Ok guys I REALLY NEED HELP ON THIS!!! CAR OVERHEATING, NOT GOOD!!!

[Paycheck713]

Ok, This really sucks a couple of weeks ago my car ran hot, and I couldn't figure out why!?!? Well I watched the car run and found out the radiator fan wasn't turning on automatically like it was supposed to, so I tested the fan to check if it was good or not and it was working so I was left to suspect that it would be whatever tells the fan to turn on when it should(im guessing when the motor hits a certain temp or something along those lines). So I was really busy and called a couple of places and asked what would or could be the cause of this they said the "radiator fan switch". So for the time being I wired my own switch in the car so Could switch it on and off, usually turned it on when I was at a stop or going slower than 20Mph. Also someone told me that if I see the needle moving to turn on the heater to run the hot air out from around the engine and it worked actually everything was working just fine, Until today when I turn the car on and left and before I made it a mile the car therm needle was on the red line so I pulled over and turn the car off immd. and I checked, I saw Antifreeze kind of steaming out of the Reservoir so I just turned on the fan and sat there for about 30 mns, then the car was cooled off so I left the fan on and tried to go back to my house to see if maybe the car was just hot because its so hot outside(100Degrees +, Tx) So I take off and before I even hit a mile I see the needle heading towards hot again, so I just pullover and have it towed back home, then later on after it gets cool outside(dark) I check the Water and see if I have a leak or wore out hose and I seen no sign of neither and I leave the car idling for about 10 mins with fan running and it gets hot again, and I see no leaks but I can hear the water boiling and it sounds pretty nasty! So this is where I stand If ANYBODY could help out in the least bit maybe I can figure this problem out without a mechanic, I really would appreciate it!!! I am not up to par at all on Bimmer's nor mechanical work, but I'm trying to catch on and learn as much as possible, so I'm all ears, Thanks

[Manolito]

If you are running stock with the original belt-driven fan, then the car should not require the electric fan. I suspect that only turns on when the air conditioner is on. It may require a combination of warm engine temperature and A/C.

These cars are very intolerant of any air in the cooling system. Have you bled the cooling system?

Does the clutch on the belt-driven fan feel stiffer as the engine gets hotter? It should. There is oil in the fan clutch that actually gets more viscous as it gets hotter, so the fan pulls harder the hotter it gets. Those rarely fail, but if the fan is not pulling when the car is hot and not moving, that can cause overheating.

If your thermostat is sticking shut intermittantly, it would not be the first time a BMW thermostat failed when it was only 4 years old. e36s used to have that problem. If it were not such a pain to get at, I would suggest just removing the thermostat for a test and running without it for a day to see what happens. Running W/O a thermostat screws up your gas mileage because the water temperature never gets warm enough for the fuel injection temperature sensor to be happy, so you would only do it for a day.

Any chance your radiator fins are full of dirt, grass seed, pet hair, etc? Try spraying the garden hose from the inside of the engine compartment outward through the radiator.

[Paycheck713]

Oh Ok, I have never bled the cooling system (how would I do that?) And I had a problem with the reservoir being to close to the alternator and the belt ate though the reservoir, now the plastic on the reservoir is pretty thick so it was cutting through it for about 2 mins b4 it actually got to the liquid in it, so i realized it and cut the car of and took the reservoir off and seen the big chunk of plastic missing but the plastic was so thick that the actual cut where water was leaking was not more that a MM wide and and about a half an inch long, so I figured no bits of the plastic could have got in there but I could be wrong because now that you say the radiator fan only comes on when the ac is on means that its not the fan, so Someone said something about a reverse flush to possibly unplug and bits of plastic that might be caught, think it might work? Also how hard is it to get the the thermostat? Oh and the car I'm talking about is my buddys but I have had it since January, its a 2000 328i

[Neel]

You could go with a custom setup, however i would recommend these guys... Zionsville Autosport. I have installed one of their kits on my e36 m3, and it really was relatively simple... i did it starting at 11pm and worked until 2am. Mind you i was outside in my driveway with nothing more then a hanging light (i doubt i will do that again unless i have to).

