mastacox

The relay was just a standard 30 amp from checker I think, nothing special. I suppose it's possible a "name brand" relay like Bosch might be some better, but you don't really want to run a relay at its maximum rating for an extended period of time. You can also think about the relay as a power rating, so a 12V relay rated at 30 amps, it can take 360 watts (12V*30A=360W). the Taurus fan on the other hand is actually about 400W. Plus, you vehicle will run up to 13.5-14V with the alternator, so you may be dissipating even more power, perhaps as high as 460W. A 12V relay rated at 40 amps is essentially rated at 480W.

As for thermal cycling, there are no web pages that explain this problem in little snippets; it is a much deeper subject. The fact is that your engine expands as it heats, and then contracts as it cools. Because of this expansion and contraction, you can cause problems in two areas that are in contact, such as your head and block with the head gasket. Additionally, parts that see a large temperature gradient accross it will have internal stresses generated each time the engine heats, which can in the medium to long term cause a failure. Overall, you are much better off if you try to maintain a constant temperature.

[EDIT]Also: an always-on variable fan will help keep your condenser for your AC much colder. Upshot: you have nice, chilly AC.[/EDIT]

As for cars with electric fans stock, I think older fans were on/off, but newer cars are variably controlled for better efficiency. Also, these cars have a cooling system that has been designed to work with an electric on/off fan, while our cars were originally designed to work with an always-on mechanical fan. The thermostat ends up doing more to control the cooling of the engine because it will control water flow to the engine, especially for our cars.

mt_goat

The DCC site has quite a bit of info: http://www.dccontrol.com/index.htm

Go to the "Technolgy" page and also the "fan control" page then "Theory of operation" if you really want some deep thinking.

Ritzy4Runner

iTrader: (1)

All gr8 stuff, but for now I am going to just hook this fan up to the slow speed only and set it for about 185 degrees.

Ok here is the daily update: After chatting with NC-B17A and how he made brakets to just bolt up the Taurus fan to the OEM mounting holes on the radiator, I decided , I am going to pull the radiator and while I am at it replace the hoses as well. Now I know for sure that the hoses are not going to blow on me on my trip to California.

As for brackets, I picked up some pieces of straping at Lowe's. Two pieces @ $.68 each. I ended up making the brackets which had three (3) predrilled holes inthem at several locations. Only needed about 1/2 of each piece I bought and I bent them 90 degrees, lined them up with the location of the mount point. marked where the 3 holes were at, took a small drill bit which you must ensure that it is not larger then the #8 screws.
After getting all three holes drill I then put sheet metal #8 screws 3/4" long through the plastic shroud into the predrilled straping and they snugged right up. Then next I had to hold the new fan inplace on the old radiator so that I could mark where the mounting holes needed to be drilled. Bolted the fan to the radiator then placed the completed unit in place in the engine compartment.

I am considering doing the ISR mod and reading all the threads about fear of losing the lock nut down the intake I thought how could I avoid that? Well if you want to avoid the lost lock nut, Do as I did, I bought some JB Weld Quik set. Mixed up a ribbon about 2" long then after mixing I put a dabble on each of the screws I had drilled into the shroud, I put it around the threads of the screw so as to bond to it and prevent the screws from backing out. DEcided on the location for the controller, located in the right side passenger inner fender wall just outboard of the battery. Allows for single run of probe to the inlet side of the radiator. Will hook up only the slow speed and see how well it handles some of the things our weather will through at it. Ran out of light again so we will try to finish up tomorrow

Ritzy4Runner

iTrader: (1)

:bigclap: For all of you who have helped especially to MarcP (dude, you're my hero! ), mt_goat, bamachem,and NC-B17A, thanks. Your help and encouragement helped me to get over the hump on this one guys! THANK YOU!
Marc your pictures were worth a thousand words. Looked at the surrounding equip in your pics, looked at my engine bay and knew where I needed to look and sure enough, it WAS easy to install the 'GREEN' A/C wire. Works GR8!

Now for those of you who are going or thinking about doing this mod, ( toferUOP take notes!) there are a few things I learned as I was doing this.

1) Plan on it taking longer then a few hours! Murphy's Law will come into play. I started on Friday afternoon and finished up Sunday around 8pm

2) If you haven't done an Aux Fuse panel, DO IT! It will save you headaches in the long run and you will be very glad you did it, trust me!. It gave me a perfect location to connect the power input for the controller and didn't have to worry about routing a wire seperately to the battery.

3) If you consider this mod, plan on taking the radiator out just like bamachem recommended. You can do it with it installed and infact I did have it somewhat installed and was preparing to use the mounting tiewraps and opted to use 'brackets' to mount the fan instead. Just didn't seem to be very 'solid' holding that fan with plastic going through the radiator fins. Best thing I did. If you want to see what I did, I will be happy to show and explain it, super simple and well worth the extra effort.

