Can anyone tell me the story about the aftermarket low temp fan switch is the installation of this switch good? bad? or what?
Any comments or experiences with said switch?

Thanks

ChezFiero

Don't be sorry, Stick with the factory thermostat and switch.
Don

While I appreciate your response I am still curious as to the results of low temp install.
I can see the lifespan of the fan motor being greatly reduced.
And I have heard that fuel consumption increases.
Has any one ever used one of these units and if so.....what was your experience?

ChezFiero

i have one in my daily driver . you will lose gas mpg and the fan motor will be running more . i going to go back to stock and just put in a switch to turn on the fan if it starts to get to hot like is grid lock that way you can nip it in the but before it gets bad

The principle behind the low temp fan switch (and low temp thermostat) is to "fool the ECM" (computer) into thinking its a cold day and a cold engine.
This causes it to supply more fuel to the injectors (longer pulse) making the air/fuel ratio richer. All it really does is waste gas.
I would avoid both.
No colder that 180 degrees on the 'stat (for HOT climates) and stock fan switch.
Assuming a stock or nearly stock engine.
GM knows best, here.

I have tried several fan switches and the best one I found other than stock was Standard Automotive Part # TS-85. It turned the fan on at 224 and off at 210. Worked real good.
Don

I installed 210 degree fan switches on my 85SE v-6 and my 85GT. I got the switches from Rodney Dickman and they work great. I no longer have to switch on the A/C in stop and go traffic to force the fan to come on and keep the temps from getting above 210.

The fan is designed to run all the time since it comes on whenever the A/C is on. In the South we run A/C for 10 months out of the year. Don't let anyone tell you that it was not designed to run that much.

A lower temp fan switch has nothing to do with the ECM or fuel delivery. It simply switches the fan on at a lower temp. I noticed no difference in performance or mileage on my 160 mile daily commute to work.

I would recommend it highly.

Well
Some conflicting reports regarding the temp switch.
Although I don't want to take sides because I am not certain myself, I have to say that I installed my low temp switch soon after I had my stock 2.8 rebuilt and I did notice an obvious increase in fuel consumption. Of course I kept my original factory switch and I am thinking I should re-install it and see if there is more than any decrease in fuel consumption.

ChezFiero

quote Originally posted by ka4nkf: I have tried several fan switches and the best one I found other than stock was Standard Automotive Part # TS-85. It turned the fan on at 224 and off at 210. Worked real good. Don

The corresponding AC Delco switches for TS-85 are D1852B and D1855B

Usage for D1852B(GM p/n 14043276, list price $13.28):

Year Make Model Engine
1989 CHEVROLET CORVETTE V8 5.7L 350cid GAS FI N Engine VIN = 8
1988 CHEVROLET CORVETTE V8 5.7L 350cid GAS FI N Engine VIN = 8
1987 CHEVROLET CORVETTE V8 5.7L 350cid GAS FI N Engine VIN = 8
1986 CHEVROLET CORVETTE V8 5.7L 350cid GAS FI N Engine VIN = 8
1985 CHEVROLET CORVETTE V8 5.7L 350cid GAS FI N Engine VIN = 8
1983 CHEVROLET CELEBRITY V6 2.8L 173cid GAS CARB N Engine VIN = X
1983 PONTIAC 6000 LE V6 2.8L 173cid GAS CARB N Engine VIN = X
1983 PONTIAC 6000 V6 2.8L 173cid GAS CARB N Engine VIN = X
1983 PONTIAC 6000 STE V6 2.8L 173cid GAS CARB N Engine VIN = Z
1982 CHEVROLET CELEBRITY V6 2.8L 173cid GAS CARB N Engine VIN = X
1982 PONTIAC 6000 LE V6 2.8L 173cid GAS CARB N Engine VIN = X
1982 PONTIAC 6000 V6 2.8L 173cid GAS CARB N Engine VIN = X

Usage for D1855B(GM p/n 14043275, list price is $22.23):

