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OK, I've upgraded my alternator and picked out a 14" PermaCool high preformance electric cooling fan. Question: How have people addressed installing the thermal sensor for controlling the electric fan? I want to use a sensor to get the benifit of not running the fan when it's not needed. It seems there are 3 kinds of aftermarket thermal sensors:

1) A universal "button" type that just mounts to something hot (radiator, block, etc.) to make a thermal measurment.

2) There is a "probe" type that gets stuck in the radiator fins.

3) There are threaded versions that screw into the engine.

The first two types don't seem to be that accurate, but I guess if an adjustable controller is used this can be compensated for. The threaded type seems to be most accurate and consistant. Has anyone out there installed a thermal sensor to control an electric cooling fan? If so, what did you use and how did it work out for you?
 

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Electric fan

Jimsky,

Takes a little while, but here is what I got going two weekends ago.

I installed a 12 inch Imperial electric fan, #226112 (the 12 indicates 12 inch), as a pusher fan. It can be configured to operate as a pusher or puller. It is rated to move 850 CFM with 675 CFM through the radiator drawing 8.3 amps. The mounting area is 11.5x12.5 inches, 2 5/8 inch at the thickest, and it fits perfectly on the front of the radiator.

Along with the fan, I installed an Imperial adjustable thermostat, #226203. This is adjustable from 32 to 248 degrees and it mounts flush with the radiator, not in it. I mounted mine under the upper radiator hose. The instructions do say to mount it on the engine side of the radiator.

It has been running now for a week and half like a champ. It is very easy to adjust, quiet, and seems to be pretty acurate.

Price from Advance Auto Parts was:
Fan - $65.28
Thermostat - $19.74
 

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I'd have to look at the package again, but I used a universal thermostatic fan control that has a probe that actually goes inside the radiator, it has a rubber seal that goes against the upper radiator hose attachment so the line that goes from the probe to the control unit seals properly with the hose and does not get damaged by the metal. It is adjustable and I have it come on around 190 degrees. It seems like it was a flex-a-lite 311147 unit, here is a picture from summit if it works



It was about $25 locally at a performance auto parts store.

For the fan I use a VW Rabbit fan reversed so it pushes with the shroud modified to fit. (it was laying around and I thought I'd give it a try)
 

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Discussion Starter · #4 ·
Thanks fort the replys, but I've already completed my electric fan conversion. I took photos and wrote an article on my installation. It's in the Technical file section on the Yahoo Classic Opel site, in addition to being published in last month's copy of "The Blitz".

I ended up using a threaded style screw in sensor. Rallybob confirmed the top and bottom section of the radiator was brass, allowing easy soldering. I just drilled a hole in the bottom radiator section, soldered in a fitting, screwed in the sensor and was done. No leaks and accurate temperature measurments.
 

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I didn't even notice the date on your original was in April. I chose the probe type because I needed the car for the weekend and didn't want to chance screwing up the install of a bung and not being able to race.
 

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Electric Fan

Can anyone direct me to an old post about switching to an electric fan? I tried searching for it, but the search didn't pull up anything very relavent.

If there isn't a prior post, what electric fan should I look for? Is it an easy switch?
 

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I did a copy and paste from an old thread to give you the info on the fan mod. I used the same fan on Willit?, but because I had room on the engine side of the fan, I was able to make some aluminum straps and bolted the fan to the radiator structure. HTH.

"There's a really good article on this by Jimsky at the ClassicOpels site on the Yahoo Clubs.

http://autos.groups.yahoo.com/group/...20Information/



Look for: ELECTRIC RADIATOR FAN UPGRADE FOR OPEL GT.doc


If your not a member it might not let you see it. If your not, JOIN!!"
 

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Thanx Jarrell, I clicked on the link in the original post and it worked, so I did a copy and paste, but it didn't work as you said. Wierd, these computer things. :banghead:
 

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after off cooling?

My GT came to me with an electric fan (to suppliment the 7 blade normal fan) installed as a pusher in front of the radiator. Has a sensor actually in the upper rad hose. Dial type control but knob is gone. Saw a thread here a week ago which had the same model but can't find it back.
Anyway, it doesn't come on when the car is running ever but has after I shut it down. Does it do the car any good to have the rad get air blown over it after she's shut off? Having cooler coolant in the rad not moving through the system can't carry heat away from where it matters so why bother? I can't really see the point and I didn't know how long it would run so I turned the dial all the way over and shut it down because I didn't want it to run down my battery.
 

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Mine will come on sitting in traffic at lights etc, and will run for a couple of minutes after shutting it off. It doesn't appear to drain the battery very much and I figured it can't hurt. My coolant overflow is to an overflow bottle, so the most it can do is help cool it down at shut off.

