JunJun

I'm planning to replace a cooling fan switch.
I understand if I take out the switch from the engine block, the coolant will come out.
Is it possible to replace the switch without draining the coolant?
Or should I drain the coolant beforehand?

eseibel67

The switch is in the cylinder head in-between cyl #6 & #8. No need to drain coolant. Unless it's due.


Get the new switch ready to stick in the hole the moment the old one comes out. Coolant loss will be minimal, if you are fast enough you probably won't even have to top up the overflow bottle. just rinse the starter and whatever else with water after you get the new switch in. The trick here is to leave the rad cap on when you are doing it, if the cap is off the coolant will shoot out with more force.

TTOP350

iTrader: (8)

I just did this 2 weeks ago. I pulled out the switch and waited till coolant stopped coming out b4 installing the new one. Then just topped off the coolant/water, wasn't much 1/2-1 gallon?
Also nice to have a catch tray under the car.

JunJun

Thank you, guys.
I'm gonna try without draining the coolant because it's not due yet.
I'll replace the switch as quickly as I can.

dmccain

iTrader: (2)

I really want to swap my switch out also I hate the idea of a fan not switching on til like 230 degrees. In stop and go traffic I run with the a/c to keep both fans turning I don't like it getting over 220. Putting in the 160 thermostat helped my car a lot also.

midias

You should do it then

Keoman

iTrader: (3)

this is a nice link i picked up on this site a while ago
may help you
http://www.wellsve.com/showall_ds_fans.php

Thornburg

Howdy everyone, so I have searched everywhere on my 1985 5.0L PASSANGER side and I can not see or feel anything, looked from the top down and from he bottom up. I found the knock sensor(blue wire) but when I look between #6 and #8 there is nothing. Will some please please please take a picture of the location on theirs for reference???

TTOP350

iTrader: (8)

If you have a single fan, you may not have the secondary fan switch.

Keoman

iTrader: (3)

^^
True that

This is where It would be (for reference)
if its not there, there should be a plug of some sort.

Thornburg

Thanks for the info and the picture, defiantly worth 1000 words!!! So with my single fan, does the signal to the relay come from the ECM? The problem is the fan always runs When the engine is on, unplug the relay and fan stops.

Ron U.S.M.C.

Unplug the "fan switch" in the head when the car is cold and the fan is running.
If the fan stops then the switch is bad and has a constant ground.
Its only supposed to ground when the car reaches the switch "on" temperature.

If that's the case , its a easy fix.

Thornburg

That's the problem Ron I can not see or feel any kind of switch or boss or anything between Cyl-6 & Cyl-8. This is why I was wondering if the switch was up on top near the throttle body. I do have AC and the A.I.R system is still hooked up. I can not even follow the green wire from the relay back to the block so that is no help. I might have to pull all the wires out of the harnes...

TTOP350

iTrader: (8)

If you have a single fan, you may not have the wiring or switch at all.