1991 CHEVROLET P30 VAN V6 4.3L 262cid GAS FI N Engine VIN = Z
1991 CHEVROLET P30 VAN V8 5.7L 350cid GAS FI N Engine VIN = K
1991 CHEVROLET P30 VAN V8 6.2L 379cid DIESEL FI N Engine VIN = J
1991 CHEVROLET P30 VAN V8 7.4L 454cid GAS FI N Engine VIN = N
1991 GMC P35/P3500 VAN L4 3.9L 239cid DIESEL FI T Engine VIN = L
1991 GMC P35/P3500 VAN V6 4.3L 262cid GAS FI N Engine VIN = Z
1991 GMC P35/P3500 VAN V8 5.7L 350cid GAS FI N Engine VIN = K
1991 GMC P35/P3500 VAN V8 6.2L 379cid DIESEL FI N Engine VIN = J
1991 GMC P35/P3500 VAN V8 7.4L 454cid GAS FI N Engine VIN = N
1990 CHEVROLET P30 VAN L4 3.9L 239cid DIESEL FI T Engine VIN = L
1990 CHEVROLET P30 VAN V6 4.3L 262cid GAS FI N Engine VIN = Z
1990 CHEVROLET P30 VAN V8 5.7L 350cid GAS FI N Engine VIN = K
1990 CHEVROLET P30 VAN V8 6.2L 379cid DIESEL FI N Engine VIN = J
1990 CHEVROLET P30 VAN V8 7.4L 454cid GAS FI N Engine VIN = N
1990 GMC P35/P3500 VAN L4 3.9L 239cid DIESEL FI T Engine VIN = L
1990 GMC P35/P3500 VAN V6 4.3L 262cid GAS FI N Engine VIN = Z
1990 GMC P35/P3500 VAN V8 5.7L 350cid GAS FI N Engine VIN = K
1990 GMC P35/P3500 VAN V8 6.2L 379cid DIESEL FI N Engine VIN = J
1990 GMC P35/P3500 VAN V8 7.4L 454cid GAS FI N Engine VIN = N
1989 CHEVROLET P30 VAN L4 3.9L 239cid DIESEL FI T Engine VIN = L
1989 CHEVROLET P30 VAN L6 4.8L 292cid GAS CARB N Engine VIN = T
1989 CHEVROLET P30 VAN V8 5.7L 350cid GAS FI N Engine VIN = K
1989 CHEVROLET P30 VAN V8 6.2L 379cid DIESEL FI N Engine VIN = J
1989 CHEVROLET P30 VAN V8 7.4L 454cid GAS CARB N Engine VIN = W
1989 GMC P35/P3500 VAN L4 3.9L 239cid DIESEL FI T Engine VIN = L
1989 GMC P35/P3500 VAN L6 4.8L 292cid GAS CARB N Engine VIN = T
1989 GMC P35/P3500 VAN V8 5.7L 350cid GAS FI N Engine VIN = K
1989 GMC P35/P3500 VAN V8 6.2L 379cid DIESEL FI N Engine VIN = J
1989 GMC P35/P3500 VAN V8 7.4L 454cid GAS CARB N Engine VIN = W
1988 CHEVROLET P30 VAN L6 4.8L 292cid GAS CARB N Engine VIN = T
1988 CHEVROLET P30 VAN V8 5.7L 350cid GAS FI N Engine VIN = K
1988 CHEVROLET P30 VAN V8 6.2L 379cid DIESEL FI N Engine VIN = J
1988 CHEVROLET P30 VAN V8 7.4L 454cid GAS CARB N Engine VIN = W
1988 GMC P35/P3500 VAN L6 4.8L 292cid GAS CARB N Engine VIN = T
1988 GMC P35/P3500 VAN V8 5.7L 350cid GAS CARB N Engine VIN = M
1988 GMC P35/P3500 VAN V8 5.7L 350cid GAS FI N Engine VIN = K
1988 GMC P35/P3500 VAN V8 6.2L 379cid DIESEL FI N Engine VIN = J
1988 GMC P35/P3500 VAN V8 7.4L 454cid GAS CARB N Engine VIN = W
1983 CHEVROLET CELEBRITY V6 2.8L 173cid GAS CARB N Engine VIN = X
1983 PONTIAC 6000 LE V6 2.8L 173cid GAS CARB N Engine VIN = X
1983 PONTIAC 6000 V6 2.8L 173cid GAS CARB N Engine VIN = X
1983 PONTIAC 6000 STE V6 2.8L 173cid GAS CARB N Engine VIN = Z
1982 CHEVROLET CELEBRITY V6 2.8L 173cid GAS CARB N Engine VIN = X
1982 PONTIAC 6000 LE V6 2.8L 173cid GAS CARB N Engine VIN = X
1982 PONTIAC 6000 V6 2.8L 173cid GAS CARB N Engine VIN = X

Looks like the D1852B is the way to go, tough to beat the price. For what it's worth, I use Rodney's 215/200 switch w/ the stock 195 degree thermostat .

