overheating problems: bad clutch fan??

[Schniddy]

My E30 reaches the 3/4 mark constantly.

testing out the clutch fan with a rolled up newspaper when the car was all warmed up showed me that it was probably the clutch fan. So Ireplaced it with a known good one from my old ETA.

The car still overheated so I tried tested out the new clutch fan and got the same results. Under further investigation I'm noticing that the fan has more resistance when the car is cool then when the car is all warmed up.

Whats going on here?

thanks for any help
Jon

[Devil Inc]

Possible stuck thermostat? Have you tried bleeding the air off the cooling system? I'm not sure on the fan clutch, because I'm not even running mine as it is bad and I no longer have overheating issues after my 327i swap.

[Todd Black 88]

Does it actually overheat, or just show hot on the gauge?

[Schniddy]

Does it actually overheat, or just show hot on the gauge?

I'm planning on replacing the coolant senor really soon to see if that's the case. The car seems to always start with the tac almost out of the blue area. I remember on my old E30 this wasn't the case. It could be a mixture of a bad temp sensor and also the tach being off a click ( I had the cluster apart to fix the obo)

Still how does that account for the clutch fan showing resistance when cool and none when hot? That doesn't make sense :p


thanks
Jon

[DCColegrove]

Hey, the fan clutches in these are difficult to test. It is normal for them to be stiff when cold.

Does the temp climb at idle or only at or after highway speeds?

The fan clutch is not a factor at all over speeds of say... 20 mph anyway.

Check if the radiator has cold spots, replace the thermostat just for GP (correct temp don't go for a low temp) make sure system is bled properly.

[smoke4ndmears]

its also pretty easy to just pop off the t-stat housing to check that. my t-stat just went bad and the symptoms were similar.

[jlevie]

If good, the fan clutch should be decidedly more difficult to stop with a hot radiator than when the radiator is cold. Your statement that it was stiffer cold would make me thing that both clutches are bad.

A clue as to the cause of the overheating is when it happens. If the car runs hot only in stop and go traffic or while idling, the fan clutch or a thermostat that's not fully opening is a likely cause. If the engine runs hot at speed, the thermostat, radiator, or air in the cooling system are likely causes. In rare cases, partial failure of water pump or a bad hose can cause overheating in both environments.

[Schniddy]

The car seems to be fluctuating between the 3/4 and halfway mark no matter what the speed/circumstance. However, it's always closer the the 3/4 rather than the 1/2 mark.

I just tested out the thermostat in boiling water. it opened up alright. I'm not sure what "fully" open looks like, so I wouldn't know there.

There is rust in the system, so that very well could be part of the problem.

I'll test the car out at highway speeds once I get the coolant back in and bleed the system.

thanks for the help so far!

edit: The car stays up there doing 50/60 around bends, So I figure that would account for "highway speeds"

[Schniddy]

Fully open??

[Schniddy]

More notes:

-noticed water coming out of the exhaust (only during initial startup)

-It seemed like the bubbling out of the bleeder screw would never stop (I’ll be testing it again to confirm)

-Air turns cold w/ the engine turned off and the temp gauge still in the middle of 1/2-3/4

- Seems to be no premature bubbling coming from the expansion tank, which is a sign of a head gasket leak.

-Trying the clutch fan test again, I lightly started to brush the rolled up newspaper against the fan, I started to add a little bit of pressure and the fan started to slow down. If I could of jammed in the papers the fan would of stopped. If my memory serves me correctly when I did this test on my old E30 with a bad clutch, the fan stopped much faster under running temps. I do not think the problem is with the new clutch fan.

And the worst one...

-Looks like there may be oil in the coolant. I'm not sure what this looks like, but when I was poring in the coolant i noticed some multi colors going on (blue, yellow) which makes me think oil...


Could I be looking at a head gasket leak here or what?

[jlevie]

-It seemed like the bubbling out of the bleeder screw would never stop
-Looks like there may be oil in the coolant.

Those could be signs of a failed head gasket or a cracked head.

Do a full and proper bleed of the system (procedure below). If you can't complete the procedure without air from the bleed screw or if a subsequent bleed results in a significant release of air, there's a problem with the head.

1) Using ramps or a jack get the front of the car 1' or more higher than
the rear. That will make the radiator and bleed screw the highest point
on the engine and facilitate removal of air.

2) With the bleed screw open, add coolant until no more air comes out of
the bleed.

3) Leave the filler cap off, or at least loose, and set the heat for max
temp and fan speed. Leaving the cap loose will prevent air that's still
in the system from causing a "coolant fountain" once the engine heats
up. Start the engine and allow it to warm up to operating temp. As it
warms up occasionally crack the bleed screw to release any air and top
up the coolant as necessary.

4) Once the engine is at temp bring it up to 2000-2500 for a few seconds
several times. Then crack the bleed until no more air is released. At
this point the heater should be throwing lots of hot air, which
indicates that the heater core is filled with coolant. You may have to
repeat this a few times to get all the air out.

5) Drive the car a bit, allow it to cool back down, and recheck the
bleed for air. Over the next few days you may get very small amounts (a
few bubbles) of air out of the bleed screw.

[Schniddy]

I was actually using those same procedures ;)

I just took a car to run a few earns and as of now, with the bleed I did after checking the thermostat, the car seems to cool down going down hill, especially "in" gear or just cruising along at 60ish 5th gear. After I left the music store I opened the bleed screw real quick, got a few bubbles, and then it was just straight fluid.


If it was just the clutch fan, wouldn't the car run at normal operating (1/2 mark) going at highway speeds? My car gets cooler, but not to normal.

-So I guess it's safe to say it's probably not the clutch fan?
-In the pictures of the thermostat I posted, does it look fully open?
-Which hose usually can cause an overheating engine on the M2025?
-If I do not experience any more bubbles, would it be safe to say I'm in the free as far as the head gasket/head?

[euro3]

sumthin to check

I had a similiar issue. Temp would bounce around from the 1/2 to 3/4 mark.

It would never overheat, but clearly something was not right. Checked all the above mentioned stuff, bypassed the heater core, replaced alot of shit that was probably OK.

In the end it was the reserviour cap...... It has several o-rings that seal it. I was missing one o-ring and the cap would not seal properly.

Changed out the cap and the temp stabilized.

G/L

[Schniddy]

Interesting. I have a cap from an early system is that fits, I'll give it a shot.

I have a feeling the temp gauge is also a little bit off, I found a pic last night of the correct position, so I'll be checking that out in a bit:



Question: When you start up your E30, does the temp tach jump straight into the blue, or does it go straight to the first line before the blue?

[franko2490]

straight to the first line