[Manolito]

The bleed screw is a black screw head with an 'X' on it (two intersecting slots) about 2" from the radiator fill cap, toward the shock tower.

I don't have instructions for an e46, but on an e36, the books say to turn the ignition to the On position (but don't start car), crank the heat to max temperature to open the heater control valve, open the bleed screw, and add water to the reservoir until water comes out the bleed screw hole.

In practice, I don't have a very good track record with bleeding these cooling systems, so I end up doing it several times on different days until I am satisfied that all the air is out. I also have been known to try it with the front of the car up on ramps, and to pour water down the bleed screw hole.

I would not expect that you have enough chunks of plastic in there to cause a problem, unless the water pump impeller is coming apart. I have not heard of that being a problem on e46s though.

I looked at the thermostat housing on the e46 and it looks like you MIGHT get it off with the fan and other parts in place. It appears to be held on by three 10 mm bolts. Pretty tight quarters in there to work, but if you have a 1/4" drive ratchet and different length extensions, you might be able to do it.

Try this test first - put down some plastic pans to catch the water, and disconnect the upper radiator hose from the radiator. Start the car. When it gets warm enough for the temperature guage to start climbing, water should pump out of that hose. If not, the thermostat is not opening, or the water pump is not pumping, or you have a massive obstruction in your radiator (like a bunch of Stop-Leak product). Clean up all the antifreeze that you spill, because it smells sweet so dogs and other animals will be attracted to it and drink it and die.

[Paycheck713]

Thanks Neel, I would take that route but not on this car, I'm going to sell it so I don't want to invest too much into it. It wasn't originally mine but I inherited because I was holding it for my friend while he was out of town, in January and he called a couple a weeks later telling me to keep it, he couldn't afford it and sent me the title so this is pretty much where I stand, it wasn't running when I got it and I've corrected most of the problems on it, now I was just having a little fun with it but I'm fixing the mandatory replacements to prepare it for sale and also using it as a learning tool. I've done just about everything my self on the car except the alignment, but yea I thought I was almost through the the temperature thing comes up! Lol

[Paycheck713]

Ok I completely took out the radiator and cleaned the fins, also took off and cleaned the thermostat, and the reservoir aka expansion tank, then I put everything back, I went to walmart and bought some Prestone Radiator Flush. BTW Before I did that I did as you said and took the upper hose off and water did start coming out. So I thought maybe The radiator needs to be flushed or something, So I got the Radiator flush followed the instructions and I was done with the 3rd step which was to let the car idle for 10 mins so the flush can cycle and then I was supposed to wait for an hour to let it cool down so I can drain it again, Well while waiting for it to cool down I came in got on the net and checked my threads to see if I had any more help when I got a message that said let the car run check the hoses and feel how hot they are and that the bottom one to the radiator should be hotter than the upper one and if not the water is not cycling properly, well I checked and the upper one was really hot and the lower one was very cool, so was this a good way to check or no? Also I am starting the think it is the thermostat, sound possible?

[Neel]

Originally Posted by Paycheck713

Let the car run check the hoses and feel how hot they are and that the bottom one to the radiator should be hotter than the upper one and if not the water is not cycling properly, well I checked and the upper one was really hot and the lower one was very cool, so was this a good way to check or no? Also I am starting the think it is the thermostat, sound possible?

Either the water pump is shot, or there is a blockage in the rad somewhere maybe. It could also be the T-stat. If you removed the Radiator from the car, you might as well have bought a T stat and done the change, hell im surprised you didn't pull the water pump out to check it out as well.


But atleast it sounds like your getting close to a solution.

[Paycheck713]

Haha, yea, I don't know where the Water pumps at. Where is it located? Also I don't think theres some blockage in the Radiator because when I took it off to run water through the fins, I also stuck the water hose in the the bottom hose opening and ran through the radiator came out of the upper hose opening, and then I ran water the opposite way and both seem to run smooth and quick. Ok tomorrow I will have the new thermostat. Any other ideas or thoughts anyone? Thanks Neel

[Manolito]

The hose temperature info you were given was incorrect. The hot water comes from the engine to the top of the radiator. It cools as it moves downward and then goes through the lower radiator hose back to the engine. Therefore, the lower hose will always be cooler than the upper hose, though it should still be quite warm if water is circulating.

