Weird E34 temperature incident!

[bimmerman]

OK guys, this is weird. I just don't get it. If you have any idea please let me know.Today I was driving home and suddenly out of nowhere, dark and heavy rain clouds surrounded me. Before I knew it, I was in a rain storm. It rained so heavy I could hardly see anything 10 feet ahead of me. But the car was ever so reliable and did not falter one bit. Then I did not see some deep flood water in front of me and splashed through it with a loud gush. Oh oh! I thought, this is a BMW and I'm surely gonna stall now! But no, not one problem. The car was reliable as a bright sunny day and I drove through more flood water. Then when I reached home I suddenly noticed that my temperature gauge was at the 3/4 mark, almost red! Huh? Overheating in a rain storm? So I got down, popped the hood and there was no blown radiator or hoses or any problems visible. Everything seemed normal.Later in the evening when the car cooled I inspected the coolant level and it was slightly low but not alarming. I released the radiator bleed valve while topping up but there was no air bubbles to indicate air in the cooling system. All the fans were working. No problem at all.What could the problem be?

 

[mafia]

air lock bro.....happened to me too....

 

[lozo]

air lock ?

how air lock happens and affect the cooling ?

 

[bimmerman]

Anyone have any idea what's causing the problem? Please help me out. What am I supposed to do with an answer like Airlock?

 

[three28]

Try to re- Bleed your water run channel. If urs has heater / climate control that has not been disabled . Make sure u on the heater and bleed .

cheers

 

[bimmerman]

Do you suppose my thermostat went bezerk when I hit the floodwaters?

 

[three28]

Originally posted by bimmerman@Nov 19 2005, 12:47 PM
Do you suppose my thermostat went bezerk when I hit the floodwaters?

Is a possibility. But rarely i guess .

:unsure:

 

[bimmerman]

OK guys, I took the car out for a few hot laps around the neighbourhood and when I came to a stop, the temperature began to rise again to the 3/4 mark. Popped open the hood and the temperature dropped 1 notch.

 

[mr_sprocked]

Originally posted by three28+Nov 19 2005, 01:58 PM-->QUOTE (three28 @ Nov 19 2005, 01:58 PM)

 

[E34EuroTouring]

I think your WATER PUMP has gone kaput. Check if the belts to the water pump is ok. If the belt is loose, it will not turn the pump well. IF the belt is slipping , also same effect.

If you have NEVER change your water pump before, good time to do so, get a new termostat as well. Symptons indicate a water pump malfunctioning. The propeller inside is either corroded badly or had loose spin on its axis. If you had a recent water pump installed, then it could well be termostat sticking in close.
Good luck.

Did you use 50% bmw coolant to 50% distilled water mix for coolant ?.

 

[bimmerman]

Hey Mr Captain America! So glad to hear from you!! I think you're right. Might as well change the water pump and thermostat.

Here's what i've been up to earier.....

I changed the thermal switch pictured here. For those who don't know, the job of the thermal switch is to turn on the auxilary fan when the coolant temperature approaches 100 degrees celcius.

Notice the red, black and brown wires on the connector? If you remove the connector and short out red and brown you get speed 1 on your auxiliary fan and if you short out black and brown you get the other speed. You have to turn your ignition on to do this test and my auxiliary fan tested out ok.

So after installing the switch i took the car out for a few hot laps including some tail out action and then let her idle.

Was it the thermal switch that was faulty? Is the problem solved you asked?

No! It's not solved. Within 10 minutes the temperature began to rise towards the 3/4 mark again. The thermal switch did not even acivate the fan meaning the coolant temperature at radiator level was not even up to temperature to activate the aux fan. So i unplugged the thermal switch connector and shorted the earlier described wires to manually activate the fan at full speed for 3 minutes and the temperature did not even come down meaning that it's not a radiator or fan issue anymore.

Now the only suspects left are the thermostat, the water pump or air trapped in the cooling circuit.

The upper radiator hose felt hot to the touch and the lower hose felt warm. This indicates that there is circulation from radiator to engine block and back to radiator but could it be that the flow is insufficient to cool the engine? Looks like Mr E34Touring is absolutely right!

Where does the temperature gauge get it's reading from anyway?

 

[bimmerman]

Originally posted by E34EuroTouring@Nov 21 2005, 11:56 AM
I think your WATER PUMP has gone kaput. Check if the belts to the water pump is ok. If the belt is loose, it will not turn the pump well. IF the belt is slipping , also same effect.

If you have NEVER change your water pump before, good time to do so, get a new termostat as well. Symptons indicate a water pump malfunctioning. The propeller inside is either corroded badly or had loose spin on its axis. If you had a recent water pump installed, then it could well be termostat sticking in close.
Good luck.

Did you use 50% bmw coolant to 50% distilled water mix for coolant ?.

I've recently had 2 belts and all the pulleys changed and yes I use 50% BMW coolant and filtered water and then bleed and bleed and bleed

 

[ICEMAN 68]

any updates mr bimmerman of ya findings .....

 

[bimmerman]

Hey Iceman, today i'll go and buy the water pump and thermostat. Don't think I can DIY on this one so I'll go look for my mechanic friend under the tree.

Items bought so far:

1. Viscous fan clutch (BEHR Brand) - RM250
2. Thermal switch - RM75

Will buy today:

1. Water pump - RM170
2. Thermostat - RM30

I'll keep you guys posted!

 

[bimmerman]

OK, bought the water pump and thermostat. There was a choice of 3 operating temperatures for the thermostat. 71 degrees, 80 something degrees and 90 something. I bought the 71 degree thermo. No need to run the engine so hot in our climate methinks.

As for the water pump, the RM170 was an OEM brand with a plastic impeller! Nasty!!! So I said what the heck and went for the RM370 BMW original. When it comes to cooling on a BMW don't play play!

 

[bimmerman]

The impeller on the BMW original part looks plastic to the naked eye but it feels cool to the touch like some sort of aluminium alloy material. Makes a metallic 'klink' noise when you tap it. Gotta be metal right?

 

[bimmerman]

Ok guys! It's fixed. What was the actual problem?

Air in the coolant? Nope. I wish it was. Would have been so much cheaper.

Broken temperature switch? Nope! Temperature at radiator was so cool it never even needed to trigger the aux fan.

Fan cluch then? Well, my fan clutch was slow but still sucking enough air through the radiators.

Water pump then? No it was not the water pump. These water pumps with metal impellars really seem to last forever until they leak. Mine had no leaks whatsoever.

It's the freakin thermostat!!! Yup, it was a sticky thermostat refusing to open when needed and the radiator also had a very minor leak which could get worse so I changed it anyway.

Here's the damage:

Thermostat - RM30
Thermal switch for aux fan - RM75
Viscous fan clutch - RM250
Water pump - RM370 (metal impellar)
Radiator (BEHR) - RM700

Workmanship - RM100 including battery water for the radiator.

As you can see, the original waterpump is still in good shape but whay the heck, I get peace of mind.

 

[mr_sprocked]

nvm la

at the very least, no worries for high temp no more, huh.
you'll just have to worry abt getting bigger hp :nyehehe: :nyehehe: :nyehehe:

regards

 

[ICEMAN 68]

hey bimmer man

glad to know all your sleepness night is over ..... ..kewl

 

[three28]

Thanks for the very detail endeavour u posted .

Glad that your problem is solved .

cheers