hope everyone had a good thanksgiving!!

ok here is what happened.

i went to pick my dad up at his shop and when i got there i looked down and my car's temperature was in the red. so i turned the car off and let it sit. my dad took the coolant cap off and we couldn't see any coolant in the tube. since we had no anitfreeze and no way to get antifreeze we got the hose and filled it up with water. it took a lot of water so i am guessing that
was the problem, that there was no coolant in the car (or very little). to be honest i don't think i have ever checked the coolant level, but i think i leanred the hard way to check it every time i change my oil.

so i started the car back up after filling it up with water and the car started to run hot again. so i turned her off and checked the level again and the water had dropped down again, so we topped her back off with more water nad started the car again. the temp stayed where it should and i drove all over and the temp stayed normal and the heater worked perfect.

this all happened wednesday night, so yesterday morning i drained the water out so i could replace it with antifreeze so the water wouldn't freeze. i took out the drain plug and let the little antifreeze and water drain. then i replaced the drain plug and filled the antifreeze back up. i started the car and let it run for a sec and she seemed fine. so then about two hours later i left to go to turkey day, i got about 10-15 minutes from my apt and the car started to over heat again. so i turned on the heater and no heat was coming out. so i turned around so we could go get my girlfriend's jeep and take that to dinner and by the time i got back to the apt the heat was coming out and the temp dropped back down. so i thought everything was ok, maybe just the antiffreeze had to work its way through the radiator.

so this moring i started to work and the heater never blew out hot air and the car eventually got in the red again.

sorru this was so long but i wanted to cover all bases so someone can help me the best they can.

thanx,
MATT

It sounds like you never bled the cooling system properly. See my website for coolant bleeding instructions, http://www.understeer.com/faq.shtml

However, you should also figure out why your coolant level dropped so low before. You likely have a cooling system leak somewhere. Also it would be a good idea to swap out the thermostat, BMW thermostats tend to stop working properly after you cook them (temps in to the red).

three issues.

1. The coolant from the engine went some where.
If the engine consumed the coolant it is needing a head gasket test.

2. Never add coolant to a hot car.
The head is alluminum and the block is steel and if they are hot and collant is added that is cold it can cause the headgasket to need replacing.

3. Anytime the coolant system is drained and serviced it requires the heater be turned on a system bleeding be done.

You may need a mechanic.

Later,

where is the thermo located?
is it the sensor on the passneger side near the top of the radiator?

maybe i didn't bleed the system right. all i did was loosen the bleed screw so all the air came out and then refilled the coolant up. so maybe when i get home tonight i should open the bleed screw up and have my girlfriend rev the engine?

thanx,
MATT
thanx,
MATT

The thermostat is located inside of the T-shaped plastic housing on the front of the motor, the two radiator hoses attach to the housing. Unlike most cars, the M44 motor does not have a separate thermostat, it is built in to the housing, so you have to replace the entire assembly. That's actually not a terrible idea though because the plastic thermostat housings get brittle with age anyways.

is there anyway to tell if the thermo is bad or just replace it and see if that will fix it?

do you think that might be why the heat doesn't work??

Thanx,
MATT

sorry just one more question for you?

i just want to verify the bleeding process. what i should do is take the coolant cap off and undo the bleeder screw right next to the cap? then start the car or leave it off just turn to the on position and turn the heater on and make sure there are no bubbles coming up from the bleeding screw?

sorry for the "stupidness?"

thanx,
MATT

It's a little hard to rev the motor while the engine isn't running ;)

If the coolant level is too low or you have air trapped in the cooling system, you won't have heat or at least you won't have any heat unless you rev the engine.

Whether or not your thermostat is working properly takes a little bit of troubleshooting. Does your temp gauge go up to normal while stopped, but then fall back to cold when you're on the freeway? Then it's stuck open. If your engine overheats the thermostat could be stuck closed... of course there are other things that cause overheating also, eg waterpump, coolant level, blown headgasket, etc. Because your temp has been in the red, I would swap out the thermostat.

thanx, i am going to try and get any bubbles out if there are any and look into getting a thermo so i can replace it.

thanx, appreciate everything,
MATT

Doesn't sound like a heater core issue....


I'd say the thermostat is sticking due to the heat from before.

Check your oil and make certain it isn't milky.

Replace the thermo and follow the directions on purging from the link above.

its your thermostat, it stuck

Originally posted by mkalle1
sorry just one more question for you?

i just want to verify the bleeding process. what i should do is take the coolant cap off and undo the bleeder screw right next to the cap? then start the car or leave it off just turn to the on position and turn the heater on and make sure there are no bubbles coming up from the bleeding screw?

sorry for the "stupidness?"

thanx,
MATT

To properly bleed yr system, you need to start yr car (cold), remove radiator cap, turn on yr heater, turn fan to low, open yr bleeder screw, eventually when yr engine warms up, bubbles or a steady flow of coolant will start running out where the bleeder screw is, if nothing is running out, that means yr thermostat is stuck and needs to be replaced.......good luck

Originally posted by ake11
its your thermostat, it stuck
If that was the only problem, he'd have HEAT :rolleyes:

that sounds like what happened to me...car ran fine to work but then i leave and go to the bank and the car overheats...i check coolant and i dont have any in the bottle. I also lost heat, but after filling it back up and driving a couple miles i realized the coolant was low again and i had a big coolant leak

so today i took the radiator, fan, and water pump out looking for the leak and im going to replace the pump and gasket along with the thermostat tomarrow to see if the leaks gone because the leak was comming from the water pump area and dripping from the crank pulley

but my coolant leak was big and noticable, like the engine was smoking because coolant was getting thrown from the pullies all over the engine bay...looks nasty now

This same thing happened to me.

I lost coolant becuase my radiator leaked, so I replaced it and flushed and bled and the car ran nice and cool. I never had heat though--it was summer and I did not care.

My waterpump then went, so I replaced that and did the same process for bleeding. My heat started working.

I do not know exactly why, but I am sure the two are related becuase always bled my system with the heat full blast then started my car and I got heat the second time.

PS - Please post your results, so we and future searchers know the result. Thanks.

i found out i blew my gasket on the plastic thermostat housing, check for coolant leaks, im sure you'll find one

ok here is what i did and what did and didn't happen.

i tried bleeding the system again but no bubbles and no overflow. the car doesn't overheat anymore but the heat doesn't come on, except when i rev the car up. i start to where i am going and let the car warm up to the 12 o'clock position. then at the next light i take off the line quickly and run the rpms up to 6-7. then the heat kicks right on.

does that sound like a thermostat issue, because i am going to order one from bimmerparts.com today if that seems to be my problem. i think they have one for $29 or if anyone recommends anywhere else to go.

thanx,
MATT

No heat at idle = low coolant level and/or air in the system. Go bleed it some more.

yeah, sometimes you need to bleed the coolant system on several separate occasions to get all the air out.........

cool thanx,
MATT