The water pump is driven by a belt, and if memory serves, is is directly behind the fan on this engine. That is, the fan bolts to the front of the water pump. I have never touched one of these and I don't have the e46 in the garage to look at right now. If you remove the water pump, you may have to replace one or more gaskets to be sure that it won't leak when you put it back.

[Paycheck713]

Ok I replaced the Tstat, and flushed the radiator and now its still running hot, before the water even heats up. I was getting on the freeway accelerating 35, 45, 50, and I saw the Temp needle was rising ever so rapidly , so I turned the car off and coasted off of the freeway, slowing down and coming to a turn, I started the car again and the temp was halfway between hot and normal, then I am driving about 25MPH for about a block and the needle started going back to normal, then I stop at a stop sign and take off again and the needle starts going hot again so I pull over and park and turn the car off. Then about 15 mins later I turn the car on and the needle is back and the halfway point between normal and hot, so I turn on the heater full blast and the temp goes back to normal very quickly, so I take off and try to head back to my apt and as soon as I try to get back on the gas to acc. the needle starts going towards hot agains, so I just get off and coast to my appts. Then I get to my appt and park and check the oil level and ATF, and I see a little smoke coming from the back of the engine, like from where the windshield wipers are, so I turn the car on and let it idle and it starts getting hot the needle starts slowly easing towards hot, and I decide to hit the gas a little and the needle literally speeds up towards hot the more I pressed the gas so thats where I just stopped and left it alone! Any ideas? Also ever since I changed the oil the last time, I reset oil gauge on the dash, but every time since then when I turn on the car after and 20seconds of starting and idling a yellow oil symbol comes on and stays on for about 10 seconds and then goes off, and idea what that is? Thanks

[Manolito]

This is quite confusing. The rapid movement of the temperature gage suggests that it is very low on water. How much water did you get back in it after having the radiator and thermostat off?

The smoke (possibly steam?) from the rear of the engine could be a leaking heater hose or heater control valve.

Too bad you did not get a look at the water pump impeller while you had the radiator off, but I think you said that it pumps water out of the top radiator hose right? so we know it is moving some water.

No one has had the head off have they? I have seen cars overheat suddenly and wildly with the wrong head gasket or a head gasket upside down.

Similarly, if someone has poured stop leak in it, those chemicals can block water passages in unfortunate locations.

The yellow oil light is the oil change light? That is very odd. I have no clue what that could mean. That is a simple mileage counter unless that light has a secondary function that I don't know about. Your oil looks OK, not milky, right?

[Paycheck713]

Your telling me! Lol... As soon as I started speeding up the temp starting rising as soon as I started slowing down, it cooled off, I filled it, then let it run, then filled it with the bleeds screw open until water came out of the bleed screw, I do not mind taking everything off again, I just want to get past this problem with out it buying too many unnecessary items you know. So I take the water pump off and check the impeller? I do know for a fact that the water is circulating. Some one suggested that the fan clutch could be a suspect? What do you think? I'm going to go check the coolant level again the car has been sitting for a few hours and the coolant light hasn't came on, but I'll check anyways, and yes when I start the car after about 20 secs of the car idling the yellow oil light comes on for about 10 secs then goes away, and this happens everytime I start the car since I had changed the oil about 3 wks ago, and the oil level is good, and the oil nor ATF looks milky, the oil actually still looks gold because I havnt drove it too much after I changed the oil last.

[Paycheck713]

Ok I took the water pump off, and it looked pretty clean no corrosion or debris, also it was a metal impeller, looks pretty good. So now its not the water pump! Any new ideas anyone???

[mpower318i]

check the oil and make sure that it is not sticky or look like it's got water in it...milky persay...did the coolant look greasy it it did the head gasket might be blown or you could have a cracked block.