E34 overheating! - BMW Forum

83245kevin · 09-28-2008, 04:56 PM

Hello all,
First i would like to say thanks to all the folks at this site, i have been reading and using the advise that has been posted by others to help me out.

The problem,
The car is overheating and i have found several different ways to bleed the system and i have used everyone of them trying to make sure that i got all the air out.
The car will warm up and overheat all the time (to the red line). I have started the car and constanly opened the bleed screw to get the air out, when it gets above the 3rd line the bleed screw only lets out steam. I really dont want to say that it is a head or the gasket because of $$, but this is what i am thinking and i am not sure that i am getting all the air out or doing something wrong. On oldler cars you can leave the rad cap off and if you get bubbles you know that it is the head or gasket but with this it will warm up push the coolant out of the fill cap or the rad bleed screw no bubbles but the bleed screw at the thermostat will turn to steam and when you shut the car off it will take 1 1/2 gallon to fill back up.

History of the car.
I bought this car and the timing belt was broke and knocked holes in the piston runind the head. I bought a used engine off of craigslist and put it in. It has a new water pump, thermostat and fan clutch. the electric fan is not working the outside temp today is only 80 degrees F so i didnt think that with the car setting in the drive way under no load that it should have any effect of the overheating problem.

Ok, i will shut up and let you all ask what i have forgotten to say. Thanks agian to all the people on this site, very helpfull to have information readily available!

Thansk Kevin

83245kevin · 09-28-2008, 08:34 PM

I went out and took the rad cap off and removed the rad bleeder screw filled with coolant untill all the bubbles were gone. installed the rad bleeder screw and loosend the thermostat bleeder screw and continued to fill with coolant untill coolant came out of the thermostat bleeder screw and tightend it up. We started the car and let it warm up but the heater was not blowing warm air. the temp guage was on about 1/2 opend the bleeder screw and all i got was steam and a lot of it. while the car was running it was constatly pushing coolant out around the rad cap. shut the car off at 3/4 and let it cool down removed the rad cap and the resvior was almost empty so i took the rad cap off and removed the rad bleeder screw filled with coolant untill all the bubbles were gone. installed the rad bleeder screw and loosend the thermostat bleeder screw and continued to fill with coolant untill coolant came out of the thermostat bleeder screw and tightend it up. I left the rad cap off and started the car. took it to 2500 rpm then idle and back to 2500 rpm. i done this maybe 10 times and the heater started working and alot of air came out so i bleed the system again and started it up. heater is blowing warm air and as it heated up it was still pushing coolant out of the rad cap. keep in mind i had it full to the top to make sure that i pushed all the air out. As it was warming up i would open the thermostat bleeder screw about once a min and i would get coolant each time. the temp was a 1/2 for a while, still getting coolant out of the bleeder screw the hoses was not hard or full of pressure then i opened the bleeder screw and got just a little bit of steam the temp guage jumped to 3/4 then all i would get was steam so i shut it off! as this was going on coolant was coming out around the rad cap the whole time.

Thansk for any help

Kevin

marti5 · 09-29-2008, 09:49 AM

Thermostat?, if your head gasket was leaking you would have coolant lose and mayo on the dip stick or in the coolant system, it could also be the temp sensor failing and giving false readings.

83245kevin · 09-29-2008, 10:57 AM

Quote:

Originally Posted by marti5

Thermostat?, if your head gasket was leaking you would have coolant lose and mayo on the dip stick or in the coolant system, it could also be the temp sensor failing and giving false readings.

Marti5,

The thermostat seems to be working unless i am missing something. The hose on the back side will warm up and the hose coming out of the thermostat is cool untill the guage reads a little above 1\2 and then it will start warming up. The car stayed at that temp for 5 or 6 min and i was still getting water out of the thermo bleed screw. then the guage was about in the middle of 1\2 and 3\4 and i opened the bleed screw. i had a little but of water and then steam, the guage shot to 3\4 and i kept getting steam so i shut it off and watched it push about 1 1\2 gallon of coolant out.

Thanks Kevin

marti5 · 09-29-2008, 11:22 AM

It will push coolant out as its a pressurized system, you are not suppose to run it with the cap off or you lose all your coolant, this is why your getting steam and the gauge is rising passed half way as your coolant is to low.

83245kevin · 09-29-2008, 11:29 AM

I,m sorry, i forgot to say that the rad cap was on when it was pushing all the coolant out. out of desperation i went to all 3 of our parts store to get a new cap and try it but no one had one so i went to the local shops to have them test the rad cap and no one has the tools to check bmw rad caps.
thanks for helping me Marti5

marti5 · 09-29-2008, 11:43 AM

Well in that case I would say new cap should solve your problem, I had this happen on mine but it was only losing say an inch a day, but I had white crystals from the coolant when it dries out all around the exp tank so went to BM new cap sorted!!!, if after you get a new cap ( I would def go for gen BM ) mine cost ( conversion £ to $ ) $22.00, if you still have a prob get back to me via PM and we can go from there.

Regards,

Marti.

83245kevin · 09-29-2008, 01:49 PM

i will order one and should have it tomarrow, I have my fingers crossed.

Thansk Kevin

83245kevin · 09-29-2008, 03:00 PM

On the hose diagram the thermostat housing has 3 large ports.
#1 The hose from the thermostat neck goes to the lower rad.
#2 goes from the housing to the water pump
#3 goes from the housing to the upper rad hose

Is ports 2 and 3 open to each other? I have noticed that both the upper rad hose and the water pump hose gets hot before the thermostat hose does. now when temps reach hot enough the thermostat opens and reaches the same temps as the other hoses. If the water in the top of the rad is hot and the thermo opens then you are putting hot water into the bottom and pushing the hot water in the top of the rad back into the engine. If the ports #2 & #3 are not open to each other then i think i have them swithched around and this might be my problem! but it still does not make sence how the circulation can flow like this. When the car cools down i will tear it apart to see unless someone reply's before i get a chance to work on it.

Thanks Kevin

83245kevin · 09-29-2008, 09:18 PM

When we bought the car it was partialy tore down and missing some parts. When i got to the hoses i worked with what i had to determine where the hoses went. I was wrong and had the 2 hoses in the wrong place. so i spent the better part of 1 1\2 day due to my lack of knowlege.

Thanks for the reply's and thanks to this site. i have read so many problems that other people have had and with the support of the members that reply to help other folks out. It is awsome. I cant not say thanks enough.

Kevin

jamalco60 · 07-18-2011, 12:28 PM

dir sir can you tell me please which the 2 hosese exactly wrong because i have the same problem in my car thank

Penngwyne · 07-20-2011, 09:48 AM

This is for a 1989 e34 525i (RHD)

Cooling System Water Hoses BMW 5' E34, 525i (M20) ? BMW parts catalog

If its not the same as your go back to the start page and put in your VIN and then find the engine group to find the right drawing