Temp Needle Moving

[1qaz]

So today I was driving around the city for a decent amount. Went to some shops and what not. After about three stores, I got in the car and turned it on. My girl was in the passenger seat and was on the phone with her mom, so I didn't wan't to leave just yet, since I didn't know where we were heading. As I was waiting, maybe three minutes, I looked down and noticed the needle had moved past the normal half way line to about 2/3 to the next line. I then shut off the engine to look under the hood for any leaks or loose hoses, and checked under the car. Didn't find anything though. Decided to drive home, and had the heater on full. The needle was back to normal on the drive home which took about 20-30 minutes, city and traffic on freeway. Then left the car on for a bit and turned off the heater to see if the needle was going to move again. Nothing happened and inspected the car again, couldn't see anything.

Some history of the car. It was over revved once, and was rebuilt with surface testing, new valves and seals, hg, etc. As well, the radiator was replaced with oem, as well as thermostat. Unsure of the housing and water pump, as my pops took it to the shop to have it taken care of. The hoses seem to be free of cracks or deteriorating from what I can see.

Any advice on what to check? Will be checking the coolant tank when the car cools down. Worried, as this is my only car, and need it for school and such. Want to try and have it taken care of to have my mind at ease and not worry whenever I drive. Trying to ovoid that blown head gasket and cracked head. :eyecrazy

[EisnerRacing]

May just be air in the coolant system - park the car level or nose up on a small incline
take out the small plastic screw next to the fill cap fill the overflow get the car to temp when the bubbles stop put in the screw and the cap

[1qaz]

Edit - water pump was replaced as well. All work was done last summer, 2012.

And you explain that procedure a little more? The coolant bleed screw?
http://todor.info/repair/coolantsensor_engine.jpg

[EisnerRacing]

Yup the bleed screw is a small dime sized screw next to the coolant cap it's black plastic and has a plus sign like a Phillips screw
park the car level or nose up on a small hill
start the car - remove screw and cap - get up to temp - pour coolant in the overflow till all the bubbles stop coming out of the screw hole and over flow - basically burping the coolant system
mince no bubbles close cap and screw

[EricP]

Could also be a bad fan clutch not grabbing enough when the engine is hot, assuming your water pump is good. You should be able to shut off your engine and try to turn the engine mechanical fan (attached to the end of the water pump.) It should give a good bit of resistance to turn it. If it is really easy on a very hot engine, like it's freewheeling, the fan clutch is toast!

[1qaz]

Found a DIY to bleed the system. Thanks, will be doing that as soon as I can.
http://forums.bimmerforums.com/forum/showthread.php?1709482-DIY-Video-Bleeding-the-air-out-of-the-cooling-system

As well, will check the fan when the car is hot again. Thanks. Also well, my car usually runs with the temp needle maybe a mm to the left of the 12 o clock position. Assuming that's normal.

What signs should I continue to look for? Thanks.

- - - Updated - - -

Just tried to bleed it. Followed the instructions. Turn on car, turn heat all the way up, removed the cap and screw. Ended up putting too much coolant in the tank accidentally waiting for bubbles to come out of the bleed screw hole, just about topped it off. Bubbles came out of the bleed screw hole, put the screw back in. Then I squeezed the upper hose, and revved with the throttle body a bit switching back and forth. The coolant level in the expansion tank rose. A lot of coolant spilled over the top, since I accidentally filled it so high. The same way soda would spill out a bottle if you were to squeeze the bottle. Eventually, enough came out that I could see where the coolant was suppose to be coming out with bubbles from the little hole, like in the video. No coolant or bubbles or anything came out of the little hole. The only thing that happened was that the coolant level in the expansion tank rose and dropped as I squeezed the hose. There were bubbles in the expansion tank itself as I squeezed.

I tried squeezing the lower hose. I noticed that my lower hose was cold. As if it were just sitting there, doing nothing in the engine bay. Is this normal?

Also, checked my clutch fan when I turned the car off. It has some resistance, it didn't spin freely, but I can move it with my finger. Not sure how difficult it should be to spin, since I can't compare it to a new one.

