Dany89

I want my engine to run cooler, i found these fan switches Hypertech part#4028 & 4026 and a JET part# 60600 at summit racing. Which would be best if I have the stock H20 pump, 180 thermostat, stock radiator. basically the whole engine is stock
http://www.summitracing.com/parts/HYP-4028/
http://www.summitracing.com/parts/HYP-4026/
http://www.summitracing.com/parts/JET-60600/

deadbird

Run an Autozone SW505 fan switch for $9, on temp is 215°

Dany89

I looked it up (SW505) online but it said that it doesn't fit my car???

KNBlazer

you're probably better off grounding the fan and getting yourself a 180 degree thermostat..., but I've ran the Hypertech fan switch, had to RMA one and get a replacement, however it still didn't work right, not sure why though...

skinny z

I'm going through this process for my fresh 353 in an 86 Sport Coupe.
A couple of things to consider.
Ideal engine oil temperature is about 220f (arguably).
Engine oil is typically 20-30 degrees hotter than the coolant temp (also arguable).
Ideally, at highway speeds the rad should cool the engine to the point of the t-stat opening. A 180 stat (with a sufficient sized rad) should have engine temps in the 180 range (often just slightly hotter). Add 30 degrees to the 180 and you have 210 degree oil temp.
For the fan/cooling system to work properly, the coolant switch should close a number of degrees (10 -15) after the stat opens and open just before the stat temp rating.
With a 180 stat, the Hypertech 4028 is just about ideally suited. Fan on at 200. Fan off at 185.
The general thinking is that you don't need the fan to be running when on the highway. Using the Hypretech 4026 (176 on/ 166 off) will ask the fan to cool the engine BELOW the stat opening temperature. A situation you don't need need or want.
Keep in mind these specs apply nicely to my non computer carbed application. Those with ECM's may have different parameters to work with.

Reid Fleming

iTrader: (2)

Pretty much describes my car perfectly. 180° thermostat and Hypertech 4028 fan switch (200/185°)

Since the fans are automatically off above 40 mph anyways, the only time the fan switch does anything is below 40 mph. Now if a person has a Hypertech 4026 (176/166°) fan switch even with a 160° thermostat, the car will never get to 165° or cooler while at the same time being below 40 mph. It just won't happen unless you're driving outside in freezing weather. So the end result is that once the fans turn on at slow moving speeds, they will never shut off. A waste as far as I'm concerned. Wear and tear, less volts available, worse gas mileage, worse emissions.

If you were driving in freezing weather, you still wouldn't want the 176/166 fan switch because

a) If you have a 160° thermostat, the car will be too cold to get any comfortable heat out of the heater.

b) If you have a 180° thermostat, the fans will be on forever even though they're completely not needed. The thermostat itself will be barely opening before immediately closing again nevermind the fans.


Looking at things from the hot summertime perspective (south Texas in my case), the fan switch is mostly a moot point during the summertime because the A/C is on 99.9% of the time. Fans are on automatically when the A/C is on......But the 200/185 fan switch still allows the fans to stay on when you turn off the A/C and engine temps are high. Say you get stuck in a traffic jam and the coolant temp hits 230°. The stock fan switch is 235°. So only one fan would be on. With the 200/185 fan switch, you get both fans running until the temps get back to 185. Perfect.

So ultimately, the 200/185 gives the best of all worlds. Works great for heatwave weather. Also allows the coolant to warm up to 200° during the wintertime, thus giving you good heater use, good gas mileage/emissions. During wintertime, the car will feel faster anyways due to cooler denser air (and lower humidity during winter here as well). During cooler weather, once it gets to 200, it will still drop like a rock down to 185. Just gives everything a chance to boil out any moisture.

Dany89

So best choice running engine stock would be the 200/185

UnderCover89TBI

iTrader: (25)

yup that is what i am running, and as far as i know the car isnt overheating lol. gauge works sometimes and somestimes it dont. damn 20 year old cars

84 1LE

iTrader: (9)

Another alternative is the GM switch 3053190.Activates the fan at 190*

Ozz1967

iTrader: (4)

Just a note about the Hypertech Switch. I have one in my car and I'm really not happy with it. IT turns on well before the advertised 200* and never...NEVER shuts off. Even after turning the car off...if there is any residual heat, the fan turns back on when you key the ignition. Even at highway speeds the fan is running. I'm going to be taking it out and replacing it with the 215* switch mentioned above. With the 180* T-stat my car rarely goes over the first tick on the Temp gauge and 215 is well below the factory settings. Also, it will definitely turn off when I'm on the highway. So win-win as far as I'm concerned.

skinny z

Interesting observations.
I'm not entirely happy with the way my switch is working either however the on temp set point seems to be ok. It's the off point that isn't to my liking. I can't blame the switch entirely though. My temp gauge sender is located in the left cylinder head near the front. The fan switch is in the right cylinder head near the back. I would think it's a safe bet that there's several degrees of difference between the two. So much so that the fan switch takes a long time to reach it's off setting.
I intend to remedy the situation and add a few benefits by switching to a Dakota Digital PAC-2700 fan controller. Programable on/off temp settings plus a few other on/off set points for times at the track when I'd like the fan to run with the engine off. Pretty slick.

Ron U.S.M.C.

I run a 16in primary fan with this very simple adjustable thermostat controlled switch and it works perfectly http://www.autozone.com/autozone/par...ier=267187_0_0_
Here's the wiring diagram. It does not get any easier than this.
(Not only is the fan temperature switch adjustable but I also ran a toggle switch inside the car between the fuse holder and ignition switch so I have the ability to turn the fan off before it starts running or when it is already running if I want to.)The controller is just below the washer fluid tank.

TTOP350

iTrader: (8)

180* T-stat uses a 4028 switch
160* T-stat uses a 4026 switch

If you read the right side of the summit page it even recommends the correct T-stat for the fan switch you select.

I run the 160* T-stat and correct 4026 switch in all my cars.

87IROC420

do you need a hypertech chip to run these fan switches .

Ozz1967

iTrader: (4)

No.

The Fan Switch ONLY tells the fan when to turn on and off. Hypertech just makes both the switch and performance chip.

Ozz1967

iTrader: (4)

That's a good remedy, if your factory wiring doesn't work properly. IN my case, I only changed switches because my switch melted from the header heat. I used the Hypertech because I had bought it as a backup years ago and had it lying around. I've found out that I don't like it much because of when it turns "off". Which is never. The temp drops well below the first tick on my gauge but still the fan won't turn off. I'll burn out the motor much faster this way. So I'm going to swap it out.