What can it be? Please help, urgent now.

[Rob]

Howzit Guys,

Well now my cooling problem is a more seriouse issue.

Here's the problem:

When I start her up, she takes the normal 5 - 10 minutes to get to operating temp. Also she takes around 5 minutes when driving to get warm. Now while I'm driving at around 60 or higher, my temp remind half way. Any slower or even if I idle the car for 1 minute, she will get hot and if I don't start moving or if I don't turn it off, she will overheat.

Here's what I've checked:

Thermostat:

I let the engine warm up, once it got to normal temp, I felt the hose going to the radiator and it was hot to the touch, no cool spots at all. This is telling me that the T-Stat is indeed working fine?

Coolant Level:

I have made sure it is at the COOL mark, however I still get the *Bing* "Coolant Level" on my dash for some reason?

Clutch Fan:

Okay, I'm not a 100% sure this fan is working 100%, if I start the engine, fan come on straight away. When I shut the engine off, the fan turns off one or two seconds later, well, stops spinning. But I'm not sure it's blowing enough air though to the radiator? Anyway to test this?

I'm really at a loss with the problem. No idea what's causing this. See if I drive the car it's perfect. If I stop and idle for less then a minute, temp gauge goes past half way.

Anyone know how I can find out what the problem is here?

Any help would be greatly appericated.

Thanks a lot guys!

[mamilapon]

Did you put a hose through the fins of your radiator and washed it nicely? Is the fan clutch working?Water pump? Any leaks from under the water pump. Strange noise from the water pump. Get yourself a mechanics stetoscope and check noise from water pump.

[Rob]

Well I thought putting a hose to the rad, spryaing it with water will have the same effect as driving the car fast enough to get air to the rad, to cool the system down. So no, I didn't do that as I know that will cool the system down. And it's not the dirty, I checked and it's pretty clean.

Well if the hose's are getting hot, the pump is working. And if the pump had failed, the car would overheat while driving as well. Checked for leaks, can't see any.

[genphreak]

Well I thought putting a hose to the rad, spryaing it with water will have the same effect as driving the car fast enough to get air to the rad, to cool the system down. So no, I didn't do that as I know that will cool the system down. And it's not the dirty, I checked and it's pretty clean.

Well if the hose's are getting hot, the pump is working. And if the pump had failed, the car would overheat while driving as well. Checked for leaks, can't see any.

Is the thermo fan working at both speeds? Jumpering the thermal switch on the Right side of the radiator will bring it on so you can test it, if this works but they don't come on as they should, the switch might be dead.

What is the ambient temp you are driving at Rob? If it is 30 plus, the thermos might be needed. The AC will bring them on, does it make any difference?

Try not to overheat the car at all, each time you risk breaking your headgasket's ancient seal on these long motors.

[ElSupremo]

Have you made sure the system is bled properly? The hoses can get warm/hot but still not be bled completely.
My initial thought is your H2O pump is going bad. It can pump at low rpms but is cavitating at higher ones. Air in the system could cause this too, though.

[Rob]

Genphreak

Ambient temp is normaly between 18 - 25c.

See this is the issue, I don't think the fan is working correctly at the right speeds it should do. How exacly do I test the fan and it's switches? You see if the engine is hot I cannot hear the fan with hoot closed, is this right? My A/C tank is empty, so I need to re fill it before I can test that out. Could you please explain how I test this fan and switch?

ElSupremo: How do I test your theroy?

Thanks a lot for the help guys!

[DaveVoorhis]

Okay, I'm not a 100% sure this fan is working 100%, if I start the engine, fan come on straight away. When I shut the engine off, the fan turns off one or two seconds later, well, stops spinning. But I'm not sure it's blowing enough air though to the radiator? Anyway to test this?

Once the engine's warmed up and idling, gently push a rolled-up newspaper against the spinning fan. Don't try to block the fan -- you're just trying to provide a teeny bit of resistance. If the fan stops, the clutch is bad.

BTW, the coolant low warning is probably a result of a corroded connector to the sensor. It's on the bottom of the coolant tank. Pull off the connector and clean the sensor and connector contacts.

[Rob]

Oh, okay that sounds like an easier way to test that fan. I will try that. And if it doesn't stop, fan/clutch is ok?

I'm going to look at that connecter either tonight when I get home, or the weekend. Will test fan as soon as I get home. So I must wait until temp needel is half way, correct?

Many thanks!

[Mitch90535im]

Is the 525 subject to the same clogged "pisser" line that I experienced with my m30? In my case I detached the line from where it attaches to the radiator, blew compressed air into it to eliminate the clog (I could then hear and see bubbling in the coolant fill tank, and that solved the problem. This was after I bled 20-30 times, replaced a perfectly good fan clutch, thermostat, tested the aux fan switch, and had a new waterpump in hand ready to replace. I believe it was Winfred who suggested I check the "pisser" line.

[Rob]

No, the 525i's don't have that line going to the Rad tank. Wish it was that simple.

Thanks for the help anyway. Appericated!