12a Front Cover questions
11-16-14, 08:46 PM
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12a Front Cover questions
I think I may have made a terrible costly mistake. I finally got my car on the road yesterday afternoon and it ran so well. Drove it around town for about 30mins and it finally felt like all this work and money was worth it. Then I came home and drained the water out of the radiator. This morning I pulled all 4 rims off and got my 30 year old tires replaced. I came home all excited put them on the car and took a ride around the block. I was so happy the car rode nice then I realized I NEVER REFILLED THE RADIATOR. I turned the engine off about 5 houses from mine and let it coast into the drive way. When I opened the hood I noticed oil on the side of the block where it says "MAZDA 12A" and dripping down the side. I only drove for about 5-10 mins and the temperature gauge only raised a 1/4 of the way but I'm sure there wasn't much water in the block. Im hoping after it cools it wont leak anymore. Im honestly like beside my self I bought this car thinking I could get it running fast because my every day car went to get repainted and so far Ive have to get rides to work like a little kid. I spent so much money getting it running and driving and problem after problem. Finally I thought I was out of the woods but now this....
Reading online it says I have to rebuild the engine to replace the seal. But everything I read says the front cover is like the first thing you remove, how come you cant just take it off, replace the o ring seals, and put it back together with out disturbing anything else? Like the timing cover on a V8? It seems like I can get to all the bolts, is there something else to it? The engine ran great before this so I doubt it needs apexes or anything like that, and it didnt even smoke. Please let me know..
Reading online it says I have to rebuild the engine to replace the seal. But everything I read says the front cover is like the first thing you remove, how come you cant just take it off, replace the o ring seals, and put it back together with out disturbing anything else? Like the timing cover on a V8? It seems like I can get to all the bolts, is there something else to it? The engine ran great before this so I doubt it needs apexes or anything like that, and it didnt even smoke. Please let me know..
11-16-14, 09:26 PM
#2
First off, don't panic. There is a chance you caught it time and once the engine has cooled you will be OK. You'll know the next time you run it (with coolant in it)
One of the main problems with the temp sensor (and not just on this car) is that it measures COOLANT temperature, not block temperature. If you have no coolant or low coolant, there's nothing for the gauge to read.
Mazda got around that by putting a coolant level sensor on the radiator, wired to an idiot light.
I went one step further and wired an oil temperature gauge in addition to my water temp gauge.
Now, as to your question; in two parts:
1)Oil on top the rotor housing at the 12-A mark doesn't usually come from the front cover; it comes from between the front side housing and the rotor housing, via failure of an o-ring that goes around one of the dowel pins. There is no way to access that o-ring without removing all the tension bolts that run lengthwise through the block, from the rear. This is why it's called the "leak of death."
One of our members (TimWilbers) was recently able to replace that o-ring without doing a complete and total tear down... but it still entailed pulling the engine and separating the trans, pulling the flywheel, etc. He could probably give you tips on what he did, but it was still not a short process.
2) if the oil is in fact coming from the join of the front cover to the front side housing... It is possible, though challenging, to remove the front cover with the engine in the car.
Challenging, because of a few facts; 1) the engine mounts via the front cover so you have to support the block. 2) The front edge of the oil pan attaches to the bottom of the front cover, so you'll be needing to re-seal that join as well, and (hardest) 3) The "front stack" of needle bearings and spacers on the eccentric shaft can and & usually will fall out of position when you remove the front eccentric pulley, and it is very hard to get those parts lined back up & keep them in position when the engine is horizontal. If they slip, the front needle bearing gets crushed on reassembly and you are back to having to replace components within that stack.
I have read that it is possible to disassemble and reassemble the front stack without dropping the bearings by keeping pressure on the clutch... I have never tried it. Others may have better guidance for you there.
First thing though is you want to be sure where your leak is coming from, and that it's still there, before you start tearing into things.
Here's a link to a write-up on the front stack at Mazdatrix's site, that should help you understand the issues there.
https://www.mazdatrix.com/faq/pulley.htm
Good luck.
One of the main problems with the temp sensor (and not just on this car) is that it measures COOLANT temperature, not block temperature. If you have no coolant or low coolant, there's nothing for the gauge to read.
Mazda got around that by putting a coolant level sensor on the radiator, wired to an idiot light.
I went one step further and wired an oil temperature gauge in addition to my water temp gauge.
Now, as to your question; in two parts:
1)Oil on top the rotor housing at the 12-A mark doesn't usually come from the front cover; it comes from between the front side housing and the rotor housing, via failure of an o-ring that goes around one of the dowel pins. There is no way to access that o-ring without removing all the tension bolts that run lengthwise through the block, from the rear. This is why it's called the "leak of death."
One of our members (TimWilbers) was recently able to replace that o-ring without doing a complete and total tear down... but it still entailed pulling the engine and separating the trans, pulling the flywheel, etc. He could probably give you tips on what he did, but it was still not a short process.
2) if the oil is in fact coming from the join of the front cover to the front side housing... It is possible, though challenging, to remove the front cover with the engine in the car.
Challenging, because of a few facts; 1) the engine mounts via the front cover so you have to support the block. 2) The front edge of the oil pan attaches to the bottom of the front cover, so you'll be needing to re-seal that join as well, and (hardest) 3) The "front stack" of needle bearings and spacers on the eccentric shaft can and & usually will fall out of position when you remove the front eccentric pulley, and it is very hard to get those parts lined back up & keep them in position when the engine is horizontal. If they slip, the front needle bearing gets crushed on reassembly and you are back to having to replace components within that stack.
I have read that it is possible to disassemble and reassemble the front stack without dropping the bearings by keeping pressure on the clutch... I have never tried it. Others may have better guidance for you there.
First thing though is you want to be sure where your leak is coming from, and that it's still there, before you start tearing into things.
Here's a link to a write-up on the front stack at Mazdatrix's site, that should help you understand the issues there.
https://www.mazdatrix.com/faq/pulley.htm
Good luck.
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