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Radiator Fan Fuse blown after overheated and HG job was done, fans run when tested...


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I'm still trying to get my '97 Legacy GT to run properly after a Head Gasket job... The radiator fans would not come on, so I checked the fuse and it is blown. Replaced and still they don't come on and the fuse seems to be getting hot. Is it commen for a relay to blow? Not sure where to go from here. Does anyone have any idea what it could be. I'll have to check the coolant temp. sensor perhaps? Thanks

Edited by 86GLScooby
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Well, truth be told and I was hesitant that this could be the problem, but a critter got to the wires that runs along the bottom of the radiator. Only one wire was bare, close to where the fan plugs in. As a test, I mended the wire with another wire to see if that changes anything and still no fan. How should I join the wire back, get the proper wiring and solder? Do the fans have fuses in them? Thanks

Edited by 86GLScooby
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To replace the damaged section, I'd use wire of the same gauge, soldered, and heat-shrinkable tubing to insulate the splices.

 

What color is the insulation of the damaged wire? (It might give us a clue as to what happened.)

 

Do you have a voltmeter, and know how to use it? If so, I can go into detail on how to troubleshoot the problem.

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The wire is black and it was one of the top wires looking down into the engine. I do have access to a volt meter, but haven't had a reason to really learn how to use it. I'll do some research so I know what you are talking about if would like to discuss how to check it. I do have the Haynes manual and did see instructions that included using a volt meter... Thanks

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Well, truth be told and I was hesitant that this could be the problem, but a critter got to the wires that runs along the bottom of the radiator. Only one wire was bare, close to where the fan plugs in. As a test, I mended the wire with another wire to see if that changes anything and still no fan. How should I join the wire back, get the proper wiring and solder? Do the fans have fuses in them? Thanks

 

Since you had a critter chew on the wire, look at all wiring to see if there is added chewing elsewhere that is part of your problem. You may want to run a test wire directly to the fans from the battery to see if the fan motors run properly. I don't think the fans have fuses in them. That is the responsibility of the fuse that you found blown.

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They discharged the A/C system to do the HG's? That was a waste of time and money. You are going to pay thru the nose for a recharge of the system and the compressor could have been laid over to the side to get it out of the way. If you went to a shop, I would tell them to recharge the system for free, since it didn't have to be discharged in the first place.

 

As for the fans, I agree, look at the entire loom under the rad and see if any other wires are damaged. critters aren't usually very discerning and they often get several wires. I had it happen in my daughter's car. What a mess the little rodent made.

 

Good luck

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If a careful visual inspection doesn't turn up the cause of the problem, we can start troubleshooting with a basic check. Look under the dash near the accelerator pedal, and find the two green test mode electrical connectors. Couple them together. Turn the ignition switch ON. This should cause several things to cycle off and on, including the fans. Let us know what happens.

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I finally had a chance to get to my car and connected the green test connectors. The radiator and ac fan comes on in a sequence and it ran for maybe 8 cycles and I decided to turn it off. Check engine light flashes. Please help, thanks.

Edited by 86GLScooby
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That rules out most wiring related problems for the fans. The secondary fan will not turn on with the AC switch if the AC is un-operational.

 

Fuse getting hot sounds strange. That would indicate that there is a load on the circuit. The fan obviously works, so maybe there is a very small high resistance short somewhere along the line.

 

You're trying to get the fan to cycle while idling the engine correct? Are you testing with the hood open or shut, and what is the ambient air temp when testing?

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Yes, I'm trying to get the fan to come on while idling. When tested with the hood open at 75 celsius the fans do not come on. I ran it till the engine heat gauge reached half way, some smoke appears in the area of the bottom valve cover bolts and I turn it off. I would assume the fans should come on before that happens and the smoke was some off-gassing and overheating...

 

Would the wire repair I did cause the fans not to come on even though they work electronicly? I haven't soldered the wire.

 

Thanks

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Yes, I'm trying to get the fan to come on while idling. When tested with the hood open at 75 celsius the fans do not come on.

75 deg C = 167 deg F. What is that the temperature of? Did you mean 75 F?

 

Having the hood open might not allow the temperature to get sufficiently high for the fan(s) to come on, especially if you're not waiting long enough.

 

 

I ran it till the engine heat gauge reached half way, some smoke appears in the area of the bottom valve cover bolts and I turn it off. I would assume the fans should come on before that happens and the smoke was some off-gassing and overheating...

