Radiator Overheated

[chong82]

Was on the way to genting, half way there i noticed the Water Temp needle tilted to the hot side a bit only and i immediately stop the car at the road side (The low level coolant indicator did not turn on). Steam started coming out from the engine bay and after waited for an hour or so, i re-fill back the radiator and check for any leakage under the car and found no sign of leakage anywhere. The water in the radiator maintained at a level and didn't reduced. So i decided to proceed to the nearest rest area and further check on the matter but before i could go more than 2km, the Water Temp needle tilted to the hot side again. I stopped the car again at a bright place and called the tow truck. Reached home dead tired after 4 hours since the incident started. 1) Is it due to the faulty radiator fan? but after i reached home, i started the car and check on the fan, its working.2) My car couldn't start after i reached home, the clock reset itself. Is it because i on the double signal for too long? I had to use another car to jump start. I knew that i will cause engine oil leakage if i still insist to drive after i re-fill the radiator, but the place where i stopped is very dark. Would not want to risk myself.

 

[K.K.]

Waiting for an hour or so sufficient to prevent the near-exploding radiator from getting stroke or not?
Bimmer rads are famous for getting stroke one leh (kena angin), lol!

 

[chong82]

Waiting for an hour or so sufficient to prevent the near-exploding radiator from getting stroke or not?
Bimmer rads are famous for getting stroke one leh (kena angin), lol!

Care to elaborate what you mean by stroke?

 

[bxnut]

Check several issues:

1. thermostat and housing
2. hoses for leaks, there are several
3. expanspion tank for leaks
4. radiator for leaks

Better drive to workshop, if closebuy, otherwise tow.Water circuit can be pressurised manually, without starting the car.

 

[zeedo]

Another thing to check is the water pump, try to run the engine and disconnect one of the top hose connection to see if there is any water flowing to ensure the water pump is still pumping. Sometime even there is no leak to the pump but the bad condition of the plastic impeller may reduce water circulation.

 

[chong82]

Check several issues:

1. thermostat and housing
2. hoses for leaks, there are several
3. expanspion tank for leaks
4. radiator for leaks

Better drive to workshop, if closebuy, otherwise tow.Water circuit can be pressurised manually, without starting the car.

Ok i just came back from the nearby workshop and the mech said the thermostat need to be change.
He open up the coolant lid and let the engine run for a while. Then he explained to me that the water in the radiator is not circulating properly because the water keep spilling out when its heated up.

So far no other leaks found and i've drove to the workshop and back in total around 9km without any problem as compared to yesterday when im on the way up hill. Yesterday i was driving full throttle up hill and today was not.
The shop is specialized in BMW and Merc (thats what it's written at the signage)

 

[chong82]

Another thing to check is the water pump, try to run the engine and disconnect one of the top hose connection to see if there is any water flowing to ensure the water pump is still pumping. Sometime even there is no leak to the pump but the bad condition of the plastic impeller may reduce water circulation.

The water pump should be working fine as i have taken out one of the screw located on the inlet hose just beside the coolant lid and started the car after re-fill. It squirts around few centimeters high.

Oh yea, when the engine is running, the main inlet hose is stiff and the outlet is not so stiff. Thats one of the checks i forget to mention in my earlier post. Does that indicate that the thermostat gone bad?

 

[bxnut]

Which model is yours?

 

[chong82]

pre-facelift model.

Thermostat and few hoses located in between the engine and firewall was changed.
Pressure test done and everything is fine now.

There's a question.
I was told by some fella that i cant simply open the coolant tank lid, is that right?

 

[bxnut]

I meant, 4 pot or 6? Yes , you shouldn't open the radiator cover suddenly. If its hot, let it cool down first. Otherwise, you'd get scorched

 

[Mouse]

pre-facelift model.

Thermostat and few hoses located in between the engine and firewall was changed.
Pressure test done and everything is fine now.

There's a question.
I was told by some fella that i cant simply open the coolant tank lid, is that right?

due to high heat and create a pressure build up, opening the lid while its hot can cause the coolant to splash. if you really need to open it, just turn the cap slightly to release the pressure inside, u will hear a sizziling sound (Psssssss.......). only open the cap fully after all the pressure is release.

 

[chong82]

err...i was told the car will get a stroke if i open it, even the engine already cool down.

