Cooling fan not kicking on

[86-lxi]

Ok so for some reason my cooling fan isn't kicking on now when I'm driving, I checked the fuzes and they're all good, my car almost overheated on my way home from b-fast this morning:omg:

When I went under the hood to check everything it kicked on then? Yet while the car is running it won't, what could the problem be?

[stephensimmons]

are you full of coolant?

[86-lxi]

are you full of coolant?

Yeah, just filled up my overflow....haven't checked under the cap in a few weeks though. I'll check that.:idea:

[charliekuney]

You shouldn't fill up your overflow. That's what it's for: overflows.

[stat1K]

^ you SHOULD fill it up to the min line, as per the manual for your vehicle.

[charliekuney]

Isn't the overflow for when the coolant...overflows? Wouldn't you want lots of space?

[86-lxi]

You shouldn't fill up your overflow. That's what it's for: overflows.

"put some in" sorry, it was empty

[LX-incredible]

With KOEO, unplug the fan switch on the bottom of the radiator and use a paper clip or piece of wire to jump the pins on the connector. Both fans should come on. If they don't, check the cooling fan relays, fan control module, and the fans. If they come on, the fan switch or thermostat is likely at fault

The fan control module is under the passengers seat. It's black and on the left side. Remove the 10 mm bolt and unplug. Pry off the cover and check for burnt diodes. There's 3 in a row that love to fry. Replace with a standard 1A diode from radio shack. Be absolutely sure that it gets installed in the same position (stripe on one end).

[w261w261]

Here's the function of the overflow tank. When the engine stops, the coolant next to the block boils and increases the pressure in the system. When the pressure reaches the psi on the radiator cap, the cap opens and relieves the pressure by allowing coolant to flow into the overflow tank. As the car cools, the coolant is siphoned back into the system through a check valve in the cap.

If the system is leaking, you won't know about it until the level in the coolant bottle drops until there is no coolant to make up the leak. Then it will suck in some air, and if you have a f.i. car, you might notice the idle jumping around. This is because the idle stabilizer valve is looking at an air bubble and reacting accordingly.

The moral of the story is always keep an eye on the level of the coolant in the bottle. This is hard to do if the bottle is crudded up on the inside. The solution is to take out the battery, the battery mounting bracket and finally the bottle. Go to KMart or Walmart, and get some "Must for Rust" or pool tile cleaning solution...anything with phosphoric acid in it. Get a bottle brush and clean out the bottle (the phosphoric acid will get rid of the rust on the inside), reinstall. Now you can actually see the level of coolant IF YOU USE A COOLANT THAT IS GREEN, like Peak. Don't use one of the yellow colored ones, they're too hard to see.

If the coolant gets low, and you have to refill, do a search and see how to bleed the system. You must do this.

And finally, fluid monitoring is JOB #1 in an old car. How people can blissfully ignore something that can at a minimum inconvenience them or at a maximum ruin their motor has always had me shakin' my head.

[86-lxi]

Well that was my problem....low coolant, I must have a small leak somewhere I "filled" the overflow tank not too long and it was totally empty when I "filled" it the other day.

And I know what the overflow tank is used for....but it should never be EMPTY.

[charliekuney]

^ So, if mine on all four of my coupes were always empty...that's bad? O_o

[nfs480]

Lately i've noticed that on my se-i the overflow is always at the max mark and yet the radiator won't be full, i've bled the air from the system several times and replaced the radiator cap but for some reason it won't suck the coolant back in from the overflow, any suggestions?

[rc00netzero]

When you remove the cap from the overflow tank - there should be a short hose that goes to the bottom of the tank. If it is missing (look in the tank - it may have come off) or has a hole in it, that would cause that. Also a hole anywhere in the hose to the tank, or a leaking radiator cap (or upper tank) could cause this behavior. A small hole might only show a small coolant leak, but can let in enough air during cooling to prevent coolant return from the overflow.

[rc00netzero]

86-lxi If you haven't done it yet, it may be time to replace the small coolant hoses under the intake manifold that run to the throttle body and Fast idle control valve. They are pain. but do-able. O'Reillys carried some of them when I did mine.

[86-lxi]

86-lxi If you haven't done it yet, it may be time to replace the small coolant hoses under the intake manifold that run to the throttle body and Fast idle control valve. They are pain. but do-able. O'Reillys carried some of them when I did mine.

Ok thanks, i'll look into it.

[skong]

i had a bad wire at the fan switch. repaired it and all fans came on