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Overheating problem



 
 
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  #1  
Old January 18th 05, 06:06 AM
Chris D'Agnolo
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Default Overheating problem

93 325i, car overheated, realized the radiator had gone to ****, the plastic
end caps just brittle crap. I don't know what shape the internals were. I
bought a new radiator, installed it and the car still overheated. Today I
replaced the thermostat (not a fun job!) and still the car (temperature
guage) says it's overheating. Strange thing is when I pulled back in the
drive today and popped the hood, the engine didn't seem all that warm and
the passenger side end cap on the radiator was definetly cool. The driver
side end cap was only slightly warm.

I'm confused, I suspect the temperature sensor but it seems to work
completly normal from cold up to normal operating temp.

I also suspect the waterpump might not be pushing the coolant as it's
supossed to but a friend of mine tells me waterpumps almost never die like
that, as it's not leaking and it's not making any noticable noise.

Other notes, I don't seem to be able to get heat from the cars heater. And,
the new thermostat did not have an "up arrow" as the original one did and
the repair manual said it was important to put it in with the arrow pointing
up. What's the deal here?

Thanks in advance,

Chris


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  #2  
Old January 18th 05, 09:54 AM
JB
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Posts: n/a
Default


"Chris D'Agnolo" > wrote in message
...
> 93 325i, car overheated, realized the radiator had gone to ****, the

plastic
> end caps just brittle crap. I don't know what shape the internals were. I
> bought a new radiator, installed it and the car still overheated. Today I
> replaced the thermostat (not a fun job!) and still the car (temperature
> guage) says it's overheating. Strange thing is when I pulled back in the
> drive today and popped the hood, the engine didn't seem all that warm and
> the passenger side end cap on the radiator was definetly cool. The driver
> side end cap was only slightly warm.
>
> I'm confused, I suspect the temperature sensor but it seems to work
> completly normal from cold up to normal operating temp.
>
> I also suspect the waterpump might not be pushing the coolant as it's
> supossed to but a friend of mine tells me waterpumps almost never die like
> that, as it's not leaking and it's not making any noticable noise.
>
> Other notes, I don't seem to be able to get heat from the cars heater.

And,
> the new thermostat did not have an "up arrow" as the original one did and
> the repair manual said it was important to put it in with the arrow

pointing
> up. What's the deal here?
>

Sounds like you've either got a air-lock, failed head gasket, cracked head
and/or the water pump impeller has disintegrated (very common if it is the
original)
Get a leak test done on the cooling system after getting rid of the air
lock.

JB


  #3  
Old January 18th 05, 04:38 PM
Don
external usenet poster
 
Posts: n/a
Default

Chris D'Agnolo wrote:

> 93 325i, car overheated, realized the radiator had gone to ****, the plastic
> end caps just brittle crap. I don't know what shape the internals were. I
> bought a new radiator, installed it and the car still overheated. Today I
> replaced the thermostat (not a fun job!) and still the car (temperature
> guage) says it's overheating. Strange thing is when I pulled back in the
> drive today and popped the hood, the engine didn't seem all that warm and
> the passenger side end cap on the radiator was definetly cool. The driver
> side end cap was only slightly warm.


No circulation.

Means either:

1. Air-lock - the system hasn't been bled properly
2. Thermostat is bad or not installed correctly
3. Water pump impeller has fallen apart

Since you didn't mention if the radiator actually failed, or you just
decided to replace it - I can't speculate further than that.

> I'm confused, I suspect the temperature sensor but it seems to work
> completly normal from cold up to normal operating temp.


This is "shoot the messenger" because it's telling you something you
don't want to hear. It is NOT the temperature sensor. You have NO
CIRCULATION of coolant. You WILL DESTROY the engine if you continue
running it without circulation.

> I also suspect the waterpump might not be pushing the coolant as it's
> supossed to but a friend of mine tells me waterpumps almost never die like
> that, as it's not leaking and it's not making any noticable noise.


