Overheating after Replacing Gaskets..

[92BMW318is]

I recently replaced the gaskets on the head and the uper front plate gaskets where the radiator hoses connect into the engine. I also repaced the o-ring to the thermostat. with all of this aside.

I put everything back together... then poured coolant into the radiator up to the full line. started the engine. coolant level lowered. put more coolant into the radiator up to the full line. then began driving my car back to my house. car started to overheat. turned off the engine & coasted to a stop.
Waited for 30mins then turned on the engine and began to drive until the engine started to over heat then turned it off and coasted I did this until I got home. I was supose to work today but couldnt due to the over heating of the car.

But today I started the engine and warmed it up to the normal running temp then shut it off. unscrewed the bleeder screw to the radiator and air came out. and the coolant level lowered. I probably did this like 5 times today. Each time the coolant level lowered, I added more coolant (when engine cooled down).

There are no sighs of coolant leaking into the engine. There was steam coming from the exhaust for like 10mins when I originally started it after replacing the gaskets on the head. With the steam there wasnt any distinctive smell.

Before i replaced the gaskets my car never once overheated. I have never had this problem before...

I have included temp readings from various spots on my car. I do not know what the normal temp readout is.








If anyone can Type up the correct porsedure to bleeding the cooling system please please please do so. As is there another bleeder valve other then the one on the side of the radiator? I work at 7am in the morning I hope to god I can solve this issue before then.... Its 10pm now.....

[DesktopDave]

I usually park it up a hill & do the same stuff you've done.  The temperatures don't seem too high, is the temp gauge in the red?

There are no other bleeder valves, unfortunately.  It'll purge sooner or later.  Mine always sits up at the 3/4 mark for a few days until it purges.  Currently it runs a little over the middle mark.

[bmwman91]

Here's the process I usually use to bleed air. I have never had an issue with the needle getting past the 1/2 mark with this.

- Let the car sit overnight so it is stone-cold.
- Fill the expansion tank up, and let the level settle down. When it looks like the level is holding steady, don't fill it past the max-cold line.
- Loosen the bleed screw.
- Start the car.
- Pull the throttle so the car sits at ~3000RPM (or have a partner inside doing it).
- Adjust the bleed screw so that coolant is not gushing out, but is flowing enough that you can see bubbles/sputtering.
- Watch the coolant level like a hawk and keep it from getting more than 4" below the max-cold line. Add coolant/water as necessary.
- Keep the engine at 3000RPM.
- When the engine temperature gets above the 1/4 mark on the gauge, the thermostat will start opening.
- When this happens, if there is a lot of air in the system, you should get a solid 5-10 seconds of air discharge out the bleed screw. The coolant level in the tank may drop rapidly at this point, and do not let the tank go empty.
- Keep at it, adding coolant as necessary until the bleed screw spits out nothing but coolant for a 10 second interval.
-- Close the bleed screw & cap the tank.
- Hose off all the coolant from your motor and driveway. You should dilute it as much as possible to reduce the harm to animals in the area.
- Once the car has cooled completely, re-fill the tank to the max-cold line, if needed.

If you have been driving the car around for a while, just warm the car up & skip to those steps. You'll probably see less air discharge from the bleed screw too since some of it has worked its way out.

[92BMW318is]

I usually park it up a hill & do the same stuff you've done.  The temperatures don't seem too high, is the temp gauge in the red?

There are no other bleeder valves, unfortunately.  It'll purge sooner or later.  Mine always sits up at the 3/4 mark for a few days until it purges.  Currently it runs a little over the middle mark.

a Little past the middle mark, is where mine sat at before changing the gaskets. I took these temps after. driving my car around the block once i had to stop and let it cool. then coasted back to my house down a hill. I never let it get past the 3/4 line. But I took these temps because I didn't know if the thermostat was "broken" or if the engine was hotter then it was suppose to be.

[92BMW318is]

Here's the process I usually use to bleed air. I have never had an issue with the needle getting past the 1/2 mark with this.

