Engine knocking/squealing:::Please Help:::

[seeohngee]

Hey guys! I posted this on R3v and now I'm posting this on here hoping for more input/advice. I would really appreciate any help/advice/input I can get. Thanks.

First let me say I own a 1991 318is and I'm no mechanic but can do most of the basics (oil, brakes, belts, and rotors change).

The other day I started my car and heard a slight knocking sound coming from the motor. I then checked the oil and it showed a little less than half on the dipstick. I didn't think too much of it since I was planning to drive home (22miles drive) to change my oil anyways and I didn't think it matter much if it was slightly less than half. While driving home that day, I didn't hear any knocking at all.

Before starting my oil change, I parked the car for a few hours and didn't drive anywhere till I had to drive my brother to the bus stop which was 4 blocks away. So while I was driving, I heard noises coming from the motor but this time it was louder. When I got home and parked my car in the driveway, I notice that the knockings sound got louder and this time I also heard squealing sound like a loose belt.

So I decided to let the engine cool off and change the oil in hopes that my problems will go away. I also took off my AC belt, thinking that the squealing is probably coming from that since I did install the belt not too long ago. After completing my oil change and removal of the belt, I started the engine and the squealing got even loud and it idles rougher than before. I notice after i changed the oil, my fan clutch spun very slow and then all of a sudden stopped. I then turned off the motor and started it again and the problem was the same but this time the fan clutch didn't spin at all.

So now my problem is that I'm not sure what's wrong with the car nor how to fix it. I think it's the fan clutch that is causing all this but I'm worried that the low motor oil had something to do with it too. I've been searching the forums for days trying to see if anyone else ever had the same problem but didn't find anything. I was hoping that someone could give me some advice and input on what to do and how to diagnose the problem.


I apologize if I posted this in the wrong section of the forum. If I did, please move it to the correct place. Thank you!

[nicknikolovski]

That knocking/squealing is most likely a worn water pump bearing. If it may have just seized when you said that the fan clutch stopped since it is attached to the water pump. I would remove the belts, the fan clutch and then try to turn the water pump. If it has seized then you just saved your cylinder head as while on the road, it would've overheated the head. Check that first and then we'll go from there. In fact, can you also spin up all the pulleys except the crank pulley. (Alternator, p/s pump, A/C comp, etc)

[DesktopDave]

+1 on water pump.  The pump also may have a plastic impeller; if that's cracked the bearings would be gone pretty quickly & cause that kind of knocking or grinding.

Pull the water pump belt & run the car for a bit to confirm that the noise is definitely coming from the pump.  It could be that the fan clutch is totally shot too, but unlikely.

Pumps are pretty cheap insurance, but they can be a pig to remove.  They're about $60 at Pelican Part IIRC.  Pelican also has a $300 coolant overhaul kit that's worth checking out...if you're doing it, might as well do it right.  If you can change the oil you'll have no trouble with a water pump.  Be sure to use only BMW Coolant or Dex-Cool and distilled water in your cooling system.  Also get a spare radiator bleed plug or two, they have a tendency to crack and they're really cheap.

Your oil level was normal, right?  Still between the marks, right?  If so I wouldn't worry about that.  Mine tends to lose a bit more than a quart between changes.  Whether it's leaking or burning, I don't know.  New gaskets are here to help with the problem...

[seeohngee]

Thanks a lot for the advice Nick and Dave!

I haven't taken out the water pump yet since I don't have the tools for the fan clutch but I did try to spin the fan. The fan did feel like it did have some play when I tried to spin it. I'm thinking about the $300 water pump kit from pelican but is it worth it? Is it safe to turn on the motor without the water pump?

[B318M42W]

if by turn you mean by hand, souldn't be a problem, but DO NOT drive without the pump!

[DesktopDave]

Pelican has been first-rate IMHO.   They always have parts in stock, communicate promptly and will ship stuff quickly (or slow if you're a cheapskate like me:D).

If the car has been good to you so far, I'd say go for it.  All those parts will need to be replaced at some point anyway; if our troubleshooting is accurate, you'll be taking care of the problem permanently.  It really sucks to replace a thermostat, then have to go back in a month later to do the water pump.

[seeohngee]

I think I'm going to get that water pump kit. I was wondering if for the thermostat, which one is best for the motor? The 88 degree or the 92 degree?

[seeohngee]

I'm replacing my waterpump system tomorrow and was wondering if there's anything that I need to know before I starts or anything other parts/materials that I need to make things go easier/smoother.

I ordered the water pump kit from pelicanparts and here's the list of parts that I will be receiving:

New Water Pump and Gasket
New Thermostat (88degree) and Gasket
New Fan Clutch
New Radiator Mounts
New Radiator Cap
Fan Clutch Tool and Counter Holder
New Upper and Lower Radiator Hoses
12 oz. Redline Water Wetter Corrosion Treatment
New Alternator Belt
Front Crankshaft seal

Is there anything else that I should think about getting?