The gauge reading about half of scale is normal, and the fans might not come on at that point. The smoke could just be burn-off of oil (etc?) from the work that was done.

 

 

Would the wire repair I did cause the fans not to come on even though they work electronicly? I haven't soldered the wire.

If the fans ran with the test connectors coupled, they're probably okay.

 

Are you sure that the fuse is getting warm?

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Smoke is normal after major engine service. It's oil and whatever else got spilled on the engine in the process getting burned off. I consider it the (bitter) sweet smell of success because it's running. :banana:

75°C engine coolant temp is still "cold". Normal warm engine operating temp is in the 190-200°F range. (about 85 - 90°C) The fan will not come on until the coolant temp reaches ~ 210°F, 95°C.

 

If outside air temp is 75°F there may be enough cooling effect due simply to heat radiation to prevent the engine from reaching the magical 210° temp needed for the fan to come on. Let the engine warm up with the hood closed. It will also help to hold engine speed around 1500 rpm rather than letting it remain at idle.

 

edit: FSM says fan, with AC off, should cut on at 203°F, which is 94.9 °C

I did my conversions wrong.

Edited by Fairtax4me
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Yeah, I meant 75 F, not celcius... So you think I should run the engine longer to see if the fans come on? It was pretty hot, the top radiator hose was hot. I'll give it a try with the hood closed later today after it heats up a little, I'm in FL. But I might suspect something wrong due to the blown fuse, would a faulty coolant temp. sensor or sender cause the fuse to blow? Also, the ac fan doesn't come on when I turn it on, but this could be because it's not charged?

 

Thanks

Edited by 86GLScooby
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You aren't running it long enough - takes 15 to 20 minutes for the fans to come on at idle with the hood open.

 

The vapor from the engine is from the work performed - pretty common with a head gasket job. Nothing to worry about.

 

Watch the gauge - if it climbs *above* half shut it down. They will run at 1/2 on the guage all the time since it's a dummy gauge. Fans don't come on till you reach the set-point in the ECU for that to happen and first the engine has to reach operating temp, then the thermostat opens, and only after the engine drinks up all the cold coolant from the radiator and can't get anymore cooling from it..... only THEN will the temp rise above the setpoint of the ECU and kick the fans on. As I said - 15 minutes is not uncommon.

 

GD

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Ran the engine at 1500 rpm for 20 min with the hood closed and fan came on. Gauge didn't go past half way mark so I decided to drive it around, went to town and back... 20 min at 45 mph to 60 mph. Seems to be good, fan wasn't running when I parked the car. Fuse is still good.

 

It sounds good, I need new belts though, so there's extra noise. I'll change them out soon.

 

I guess I wasn't sure when the fan should come on and didn't run it long enough, the smoke freaked me out to be honest. It's a sweet smelling smoke. But that seems to be gone now.

 

Success? Perhaps.

Thanks for the help, I feel more confident driving my subaru again and look forward to doing some more work on her. First time head gasket job and it took me about 6 weeks to complete all in all.

 

Do you recommend that seafoam stuff to clean the engine with? How do you clean the pistons?

Edited by 86GLScooby
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Ran the engine at 1500 rpm for 20 min with the hood closed and fan came on. Gauge didn't go past half way mark so I decided to drive it around, went to town and back... 20 min at 45 mph to 60 mph. Seems to be good, fan wasn't running when I parked the car. Fuse is still good.

Congrats! :clap: It would probably be a good idea to make the fan wiring repair permanent now.

 

 

[...] the smoke freaked me out to be honest. It's a sweet smelling smoke. But that seems to be gone now.

Hot antifreeze typically has that kind of aroma. It's nothing to be concerned about if it doesn't return.

 

It would be a good idea to keep tabs on the coolant level for a while, just to make sure that if there were any air pockets to fill, the level doesn't drop too much.

 

 

Do you recommend that seafoam stuff to clean the engine with? How do you clean the pistons?

Why do you think the pistons (etc.) need cleaning?

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Yeah, I'll keep a close eye on the coolant since I didn't get a new radiator nor got the other one cleaned.

 

As for the pistons, I've always felt my subaru doesn't have much kick and wonder what the problem is... I don't know, thought I would take some extra steps in cleaning what I can.

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