------------------

I do agree with the fact that the lower temp switch will make the mpg go down. I do believe because the engine is running cooler it does use more fuel. However heat can be an enemy. When a car over heats badly the heads get warped and head gaskets become a problem, atleast from my experiences. I for one and willing to pay that little bit more for more gas. I do run the low temp switch with a 160 thermostat. After doing that I noticed a small increase in power. Its a proven fact that if your at the drag track running run after run getting hotter and hotter your times will not go down. Your car will get slower and slower each run as you heat up.

What I seem to find is that there are ups and downs to everything. The down in this case is the loss of mpg, the up though I find to be more power and in the long run possibly less engine problems.

I run a hypertech 185 fan switch in every Fiero I own (and every GM vehicle with out an engine driven fan) and have done so for many years.

The fan switch does nothing for engine temps (and ecm calibrations) under your thermostat setting. If the engine is too cold and not going into closed loop - it is the thermostat - not the fan.

The fan switch does not keep a car from overheating - poor coolant flow, excessive engine heat, poor airflow through the radiator, and an undersized radiator can all cause overheating and the fan switch only partially covers 1 of these 4.

A fan switch DOES keep the coolant (or tries to keep) in the radiator at a lower temp and helps keep the engine at the thermostat temp. It does this by providing as cool of coolant as possible to the engine when the thermostat opens to allow coolant circulation. If the temp does rise above the thermostat temp, then 1 of the 4 conditions above apply but to what degree is unknown and depends on how much above the thermostat temp it gets and under what conditions.

So why do I run them in everything? I want a rock steady temp gauge under all conditions. The GM setup allows the gauge to run from 195 to 230ish and that really annoys me. It also does not let me know in an instant if there is a temp issue coming on or is it just doing its normal thing. You have to wait until the temp is beyond 230 to know something is amiss and I want to know at 190. For me and my cars any temp change is an anomaly and should be monitored.
Sure you can do this with a mechanical switch in the passenger area, but I really dislike them because they usually look rigged and people will think you have a problem.

To keep the fan from running all the time, I also put a 1/8" hole in the thermostat to allow the engine to run a few degrees cooler than the thermostat setting, but still plenty high enough for the engine to operate in closed loop.

Greetings,
Well I re-installed my factory fan switch/sensor + 190° stat.
Then went for a 1/2 hr hwy drive.
- # 1- definite rise in coolant temp.
- # 2 - did not notice any lack of power.
- # 3 - definite decrease in MPG.

My summation
Now some people have expressed that one should leave everything stock because they believe the GM engineers knew what they were doing and this is the best for the 2.8 motor.
Others think more linear and logical that low temp will save seals and heads and general engine wear + tear over time.
This seems to be the two mindsets involved with this issue.
Personally I believe a giraffe is a horse designed by a commitee and GM engineers have proven over time that they are not perfect, so I don't see their specs as being the word of god.
I tend to believe the former that the lower the temp the longer the engine components will last without a failure.
As far as fan motor life goes...not an issue as a previous member stated "In the south we run our HVAC 10 mos. of the year and the fan motor can take it. I agree, and besides Fiero fan motors are easy to find if one fails.
If I have to pay a bit more for MPG then fine. I am sure we have all watched that temp gauge rise sitting in traffic and reached over and turned on the HVAC to lower the engine temp.
This is something I've never had to do since insatalling the low temp switch.
This may not be everyones opinion, such is life.
I will leave the stock switch in for a few more outings just out of curiousity but right now I believe I will find myself re-installing the low temp switch + 160° stat.

Thanks to all who chimed in, very very helpful A+++ to this site and it's members.

Regards

ChezFiero

A few things to remember when adressing this issue:

When you are moving down the road, the air movement from the fan is overcome by air velocity. The fan reeally only works when stuck in slow traffic.

On a HOT day the thermostat will be in the open posetion, so it does not matter what thermostat you have in at the time, it will still be over 200 degrees. On a COOL day, the 160 degree thermostat will be very effective at keeping the engine in open loop, thus keeping the computer from being able to correctly adjust the air fuel mixture. It will also keep the ratio on the rich side when it does heat up enough to go into closed loop.

An engine is NOT overheated at 230 degrees. But yes, it is hotter than 200 degrees. Proper operating temperature is critical to burning out the moisture and contaminates inside an engine.

