stylEmon

iTrader: (2)

great write, and great execution!
+1 for archive

connors14

iTrader: (2)

so does that audi/vw relay have another thermostatic switch that its connected too.

cause it says vw thermostatic switch below the audi relay in the diagram


*nvm i didnt relize that switch was 3 wire*

and how much did this all cost you?

and instead of the greddy buddy club makes a adapter thats cheaper...

clokker

iTrader: (2)

Excluding the rad hose adaptor (which I bought new for @$25), the Taurus fan/fuse, the Volvo relay, the Nissan relay and the Audi switch cost me $25. I snagged enough associated wiring with these that I didn't need any more.

I spent another $18 on a 22mm tap for the thermoswitch and a few bucks for consumables (heat shrink, solder, etc.).

Of course, YMMV.
I have an excellent relationship with my junkyard (they know me by name) and their pricing is cheap.

Rob XX 7

iTrader: (8)

for those who dont have good junk yards near them there is a guy who sells a new set up on ebay, looks like a pretty good deal and set up.

The kit contains two 60 amp relays and one 30 amp relay, one 50 amp J case fuse with water resistant fuse holder, one 180* temp sensor, various connectors, shrink tubing and installation instructions. The Beuler relays can handle 150 amp surges and a 60 amp constant induction load which is well below the Mark VIII fans requirements.



http://cgi.ebay.com/ebaymotors/Tauru...Q5fAccessories

RX-7tII88

iTrader: (1)

So I went to the junkyard today, and I think I found everything I need for this. I have some
questions though as I don't know much about electrical.


I found the plug sugested from a VW. I grabbed the whole sensor and it looks to be the one
mentioned. Is it? Or what temps is it set at? Can it be used?


I nabbed some relays just like this. Is it sufficient? I have a bunch of different 12V ones.

papiogxl

iTrader: (6)

Good write up. I might do this to my car when I start working on it again.

clokker

iTrader: (2)

Only way to tell is by testing.
Suspend the unit in a pan of water on a stove, apply heat and check when the "+" pin has continuity with pin #1 and pin #2.

No way to tell just from the picture.
Either google the specs using the info on the piece or track it down by make/model/location.

Many OEM relays are difficult to spec out- especially when pulling from a junkyard.
I have noticed though that you can estimate the relay's amp rating by looking at the associated wiring.
If they ran 10 ga. wire to the relay, you can be pretty sure the manufacturer put in a relay beefy enough to handle the load.

OK, pretty unscientific, I admit it.

New relays (of known spec) are relatively cheap brand new...maybe save the guesswork and just buy new.

Rob XX 7

iTrader: (8)

I bought a 70amp relay kit, with socket and .250 and .375 terminals for $16 brand new. Im only going to wire high speed though, I see very little need for the low speed setting. I also got the harness end of the fan connector new for $9 as well, it comes with 10 gauge wiring, nice unit.

juice22

iTrader: (4)

nice write up. I went looking for sable/taurus fans today. There were a ton but the plastic was either broken or they were rusted. I think I might spend the $70 to get a new one on ebay rather than use a 15 year old fan.

I did pick up 2 like new volvo relays and 4 thermoswitches for $10. The other parts will probably have to wait until next weekend.

clokker

iTrader: (2)

I know what you mean by the broken plastic problem.
My favorite yard pulls all the radiators (I assume for recycling) and the guys who do it just rip the fans off to get to the rad.

My particular fan was one of my best junkyard scores...it was brand new- still in factory packaging- found in the trunk of a car.
Obviously purchased and then forgotten before install, I just totally lucked out.

Rob XX 7

iTrader: (8)

I have a local yard I stopped by and they have a barrel of fans all jacked up, he said someone buys the cores from him.

Im going to give the Taurus set up a shot, but I got all new stuff, looks like I made out under $100 with a new fan, plug, and 70 amp relay kit.

clokker

iTrader: (2)

Probably going for the copper in the motor windings.

For a period last year my yard was cutting out all the wiring harnesses- at least the easy , big parts- because the cost of copper had risen so high.
Now that copper is again (relatively) cheap, they've stopped this abominable practice.

Rob XX 7

iTrader: (8)

this place wont touch a harness, he says he cant cut plugs off because people want the entire harness intact

clokker

iTrader: (2)

Followup/update:

The cooling system worked flawlessly through the summer.
Admittedly, Denver doesn't have the brutal heat some of you are exposed to but my temp gauge never exceeded 195° (which is where the low speed trigger kicks in) and the high speed setting never activated at all.

