Edit: Here's a video- the sound starts when the clutch engages at about 10 seconds in. Sounds to me like a "warbling" sound.
https://www.youtube.com/watch?v=PgxhPOpzBjc
My truck overheated a month or so ago and my mechanic replaced my radiator. Shortly after getting it back the engine starts making a grinding sound alongside increased vibration. I'm not a mechanic, but I do some DIY and this seems like a real mystery to me.
This shop is owned by a family friend and they've been rock-solid for over 10 years, so my inclination is that the sound is unrelated to their work. At any rate, I want to do my best to figure this out on my own before I take it back to them saying they might have caused a problem.
The sound only happens when:
- The truck is in drive or reverse
- Any of the upper blowers are selected (AC/MAX AC/defrost/upper vents/ or the upper and lower vent combo)
- The compressor clutch is engaged
So, for example, the sound/vibration does NOT happen when the truck is in park or neutral. It does NOT happen when it's in drive and only the lower vents are selected.
In particular, I don't think it is the AC compressor or AC clutch. I've visually inspected the action of the clutch while the engine is running, both in park and in drive, and in both cases it looks like the clutch engages and spins fine. When the truck is in park the clutch engages and spins without any of the noise or vibration.
But that said, the noise and vibration only happen when the clutch is engaged. Is there any other component that would cycle on/off with the AC clutch? I have put my finger on the AC drier while it was running and didn't feel any excessive vibration, so I don't think that was the source. I did the same for the compressor, the alternator, and the power steering pump and none of those felt excessive vibration.
It's hard to tell, but the sound seems like it's coming from the middle/front of the engine, which is where the water pump is on this engine. Does the water pump run continuously or does it cycle on/off?
Also- both the AC and the heater seem to run fine and blast out cold/hot air as expected.
Unfortunately on this model of vehicle the AC compressor runs whenever any heating/cooling is selected, which means I can't just turn off the AC for the winter and ignore the problem.
Thanks for your help. I'm happy to run any tests I can manage on my own.
To preface I came from a 2013 Crosstrek with a CVT, and now own a 6MT Mazda3. Anyway, I've had my Mazda for a couple weeks now. In paper the engine seems similar to my old Crosstrek. Both are a 2.0, power is similar (though not enough for me to think it'd make a difference)... I thought maybe the CVT was holding me back in my Crosstrek, but my girlfriend has a 5MT '17 Impreza, and even with the transmission it's still a dog.
So what specifically is Mazda doing different/better?
https://preview.redd.it/mc3jbw6x7oc81.jpg?width=1920&format=pjpg&auto=webp&s=93941f0789922d7f1d3c7d0803de941b114f2ebf
One thing I liked about cms 2018 was the rotarys, and I really wish or hope that they make something like a mazda DLC.
I'm struggling with developing the right driving style for fuel economy on smaller drives. My car is a Mazda 3. I live on top of a big hill and sometimes go into town with lots of lights, which maybe contributing. Best I have done so far on a given trip is ~26 MPG, which seems on the high end. Often I'm sitting at 20 MPG.
I have tried with using the sportmatic style transmission to manage the gears, but I'm not sure I'm seeing much benefit for economy. Mostly I shift up around 1500-1700 on the tac when holding speed or accelerating, and down around 1000-1200. I may try running the car in fully automatic mode and see how that compares.
I'm interested to hear about your experiences.
Would anyone know a good engine that can fit like a glove or be close enough to where I might have to do fewer things than dropping a big block or something. Looking for more power so maybe a turbo in the near future
Hi all. I have recently bought a 10 plate mazda and have discovered a rattle under the bonnet. The car has 73k miles but has been sitting for the past year un used before I bought it. It has had new oil and filter and an mot before I picked it up but have noticed when it gets warm there is a prominent rattle noice when revving at around 2 to 3k rpm and sometimes when accelerating. The rattle isn't constant and very intermittent. Doesn't sound like bottom end however as it's not doing it all of the time. The car drives really smooth with no loss of power and nice delivery. Ive ran some injector cleaner through in combo with 99 petrol. Could this be just a build up of crap from sitting? Needs new plugs maybe or the timing is off? I should also add that it has improved over the week that I have used it and after the injector cleaner but still makes a rattle.