[Jrrrrrrr]

Bleeding the cooling system effectively is easier than people seem to angle at on these forums. Just raise the front passenger side, install a plastic type fitting nipple (like an M10 fitting with nipple you'd find in a master-cylinder bench-bleed kit) and run a hose from the fitting with the other end of the hose submerged in the expansion tank's coolant. Be sure to have the heat on full blast and squeeze both radiator hoses a few times in the process. See the attached photo to see what I'm talking about.

I agree that you should be looking at the fan clutch, though. If the system cooled down when you started moving again, that hints at bad airflow across the radiator fins when stationary, which hints at a malfunctioning engine fan and/or auxillary fan.

[1qaz]

What should I be looking for from the clutch fan?

[MauiM3Mania]

What should I be looking for from the clutch fan?

Check this post. http://forums.bimmerforums.com/forum/showthread.php?1903563-fan-clutch&p=25222574#post25222574

[1qaz]

So I should put newspaper up to a spinning clutch fan.
Seems terrifying

[EricP]

The behavior of the expansion tank is "interesting" at best also. Pretty sure the hoses on a hot engine shouldn't be cold, right? O_o And I haven't bled the M3 in a while but the E39 always has a constant little stream of coolant into the top of the overflow, if not then coolant is not circulating in the system correct?

[1qaz]

Yeah, the lower radiator hose was 'room temperature' I guess you could say. The upper was hot. As well, there was nothing coming out of the little hole at all. From squeezing and everything. Just coolant rising and falling in the expansion tank as I squeezed the hoses.

[MauiM3Mania]

So I should put newspaper up to a spinning clutch fan.
Seems terrifying

If that is the case, you may be better off by taking your car into a shop that knows BMWs.

[hide1]

May just be air in the coolant system - park the car level or nose up on a small incline
take out the small plastic screw next to the fill cap fill the overflow get the car to temp when the bubbles stop put in the screw and the cap

+1 or poss minor coolant leak somewhere in the system.

[1qaz]

Tried the paper trick, used one of my school brochures, basically three sheets of paper. Put it up to the fan at operating temp, it didn't stop immediately, but slowly came to a stop. Went and bought a new fan clutch from AZ, and ordered a new euro cooling fan from the stealership. Paying so much more than internet prices :mad But I need to get this fixed as soon as I can. No car is not the biz.

[ThreeD]

A bad mechanical fan will not cause overheating by itself. I would just assume it's an air bubble in the system.

[jjoel]

make sure your electric fan is kicking in. that would cause slight overheating at idle or when stuck in traffic, but it would go away once you hit ~35MPH. could be a bad connection to the fan switch or just a bad fan switch temperature sensor (the one that plugs into the side of the radiator).

[1qaz]

The electric fan, for the A/C? How am I supposed to know if I have an air bubble for sure? I tried bleeding the system, but there was nothing coming out of the little hole where there was to be a stream? There were bubbles from removing the bleed screw, but I believe after a while, it stopped. As well, some bubbles from the expansion tank as I squeezed the radiator hose and the coolant level rose and dropped.

[RRSperry]

Jeez, how hard it this? DOES THE AUX FAN WORK!!!??? By the time you see the stock water temp move to 2/3's, the aux fan should be running.

These cars aren't hard to bleed. You all make it too hard.

Jack the car up in front, put it on stands.
TURN HEAT TO HOT
open expansion tank and bleed screw
Start engine. let it warm up. The rest will take care of itself.

I bet your problem is with the aux fan.

[anotherhaus]

I tried squeezing the lower hose. I noticed that my lower hose was cold. As if it were just sitting there, doing nothing in the engine bay. Is this normal?


Wouldn't this indicate no coolant is flowing through the radiator...i. e. thermostat stuck or water pump failure? If it were just the aux fan or puller fan the hoses would still be hot.

[1qaz]

Just installed my new fan clutch and euro diesel fan. Went for a test drive. Let it idle to operating temp. Then waited for 10 minutes, car temp stayed at 12 o clock. Went for a drive, mixing between high and low rpms, as well as on the freeway. Turned on the A/C too just to see if that'll push it at all. Not sure if that was the fix or not, but so far no over heating.

