Recently, I had a blog reader with a blown spark plug on a 2002 Mazda Tribute, she may have found us by using the search engines for blown spark plugs, even though our articles are mainly for specific Ford engines that do have this problem. She asked my advice about what she should do with her Mazda. While this is not a common problem with 3.0 engines, like in some Ford 4.6 and 5.4 engines I offered my advice. More than likely the spark plug had either been left loose or was cross threaded at some point and it blowing out was the end result. Below is what this reader had to say and my response.

Dennis, thanks for the insight. I understand clearly now what went wrong with my 2002 Mazda Tribute, V6, LX, which I understand has a Ford motor. My Mazda Tribute has 112,000 miles on it and ALL the repairs have been done by the dealership. I am meticulous with the upkeep of the car. However, one of the spark plugs blew out of the cylinder head. They could never tell me what caused this, but my opinion is that it was a human error. The dealership gave me 2 options. Option 1 for the cost of $3100 plus tax is to send the cylinder head to a machinest to repair the threads. Option 2 is to get an engine with 68000 miles on it and give me a warranty of 1 year. What do you suggest Mr. Dennis?
Thanking you very much.

Olga, 

Thanks for your comment. If you have documentation (receipts) that ALL of your maintenance has been done at the dealership, most importantly the spark plug replacement, you may have an argument for them to do the repair for free as good will or customer satisfaction. Try talking to the service manager or contact their corporate office and see what they will do for you. Your case would be strongest, if the spark plug replacement was done just recently before it blew out. 

If you are stuck footing the entire bill, your options as I see them is to: 1. Have a shop repair the threads in the vehicle. 2. Send the head out to be repaired. 3. Replace the engine. 

1. The dealership may not agree to install a repair insert, but an independent shop may be willing to do this and it’s a much less expensive repair…it might be worth doing this and taking a chance on the repair holding. This option would be the least expensive, but the gamble would be yours and not warrantied by the repair shop against failure of the repair.

2. Sending the head out for repair is labor extensive and there’s additional parts needed like gaskets, coolant and machine shop work, etc, so I would explore other options. Also, sending the head to the machine shop for repair does not guarantee that the threads will hold. This is an expensive gamble.

3. Since the value of a 2002 Tribute according to Kelley Blue Book is around $5,000 to $6000, I would be hesitant to put $3100 in an engine repair or even replacement. But, if replacing the engine is absolutely necessary, I would comparison shop other repair facilities and maybe even call the salvage yards myself  for estimates for putting a used engine in. The economy is slow right now and shops are likely to be very competitive. Make sure the engine replacement estimates are for engines with comparable miles on them and that the warranty is for the same duration. Also have the valve covers removed to inspect for sludge which would indicate a lack of maintenance (regualr oil changes). And of course have a written estimate prepared once you decide, so there’s minimal surprises on the final bill.

Good Luck