My opinion on this has always been that is you are dirving on a racetrack, then it is mainly just an issue of how fast you can cram fuel into the engine. Good for racing, bad for engine life. Many of us drive our cars on the street though, and there it is a matter of long term engine life and relitively clean exaust. For that, keep the 195 thernostat.

Electrathon
Just to be sure...
Are you saying that one should keep the low temp switch and use the 190° stat? or use the factory switch + 190° stat?

Also, are you saying ...
Low temp better for engine or high temp better for engine?

Electrathon......"I like that"

In the old days engine technology wasn't very advanced, including metallurgy and seal durability, so keeping an engine running at low temperatures was key to longevity. Lower temperatures reduce efficiency but back then gas prices were low enough that it wasn't too much of a concern, designers just put in a 20-25 gallon tank to keep driving range up. However, modern efficiency standards required developing much better engine technology such that now it's perfectly fine to run an engine at 230°-240° and expect to get double the life out of the older designs. Since these engines are designed to run at higher temperatures now, for instance the Fiero will run at 195° on the freeway or when travelling faster than around 20-30 MPH, reducing the operating temperature will confuse the ECM and put it into a mode where additional fuel is delivered for a given amount of air. Now, the O2 senor will detect this rich condition and the ECM will make adjustments, but drivability will be reduced because now the ECM will be running with lots of correction instead of on the default values.

In my honest opinion, lowering coolant temperature will not add any to engine life at all, will reduce power a little and certainly won't increase power at all, and any perceived gain in performance is strictly placebo effect.

JazzMan

quote Originally posted by ChezFiero: Electrathon Just to be sure... Are you saying that one should keep the low temp switch and use the 190° stat? or use the factory switch + 190° stat? Also, are you saying ... Low temp better for engine or high temp better for engine?

You definatly want to use the factory thermostat. You can put in the install the mid temp fan switch (I think it is 205/225) and it will likely keep your engine a little cooler when sitting in traffic. I don't think this will really hurt anything, not really help either. It will keep it cooler at idle on hot days. Personally, I have a factory fan sensor (I think it kicks on at 230).

Higher temp is definatly better for long term use. Think bask to the 60's, we were glad to get 100,000 out of an engine. Now we are pissed if one fails at less than 200,000. There are MANY other variables involved, this is just one of them. Many people do not understand the engineering advances that have been made, so they cling to the past. In the last 40 years automobile engeering has advanced a LONG way!

Jazzmans explanation is a very good one.

quote Originally posted by ka4nkf: I have tried several fan switches and the best one I found other than stock was Standard Automotive Part # TS-85. It turned the fan on at 224 and off at 210. Worked real good. Don

Anyone that is driving on the street should be looking at a fan switch no colder than this... It will turn on reasonably quick in dead traffic but shut off when running down the road, which is exactly what you want. Radiator fans draw quite a bit of power and that will increase load on the alt and that will cut into both MPG and performance. If you aren't moving enough air thru the radiator at 20+ MPH then something is wrong with the car. (Some of the L4 engines are already programmed/switched in the 220-225 range. See the fan article in my cave.) There is no reason to run the fan all the time unless the cooling system has problems and even that may not be enough depending on the problems.

An engine at 220-230 is NOT an overheat. The engine, it's lubricants and controls, EXPECT this much heat in normal operation.

Engine temperatures that climb fast are most often a sign of a cooling system with major problems. Installing a low temp switch, especially lower than what Don listed is a bad bandaid. You still have the cooling problems. They are still getting worse. Only now you are hiding them with the low temp switch.

Yes, the temp should climb when idling for long periods. In normal driving you'd have to be crawling at low speed, like 5-10 MPH. Most traffic lights don't last long enough that a cooling system in good condition will let the engine switch the fan except maybe in real hot weather. If it takes you three turns to get thru a light, that may kick on the fan.

The point is the fan should not run very often for allot of driving. Running it when you don't need it causes more problems than it solves.

I'm ignoring running the AC... Running the AC automatically puts the fan on full time. I'm not sure that's a good thing but it was the easiest to impliment. Still is really.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurasic Park)

The Ogre's Fiero Cave (It's also at the top of every forum page...)