Also got to check the lower radiator hose, it was hot, not as hot as the upper, but definitely hot.

As well, since I tried to bleed the system, I think I did the opposite...I now have no heater, the air blows, but it is practically room temperature. SMH. Can someone explain to me how air gets in and out of the system. Trying to understand how it works. Also, my aux fan does not work. It never turned on, even with A/C or heater on. Will check the fuse tomorrow, as well as fan switch.

Thanks guys.

[1qaz]

Update - Just bled the system again, or tried to. I think I was successful this time. When the car was at operating temp, the heater wasn't hot, but a bit warm, definitely a lot better than yesterday. I went for a drive, and felt the heater get a lot hotter as I was driving. I'm not sure if this is normal but the heater blows hot as I drive or rev the motor, but when I come to a stop light or sit at idle, it is nowhere near as hot as when I'm driving. The air blowing becomes warm.

Note - The problem I guess I was having with bleeding the system was because every time I squeezed the radiator hose and air came out of the bleed screw hole, I felt as if air was sucking back into the hole when I released grip from the hose. Kind of how a turkey baster works. Ended up adding as much coolant as I could until the bleed screw hole was drowned in coolant. It made a mess every time I squeezed the radiator hose, a bunch of overflowing from the expansion tank and hole, but I think it worked.

[anotherhaus]

I still think your thermostat is stuck or your water pump is failing. Just putting that out there. But seems like you're up and running for now.

My reasoning is that your lower rad hose should never be cool when the engine is hot, and your heater core temp should not drop noticeably at idle. I suspect you have a problem with coolant flow through the radiator and engine (particularly at low engine RPMs like idling), and that is why you overheated while idling the first time. Time will tell - keep us posted if anything weird happens again.

[RRSperry]

If your aux fan doesn't work, you need to fix that. 2 fuses, and 2 relays, or the fan itself.

Without actually knowing what your water temp is doing, you are just guessing. Break down and get a Bluetooth obd2 scanner and see.

[1qaz]

I read that


If the thermostat is stuck open, coolant always flows through the radiator, and the engine is cooled off more than needed. If the thermostat is stuck closed, coolant never flows through the radiator, and you overheat

If the heater valve is stuck open, coolant always flows through the heater core, and you always get hot air out the vents (though if you run the A/C it'll cool it off quite considerably). If the heater valve is stuck closed, you'll never get warm air from the vents.

How would I know if the thermostat were going out? Same for the water pump. Everything seems somewhat fine, for now at least.

As well, for the aux fan, I'm not too big on electrics and what not. I was reading some stuff about jumping terminals? Not exactly sure what any of the diagnostics ideas mean. Testing 12 volt, low and hi turning on, etc. So there's two fuses and two relays in the fuse box, as well as the fan switch on the side of the radiator. I'm supposed to take the plug out of the radiator and put a paper clip end in two of the holes and see if the fan turns on?

[RRSperry]

Look, I'm not trying to be a dick, but if you want to work on your car, at least prepare yourself...

Buy a Bentley Repair manual, and some way to read OBD2 data. You can buy a Bluetooth scanner that plugs into the obd2 port and sends real time data to your phone. (along with scanning codes and clearing them. Available for both android or apple. It will be useful for any car you own built after 1995) Buy some tools. A Digital multimeter is a must for doing anything electrical.

Even if you paid next to nothing for the car, you have to remember that it 's still a car that cost a lot of money when it was new. (About $60,000 in todays money) It still requires expensive parts, and maintenance. People that don't have deep pockets and sound mechanical reasoning shouldn't own old German sports coupes...

Ok, yes, to test the fan you can pull the connector from the temp sender in the passenger side of the radiator. There are 3 wires. 1 ground, (usually grounds are BROWN wires. If you jumper 1 wire to the ground, (thereby energizing one of the relays), the fan should turn on, jumper the other wire to ground and the other speed should come on. DO not jumper the 2 power wire together...lol Duh.

If this is too much, find somebody local that will help you, or break down and pay someone to figure it out. The last thing you probably need is to overheat the engine and kill it, because you were too inept to learn to use simple tools and read a wiring diagram...