Your friend is absolutely WRONG. The early M50 engines (up to mid '96)
used a water pump with a plastic impeller. This is known to fail and
cause EXACTLY the symptoms you have. If you don't know if it was
replaced with a newer one with a steel impeller (or BMW's new plastic
impeller one) - this is a real possibility. And when this goes bad - it
doesn't leak and it doesn't make noise. What it can do is really screw
up the system if the impeller breaks up and chunks of it circulate
around to be lodged in the system blocking flow even after you replace
the pump.

> Other notes, I don't seem to be able to get heat from the cars heater. And,
> the new thermostat did not have an "up arrow" as the original one did and
> the repair manual said it was important to put it in with the arrow pointing
> up. What's the deal here?


If there was no UP ARROW - there should have been printing on the
thermostat (I installed one about a week ago with no up arrow) - it gets
installed with the printing up.

> Thanks in advance,
> Chris


HTH

  #4  
Old January 18th 05, 05:58 PM
The Malt Hound
external usenet poster
 
Posts: n/a
Default


"Chris D'Agnolo" > wrote in message
...
> 93 325i, car overheated, realized the radiator had gone to ****, the
> plastic
> end caps just brittle crap. I don't know what shape the internals were. I
> bought a new radiator, installed it and the car still overheated. Today I
> replaced the thermostat (not a fun job!) and still the car (temperature
> guage) says it's overheating. Strange thing is when I pulled back in the
> drive today and popped the hood, the engine didn't seem all that warm and
> the passenger side end cap on the radiator was definetly cool. The driver
> side end cap was only slightly warm.
>
> I'm confused, I suspect the temperature sensor but it seems to work
> completly normal from cold up to normal operating temp.
>
> I also suspect the waterpump might not be pushing the coolant as it's
> supossed to but a friend of mine tells me waterpumps almost never die like
> that, as it's not leaking and it's not making any noticable noise.


Your friend does not have any BMW experience. BMW waterpumps fail like this
all the time.

>
> Other notes, I don't seem to be able to get heat from the cars heater.
> And,
> the new thermostat did not have an "up arrow" as the original one did and
> the repair manual said it was important to put it in with the arrow
> pointing
> up. What's the deal here?


You got a cheap replacement t-stat. Go buy a good one, even if means paying
a little more or having to ship it. The importance of the air hole is so
that you can bleed the system of air at a cold temperature, which is
important.
-Fred W


  #5  
Old January 18th 05, 10:41 PM
Jeff Strickland
external usenet poster
 
Posts: n/a
Default

The water pump impeller is made of the same plastic as the radiator tank.
The same thing that happened to the tank happens to the water pump. After 12
model years, this should have been changed out by now, but I assume that you
either have the stock pump still, or the replacement pump is also the
plastic variety. When the water pump fails, the heater will blow cold even
though the temp guage says the temp is up to spec, or above. That's the good
news.

The bad news is that the head on that motor is prone to cracking in the area
between one of the #3 Exhaust ports and the adjacent water galley. If the
head is cracked, the motor will over heat. Particularly severe cases will
show visible steam in the exhaust stream, marginal cases might not steam,
but water vapor can be detected by a smog sniffer.






"Chris D'Agnolo" > wrote in message
...
> 93 325i, car overheated, realized the radiator had gone to ****, the

plastic
> end caps just brittle crap. I don't know what shape the internals were. I
> bought a new radiator, installed it and the car still overheated. Today I
> replaced the thermostat (not a fun job!) and still the car (temperature
> guage) says it's overheating. Strange thing is when I pulled back in the
> drive today and popped the hood, the engine didn't seem all that warm and
> the passenger side end cap on the radiator was definetly cool. The driver
> side end cap was only slightly warm.
>
> I'm confused, I suspect the temperature sensor but it seems to work
> completly normal from cold up to normal operating temp.
>
> I also suspect the waterpump might not be pushing the coolant as it's
> supossed to but a friend of mine tells me waterpumps almost never die like
> that, as it's not leaking and it's not making any noticable noise.
>
> Other notes, I don't seem to be able to get heat from the cars heater.

And,
> the new thermostat did not have an "up arrow" as the original one did and
> the repair manual said it was important to put it in with the arrow

pointing
> up. What's the deal here?
>
> Thanks in advance,
>
> Chris
>
>



 




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