coolant problem plkease help

[96CosmosM398TI]

i put a new radiator in, bmw thermostat plus housing, metal impeller water pump! here is the deal i have bled the system a few times now, but it keep pissing coolant out due to pressure build up....... i cant figure out why though, this morning after the car sat for 8 hours in 32 degree weather i went to put coolant in and as i unscrewed the radiator cap it started to push air out like out of a air compressor... what is going on anyone? also the car does not over heat at all i have driven the car for 400 miles like this and no over heating and i know the gauge works because it use to over heat before the radiator

[Bam2002]

Why did you replace all those parts? did the car oveheat?

If so you could have a blown head gasket, allowing air into the system.

Also there are 2 plastic parts, one off the back of the head and one under the intake manafold. These get brittle and crack, thus letting air into the system. But if these were cracked you would have coolant leaking.

[96CosmosM398TI]

the radiator was cracked at the plastic end caps on each sides, their was no thermostat in the car, so i bought a new thermostat, and a radiator off a guy on bimmer forums who had it in his car but removed it for an ls1 swap.... their is no coolant in the oil, i jsut changed it as well, and their is no oil in the coolant... so i am assuming that is the problem ,,,, i hope and the coolant blowing out the radiator cap area due to the pressure and possible somewhere underneath....

[96CosmosM398TI]

also the car just went through emissions, runs great, no check engine, heat works great, comes up to temp normally, and just sits at half way..... i am wicked stumped

[Bam2002]

Well thats a tough one then.. Unless some thing is plugged up inside the engine. Id say keep an eye on the coolant to make sure there is no oil, if it stays clean I agree that its not a head gasket issue.
When you are bleading the system do you have the heater on in the car. to make sure there isnt air trapped in the heater core?

If its not overheating then you may be over filling it. The Radiator on the side has a Cold and Hot level.. so it looks low when its not.

B

[96CosmosM398TI]

the radiator has a separate bleeding screw next to the reservoir. the only thing that i haven't done yet to bleed the system is to let the car run for 15 min with the heat on and the cap off, i typically just bleed the system with the bleeding screw on a cold engine .... via pouring coolant into the reservoir till it bleeds out the bleed hole.... but i will try this next... thnaks

[96CosmosM398TI]

so i just re bled my system started it , let it run to operating temp, with the heat blasted.... but the heat wasn't very hot .. warm at most??

[cooljess76]

Originally Posted by 96CosmosM398TI

so i just re bled my system started it , let it run to operating temp, with the heat blasted.... but the heat wasn't very hot .. warm at most??

park the car on a hill or driveway with the nose up. Leave the car off(not running) and run the heater full blast with the bleed screw off. Slowly add coolant and wait for a steady stream of coolant (with no bubbles) to flow from the bleed hole. Plug it back up and top it off. It might take a few tries to get all of the air out. If the problem still persists, I'd say you either have a BHG or part of your water pump or thermostat broke off and is plugging things up. The heater won't work if the coolant level is low, and the coolant level won't look low if there's air in the system. Your car just needs to burp. A proper bleeding should do the trick.

[aceyx]

Your cooling system is pressurized--that's why it sounds like an air compressor. It's also why they suggest NOT OPENING IT WHILE RUNNING so you don't splash 170 degree liquid on you.

Bleeding only works when the engine is running. If you're not following instructions and you're finding problems, go back and follow instructions. Maybe that will solve your problem.

[96CosmosM398TI]

i have bled more bmws in my life time then you could possibly imagine.... never had a problem, till this day 25k miles on my m3 in the summer heat with a fan delete kit and have never had the needle go over half, but this thing is keeps pissing coolant out the radiator cap or bleeding screw...... also i never opened it while it was hot if you read carefully above the car sat over night...... but thanks for all the responses.. i have tried your yet cool jess76 ill give it a whirl thanks

[cooljess76]

Originally Posted by aceyx

Your cooling system is pressurized--that's why it sounds like an air compressor. It's also why they suggest NOT OPENING IT WHILE RUNNING so you don't splash 170 degree liquid on you.
Bleeding only works when the engine is running. If you're not following instructions and you're finding problems, go back and follow instructions. Maybe that will solve your problem.

Not true, and as you mentioned just before this, the instructions state to do this while the engine is not running.

[aceyx]

We must have different instructions then.

Bleeding the system is to remove air bubbles / pockets from the coolant system. In order to do so, the fluid must be running through the block, hoses, and condenser (thus allowing the fluid to take the place of air).

Some instructions tell you to "massage" the hoses, as tiny air bubbles will often form on the inside of the hoses like a bottle of soda.

[Rich]

You could also look at the o rings which join the connector from the engine bay to the internal heater.
http://bmwfans.info/original/E36/com...4/ill-64_0663/

see part 4 in the above link. This can be found behind a metal plate at the back of the engine bay. The plate is held in with 3 hex bolts.

Coolant can leak & gather here and is not visible. It maybe worth a check; if it is the problem its a simple 50p fix.


(plate is below air intake grill for internal heater & above the two water tubes that go to the internal heater)