 

[transporter]

bro,
i have this problem too. my e39 temperature went up and down from midpoint to the 3/4 mark.
i open the coolant tank before reading your post and the same thing happen, some pressure came out and follow by hot water..then i closse back the cover immediately..

 

[chong82]

bro,
i have this problem too. my e39 temperature went up and down from midpoint to the 3/4 mark.
i open the coolant tank before reading your post and the same thing happen, some pressure came out and follow by hot water..then i closse back the cover immediately..

Better dont drive the car even after topping up the coolant tank.
You need to properly bleed the water cooling system to remove all the air pocket inside
before you start driving the car.

 

[transporter]

bro, how do i 'bleed' the cooling system ?

 

[safuanorsham]

bleed to prevent airlock.. just wait until ure sure that no bubbles in the tank left,then only you can start.. anyway, expansion tank itself was designed to prevent airlock..

 

[jarance]

bro, how do i 'bleed' the cooling system ?

This is how my workshop does to bleed the air from the radiator.

1. Ensure engine is cool down.
2. Remove radiator cap.
3. remove bleeder plug/cap (as shown in pic below).
4. prepare a cut-out plastic bottle (half of it) - mineral water bottle will do.
5. Use the cut-out plastic bottle to cover the bleeder hole to prevent water from splashing.
6. prepare a running water from hose.
7. Start engine and pour or divert running water into the radiator.
8. rev engine and flushing filling for a minute or so.
9. water should be seen splashing out from the bleeder cap.
10. stop engine and install back the bleeder cap.
11. check water coolant level and top up if necessary
12. install back radiator cap.
13. start engine and warm up for about 2 minute and check for leak.

 

[transporter]

jarance, excellent explaination and pic bruther! thanksss! will try it back home later...

 

[bimmerholic]

This is how my workshop does to bleed the air from the radiator.

1. Ensure engine is cool down.
2. Remove radiator cap.
3. remove bleeder plug/cap (as shown in pic below).
4. prepare a cut-out plastic bottle (half of it) - mineral water bottle will do.
5. Use the cut-out plastic bottle to cover the bleeder hole to prevent water from splashing.
6. prepare a running water from hose.
7. Start engine and pour or divert running water into the radiator.
8. rev engine and flushing filling for a minute or so.
9. water should be seen splashing out from the bleeder cap.
10. stop engine and install back the bleeder cap.
11. check water coolant level and top up if necessary
12. install back radiator cap.
13. start engine and warm up for about 2 minute and check for leak.


Boss, what happens to the BMW coolant if you were to pour the coolant first? All will spill out through the bleeder cap. Or rather when do we add the coolant?

 

[jarance]

This is how my workshop does to bleed the air from the radiator.

1. Ensure engine is cool down.
2. Remove radiator cap.
3. remove bleeder plug/cap (as shown in pic below).
4. prepare a cut-out plastic bottle (half of it) - mineral water bottle will do.
5. Use the cut-out plastic bottle to cover the bleeder hole to prevent water from splashing.
6. prepare a running water from hose.
7. Start engine and pour or divert running water into the radiator.
8. rev engine and flushing filling for a minute or so.
9. water should be seen splashing out from the bleeder cap.
10. stop engine and install back the bleeder cap.
11. check water coolant level and top up if necessary
12. install back radiator cap.
13. start engine and warm up for about 2 minute and check for leak.


Boss, what happens to the BMW coolant if you were to pour the coolant first? All will spill out through the bleeder cap. Or rather when do we add the coolant?

Do this while the engine is cold.
Coolant can be add later. If "air lock" is removed from the system, you can crack open the bleeder plug and let the water spilled out from the cap.

1. Open the radiator cap. You should see the orange float sticking out. Try to put it. If it full, you will not be able to pull it further.
2. Crack open the bleeder plug.
3. Start engine.
4. Water should be coming out from the bleeder plug. Make sure air bubbles is purged.
5. Water should dropped and the float will sink. Add the BLUE coolant. The water should be coming out of the bleeder plug. Keep adding until all the blue coolant is drain from the bottle.
6. Check water level. The float should be sticking up. make sure there is some air space in the radiator. This allows the water and coolant to expand when it heat up.
7. Tighten bleeder plug and radiator cap.

There is another way but it is a bit tedious. Open the bottom cover (wind/water shield) and drain the radiator. Top up with coolant.