If I remember correctly, from another thread, your's was running cool around town. I'd just set it up to cool at shutdown by watching the temp gauge with the car cut off, ignition on, and see how much the gauge rises and set the sensor accordingly. Can't hurt. Hth, Jarrell
 

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Yes, mine seems to stay pretty cool. Very hot here yesterday upper 80's and down highway, through town temp got close to half. It could be the fan kicks in and I never know it, it is quiet but up until a few days ago after I jiggled it's wires, it had never come on, so there must be a bad connection in the mix. I might hook the switch on the dash back up but I don't understand the point of that switch. If it is set (by dial on sensor) to come on when hot enough why have a switch? It seems the switch can over ride the sensor (if hooked up that way, not sure why you'd want to do that) or simply disable it (again, why?). Maybe you could turn it on from the dash despite the sensor saying it isn't warm enough to need it (again, why?) but I don't think it's intended to do that. There is also a little red led light right above the switch, has it's own wires. Not sure what that's for. From their website:
Part# 31148-Aux. Illum. Switch
For cockpit control or override of fan function. May be wired to actuate fan regardless of temp setting (end of a heat, or at the beginning of a hard pull), or -wired alternately - can be made to disable fan function, regardless of temp setting (for water crossings, etc.)

I don't know what thermostat is in there but it's yet another case of "if it ain't broke don't fix it" syndrome. I'm just too inclined to mess with stuff. Makes me wonder if I could get away without the engine fan (highly unlikely and dangerous to try) and get a couple HP. I also have a coolant overflow.

Have to assume the PO put in on for a reason, but well, PO assumptions are very treacherous.
 

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Jimsky,

Takes a little while, but here is what I got going two weekends ago.

I installed a 12 inch Imperial electric fan, #226112 (the 12 indicates 12 inch), as a pusher fan. It can be configured to operate as a pusher or puller. It is rated to move 850 CFM with 675 CFM through the radiator drawing 8.3 amps. The mounting area is 11.5x12.5 inches, 2 5/8 inch at the thickest, and it fits perfectly on the front of the radiator.

Along with the fan, I installed an Imperial adjustable thermostat, #226203. This is adjustable from 32 to 248 degrees and it mounts flush with the radiator, not in it. I mounted mine under the upper radiator hose. The instructions do say to mount it on the engine side of the radiator.

It has been running now for a week and half like a champ. It is very easy to adjust, quiet, and seems to be pretty acurate.

Price from Advance Auto Parts was:
Fan - $65.28
Thermostat - $19.74
I just installed this exact same setup on my GT. Everything physically works and is operational, but the fan just isn't keeping up with the heat. I have a 165 deg. thermostat. It's 96 outside with 60% humidity. An average eastern Kansas summer day. I replaced the original fan which was all chewed up because the bolt came loose from the bottom of the radiator and allowed the fan to encroach. Thank the engineering gods for plastic fans. In any case, it chewed about an inch off each blade. No original shroud. That poor setup worked fine, keeping it around 180 at idle, So I don't think I've got a blockage. The setup I have now barely maintains whatever temperature it's at. Any idears? I bought this setup because it does bolt right on, and any other fan looked like it would require a little more metal work. I've double checked all my wiring, made sure it was turning the right way, etc... No love. Anyone else have the same kinda problem? I get the feeling that 675 CFM just isn't quite enough.. Anyone know what the original stock CFM rating was?
 

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I've commented on this far too many times, but here it goes again, along with what I have in Willit? just for an example. First off I think your thermostat is way too low, it should be a 180-196, that's what's recommended by Opel. Here's the reason, and most folks don't think about it. The thermostat does two things. It speeds up the initial warm-up of the engine and then, restricts the flow through the radiator so the coolant has enuff time in the radiator to cool down. It then modulates open and close to maintain the thermostat setting, which again, restricts flow through the radiator allowing ample time to cool the fluid. Now with your old fan continually running, there was ample air-flow through the radiator to cool the fluid, but with an electric fan shutting off and on you have intermittant air flow through the radiator which doesn't cool the fluid down enough and you go through an overheat cycle. Now for what I have In Willit? and what is recommended by GM for the engine I have, I have a Perma-Cool 14" fan as a puller and it turns on at 229 degrees and shuts off at 200 degrees, computer controlled. I also have a 180 degree thermostat and a 3-row radiator. As long as I'm above 40 MPH, there is ample air-flow through the radiator to keep the fan off. Driving in town, it comes on intermittantly as required by the computer. Using the stock Opel temp sensor on my engine, it almost pegs the temp gage, but that's the way the engineers designed the 3.4L engine. In Margaret's Montana with the same engine, her temp gage starts at 100 degrees and goes to 260 degrees with normal at 3/4 gage travel or around 220-230 degrees. Scary to say the least, but normal. :eek:
 

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I was asked to find and order a 6 inch 100 CFM fan for the heater in the 1900. It gets very cold here in the winter. I'd think that a 12 inch fan should be around 2000 CFM if a 6 inch does 100 at 1250 Revolutions per minute. I don't know the math for this one but the little heater fan works great now.
 