That said, last week I ran into trouble that exposed a weakness, not with the hardware itself but with my installation.

For no apparent reason- independent of speed or load- temps started to swing up and down erratically. Fortunately, I was able to get home with only a few stops for cooldown and temps never breached 210° but I was nonetheless pretty freaked.

After thinking about the symptoms I decided that the most likely culprit had to be the thermostat, which I replaced and the problem went away.
Good for me.

The real issue though was that when the temp was spiking, the fan never came on.
I realized that this failure was due to my placement of the thermoswitch in the upper radiator hose, downstream of the thermostat.
Since the thermostat was sticking closed, the switch never saw the elevated temps and didn't save the day.
This was definitely my fault, not the switch's.

So, what to do now?
I've come up with a few options but haven't decided which to implement.

-The least destructive, yet least elegant, solution would be to splice a "failsafe" manual switch between the Volvo relay assembly and the Audi dual point thermoswitch. A simple toggle in the cabin that provided an alternative ground point for the low speed circuit would have allowed the fan to activate regardless of the thermostat fooling the thermoswitch and gotten me home safely.

-Figure out a way to plumb the 22mm Audi thermoswitch into the cooling loop before the thermostat.
This would be ideal but difficult to implement as the switch is physically rather large and can't fit into the traditional locations. This would be my preferred solution but I may just be clinging to a part that's not going to work out and should be discarded.

-Split the thermo trigger function into two separate and smaller switches.
Low speed could be plumbed into the standard location in the waterpump housing and high speed could go somewhere else (in the radiator or even back into the upper hose).
Maybe the most logical and effective solution...especially if starting from scratch.
This also has the advantage of allowing for greater scope in trigger temps...the two could be changed independently and activating temps fine-tuned as desired.



Somewhat later...
After all this pondering and now, all this writing, it occurs to me that I may be making a mountain from a molehill.
If the thermostat is going to stick closed, will a working fan make any difference?
If cooled water in the rad isn't going to be allowed to circulate, does the fan matter?

Seems like a faulty thermostat is just one of those failures that can't be mitigated...you fix it or you're dead in the water, nothing short of replacement is effective.

Oh well, nevermind.

jackhild59

iTrader: (7)

Bingo!

Rob XX 7

iTrader: (8)

however- drilling a small hole in the thermostat when you install it and having your fans able to come on might allow you to limp home and save your engine

clokker

iTrader: (2)

Isn't that essentially what the jiggle pin is?

jackhild59

iTrader: (7)

I actually drilled another hole beside my jiggle pin for that exact reason. 7/32".

jackhild59

iTrader: (7)

Hey Steve!

I just picked one of these up last night at my local PNP.

Regarding this setup: do you know if the VW thermoswitch provides mutual exclusion for the two relay circuits or does the volvo switch accomplish this task? IOW does the volvo unit have lockout designed in to prevent both low and high speed from operating simultaneously or does the VW switch provide the lockout?

Thanks

clokker

iTrader: (2)

See your PM.
The switching function is handled by the Volvo relay.

no_luck

iTrader: (3)

you kno.. i got the taurus fan from like a 94-95 i think it got the 3 wires...anyway
i have it on a switch and just have the hi on... if i really get on it the temp goes past 180 into the 190s and i back off. is it a possibility i got the wrong fan? or my fan is just beat

clokker

iTrader: (2)

Your fan is probably fine, you're just expecting it to fight with the thermostat, which isn't fully open till the low 190's.
I've got my low speed triggered at 194°, high at 205°.

You still have a stock radiator?

no_luck

iTrader: (3)

yes... i thought operating temp was at 180 for a s4.?

jackhild59

iTrader: (7)

Factory thermostat starts opening at 182*f; it is not fully open until 203*f, per the FSM specs.

Those guys expecting the car to stay 180*f are just fooling themselves if they don't believe it.

solareon

iTrader: (1)

just to add to this thread. I ordered a radiator hose adapter and GM water temp switch that switches on at 200 and off at 190. I also have the push in radiator probe thing. I will be wiring the gm water temp to the low and the radiator probe to the high on the fan.

I had planned on using the VW switch but couldn't find a decent place to mount it and didn't want to buy the tap.