my options from here? I do not accept that they did the service properly and that the original master warning light was for the battery
3. Is it unreasonable that a 7 year old car that has been serviced it’s whole life blow a head gasket?
4. Mazda are relying fully on a diagnostic report which said the main warning light originally related to the battery. Is it reasonable to rely fully on this?

Seems very convenient for them that none of this was detectable 5 days earlier and to claim no responsibility.

Hi there,
All though not too common, a headgasket can blow with little to no warning. As a headgasket is a physical component, it is not monitored by the engine computer and hence no warning light would directly relate to this.
A blown head gasket would often be detected by its symptoms, engine overheating, coolant loss, oil loss or leakage, or the mixing of coolant and oil.
Each time the engine warning light stays on- a fault code is recorded- this will give a basis for further diagnosis. So if the code was a low voltage system code or similar for example, then the first test would be the battery- and replacement if the battery was faulty, the code would be cleared and the vehicle deemed repaired.
It could be possible that there was indication at service that the vehicle head gasket was compromised, and the fault code present would not have pointed to this either.