[1qaz]

Thanks for the tips.

Just tried to jump the wires. When doing so, I could hear the relays click. This happened for both high and low, but the fan never powered on.

Where do I go from here? How would I know if my relays are bad or if the fan motor is out?

[anotherhaus]

It's a common failure in the E36. Mine has been replaced once and I'm still under 80K miles. Odds are the aux fan is just fried, but since they cost $150 or so (last I checked) there are probably some additional troubleshooting steps. There are tons of threads about this. Not to be a dick either, but

http://lmgtfy.com/?q=e36+aux+fan+troubleshooting

The simplest of checks would be to see if it even spins by hand (i.e. is it seized). Following that, you should use a meter and check for voltage at the wires where they plug in - I believe at the bottom, accessible from under the car (the Bentley guide Richard noted probably shows pinouts, or some of the threads above should too). If that checks out, personally I'd probably pull it and carefully bench test it assuming it was dead, but be careful because it spins rather quickly and could probably do some serious damage to your fingers.

[1qaz]

I've read a majority of the threads from the googling you posted. A lot have one speed that turns on for them, so not really the same problem. They don't say anything about the clicking relays usually either. Thanks for the tips

[1qaz]

Just tried swapping the 266 relays, still doesn't work. Tried to spin the fan by hand, moves just fine, not seized. Is it looking like the aux fan is dead at this point?

[RRSperry]

Then check for voltage at the aux fan connector. You have to pull the bumper cover, but that's a 5 min deal.

[shaft9ii]

The relays should click, think of them as a light switch but instead of being turned on by your hand, they're turned on by electricity. So if they're clicking that means they're likely working. The problem is likely further down the line.

[1qaz]

I went and checked the voltage of the aux fan connector. 12v from both hi and low. I then tried to test the fan by using the positive terminal in the engine bay and took ground from the chassis. I accidentally took the positive terminal and put it on the hi (or low) of the fan, and took the negative terminal and put it on the low(or hi). It sparked and the fan spun a little. It was only a brief second, the keys were not in the car either. The fan motor also made a weird noise, I spun it by hand again later and it sounded like something was grinding inside (that or the fan was spinning backwards, it went counter clockwise). I then put the negative terminal with the ground, as it should be, but nothing happened. I went in the car and put the key in and turned it onto accessory, still nothing.

Wondering if I fried my fan when I accidentally put it on hi and low with no ground.

Guess it's time for a new fan as this one is 16 years old.

As well, went ahead and turned on my car, everything seems fine so far.

[1qaz]

Just bought a used fan for cheap. Tested it directly before buying, and then through jumping the wires at the radiator before installing, works on both high and low.

One last question. When is it supposed to turn on on high? I turned on the car, and turned the a/c on, and the fan turned on (assuming this is low). I drove around (now with a/c off), let the car get to operating temperature, but the fan didn't kick on. When should it be running? I figured operating temp would be more than enough for the fan to be on.

Thanks for all the help everyone

[RRSperry]

The stock temp switch in the side of the radiator is a 90-99C switch. (or should be). (194-210F) Remember that that's on the outlet of the radiator.

For reference, in my car I have a temp sender in the outlet of the thermostat housing. Normal operating temp is about 190-200F. So in normal driving without AC, the aux fan never comes on. I have a 80C thermostat, and an 80-88C aux fan switch. (fan delete mod) and no mechanical fan or fan clutch.

Without a real temp gauge, or the ability to read OBD2 data, the stock gauge in the cluster is about worthless. It is heavily buffered and sits in about the middle for a wide range of temps. (mine is in the middle from about 130F to 220F. When you see it really move, it's almost too late. By the time it hits the red, it is too late..lol

[1qaz]

That helps a lot. So I guess the aux fan turns on only when it is really needed. Any recommendations on obd2 temp readers?

[RRSperry]

There are a billionty eleven of them... If you have an Andriod, get the Torque app and a blue tooth OBD2 adapter, or a Scanguage 2, or and other reader. If you are an Apple guy, then it just cost more. (a lot like owning a BMW)...