TBI305Camaro

ok how cool can i keep my car before the ECM goes nuts? right now it stays at the 160 degree mark...i have a 180 thermo, new water pump, radiator, hoses so its stays pretty cool. my fan switch broke so i actually have a toggle switch now to control the fan its a pain in the *** and i want to get a hypertech cool fan switch...i plan on switching to carb later in the summer when i switch motors (lo5 so i may stay TBI im still not sure but if i go carb i dont have to worry about the comp)anyways should i get the one that cuts on at 176 and off at 166 or the one that cuts on at 200 and off at 185...id like to keep the car as cool as possible. soon as it warms up alittle bit i wanna run water wetter and water so it stays real cool.

TKD89RS

im my 89 rs i had a 180 thermo and the hypertech 160 fan switch. i liked it. temp on the freeway stayed at the 1/4 mark and a long city drive it was still below the half mark. with this temp i say a lot of more power. when the tbi engines get too hot, like at factory specs it loses a lot of power.

TBI305Camaro

I ended up with the fan switch that turns on at 180 degrees. The fan is almost always on. My guage says 160 but I think its more like 180 I dont think any of my gauges are right. Anyways its working well seems to help alot. The connector going into my switch was completely broken except for the little metal needle sticking out which i just stuck it into the switch. The fan switch came with a new part of the harness but my wiring harness didnt have the hookup for it. Oh well.

camaronewbie

Where are you getting these fan switches from? Are we talking about the gizmo that looks like a sensor and is on the block, pass side, just above the knock sensor?

I ask b/c I have a cooling fan problem I can't resolve in my 90 RS LO3. Fan works if I straight wire it, and it works when I ground the green/white wire at relay, and it works when I ground wire at this switch, but it doesn't work on it's own behalf. I've replaced temp sensor (on top by thermostat), fan switch (on pass side block above knock sensor), cooling fan relay (firewall next to fuel pump relay), and still no luck getting fan to come on when it gets hot.

You mention Hypertech - same as the chip people? I don't see anything on their website about switches, just thermostats and chips. Do they not have everything on their site, or am I at the wrong spot?

Any help with tis cooling problem would be greatly appreciated!

JPrevost

If you've got a 180 or 190 thermo go with the GN fan switch.
I'm cheap so I just got the local carparts adjustable fan switch for $20 and it comes on at 190 and off at 175. BTW, I've got a 180 thermo, mild 350 and still am using the single fan stock radiator setup.

TBI305Camaro

You mean to tell me I could have gotten a Grand National Switch that would have did the same thing but for much cheaper? Damn.
Newbie the fan switch is on the pass side head right near the spark plugs. Your fan switch may be broken or just messed up and not turning the fan on.

92blue

iTrader: (1)

I thought I had a problem with my fan, but its fine. The only thing was I never realized it was meant to come on at 238 degrees, and so I never let the car get that hot. I'm definitely going to replace the fan switch with a colder temp one.

TBI305Camaro

Yeah it will help alot. Get rid of the 195 degree thermo to. I dont know why GM wanted our cars to run so hot. Isnt 210 degrees F boiling?

Keith5

It's not boiling at the pressure it's at in the cooling system. Plus the antifreeze raises the boiling point.

Be careful when getting the GN switch. I tried it at my parts store and they had it listed as the same part no. as the fbody switch.

JPrevost

Good point!

TKD89RS

i forget the correct formula but its like for every pound of pressure the boiling point is raised like 10 degrees. and the boiling point of water is 212. with antifreeze it rises.

camaronewbie

OK...

I got the Hypertech switch ... the one that cuts on at 200. My fan runs almost always, temp guage says 160 but I learned that it is wrong by about 25 degrees. So NOTE: Guages are highly possible to be inaccurate!

I checked with a candy thermometer - ran car with rad cap off, measured temp of inflowing water at top of rad ... was 190 when fan came on - I think it's safe to assume that 10 degrees was lost between block where new Hypertech switch was installed and the top of rad. I also quickly yanked housing and checked temp at thermostat - 185 degrees there - and thermo was open (I know cause hot water came up through it when I pulled housing off (I have a 180 thermo).

So - my conclusions -

1)Hypertech fan switch works, how it's suppose to, and when it's suppose to.
2)Autozone switches, sensors, etc are crap!
3)Guages in dash are innaccurate - don't trust them - want to know temps, get a reading of the fluid itself with something accurate.
4) My almost always on fan? Hypertech switch does cut it off when cools enough - problem is it just doesn't cool enough in my RS when parked in idle. I checked by turning car off, waiting for cool down, and turning key back on - no fan. If I turn key off and back on while still warm, fan comes on - so switch does work.

Finally I'm satisfied! I spent 2 months of aggravation, grounded so many wires under the hood I have a test light permanently embedded between my fingers, expended way too much energy on developing new curse words, and wasted $70 on switches/sensors/relays from Autozone/Advance.

Food for thought for anyone that might have cooling fan troubles - wait for the shipping times and get the good stuff!

Thanks for the help all have provided