BMW Over heating?

woggas1972

Hi

I just bought a 98 BMW e36 1.8 Petrol. Last night I was driving and the temperature gauge went into the red, I noticed steam coming from under the bonnet, so I turned off the car and opened the bonnet.

The radiator cap was bubbling so I checked it, it wasn't closed fully, so I tightened it. There was a stream of green fluid (coolant?) on the ground running from under the car.

I got water from a hotel I was parked outside and added it into the coolant tank (which was only about half full) and let the car off for a few minutes.

After about 10 minutes I started the car again and the gauge was in the middle, so I drove a short distance and it went back into the red again.

I stopped again, opened the bonnet and left it sitting for a while. I checked the coolant tank and the level hadn't gone done significantly. I checked on the ground and there didn't appear to be anything leaking. I left the bonnet up and waited for another ten minutes. Started the car and it was back in the middle. I drove for another 4 blocks or so and again it went into the red.

I repeated the same procedure again but this time when I restarted I turned on the heating full blast. This time I made it a bit longer before the red light came on.

Again, I repeated the same procedure and restarted the car after another 10 minutes or so, with the heating still on, and was able to drive the rest of the journey home.

It was 1am on a Saturday night/Sunday morning so there was no garages open or anything, and I didn't fancy leaving the car on the side of the road and getting a taxi home. It's parked out front now and it being Sunday I won't be able to get a mechanic to look at it today.

Is there anything I can do to check what the problem is?



This is only my second post on boards so if I've put it in the wrong area or anything feel free to move it mods.

Thanks, in advance for your replies.

burke027

woggas1972 wrote: »

Hi

I just bought a 98 BMW e36 1.8 Petrol. Last night I was driving and the temperature gauge went into the red, I noticed steam coming from under the bonnet, so I turned off the car and opened the bonnet.

The radiator cap was bubbling so I checked it, it wasn't closed fully, so I tightened it. There was a stream of green fluid (coolant?) on the ground running from under the car.

I got water from a hotel I was parked outside and added it into the coolant tank (which was only about half full) and let the car off for a few minutes.

After about 10 minutes I started the car again and the gauge was in the middle, so I drove a short distance and it went back into the red again.

I stopped again, opened the bonnet and left it sitting for a while. I checked the coolant tank and the level hadn't gone done significantly. I checked on the ground and there didn't appear to be anything leaking. I left the bonnet up and waited for another ten minutes. Started the car and it was back in the middle. I drove for another 4 blocks or so and again it went into the red.

I repeated the same procedure again but this time when I restarted I turned on the heating full blast. This time I made it a bit longer before the red light came on.

Again, I repeated the same procedure and restarted the car after another 10 minutes or so, with the heating still on, and was able to drive the rest of the journey home.

It was 1am on a Saturday night/Sunday morning so there was no garages open or anything, and I didn't fancy leaving the car on the side of the road and getting a taxi home. It's parked out front now and it being Sunday I won't be able to get a mechanic to look at it today.

Is there anything I can do to check what the problem is?



This is only my second post on boards so if I've put it in the wrong area or anything feel free to move it mods.

Thanks, in advance for your replies.

How's a going I'm a BMW mechanic and a weak point of that engine is the water pump and you also need to know how to bleed the coolent system properly after you filled it up which you did not do so either of these could be your problem. There are of course one r two other common problems on that engine that can cause over heating. If your stuck just ask away il gladly help you out.

woggas1972

burke027 wrote: »

How's a going I'm a BMW mechanic and a weak point of that engine is the water pump and you also need to know how to bleed the coolent system properly after you filled it up which you did not do so either of these could be your problem. There are of course one r two other common problems on that engine that can cause over heating. If your stuck just ask away il gladly help you out.

Thanks for your reply. You're not in Limerick and free today are you? ;-)

Ok, so the first one, the water pump, is there a way to check that to see if that's the problem? I was going to get some coolant today and either replace the stuff thats in it or add it in. Is it easy to bleed the coolant system? I should also check if there's any fluid underneath the car after it being parked up all night?

burke027

woggas1972 wrote: »

Thanks for your reply. You're not in Limerick and free today are you? ;-)

Ok, so the first one, the water pump, is there a way to check that to see if that's the problem? I was going to get some coolant today and either replace the stuff thats in it or add it in. Is it easy to bleed the coolant system? I should also check if there's any fluid underneath the car after it being parked up all night?

I'm not in limerick sorry kildare I live in. It's kinda hard to describe how you would check to make sure the impeller isn't broke. Prob be easier just to take the waterpump and check it by hand then u can fully bleed when ur finished everything

JoeySully

I have the same car for the last 4 year and have had much experience with a failing cooling system. Don't drive it if its overheating!!! your will most likely damage the head gasket if not the head itself.

Its most likely ran low in coolant, overheated and then spouted steam out the filler cap. You topped it up but never bled the system.

I wouldn't bother putting coolant into it until you have found the problem! plain water will do just fine !

To bleed it drive uphill, the steepest hill you can find would be best, or raise the front of the car on axle stands.
Open the radiator cap and remove the bleed screw next to it. Keep topping up the water until it pours out the filler neck and the bleed screw.
Now start the engine and ensure the heater is set to HOT.
the coolant may drop a bit, top it up if necessary. Fit the bleed screw and cap and let the engine heat up to normal operating temperature.
It shouldn't over heat. Turn it off and go and have a few cups of tea and let it cool down fully (1hr+)
Open the filler cap and check the level. Top it up if necessary. Put the cap back on. Squeeze the top hose while opening the bleed screw. If coolant come out then there is no air in the system if air comes out then tighten the bleed screw again before releasing the squeezed hose. Do this as many times as needed to expel any remaining air.

You most likely have a leak somewhere! Prime suspect is the water pump. Best to check it in the dark with a flashlamp. Check the back of the engine, there is a plastic connecter that can leak. Under the inlet manifold too there is a plastic connector that can leak with age. Check the passenger footwell! if its wet then there may be a leaking heater matrix or 2 little seals where the heater matrix connects tot he bulkhead.
If you have no leaks and it still overheating then you probably have a bad pump. The thermostat may also be stuck closed.

If you over the 100k then all the plastic coolant connectors should be changed! They will soon crack especially after over heating

woggas1972

Thanks JoeySully for the reply.

I decided to bring the car to a mechanic, rather than fiddling around with it. He did the what you had suggested JS, and advised me to drive it in traffic and see if the temp gauge goes into the red. It hasn't since so hopefully it's sorted. He said that if it goes into the red, they'll replace the water pump and see if that works.

franorzxrh2

sounds like an airbubble caught inside!! with the radiator not closed fully pressure would allow the coolant to flow from d rad!! then whun you topped it up youy may (most likely)created an air bubble!! im pretty sure there is a bleed nipple on top of the thermo housing on these!!