Tip & How-To about 2006 BMW 545i

Over heating

Cold engine - - check that coolant level is correct - Ignition on but engine not running - set heter temp settings to max - set fan manual to one of the lower speeds - start engine and within 30 seconds rev it 3-4 times up to 3000rpm - shut off engine before end of 30 seconds (before it starts to heat) - reset climate to normal settings - recheck coolant and top up if necessary. Hot engine. - take car for a run to get up to operating temp - using caution - slowly open the bleed valve (steam and bubbles may come out) - close as soon as you see liquid coolant without excessive bubbles. - do not overtighten this as they are plastic threads. Just snug till it seals fully. - after engine cools check the coolant level again and top up if necessary. Check coolant level every few days for a few weeks and top up again if required - repeat the Hot engine bleed process again. If coolant keeps droping after 2-3 top ups have the system pressure tested. If you are still getting over temps have it analysed by a dealer. The temp is controlled by the engine computer so there may be another fault.

Posted by on

Cars & Trucks Logo

Related Topics:

Related Questions:

1 Answer

primary cooling fan only comes on when i turn ac on


You would need a scanner and an inferred temp sensor to troubleshoot the system.
You need to know what the actual engine temp is, and what the temp sensor is telling the computer.
If and when the engine reaches 220 degrees, the engine temp sensor should be sending that data to the computer and it should ground the fan relay to activate it.
Unplugging the sensor and having the fan run tells you the sensor is connected, and there should have been a trouble code set at that time.
It is possible the coolant level is low, or something else preventing the temp sensor sending the correct data.

Apr 16, 2013 | 2002 Chevrolet Malibu

1 Answer

Hi, there is a gurgling sound coming from my BH5 2 litre N/A Legacy. Yesterday it started overheating, it has yet to reach past 3/4 on the temp gauge but that's only because I stopped driving it


Sounds that you are low on coolant so low that the coolant sensor is no longer immersed in it If the coolant sensor is prevented from working, due to low levels of coolant, then the engine radiator cooling fan will not be started and overheating will result. The gurgling you hear is due to air in the system. When the engine is cold remove the coolant reservoir cap. Set the interior heater to max temperature. Top up the reservoir to the maximum limit with water/antifreeze mix (2:1 is usual). Start the the engine. Be prepared to add more coolant mix as air is cleared from the system. When the top hose from the engine to the radiator gets warm give it plenty of squeezing to help shift any air pockets. The fan should also start at about this time. Make sure that the interior heater is blowing hot air. When the gurgling has stopped and no more coolant needs to be added to stay at the max level then replace the reservoir cap and secure it firmly. Allow the engine to reach running temperature. Check all hoses, junctions, gaskets water pump seal etc for any signs of leaks as it would be good to detect any cause for the previous loss of coolant.

Apr 30, 2011 | Subaru Legacy Cars & Trucks

2 Answers

my temp gauge goes to the third line before fans come on and only the low fan comes on. I already replaced thermostat, engine coolant temp. sensor and radiator flush... any idea why high fans dont come on when gauge reads this high?


CHECK COOLANT FAN FUSES AND RELAYS. CHECK COOLANT LEVEL.MAKE SURE ITS NOT TOO LOW BECAUSE IF COOLANT TOO LOW . BY NO COOLANT AROUND OR COOLANT SENSOR NOT SUBMERGED IN COOLANT COOLING FANS WONT TURN ON.MAKE SURE YOU HAVE 50/50 ANTIFREEZE AND WATER. CHECK FOR CLAPSE RADIATOR HOSES.CHECK RADIATOR HOSE AT WATER PUMP.IF HOSE LOOK CLAPSE REPLACE IT AND BLEED COOLANT SYSTEM.IF EVERY THING HAS BEEN DONE YOU NEED ENGINE BLOCK FLUSHED OUT.HEATER CORE ALSO COULD BE STOPPED UP.A VERY HIGH MILEAGE ENGINE WILL OVER HEAT.OLD ENGINE LOSES COMPRESSION AND HORSE POWER.PUTTING MORE LOAD ON THE OLD ENGINE WILL MAKE IT OVER HEAT.IF COOLANT LEVEL IS LOW.BLEED COOLANT SYSTEM.START THE ENGINE LET IT IDLE FEW MINUTES WATCH THE COOLANT TEMPERATURE GAUGE.WHEN TEMPERATURE START RISING.TURN OFF THE ENGINE LET IT SET FOR 20 MINUTES.TAKE A LARGE RAG PLACE OVER RADIATOR CAP ON COOLANT EXPANSION TANK SLOWLY OPEN RADIATOR CAP JUST A LITTLE TO RELEASE A LITTLE PRESSURE AT A TIME.DONT OPEN CAP RAPIDLY OR YOU WILL GET SCALDED.ONCE THE RADIATOR CAP REMOVED.IF COOLANT LOW ADD MORE COOLANT IN THE THE COOLANT EXPANSION UNTIL YOU GET TO THE COLD MARK.REPEAT THIS PROCEDURE START ENGINE LET IT RUN UNTIL TEMP GAUGE START CLIMBING A BIT DONT LET CAR RUN TO OVER HEAT JUST IDLE UNTIL TEMP JUST START TO RISE.THEN YOU TURN OFF ENGINE. WAIT 20 MINUTES.THEN USE LARGE RAG OPEN RADIATOR CAP LITTLE AT A TIME. DO THIS PROCEDURE UNTIL THE COOLANT IN THE EXPANSION TANK STOP DROPPING. THEN ALL THE AIR IS BLEED OUT THE COOLANT.WHEN COOLANT LEVEL STOP DROPPING, WHEN YOU DRIVE CAR AROUND.AND TURN OFF ENGINE.WHEN ENGINE OFF CAR SET FOR A WHILE KEEP CHECK ON THE COOLANT LEVEL IN COOLANT EXPANSION TANK. THE COOLANT LEVEL SHOULD BE AT THE COLD MARK IN THE EXPANSION TANK.MAKE SURE COOLANT IS IN THE EXPANSION TANK.IF NOT AIR WILL DRAW IN COOLANT SYSTEM. CAUSING ENGINE TO OVER HEAT.IF BLEEDING AIR OUT THE COOLANT SYSTEM DONT HELP AND COOLANT FANS DONT TURN ON YOU HAVE PCM PROBLEMS.

Apr 22, 2011 | 2004 Pontiac Grand Prix

1 Answer

Front heater blows cold all the time


have u checked the coolant level?

Jan 03, 2009 | 1994 Ford Econoline

Not finding what you are looking for?

1,421 people viewed this tip

Ask a Question

Usually answered in minutes!

Top BMW Experts

Frankie B

Level 2 Expert

65 Answers

Fred Sops

Level 2 Expert

272 Answers

Doberman

Level 2 Expert

254 Answers

Are you a BMW Expert? Answer questions, earn points and help others

Answer questions

Loading...