One of the most common critical engine problems is the blown head gasket. If your Mazda MX-5 has blown its head gasket, you may find it running poorly or not at all. Below you’ll find the symptoms, causes, and price of a Mazda MX-5 head gasket.
A head gasket’s job is to create a seal between the engine block and the head(s). Outside of this job, it needs to fail before the head cracks or warps. If the head gets damaged, the repair becomes much more costly.
It should be noted that when you blow the head gasket, the head itself may be warped or cracked. If you do the head gasket replacement yourself, you should take it to a reputable machine shop and have it tested. Even if it looks perfectly fine to the naked eye, it still could be damaged. Otherwise, you’ll go through all of the trouble of replacing it (it’s never a quick or easy job) only to find out that the head needs to come back off and be replaced. Here’s a good YouTube video on how to tell if your head or block is cracked.
Blown Head Gasket Symptoms: Mazda MX-5
Most of the symptoms of a blown head gasket are obvious, since the way that the engine runs is usually affected. Here are some of the most common signs of a blown head gasket:
- Rough/Choppy Idle- When a head gasket blows, it will lower the effective compression ratio of one or more cylinders. This is always most noticeable at idle speed.
- Loss of Power– A blown head gasket can leave your MX-5 feeling sluggish at speed.
- “Milky” Oil– Depending on how bad and where the head gasket has broken, engine coolant can mix with the oil. This is a very serious concern. Oil that is too this can lock the motor up and leave you stranded.
- White Smoke from Exhaust– A certain amount of white smoke is completely acceptable. But, if you feel that it has greatly changed recently don’t ignore it. Related: White Exhaust Smoke Diagnosis: Mazda MX-5
- Loss of Coolant– If your MX-5’s engine coolant level is going down, but there is no noticeable leak, it could be a sign that the head gasket has blown.
Mazda MX-5 Blown Head Gasket Causes
While there are many reasons that your MX-5’s head gasket can fail, the most common ones have to do with the cooling system causing the engine to overheat.
- Low Engine Coolant– If there is not enough coolant to properly cool the engine, it’ll overheat and blow the head gasket. Low engine coolant can be both the cause and a symptom of a blown head gasket.
- Bad Thermostat– The thermostats job is to regulate the flow of coolant in and out of your MX-5’s engine. When it refuses to open, the engine can get hot enough that it’ll crack a head or blow a head gasket.
- Poor Coolant Flow– If there is not enough coolant flowing through the engine, it’ll overheat. This could be due to a bad radiator, radiator hoses, or water pump.
- Head Gasket Failure– It’s not uncommon for some vehicle makes and models to have head gaskets that just fail for no other reason than bad engineering.
MX-5 Head Gasket Repair Cost
Head gaskets themselves are very affordable. It’s the labor involved with getting them replaced that will get you.
With engines that have overhead cams, it’s can be an incredibly arduous task. It’s a bit easier with traditional engines that have the camshaft in the block.
With parts and labor, the average head gasket price is north of $1200. They can be significantly more depending on the model year and engine.
If you plan on tackling the job yourself, start at the beginning of the weekend, and make sure that you use a torque wrench when putting everything together.
Replacing a head gasket on your own can be time consuming and challenging, but it can save you a lot of money. If there is anything that you’d like to add, please feel free to leave a comment below. Good luck diagnosing your Mazda MX-5!