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Overheating, radiator fans question


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Hello I have a Legacy 1996 Outback with 2.2L engine and manual transmission.  it had some steering issues, and I had a bunch of other stuff going on in the game of life, so I parked it for a few months.  I put a rebuilt steering rack in it and am now trying to get it going again.  The steering still doesn't seem quite right but that's another topic.

Now it overheats from just driving a few blocks.  At least the temp gauge shows it's overheating, it doesn't boil over or really act like it's overheating otherwise.  I noticed while it was running hot that only one of the two fans was working.  I plugged the green test connectors together and turned the key on and only the right (passenger side) fan comes on.  Aren't both fans suppose to come on with the green connectors mated?  I wouldn't think that in itself would be enough to cause it to overheat, but that's a start I guess.

The air conditioning doesn't work but it's all intact except for the drive belt has been removed from the compressor.  It didn't seem to matter whether the AC was turned on or not as far as the left (driver side} fan coming on.

So again, my question is whether or not both fans are supposed to cycle with the green connectors mated?  If so, what do I need to check?  The relays in the attached pic?  I hot wired the left side fan and it came on so there doesn't appear to be anything wrong with the fan itself.

Thanks as always.  I want my daily driver back!

Fuse and Relay Box Subaru1.jpg

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Yes, both fans should cycle in test mode. I would use a test light or multimeter to backpin the fan connector while in test mode and see if it's getting power. Might just be a failed fan.

 

The fans really only make a difference under 15-20mph. So with those symptoms, I would question the gauge reading. Might be worth plugging a code reader in and seeing what temp the ECU sees (separate sensor), and/or using an infrared thermometer to test.

 

Might be a grounding issue causing both problems....

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I just replaced a fan on a 99 Legacy.  The 20 amp fuse was blown.  The one at the top left of your picture.  I put a new fuse in and the fan worked in low but blew the fuse as soon as it went to high speed.  I put a used fan in and it works great!

Check the radiator fluid level to make sure it's full when cold!  Pull the radiator cap.  The car I just worked on for a friend was almost empty.  It took a gallon of coolant.  I did not find any leaks.  I suspect it was overheating and pushing the fluid out the overflow bottle.  It's a 2.2 as well.  It has a little black oily scum in the overflow bottle.  When I see that I think Head Gaskets.  Time will tell.  212K  Auto Trans.

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Thanks for the replies.  I checked and swapped that 20 amp fuse.  That wasn't the problem.  I had already tested the fan that wouldn't come on by hotwiring it with a battery charger and the fan definitely works.

I was just messing around with it in the garage, and the "burping the air out of the coolant" phenomenon presented itself.  I had heard that it can be difficult to get all the air out of the system.  I guess I just never knew for sure whether it was critical or not.

So I got one of those radiator funnels or buckets that have the funnel built in to an included radiator cap with a bunch of adaptors.  I put the funnel in place and started it up.  It probably took about a quart or maybe even a half gallon to fill it, even though I had tried to top it off a couple of days ago.

I started it up and let it idle for a while and watched the bubbles come out.  I didn't really have to add all that much to keep fluid in the funnel.  I kept an eye on the temp gauge and it got up fairly close to the H.  Higher than it should have sitting in my garage.  The "main" fan clicks on when the gauge gets to about half way.  The other fan never did come on.

Here's where it gets crazy.  I stopped the engine, started it again, and watched the funnel some more until I was sure there were no more bubbles coming out.  Then I gave the upper radiator hose one good squeeze.  I hear this "bloop" and it sucked all the coolant out of the funnel into the system.  I had previously given the hose a similar squeeze two or three times previously without the same effect.  It sucked in about 1/4 of the capacity of that funnel bucket.  Maybe not that much but a pretty good bit.

As soon as that happened I filled up the funnel again.  I noticed that the temp gauge dropped back down to mid range and it's been staying there ever since.  Could that trapped air actually have made that much of a difference?  From running up near the H, to down to mid level all just sitting in the garage idling the whole time?

radiator bucket.jpg

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Yeah I agree with that sentiment.  I'll drive it around the neighborhood the next couple of days and keep an eye on the coolant level and the temp gauge.  It would not surprise me at all if my head gaskets were leaking.  It is a 2.2L but I've got 308K on her!

