Funky Sound comming from engine. - United Bimmer Community

**doughboyea** · 03-21-2006, 08:56 PM

Got a new sound comming from my engine. I'm not entierly sure what it is. I know that the belt tensioner is getting weak, and that is what it could most likely be. I'm just not 100% sure. And if it is, I'm not sure on how to replace the two? tensioners as my bentely manual doesn't exactly mention how to.

The sound is high pitched, mainly when the engine is cold. It fluctuates as the RPM's change. Even when the engine is warmed up, while on the highway, crusing at 70mph, I can still hear this high pitched squeal (Heating is turned off). When I opened the window, while at slow speeds, the sound is REALLY loud. When crusing, it tends to fad away, then as I gently tap the accelerator, the sound spikes.

Curious thing though. I had driven 20 mi with that sound today until i got to a gas station. Turned off the engine while was being refueled, started her up once done and the sound was gone.

It's been occuring for the past 2 days now.

Any thoughts?

Dough

**xsperf** · 03-21-2006, 10:00 PM

happened to me as well.. its basically somehow water gets in there and there is like some piece of plastic that is supposed to prevent that, it may be cracked.. all i did was take WD40 and spray it right into the tensioner and it stopped.. spraying into the tensioner means the part that actually spins with the belt

**doughboyea** · 03-21-2006, 10:59 PM

Your saying to spray the joint between the pulley and the assembly or the belt and pulley. If you mean the belt and pulley, isn't that a bad idea? I mean, do you really want that to be slippery?

Dough

**xsperf** · 03-21-2006, 11:35 PM

well i cant explain it, i will try to explain ti as best as possible, then ill try to find a pic

the belt tensioner has a pulling, its like a circle, right? pretend its a cup(the belt goes on the outside edges of the cup).. you want to spray WD40 INTO the cup.. ill try to find a pic

**barney** · 03-22-2006, 12:31 AM

Right, you dont want get it on the belt, just on the stud/shaft that the tensioner pulley itself spins on. Ive had this happen on several of the vehicles i've owned. Had to remove it on one to get the oil worked into the tensioner bearing.

**c1apton** · 03-22-2006, 12:41 AM

I think I would change out the tensioner before spraying anything on it. First if the tensioner is starting to "go south" spraying anything on it is going to act like cutting oil and speed up the wear process. It's not worth the risk of having it seize or "grenade" on you, if it does you'll have a major $$$ bill on your hands (belts wrapped around crap, overheating, broken fan schroud, - ugly possibilities)

witeshark · 03-22-2006, 12:49 AM

That makes sense

**barney** · 03-22-2006, 01:00 AM

True, it comes down to piece of mind. Inspect the pulley, if its loose at all (rocks on the shaft) replace it. some pulleys have a sealed bearing in them and you cant really lube them. If you can its most likely because its wore out enough that the bearing is no longer "sealed" an you would be living on borrowed time. On the other hand ,I've only ever had one fail on me and got lucky that it only shreaded the belt when it did, but the new tensioner assy. was over $200 (rare oldsmobile dealer only part)

**doughboyea** · 03-22-2006, 10:06 AM

Um, ok, so if I were to replace the tensioner, how do I replace it? My chubby fingers don't seem to be able to sqeeze between the shroud and engine too easily.

Dough

**barney** · 03-22-2006, 10:34 AM

to make room you will have to remove the fan and shroud.
let me go take some quick pics of my 330 to explain, should be about the same.

**barney** · 03-22-2006, 12:06 PM

I didnt want to steer you wrong so decided to see what it would take to actually remove mine. You will need metric allen wrenches and torque bits, at least i did. you can remove just the pulley too instead of the whole tensioner assy, might be cheaper if you can get just the pulley. You want to make sure which pulley is making the sound because there are some idler pulleys which could go bad also.

**barney** · 03-22-2006, 01:40 PM

[ATTACH][/ATTACH]first thing was to remove the air cleaner cover and inlet duct. the duct is held on by those plastic fasteners. Then theres 1 torque screw on the right and another plastic fastener on the same spot on the left side of the fan shroud. disconnect the two electrical connectors from it then lift straight up to remove the fan/shroud assy.

