Cooling System Help Needed

[vmelikRUS]

Hi, I was hoping someone could give me their advice. I have a 97 328i w/ manual transmission.

Problems:
1. "check coolant level" illuminates when I shut off the car, regularly.
2. A little Coolant leaks out the coolant tank's cap regularly.
3. Car overheats under extreme tempatures during summer.
4. temp. gauge leans towards the cooler side at high speeds during winter.

Observations:
1. Coolant levels in tank are good.
2. heater/AC work, but do lack in performance.
2. Hoses don't show any leaks, coolant leaks only out of the tank's cap.
3. After car operation, all hoses around the radiator are hot. So are the ones connected between the thermostat.
4. I spinned the radiotor fan, and it has some resistance, not too loose, and not too hard to spin, but I still don't know if the fan clutch is ok.

I know there are several possibilities:
Pump, Thermostat, Clogged Radiator, Fan clutch, ...
I am leaning towards replacing the thermostat, but I need some feedback before I start changing parts. Does anyone know any tests to perform? Do you think a thermostat that is stuck open could produce these things, or something more?

Also: A side problem, I don't know if it relates.
The AC control unit inside my car is having electrical problems. The digital temp. controls have power glitchs regularly, and shut off the blower along with the digital display. They could be every 5 sec. or every 1 hour. However the buttons that select the direction of air flow stay illuminated, but will not toggle back during the glitch interval. I think it could be some relays or fuses, or do you think its connected with the cooling system?

Please help me out if you can. Thank you for any comments you may have.

- VADIM

[Cassandra]

Originally posted by vmelikRUS@Apr 8 2005, 02:19 AM
Hi, I was hoping someone could give me their advice. I have a 97 328i w/ manual transmission.

Problems:
1. "check coolant level" illuminates when I shut off the car, regularly.
2. A little Coolant leaks out the coolant tank's cap regularly.
3. Car overheats under extreme tempatures during summer.
4. temp. gauge leans towards the cooler side at high speeds during winter.

Observations:
1. Coolant levels in tank are good.
2. heater/AC work, but do lack in performance.
2. Hoses don't show any leaks, coolant leaks only out of the tank's cap.
3. After car operation, all hoses around the radiator are hot. So are the ones connected between the thermostat.
4. I spinned the radiotor fan, and it has some resistance, not too loose, and not too hard to spin, but I still don't know if the fan clutch is ok.

I know there are several possibilities:
Pump, Thermostat, Clogged Radiator, Fan clutch, ...
I am leaning towards replacing the thermostat, but I need some feedback before I start changing parts. Does anyone know any tests to perform? Do you think a thermostat that is stuck open could produce these things, or something more?

Also: A side problem, I don't know if it relates.
The AC control unit inside my car is having electrical problems. The digital temp. controls have power glitchs regularly, and shut off the blower along with the digital display. They could be every 5 sec. or every 1 hour. However the buttons that select the direction of air flow stay illuminated, but will not toggle back during the glitch interval. I think it could be some relays or fuses, or do you think its connected with the cooling system?

Please help me out if you can. Thank you for any comments you may have.

- VADIM

[snapback]327889[/snapback]

Either you have shorts on your wiring harness or you have air in your cooling system or BOTH.

[Ferrahs]

I had roughly the same experiance, you can bleed the coolant system if you think it will help but its going to be the thermostat. If you feel like doing this yourself then start out with the cheapest parts and move your way up to the more expensive and difficult. The thermostat is like $10 and it took me like 1 hour to do it cause it was the first time i did it on this kind of car, if that doesnt work then its probably the water pump, its the plastic one that everyone hates, its a little more difficult but its inevitable to go out. And regarding the ac unit, get it changed, they are commonly known to go out, i changed mine also, eventually it will not come on like mine didl.

[vmelikRUS]

Originally posted by Ferrahs@Apr 7 2005, 09:35 PM
I had roughly the same experiance, you can bleed the coolant system if you think it will help but its going to be the thermostat. If you feel like doing this yourself then start out with the cheapest parts and move your way up to the more expensive and difficult. The thermostat is like $10 and it took me like 1 hour to do it cause it was the first time i did it on this kind of car, if that doesnt work then its probably the water pump, its the plastic one that everyone hates, its a little more difficult but its inevitable to go out. And regarding the ac unit, get it changed, they are commonly known to go out, i changed mine also, eventually it will not come on like mine didl.

[snapback]328000[/snapback]

Thanks for your confirmation. Do you know if there is a way to check if the water pump is okay, without actually taking out? And I heard some people replace the plastic one with a metal one. Should I do that? I'll be changing the thermostat today or tommorow. I have the feeling it could be the water pump too. I remember I had a gruesome overheat last summer. I left my car running outside, and forgot about it. When I came back the car was the hottest I ever seen before, coolant was evaporating, and it looked like it was gonna blow up. Anything plastic must have melted, but is there an easy check for me to do to determine if the pump is ok. Or is trial and error the best scenario?

Also, does anyone know the best way to check relays? Only with a DMM?

P.S. - Thanks for the help. I think BMW is the only car that has such a LIVELY community. Take care.

[PR325is]

Originally posted by vmelikRUS+Apr 8 2005, 11:16 AM--><div class='quotetop'>QUOTE(vmelikRUS @ Apr 8 2005, 11:16 AM)</div><div class='quotemain'><!--QuoteBegin-Ferrahs@Apr 7 2005, 09:35 PM
I had roughly the same experiance, you can bleed the coolant system if you think it will help but its going to be the thermostat.* If you feel like doing this yourself then start out with the cheapest parts and move your way up to the more expensive and difficult. The thermostat is like $10 and it took me like 1 hour to do it cause it was the first time i did it on this kind of car, if that doesnt work then its probably the water pump, its the plastic one that everyone hates, its a little more difficult but its inevitable to go out.* And regarding the ac unit, get it changed, they are commonly known to go out, i changed mine also, eventually it will not come on like mine didl.

[snapback]328000[/snapback]

Thanks for your confirmation. Do you know if there is a way to check if the water pump is okay, without actually taking out? And I heard some people replace the plastic one with a metal one. Should I do that? I'll be changing the thermostat today or tommorow. I have the feeling it could be the water pump too. I remember I had a gruesome overheat last summer. I left my car running outside, and forgot about it. When I came back the car was the hottest I ever seen before, coolant was evaporating, and it looked like it was gonna blow up. Anything plastic must have melted, but is there an easy check for me to do to determine if the pump is ok. Or is trial and error the best scenario?

Also, does anyone know the best way to check relays? Only with a DMM?

P.S. - Thanks for the help. I think BMW is the only car that has such a LIVELY community. Take care.

[snapback]328304[/snapback]

[/b][/quote]


well if you go to a regular auto repair shop they would still tell you to change the thermostat and the water pump at the same time... if i were you, you should get the water pump with a metal impeller in it... funny thing is, i replaced my water pump and thermostat last month and my car's overheating again.. yikes!!! i gotta post a new thread for some insights... i think i have to replace the radiator now...
good luck!

[new guy]

Radiator fluid shoul not leak from the "tanks cap." if this is happening, you are not keeping pressure in the system which will lead to overheating, and of course, especially under extreme conditions.

Check cap gasket, bleed system, check fan clutch. Fan clutch is damaged if oil and dirt are found around its shaft.

New Guy

[new guy]

Oh, several more things,

If you overheated your engine, you may have a blown head gasket; do a cylinder pressure check. Otherwise the water pump is only considered "bad" if it leaks around the bushing (where the shaft enters the unit). Of course, it the engine ever runs "cool" you need to change the thermostat.

New Guy