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180 Degree Thermostat and Water Wetter

I just installed this exact same setup on my GT. Everything physically works and is operational, but the fan just isn't keeping up with the heat. I have a 165 deg. thermostat. It's 96 outside with 60% humidity. An average eastern Kansas summer day. I replaced the original fan which was all chewed up because the bolt came loose from the bottom of the radiator and allowed the fan to encroach. Thank the engineering gods for plastic fans. In any case, it chewed about an inch off each blade. No original shroud. That poor setup worked fine, keeping it around 180 at idle, So I don't think I've got a blockage. The setup I have now barely maintains whatever temperature it's at. Any idears? I bought this setup because it does bolt right on, and any other fan looked like it would require a little more metal work. I've double checked all my wiring, made sure it was turning the right way, etc... No love. Anyone else have the same kinda problem? I get the feeling that 675 CFM just isn't quite enough.. Anyone know what the original stock CFM rating was?
I would install 180 degree thermostat to allow coolant to flow slower in radiator; simple to evaluate and low cost.

Also try Water Wetter instead of antifreeze mix for summer. I use distilled water.
Amazon.com: Red Line WaterWetter - 12 oz.: Automotive
 

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At 1200 revolutions per minute a 5 blade fan with a 32 degree pitch will produce 900 cubic feet per minute if shrouded correctly. Unshrouded will drop to as low as 400. At just over 3000 RPM the air speed flat lines around 1800 CFM. I don't know the air coificient of drag for a radiator and the numbers are rounded off. Sorry it took me so long to get it through the company software. I'm not supposed to use it for personal stuff and measuring pitch took a moment.
 

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I agree with Ron, it takes a lot of CFM to do the job. From what I've read, 1600 - 1800 CFM would be the smallest fan I would think could replace the stock fan. And, if you live in the tropical regions of North America, say in Kansas, you'd probably need 2500+ CFM. In addition, complete coverage by the fan shrouds is a must!!! If I were installing a pusher fan, I would probably leave the stock shroud in place to help with the chiminey effect...

BTW Summit Racing catalog lists the 14 in Perma-Cool fan at 2950 CFM

As far as the temperature probes go, the best way would be to have a radiator shop braze in a fitting.
 

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Thanks for all the advice and feedback. Except for the electric fan, nothing has changed on my cooling system, and all was right with the world until the electric went in. I've never had a shroud. With everything else being equal and all was working good before, I'd think anything I do now to overcome the overheating would be compensating for too wimpy a fan.

The packaging the fan came in specifically stated it could be used as primary cooling for up to 2.0L engines, was 800CFM, with 675 effective in pusher mode. While yes I thought that seemed a little weak, it did say it was designed to be primary on up to 2.0L engines, so I deferred to the box's better knowledge. That coupled with the hands-on experience of someone else here, I figured it was a done deal. What would be the reason the manufacturer would say 675 is enough, but most here are saying three-times that is right? That's a pretty big difference. :confused:

I've never had the engine opened up before, maybe the PO bored it out and it's really a 2.4 and I just found out.. :no: Would the stock system keep a 2.4 cool? Unless someone here thinks they've seen this before, and it's something other than the CFM, I fear I'm going to be replacing the fan with a beefier one.

Namba, The 160 Degree thermostat idear came from OMC. GT "Things to Know"
They don't explain why, but they say 160 in summer, 180 in winter. However, I wouldn't think that's my problem right now. The fan is always on because the fan can't cool the car down enough to shut off. When the coolant is hovering around 210, wouldn't it not matter if the thermostat's a 180 or 160? I'd think they'd be wide open, flowing exactly the same between them.
 

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Namba, The 160 Degree thermostat idear came from OMC. GT "Things to Know"
They don't explain why, but they say 160 in summer, 180 in winter. However, I wouldn't think that's my problem right now. The fan is always on because the fan can't cool the car down enough to shut off. When the coolant is hovering around 210, wouldn't it not matter if the thermostat's a 180 or 160? I'd think they'd be wide open, flowing exactly the same between them.
As I said earlier, most folks don't understand the main function of the thermostat. With it in full flow mode there's not enuff time for the coolant to radiate heat to the air flow through the radiator. I've seen this many times when folks take out the thermostat in the summer to try and keep their engine running cooler. It just doesn't work, because there's not enuff time in the radiator for the coolant to be cooled down. Let's say you put in a 180 thermostat and it slows down the coolant flow so it loses more heat to the radiator and gets cooler by 20 degrees. That's 20 degree cooler than with a full flow thermostat, so you get cooler fluid going into the engine, which absorbs more heat and take a bit longer to open the thermostat, which allows more time for the coolant in the radiator to cool down even more. Just the opposite effect of an open thermostat or none at all. Now, getting to your fan, Perma-Cool says on their website, that their fan in a pusher mode loses about 20% of the rated efficiency/CFM than in the puller mode. So if you cannot use a fan in a puller mode, figure on that loss in a pusher mode. HTH.
 
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