Overheating issues

tinygiants

tinygiants

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I have a 94 BMW 325I. It started overheating this weekend. I changed the thermostat, but it is still overheating. Something I found strange was that the heater would not blow warm air even thousgh it was overheating.

Any Ideas? As soon as it cools, I will pull the front end off and check the water pump?
 
tinygiants said:
I have a 94 BMW 325I. It started overheating this weekend. I changed the thermostat, but it is still overheating. Something I found strange was that the heater would not blow warm air even thousgh it was overheating.

Any Ideas? As soon as it cools, I will pull the front end off and check the water pump?
Click to expand...


Sounds more like the heater core in the dash. When you pull the cap off it (after it's cooled obviously) you should be able to see the water moving with the engine running....
 
BlackKnight said:
Electrical problem perhaps? Maybe a fuse or something else that would shut-off the cooling fans?
Click to expand...
One fan is mechanical, and it is working.

The auxiliary fan is a 2 speed electrical unit. And I was able to verify it working.

Thanks for the suggestion.
 
ntw0rk said:
Sounds more like the heater core in the dash. When you pull the cap off it (after it's cooled obviously) you should be able to see the water moving with the engine running....
Click to expand...
I will have to do some research to find that bad boy.

My question is how would that core cause overheating of the engine? Unless I have a blockage in the block some where?

Thanks, I will do more reading and looking.
 
tinygiants said:
I will have to do some research to find that bad boy.

My question is how would that core cause overheating of the engine? Unless I have a blockage in the block some where?

Thanks, I will do more reading and looking.
Click to expand...


I have seen that happen before when the core is blocked/backed-up. It's just a suggestion though, because I am not sure that ALL cars have that core. I had to replace one once in my Cavalier Z24. Was a huge pain, but fixed my issues...
 
Tiny, remove the rad cap cold, crank the car, put it somehow at a fast idle, around 1500rpms, watch the water as it heats, some may trickle out, but as the thermostate opens the water level will drop, and then you should see it circulate for a moment, then the thermostate will close an circulation stop,

if no circulation, then probably a water pump, if you had blockage , most likley your fluid would look awefull nasty dark color,
it is possible tho to have blockage and the fluid still look good too.
you can drain all the fluid , and flush the system, but depending on the mileage, and if I remembeer correctly , they had a prob with the pumps,

pm blackviper, he cna help ya better on this bo:D
 
crap Dale! I jsut woke up and got on the forum, and then check my messages:p

well dang! I hope this helped:D If not you holla, will be up all day morrow bo:rock:

but if the cap is off, when that thermostate opens up , the water pump will suck the fluid thru, therefore the level drop at the cap, then as the cooler fluid hits the thermostate it will close again, so if it sucks it down and circulates, then the pump is fine,

but I am betting either a pump(especially since you siad no hot air from the heater, fluid no circulating) maybe a blockage, but even then you should get some kind of heat or circulation

I would check for circulation, then if ya not sure, flush the system real good, and try to see if any crud comes out
 
Thanks for all the replies. I am leaning heavily towards the pump myself. I called and found one local.

Tomorrow is my B-day, so I have my daughter for dinner. Her mom is dropping her off early to make the cake, then I will get home and celebrate. After dinner I will tear back into it.

I plan to tear the front end down till the pump is exposed and inspected. If I still feel it is the fault, I will pick up a new pump Tuesday and put it in Tuesday night.

Thanks again.
 
Here's what I would do:

1. Release the tension on the drive belt. With the engine cold and turned off check waterpump pulley for any bearing slack by trying to wiggle the pulley. If the pulley wiggles at all it your waterpump.

2. Start the engine with the rad cap off and see like mentioned above that there is circulation after you reach normal operating temps. You can also verify that your thermostat is working by feeling the upper and lower rad hoses to see if they are relatively the same temps. If the temps feel the same then it tells you the rad and thermostat are good.

3. If steps 1 and 2 are good then check for water bubbles in the radiator. If you see any bubbles you have a blown head gasket that is leaking compression into the coolant. You can verify this with a compression check (much lower readings).

4. If steps 1 thru 3 are good then bypass your heater core by cutting the in and out tubes to the heater core and join the two hoses together.

5. If steps 1 thru 4 are good then try a backflush of the engine to clear any debris in the water passages of the block.

6. If steps 1 thru 5 are good then its time to pull the engine and investigate further.

Hope this helps,
Brad
 
Last edited:
had a problem like that once and found out my catilatic converter was pluged up ,,,
 
Ironhead said:
had a problem like that once and found out my catilatic converter was pluged up ,,,
Click to expand...
now thats thinking outta the box right there:rock:

that is true, a clogged convertor will do the same:D
 
reason i say that is cause its is a 94 so i would bet it has the original one on it so that makes it 14 years old ,,unless its been replaced in between that time
 
If memory serves correct, a rotten egg odor might be present and loss of power if it is the convertor...

Wil
 
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