**barney** · 03-22-2006, 02:27 PM

then take the plastic center cover off the tensioner pulley. Then using the correct size allen wrench and a cheater bar, (unless you own the correct tool, which is pretty much the same thing) relieve the tension (try to tighten the allen bolt) remove the belt then remove the allen bolt from the pully and remove the pulley.

**c1apton** · 03-22-2006, 02:46 PM

DAMN, Barney - I dig these DIYs while you wait...LOL Can't ask for a better than that. Cool Stuff!

**Antiburn** · 03-24-2006, 05:25 PM

Changing your pully isnt going to change anything if you have the out of date tensoner. The upto date tensoners have a small hdryaulic piston instead of a spring.

If you need to change it do the same thing as barney told you to do but you will also need a 13mm and a 10mm socket. Theres 3 10's and 1 13mm that holds the pully on.

The new tensoner comes complete with pully and all the hardware your need to assemble it. There is 1 trick putting the tensoner together, you have to compress the piston with a pair of large plyers or a vice. You cant do it with your hand so dont even waste your time. The job is sliglthy complex, if your more hands on Im sure you can find a how-to on line somewhere. If you dont know how to open your hood, it might be a good idea to take it to the dealer.

**doughboyea** · 03-24-2006, 07:04 PM

Thanks Barney for the info. I was looking at my plastic fasteners. How exactly do I remove them without breaking them?

I would rather just replace the entire tensioner assemply. Would anyone know if the assembly on the top and the one on the bottom are the same?

Another general question would be where to purchase a quality assembly? I saw one on Autohaus that says they sell OEM parts yet the accessory belt tensioner on thier site is made by Ina/Luk. Are they OEM part makers? Thier prices are ~$40 which i think is REAL cheap considering the stealership wants $239.93 for the parts alone (labor would be another $262.50!). Makes me wonder if that has anything to do with quality. After all, I wouldn't want it to break.

Mechanical Type, Accessory Belt Tensioner for Water Pump/Alternator--made by Ina/Luk

from: Autohaus: 1999 328i E46 Tensioner

Antiburn, I appreciate the advise. I have a question relating to the hydraulic vs spring tensioners. I know that it is obvious that the spring tensioner will fit on my car, but how do you know that the hydraulic one will fit as well? I hope it's not a dumb question, it's just, I don't want to purchase the "updated" one only to find that it doesn't fit. Another thing... I can't find a hydraulic tensioner (not even for the 2005 E46's). Only the spring/mechanical version is avaliable (even though autohaus mentions it in thier description). The only thing relating to a hydraulic one is the "Belt Tensioner Shock."

Dough

PS, I am willing to get my hands dirty

I just want quality parts and promise to draw up a DIY once everything is set.

**barney** · 03-24-2006, 07:15 PM

On mine the upper one next to the alternator is the hyd one and the lower is the spring loaded one like the one you have pictured. The hyd one would be most likely be considered a shock and can probably be replaced seperately. I should have taken a pic while i had the pully off, would have made more sense.

**barney** · 03-24-2006, 07:22 PM

I used a pair of wire cutters to carefully pull the center up then a small straight pocket screwdriver to work the fastener out.
I wish I was closer, it would only take about 1-2 hrs to change.

**barney** · 03-24-2006, 07:31 PM

I have to go to work for about 4 hrs, Ill check back tonight. Maybe since it only takes an hr I might pull the pulley back off and take a pic to explain.

**doughboyea** · 03-24-2006, 07:39 PM

Ok, good, so the plastic fasteners can come out...just gotta be gentle I guess.

It's cool Barney, besides, there's a sence of pride one gets out of doing it by one's self

I don't want you to go through the trouble man, of taking it apart again. I do appreciate the advise and effort that you've given thus far.

I did happen to come across this diagram from Circle BMW's site.

Circle BMW: E46 328i Hydraulic Tensioner

No prices though

I'm confused now... are there two pullies for the assmembly and how big is it? From the diagram, which if assumed to be to scale, shows that the tensioner has a pulley along the bottom, but I thought it was on top?

Dough