- Let the car sit overnight so it is stone-cold.
- Fill the expansion tank up, and let the level settle down. When it looks like the level is holding steady, don't fill it past the max-cold line.
- Loosen the bleed screw.
- Start the car.
- Pull the throttle so the car sits at ~3000RPM (or have a partner inside doing it).
- Adjust the bleed screw so that coolant is not gushing out, but is flowing enough that you can see bubbles/sputtering.
- Watch the coolant level like a hawk and keep it from getting more than 4" below the max-cold line. Add coolant/water as necessary.
- Keep the engine at 3000RPM.
- When the engine temperature gets above the 1/4 mark on the gauge, the thermostat will start opening.
- When this happens, if there is a lot of air in the system, you should get a solid 5-10 seconds of air discharge out the bleed screw. The coolant level in the tank may drop rapidly at this point, and do not let the tank go empty.
- Keep at it, adding coolant as necessary until the bleed screw spits out nothing but coolant for a 10 second interval.
-- Close the bleed screw & cap the tank.
- Hose off all the coolant from your motor and driveway. You should dilute it as much as possible to reduce the harm to animals in the area.
- Once the car has cooled completely, re-fill the tank to the max-cold line, if needed.

If you have been driving the car around for a while, just warm the car up & skip to those steps. You'll probably see less air discharge from the bleed screw too since some of it has worked its way out.

Thanks man, I'm going to do this. tell you how it goes.

[92BMW318is]

Okay sooo, while aiming a temp gun into the engine (removed oil cap) it is reading at 203. the two hoses are reading 150 driver side 148 passenger side.
The lower hose on the driver side coming from the radiator is reading 88-90 (couldn't get a solid number)

While aiming the temp gun under the intake manifold by the injectors it reads 210-203. The front of the engine reads around 160. while aiming the temp gun at the middle of the radiator i get a solid 158.

Ive been bleeding it at the thermostat housing (losining the hose clamp on the hose leading to the radiator on the driverside letting air pockets disipate) and at the radiator bleeding screw(not really any noticible air coming out of bleeding screw, more comes out at the thermostat housing.).

So I'm going to keep adding more coolant...
When the car cools down the coolant lowers alot. then its heated up the coolant raises alot.

Read me before commenting V
While I do not know if these are normal operating temperatures. My car only shows the needle on the coolant gauge, little over the middle. The heater blows air hot enough to probally burn your fingers If you were to leave them there long enough. Once today the heater went totally cold like I had air conditioning. I stoped took readings from the engine and they are almost the same as the ones above. But only half the radiator was hot hot, other side was cool enough to touch. After the heater went cold i waited until the engine cooled enough to add coolant when taking it for a spin after adding coolant The heater was hot again.

Do you think I should not drive my car at these temps or is it perfectly fine since the coolant gauge is only a hair past the middle.

[bmwman91]

1) I am not sure if bleeding it at the thermostat housing is helping. It is not really a high-spot in the system and air might just as easily get in, although it is a little unlikely since it is the pressurized side.

2) The air coming out of the radiator bleed screw isn't always that obvious. It can be easy to mistake for normal leaking of coolant. When it is air-free, it will just piss out fluorescent green liquid without any spraying or sputtering.

3) When you notice the coolant level changing dramatically, is this with the expansion tank cap on or off? It sounds like you are observing this with the cap off, which sounds about right. When the system heats up and runs under pressure, the hoses expand and hold more coolant, dropping the tank level. If you take the cap off while it is hot & the thermostat is open, that will release the pressure & the coolant goes back into the tank. If you let it cool and then pull the cap, nothing should happen.

4) For how long did the heater blow cold air? That sounds like either a huge air bubble, or a problem with the heater core thermostat (or maybe the flap that controls hot/cold air).

5) The coolant hose and radiator temps sound fine. I am not sure about the engine temps, but they might be OK too. If the needle stays below the 3/4 mark on the temp gauge, you are probably fine.