I am hoping that the coolant I added today was because it just hadn't replaced the air in the system yet.  Even if it were leaking coolant to somewhere it doesn't belong I hadn't driven it enough to get rid of that much coolant.

I was trying to get a feel for whether or not I could tell if the bubbling in the funnel was an indication of a head gasket leak, but I don't know enough about what I am looking for to make that determination.  It wasn't like there was a constant bubbling in the funnel.  There was intermittant bubbling, but there were long periods of time where there were no bubbles at all.  When I reved the engine it would bubble a bit.  I don't know if that's indication of a head gasket leak or just pushing more air out.

Anyway, thanks again.  I always appreciate it.

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They do have the testers to see if there is combustion gas in the coolant.  It's not 100% but another indication.  Sometime HG only leak under heavy load when hot.  Watch the temp gauge.  Subaru's most often sit just below half way.  They come up to temp pretty quick and then stay there.  Same position all the time.  If the temp gauge is going above normal you have a problem.

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yup, just slightly below halfway is the normal position... if the needle moves above that, you need to figure out why.

best way to fill a Subaru cooling system that has been drained...

1. raise the front up
2. fill block thru the upper radiator hose
3. attach hose to radiator
4. fill radiator
5. check and adjust overflow level as needed.
6. seal it all up and run to operating temp (with front still raised)
7. let it cool completely, check radiator and overflow levels, top up if needed.

you should be good to go at this point, but it should be monitored for a week or two after to make sure levels remain consistent.

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Well I am pretty sure I have all the air out of it by now.  It sat overnight with that funnel on it and I just ran it for a half hour or so in the garage and no more bubbles, even when I rev it.  I can't get the temp gauge to go above the mid level sitting in the garage so I'm going to put it all back together and start driving it.

I guess one thing that confuses me is that I have owned and driven this car since 2007 when it had 57K on it.  I put 250K miles on it over 15 years.  I have had plenty of opportunites to remove and replace the coolant over that period.  I knew about getting the air out but all I ever did was fill it up, drive it, and check it again later.  I never worried about meticulously making sure I got every breath of air out of it before.

I also still can't get that back up fan or sub fan or whatever it's called to come on, which was the original point of my post I guess.  I still don't understand when it's supposed to come on.

Now, when the gauge gets to about half way between C and H, the right side fan comes on.  Seems normal.  Is the left side fan only supposed to come on when the air conditioner is being used?  What is supposed to trigger it seperately from that which triggers the right side fan? 

I'm thinking I have seen the left side fan on before but TBH I'm not completely sure I have.  I verified that the fan works by disconnecting it and powering it up with a battery charger and a couple of nails and I checked all the fuses.  At least I think I have.

Again, thanks for all the replies.  Much appreciated!

Edited by jeffroid
clarity
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Cooling fan speed and duty cycling depend on cooling demand. If your car is overheating both fans will run max speed. These fans have a number of ways they can die. Locked rotor, bearings, interference with the shroud, etc. Aftermarket fans tend to run larger footprint and fitment can be tricky but work well otherwise.

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Thanks everyone.  I have been driving it around a while now.  The temp gauge has not risen above the middle and I don't seem to be loosing any coolant.  I am still trying to figure out why the LH (driver side) fan won't come on.  Recall please that I have tested the fan on the vehicle by disconnecting the fan and applying power to the connector pins on the fan side with a battery charger.  The fan comes on and runs fine.  Recall also that the LH fan does not come on with the green test connectors hooked up.

I'll take a look at those wiring diagrams,  at first glance it looks like it's going to take me quite a while to figure out what's going on and how to troubleshoot where the problem is.  Thanks a lot for the link, but I believe I already had the PDF files for my car.  

Again, thanks as always.

Edited by jeffroid
Mistakes
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