Ongoing issues , noise, random cut outs, temp gauge.

[N10S]

Hey guys, I am racking my brain with my 89 325is. Normally never have issues identifying and resolving issues but this one has kept the car off the road for the past year and various attempts to resolve.

Last summer the car overheated and it appeared to be related to the water pump leaking. I replaced the water pump, all of the hoses, the thermostat, the coolant sensor (for the gauge), the timing belt and tensioners, all of the belts, the cam seal, and distributor cap and rotor.

The car started and idles, but I was getting an intermittent stall and rough idle and when throttling sometimes it sounds great and other times it cuts out badly. I ended up replacing the crank position sensor, cleaned my iac and adjusted and cleaned my tpa and adjusted and tested it. I Alfa cleaned my maf sensor. No dice as it still has this same random stalling issue.

In addition it also exhibits three other problems. The first is that after you start the car when cold the car will run fine and usually idle well with maybe a small amount of uneven surge. After about 10 minutes if idling I hear this noise kick in. It is a noisy bearing sort of noise, and it kicks in for a period of time, maybe 3-4 minutes then seems to gradually disappear. I will try and get a video of this as this is a consisted issue that repeats on start up.

The noise appears to come from the new water pump or perhaps the clutch fan. My first thought is that once the coolant heats up and the thermostat opens this may be the point where the noise starts. Maybe the new pump is bad? It could be the clutch fan but not sure why I-64 would start like clockwork after about 10 minutes and then subside.

After the noise subsided if I watch the temp gauge it will start to climb towards red. Typically not a smooth gauge climb but it will bounce up 2-3-times from mid gauge very rapidly. After it gets closer to red I shut it down.

The other issue is that the car seems to lose its charge over a period of time. If I place a smart charger on the battery it indicates that the alternator is charging. Now I have not left it on to see if it is still charging when that aforementioned noise starts, and I suppose the noise could be a bad alternator that starts to make noise add the alternator stator shaft bushing/bearing surface heats up.

I did check the thermostat housing with an infrared gun and it appears top climb up over 220 so I am guessing that the high temp reading may be legitimate.At any rate I am interested in trying to figure this one out and would like to hear others thoughts on these issues.

Thanks

[Cephas]

Are you sure you bled the system properly? These cars can be terrible to bleed.

The noise could be alternator bearings or the water pump. Does the car overheat when it is moving or only when stationary?

Stall and rough idle could be tons of things. You started on the right path with CPS, but I think a smoke test will be needed to check for vaccuum leaks.

[N10S]

Are you sure you bled the system properly? These cars can be terrible to bleed.

The noise could be alternator bearings or the water pump. Does the car overheat when it is moving or only when stationary?

Stall and rough idle could be tons of things. You started on the right path with CPS, but I think a smoke test will be needed to check for vaccuum leaks.

Regarding bleeding the system, I jacked up the drivers side front, used the bleed screw, and tried to put pressure on the hose to make sure that all of the air pockets were eliminated. I did get a period of time where I was just getting steam out of the bleed hole and then coolant. Interestingly this afternoon I see a small coolant puddle under the car again so it looks like it is leaking again and it appears to be coming from the water pump. Man if that new pump is bad I am really bummed.

When the thermostat opens the water pump has a different level of load on the impeller I would think. This might account for the noise starting after the car has been idling for a bit if the problem is the water pump.

The car overheats while sitting still idling. The last test trip I made down the road resulted in the car cutting out badly and then dying and me having to get the car towed back home. Needless to say my testing has been stationary. While sitting still with a fully charged battery the car starts right up and sounds great under idle or when revved. When I take off it might run good for a bit then will start cutting out. Sometimes all it takes is putting it in gear and giving it gas and it stalls. Maybe there is a vacuum issue connecting to the tranny? Just an fyi this is my son's car and it's an automatic which I am not used to dealing with.

[goldenbb]

The noise could be a belt that is too tight. As far as the overheating goes, either you have a cooling system issue or you need a new head gasket. I chased a coolant leak on mine for months. Look at the aluminum housing where the thermostat resides and make sure all the hoses are tight there. My leak was underneath, not on the hose, but the little L-shaped pipe itself had come loose from the rest of the housing.

Lots of things could cause the car to cut out. Have you tested the fuel pump? Your symptom seems like it happens under load.

[ahlem]

I had a similar issue where the crossover radiator hose needed to be trimmed on the driver's side. The end of the old hose was at least 1" longer than the Gates brand I replaced it with. The extra length caused the hose to contact the fan and slowly grind a divot where coolant would leak. You may want to keep a 1/4" drive socket 8mm handy to bleed the coolant every time you get the car warm for the next 1/2 dozen outings. Eventually you will get the air out.

Did you identify the noise?

[peterman]

If it overheated you should do a leak down test - not just a compression test. If it all checks out good:

Did you change the spark plugs? New plugs would probably help tremendously. At idle, go down the line and pull each plug wire one at a time and see if the idle changes. If it doesn't you have a bad plug/wire/no fuel/etc. on that cylinder
As far as the noise - if it goes away when it gets warm it kind of sounds like you have a cavitation issue that would be related to not having the system fully bled. This would be weird, but not out of the realms of possibility.
Turn the car on with the cap off of the reservoir and keep filling it up. open the throttle body to have it suck down more fluid. Once it doesn't want to suck any more in, put the cap on the reservoir, rev it up and crack open the bleed screw. Make sure your heat is turned on, too. The temp needle should start to drop immediately.
But first fix any leaks or you'll just have to do it again.