- :
- San Antonio, Texas
- :
- '15 CX-5 Miata AWD
On Thursday the aug 24 I was leaving a taco joint. As I pulled out the parking lot onto the street and revved, I heard a "whir" and then clunking. I immediately let off the gas and parked nearby. I was certain I had spun a rod bearing. I dumped about a half qt of oil I had in the boot into the engine. I was about 1 mile from home so I slowly drove it there. The following morning I picked up a rental and ordered some rod end bearing from the dealership. I figured since I noticed it as soon as it happened, I may be able to rescue the motor. I picked up the part on Saturday. Being in Texas with the hurricane and all, I waited until Sunday for maybe better weather, which didn't happen.
Sunday I go ahead and work on the car so that I could handle business during the week. I removed the oil filter, oil pan (including having to drill out a stuck bolt which took about 20 minutes on its own), the balance shaft and then the oil pump, followed by the rod end caps, accessing them by moving the crankshaft as needed. To my surprise (and relief) none of the bearing I removed showed any signs of abnormal wear, nor did I see any metal anywhere. I went ahead and replaced all of the bearing with standard size, torqued the caps back on to spec, plus the 80-100* turn , aligned the timing chain, balance shaft and oil pump sprockets as specified and reinstalled everything. As long as I didn't **** something up there I just renewed my engine a bit, if I did, well I guess I'll find out lol.
So after about 5 changed of clothes and 4 pairs of soaked shoes, and some time for the RTV to cure, I fill up with 5w30 I start the engine. So far I'd spent about 6 hours on this repair. I let it idle for about 20 minutes; everything sounds good. I cut it off, remove the jacks etc and start it again. I rev the engine a few times, no knocking; all seems good! I put the car into gear and move it, and the same knocking is back. ****, I guess I have a scored crankshaft, new engine time. So I begin to make preparations to buy a new engine and labour to install it.
In the meantime I'd put some lucas synthetic into the motor, and had been moving it back and forth in the parking spot. I noticed that in addition to knocking while only in motion, it was always constant and increased with speed. I realized I could get the car rolling, put the car in neutral, rev the engine and the knocking frequency did not change. I realized it was most likely the trans at this point. I put the car up on jacks, removed the DSC 30 and then 50 amp to test FWD/AWD clunking, which it did on both. Finally I put the car on jacks and (with DSC ABS 50 out) did some testing to confirm the clunking was based on movement of the driveline and not the motor. I isolated the noise to the transaxle, directly under the ATF pan. The ATF does not appear burnt nor is it at an improper level.
My car is out of warranty, but I'm going to contact mazda to see what the are willing to do considering the problems with other copies of this transmission. If anything, at least a transaxle is cheaper to buy and install than a new/used motor.
Here is a video of my problem. Noticed the RPM/gear indicators compared to the clunk sound.
Sunday I go ahead and work on the car so that I could handle business during the week. I removed the oil filter, oil pan (including having to drill out a stuck bolt which took about 20 minutes on its own), the balance shaft and then the oil pump, followed by the rod end caps, accessing them by moving the crankshaft as needed. To my surprise (and relief) none of the bearing I removed showed any signs of abnormal wear, nor did I see any metal anywhere. I went ahead and replaced all of the bearing with standard size, torqued the caps back on to spec, plus the 80-100* turn , aligned the timing chain, balance shaft and oil pump sprockets as specified and reinstalled everything. As long as I didn't **** something up there I just renewed my engine a bit, if I did, well I guess I'll find out lol.
So after about 5 changed of clothes and 4 pairs of soaked shoes, and some time for the RTV to cure, I fill up with 5w30 I start the engine. So far I'd spent about 6 hours on this repair. I let it idle for about 20 minutes; everything sounds good. I cut it off, remove the jacks etc and start it again. I rev the engine a few times, no knocking; all seems good! I put the car into gear and move it, and the same knocking is back. ****, I guess I have a scored crankshaft, new engine time. So I begin to make preparations to buy a new engine and labour to install it.
In the meantime I'd put some lucas synthetic into the motor, and had been moving it back and forth in the parking spot. I noticed that in addition to knocking while only in motion, it was always constant and increased with speed. I realized I could get the car rolling, put the car in neutral, rev the engine and the knocking frequency did not change. I realized it was most likely the trans at this point. I put the car up on jacks, removed the DSC 30 and then 50 amp to test FWD/AWD clunking, which it did on both. Finally I put the car on jacks and (with DSC ABS 50 out) did some testing to confirm the clunking was based on movement of the driveline and not the motor. I isolated the noise to the transaxle, directly under the ATF pan. The ATF does not appear burnt nor is it at an improper level.
My car is out of warranty, but I'm going to contact mazda to see what the are willing to do considering the problems with other copies of this transmission. If anything, at least a transaxle is cheaper to buy and install than a new/used motor.
Here is a video of my problem. Noticed the RPM/gear indicators compared to the clunk sound.
Last edited: