So why does my car have blower whine?

[Cloud]

The car recently developed a very loud rpm dependent whirring noise that sounds very much like a supercharger. In the past I have seen accessories make this noise but I pulled the alternator belt and it's still making the noise... I had an oil pressure failure recently which lasted for a few seconds before the car was shut down but the noise did not develop till several days later. It seems to be coming from the front side of the engine but it's very loud and I can't tell where. If I had to take a guess I would say front case, or timing area but it could also be internal and reverberating. Do main bearings make noise like that when they fail sometimes? The car doesn't really display any obvious symptoms of thrust bearing failure. The oil pump was new about 5000 miles ago so but who knows... anyone have a really loud whirring noise like this before? ideas?

[D Walker]

turbo death whine

[mpdeneen]

turbo death whine

Yup. Mine made the same noise before she went. That's either the compressor or turbine eating itself. Either way, you can't count on the balance anymore. The next step is a spy hunter-esque smokescreen...

Someone had a s16g for sale...

-M

[Cloud]

To be honest the noise is much quieter near the turbo so I don't think that's it, also it varies with rpm not rpm and boost, etc.. indicating it isn't a function of turbine rpm. The car does burn oil though, however i am more tempted to believe that is from the engine as it started smoking when it was rebuilt as a stroker about 3000 miles ago. I recently inspected the turbo and it didn't seem like it had much noticable shaft play either, but not after the whine started. I may go double check that right now though to make sure...

[D Walker]

Feel free to swing by and we can check it out for you if you want.

[StockVR4]

I'm going to guess it's a balance shaft bearing that went bad. Now if they have been eliminated, I'm obviously wrong. That happened on my 1g. I remember it starting quiet and getting louder and louder.

Brian Z.

[Cloud]

Doesn't appear to be the turbo, shaft play is minimal with 0 thrust play and no impacting blades. The quest continues... oil appears to have a metallic sheen to it, that may not be a very good sign. I'd swing by but it looks like you are in Aurora? A bit out of the way for me in Ft Collins.

Balance shafts are out already. Stub shaft is in for the oil pump and that's it.

[mpdeneen]

To be honest the noise is much quieter near the turbo so I don't think that's it, also it varies with rpm not rpm and boost, etc.. indicating it isn't a function of turbine rpm. The car does burn oil though, however i am more tempted to believe that is from the engine as it started smoking when it was rebuilt as a stroker about 3000 miles ago. I recently inspected the turbo and it didn't seem like it had much noticable shaft play either, but not after the whine started. I may go double check that right now though to make sure...

Never mind. Just answered all of that business...

-M

[rlarsen]

I've had a noise very much like you describe when a timing belt pulley went bad...something to check out.

[JackM]

Could be the upper timing belt cover hitting the cam sprockets. That would make a noise that sounds like you describe.

Jack

[Cloud]

I have considered the timing assembly and i think it is probably a good candidate. I am going to pull the cover tomorrow and run it to see if it still makes the noise or not and check the pullies for excessive play. The metal in the oil could be coincidental residue from the rebuild that was still fairly recent. I hope it's just that simple at least =P

[g34rh34d]

My car made the sound the day I had the timing belt replaced. Possibly the composition of the new timing belt?

Have you had the belt changed and the sound started, or did the sound just start one day? If it is the latter then I would check all items relatd to the timing belt as suggested.

FH

[Cloud]

It just started one day. I am going to give it a look over today and see what I can see, the belt is only a few thousand miles old and doesnt appear to have any issues though despite getting oiled down pretty well. I am thinking it's likely a tensioner/idler bearing or the timing cover is hitting a sprocket or something at this point though because the timing cover is pretty mangled.

[Cloud]

Well this is starting to become baffling. I pulled the timing cover and looked everything over, the belt seems a bit loose but it is a newer belt and maybe stretched a bit. It doesnt appear anything is contacting anything and the pullies seem fine except the idler pulley has a bit of play to it. I don't know how much play is necessarily acceptable but it doesn't seem like all this noise is coming from that pulley. It is very hard to pinpoint the source of the noise too because it is very loud and seems almost just as loud from the bottom or top of the engine. It does seem rather loud at the top though and I am wondering if there is cam thrust wear or something that might also cause this type of noise. Loose bolt on the oil pump driven gear? That idler? It's quite mind boggling. I did notice that when I start the car the engine revs up without the noise for about half a second before the noise begins... seems like it comes on about the time oil pressure begins. It hasn't gotten any worse but it's still pretty worrying.

[yokotabrat]

Might be worth it just to pull the timing belt again and turn each of the pulleys/sprockets individually. You did mention a metallic color to the oil, so it would suck to have something like an oil pump fail at the wrong time.

[Overkill]

Mine was from my dampner seperating and grinding slightly on the lower timing cover. The noise was louder the higher the RPM!

[Cloud]

I have ruled out timing cover, accessories, it could still be a pulley I guess but it seems unlikely at this point. It has been run with just the stuff necessary to keep the timing belt and it still does it. I checked the cams and none of them have any significant bearing problems that I can see. What should I check next? I would use a stethescope/hose to try and locate it but the noise is loud enough to make my ears ring just by listening by ear.

[Cloud]

After some more diagnosis and some online research I am led to believe that it is most likely a problem with the oil pump. I read exactly the same symptoms from a couple people who had oil pumps fail, one of which had their stub shaft fall out completely. The oil pump is only a few thousand miles old which leads me to believe this isn't a terribly good sign. Oil pressure has been slightly lower than usual... anyone know how much a new front case is from mitsu? I got this last one from ebay and I am wondering about the quality at this point.

[renovatio]

I think your right on with the oil pump being the problem. I think there might have been a recall on them and I think that the gears where changed from a striat cut to a hecial cut gear might be somthing to watch for if you plan on buying a used one. The oil pump in mine came in the engine kit from epw and has proven itself to be good pump.

[Cloud]

Well this oil pump has the helical gears and was new and working perfectly 3000 miles ago or so. I am guessing something bad happened when it starved for oil for a few seconds, or the loctite I used on the stub shaft didn't hold, or something similar that caused it to fail. That or aparently there is some quality control problems in these aftermarket oil pumps assuming it is in fact the oil pump.

[Cloud]

FYI, I finally got everything apart today and it turns out that my stub shaft did indeed fall out. It was floating around in my oil pan. I guess the moral of the story is make absolutely certain there isn't a spec of oil in the threads before you loctite it or it will fall out 6000 miles later :rolleyes: I might post some pictures of the oil pump and what havoc it wrought upon itself when I get it out and apart later. Stub is a little chewed up now too so I think I guess it's time to call around and see if any dealers stock them...

[drcustom]

I'm thinking Mile High Mitsubishi stocks them, at least they can special order them fairly easily. 303.369.7800, 3 for parts, 3 for mitsubishi.

On another note, I heard of an alternative I've been considering. Instead of using the stubby, use the stock shaft but cut it just after the bearing. This way you don't have any issues with oil pressure, and you don't have an unsupported shaft spinning in there. It seems like the chances of the modified shaft locking are pretty minimal since the bearing doesn't have to do very much without the counterweight spinning. I don't know that a supported shaft is necessary, but the idea seems promising.

[Cloud]

Yeah, looks like I am just going to have to try and order it today and rush myself on sunday to finish. I actually already had a stub shaft that I made from a balance shaft, but that's the one that got chewed up a bit. It still looks like it would work ok but it has some grooves i can feel in it and would rather not reuse it if it's questionable. Thanks for the help though.

[drcustom]

Yeah, looks like I am just going to have to try and order it today and rush myself on sunday to finish. I actually already had a stub shaft that I made from a balance shaft, but that's the one that got chewed up a bit. It still looks like it would work ok but it has some grooves i can feel in it and would rather not reuse it if it's questionable. Thanks for the help though.

I've got a stock shaft from a 6 and a 7 bolt...you can use whichever you need if you can pick it up (I live near 25 and Colorado, and work downtown).

[Overkill]

You need to replaced your frontcase, oil pump gears, etc since you no longer have the right tolerances to make the correct oil pressure.

Not sure how long it ate away at the aluminum casing, but I would replace the parts.

[Cloud]

Already have a new case complete with gears and seals on the table, I ordered the stub shaft today so everything should be in order. This time I am going to try very hard to get the loctite not to fail and avoid this in the future. The inside of the engine looks fine, bores very smooth and unscored, so I imagine the metal particulates were fairly small but I have a funny feeling the bearings look horrible since the oil that came out had a very shimmery metallic look to it.

[Overkill]

I would venture a guess that you are correct. This happened on a car I purchased not running and the cam seized before a bearing spun just as an FYI.

I would pull a cap while your replacing the front case to check a bearing.