Radiator Fan Question

Chris01gtp

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Hey guys posted this on gpf and never got any help so I figured maybe one of you guys would know. So my car's been overheating a little. When i'm idling, the car will just get warmer and warmer. Once I start driving the car cools down quickly. The drivers side fan seems to be working great. However, the passenger fan seemed to be slow. So i pulled the passenger side and replaced it with another spare I had laying around. Started the car up cold, turned the a/c on and both fans were blowing hard. So i thought the problem was fixed. Fast forward a couple days, now the car is starting to over heat again. I then found this out... I switched relay 2 with relay 3. The passenger fan will work when idling but it seems weak. I then will turn the a/c on. The passenger side fan shuts off. Then I'll turn off the a/c, and the fan will turn on, but it won't be blowing as much air as the driver's side. The coolant temp while doing this was at 206. I then drove home and it did fine since traffic was minimal. When I got home, i parked it and let it idle. It went up to 215, and the passenger side would be going slower than the drivers side. The car has an overkill PCM that Is set for a 185 Tstat, which is what's in there.


Thanks
 

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Is the radiator clean in front?

Is the coolant level okay?

Sometimes with those cooler t-stats the cars cooling system can become heat soaked.

You *could* potentially need a new water pump as well.

The passenger side fan should come on as soon as the AC is on. It also will come on full blast once the car starts to overheat. I can't remember the parameters, but I want to say it's around 225°.
 

SaturdaysGS

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I had a bad ground (this is on an 04 ymmv) under the passenger side headlight that caused the fans to not work right and the car to want to overheat. Also my horn didn't work and the headlights were weak.
 

Turbocharged400sbc

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also check the loom across the top of the radiator/core support, ive seen 2 cars with odd fan control issues as fan relay wires get rubbed through as someone leaves off the harness shields during a radiator/ac condenser service/replacement.

its a 3 way system with the relays set to have the single fan under most conditions, then switch to both fans in series (both at half power) and both in parallel (both full power/current) under ac/overheating request.

diagnostics is fun but not too bad, pop the covers off for easier testing, snag relays from newer model year at Jyard, if the one fan was nearly dead and drawing excess current it'll kill the contacts and present voltage drop to a good fan
 

Chris01gtp

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Hey guys, thanks for the response. Went and grabbed some relays at the junk yard today. Threw them on and then kept the hood open with the ac on. Just the driver's side was on. I also drove home with the ac on and kept an eye on the temps, temps were fine today, was a cool day tho. This really only happens in traffic under high heat.Will have to wait for a hotter day to see if the high speed works.
 

jdredd

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Pop the wiring harness for fan apart? I was having all kinds of goofy problems with
the fans recently... one fan... two fans.. no fans... ect.

 

Chris01gtp

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I'll have to look into it. My low coolant light came on today for like 5 seconds.
 

bikrboy128

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so...silly question but is the radiator (not the reservoir) full? if the coolant is a little bit low it can cause temps to rise at idle.

but. if the coolant level in the radiator is full, but the low coolant light is coming on chances are you have some dexcrap sludge creating a blockage somewhere (that sludge eventually makes it's way to the coolant level sensor and confuses it).
 

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Chris01gtp

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Hey guys, sorry i haven't gotten back to you. So I just found out I can control my fans on my aeroforces. So, on low both fans blow good, but once I set it to high, the drivers side blows hard and the passenger side almost shuts itself off. I'm thinking fans?
 

SaturdaysGS

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Hey guys, sorry i haven't gotten back to you. So I just found out I can control my fans on my aeroforces. So, on low both fans blow good, but once I set it to high, the drivers side blows hard and the passenger side almost shuts itself off. I'm thinking fans?


I'm thinking grounding issue. Note my post up above.

Low speed they were fine but to go into high I was having a similar issue where one was running and the other was basically off.
 

SaturdaysGS

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Check the connector to see if it's damaged, also not sure how they ground on the earlier cars but on mine there is two ground wires bolted to each side of the bumper support brace, underneath the headlights. May need to remove them and clean them up if they're rusty or crusty.
 

Chris01gtp

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I've checked the connector. That all looks good but I'll have to check the ground later. I'm going to try and drive home from work with the fans on low the whole time since both are spinning. I'll see if that helps at all.
 

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