[This message has been edited by theogre (edited 08-13-2005).]

quote Originally posted by 2000RagTop: Electrathon......"I like that"

Electrathon is a form of electric car racing. Basicly they are a battery powered go-cart. The race lasts one hour, whoever goes the farthest wins. Electric marathon.

http://www.electrathonamerica.org/

quote Originally posted by Electrathon: A few things to remember when adressing this issue: When you are moving down the road, the air movement from the fan is overcome by air velocity. The fan reeally only works when stuck in slow traffic. On a HOT day the thermostat will be in the open posetion, so it does not matter what thermostat you have in at the time, it will still be over 200 degrees. On a COOL day, the 160 degree thermostat will be very effective at keeping the engine in open loop, thus keeping the computer from being able to correctly adjust the air fuel mixture. It will also keep the ratio on the rich side when it does heat up enough to go into closed loop. An engine is NOT overheated at 230 degrees. But yes, it is hotter than 200 degrees. Proper operating temperature is critical to burning out the moisture and contaminates inside an engine. My opinion on this has always been that is you are dirving on a racetrack, then it is mainly just an issue of how fast you can cram fuel into the engine. Good for racing, bad for engine life. Many of us drive our cars on the street though, and there it is a matter of long term engine life and relitively clean exaust. For that, keep the 195 thernostat.

LOL......... I was saying "I like this".........sorry for the 'tion"

[This message has been edited by 2000RagTop (edited 08-13-2005).]

Hi,

I started a thread about a month ago about low temperature fan switch (176F) and 160F thermostat.

After installing them i noticed that the engine was running rich, i lost power and gas mileage.
Installed the stock 235F fan switch and the 180F aftermarket stat.
I`m contemplating switching back to 195F stat.
I`m curious if 15F in temperature difference would give me more power and gas mileage.

JazzMan...you da man...chime in !

It is likely that you are running in open loop most of the time. That would definatly make it run poor. With a 180 thermostat, it will get into closed loop more often, and it is likely that you computer then could adjust other stuff to make up partially for it not running up to proper temp. You are better off though having the car run proper in the first place, not making the computer try to compensate for the undertemp situation.

The ECM will go into closed loop as soon as the O2 sensor starts reading reliably, generally at almost any coolant temperature and often times within a very few minutes after starting the car. The ECM adds fuel for colder temperatures because it assumes the car is still warming up.

JazzMan

Greetings,
I have read all of the posts on this topic a few times over and there have been some amazingly informative responses because this is an important topic for the 2.8 Fiero.
Now.....how does all this wonderful information currently equate into a vehicle which had only 5 production years and is now hitting the 20 yr.mark.
There are thousands of Fiero 2.8's that are well over the 200,000 klm/mile point.
There are thousands of Fiero's in the junkyard as well.
How many members have struggled with a cracked manifold? (probably the front one)
How many members have watched helplessly as their temp gauge wanders up into the Chernobyl range?
One wonders how the engineers from 84 thru 88 could possibly have pre-designed combating heat issues 20 years later, especially from an industry that thrives on planned obsolescence.
This topic of heat control which is essentially what we are all discussing, has a devastating effect on all things natural or man made.
We are really just trying to pospone the inevitable piece by piece, part by part demise of this particular machine due to intense heat.
The one major design flaw the car has, is the lack of air flow across the engine.
You can see the engineering compensations for this by the trunk fan and the air ducting into the engine bay as we know for the coil and alternator respectively. Also there is alot of the bottom of the engine bay exposed as well for venting.
The rad is at the front for obvious reasons and the coolant pipes run the length of the car also more time for coolant to cool albeit minimal.
Now I don't know about anyone else but I had removed the lower grates on my engine vents a few years ago because they just were there for aesthetics in order to hide the filter housing and the battery area. lets be honest ...the car runs very hot. Why not help it out?
We see alot of after-market engine vents,side vents air intake vents roof vents all being offered and installed and some of them are quite tasty and obviously make alot of engineering sense.
The engineers knew the heat challenge, we know it, and owners are taking steps to combat it.
So.....perhaps with the two schools of thought here so far ie: (stock sensor vs. aftermaket sensor cooling techniques) the focus should be that the vehicle remain stock and the venting be upgraded or improved in some fashion allowing the engine to vent heat as opposed to being falsly vented by tricking the ECM . So....the ECM remains "unconfused" and will run in open or closed loop mode by it's own choices and engine/ vehicle longevity and MPG will be increased.
At the end of the day the 2.8 Fiero is a highway sports car . And as we all know an amazing vehicle to drive fast on a winding road or race with.. This is the true engineering / driving spirit of the 2.8 Fiero. Sitting in rush-hour traffic is not what this car is all about, it wants to be driven.

Regards
ChezFiero