4) If you have the skid plate installed, remove it first and then as you're taking the radiator out, replace your hoses. Simple but in the end, very cost effective. I also cleaned up the skid plate and repainted it a nice bright red.

5) Hooking the A/C control wire to the A/C aux fan didn't work. Seems somehow there is 12V sitting on the connector, when I tapped into the wire, the fan came on. Go with the tap into the black/white wire. Once I found it (way to go MarcP) was soo easy I was shaken my head. It is located above the compressor and right behind the power steering pump. You will see a single black/white stripe wire that has a connector about 1/2 way down to the A/C compressor exactly like MarcP said!

6) Really think out and give serious consideration to the location of the controller. You can cut the wires and lengthen them, but to do it correctly you will need to solder in the new wires and use shrink wrap. Not only will you be concerned with engine compartment temp but you will need to consider being able to get to the controller to adjust the temp setting. I have to take the battery hold down off and move the battery away from the mounting location enough to get a very small screw driver in to adjust the poteniometer. Not optimum, but it did work and I didn't have to cut wires or alter the probe sensing line.

I mounted the controller on the right inside fender well outboard the battery. Maybe not the best location, but it is near the right headlight bucket and there is airflow around it. This location gave me just the right amount of distance so I didn't need to cut and splice wires. Difficult to adjust the temp on the Controller but there are trade offs to everything.

7) I also decided to mount the temp probe from the FRONT of the radiator. My instructions said to place the probe high in the radiator and near the inlet, so mine is about 2-rows of fins down and about 1/2 from the inlet pipe. Multiple reasons for the placement of the probe in this location.

8) When you pull the radiator there is foam around the upper lip of the radiator. When I reinstalled the radiator with the new fan mounted, I pulled a corner piece off at the right upper corner. This is right next to where I inserted the probe as stated above in 7).

After using an awl to lightly enlarge the space between the fins, gently press the probe into position. Be careful so you don't over do the space between the fins with the Awl. The probe will slip in with a slight amount of pressure. You may hear or feel a popping sound. This is the fins giving way to the insertion of the probe. Align the back end of the probe to the back edge of the radiator.

My Controller instructions said not to have it past the thickeness of the radiator. I then used the foam piece I removed and wrapped it around the wire end of the probe to help hold it in place. Then push the radiator back into position, bolted it back up and now the probe will be held firmly inplace and protected.

9) Temp setting-If you have one of those old style meat cooking thermometers, this will work really well. What I used. Mine went up to 200 degrees. You need to place the bulb of the thermometer in direct contact with the inlet pipe/top of the radiator housing. If you have something that will hold the thermometer in place gr8, but be careful as you can melt stuff like tape.

It tracked temp right up. Remember to keep checking your engine temp. After about 10 minutes, you can shut down the engine. You may have sufficient cooling to keep the temp from going too high but be watchful. I shut down the engine around 180+ and watched the thermometer. When it got to 185 I monitored the temp until it seemed to be decreasing. I then adjusted the pot on the controller just so the fan would come on. Job done!

I did take some pics of the brackets, and fan clearance with the pulley and the A/C tap. As for the brackets here's another little tip. With the radiator out of the truck and resting on the ground, you can place the fan directly on the radiator and then use the one screw that lines up with the one hole on the fan shroud and radiator. Mark the location of the other 3 OEM screw mounts on the fan shroud. You will need to do some trimming of the shroud for flush screw placement.

I picked up a couple of pieces of joist strapping material at Lowe's (68 cents each). They were about 6 inches long and 2" wide with small holes for nailing. Bend the strapping in a vice if you have one so it is in an L shape. Make the strap about about 1" deep for the first bend, then allow about 1.5 " for the mount to the radiator. I used #8 sheet metal screws and then predrilled the holes in the shroud after marking their location through the holes in the strapping. Screws are mounted from the outside edge of the shroud into the strapping. I then used some JB Quik Weld around each screw. This way they will not come out.

Once I figure out how to add pictures to the posts I will, but if you wish to see the pics email me.

If anyone is considering this mod, and you would like to see the pics of my install, please feel free to email me and I will be happy to share my experience and the pics. I will be leaving for Southern California from Seattle this coming weekend and will give you a report on how the mod performed. Until then .... THANK YOU to ALL who helped me. That is what this forum is all about! ritz

siarl

I know this is an old post but I'm hoping that someone still connected to this post will see this and help out with some information related to the fan blade and shroud. My fan blade shroud finally gave up the ghost and took the fan blades and radiator with it on the way out. I have a 95 4runner in excellent health but the zip ties dry out very quickly here in the desert. I ordered a new radiator and fan blade and top and bottom shrouds. I just received the radiator and fan blade today. The fan blade looked quite a bit larger than the toyota blade that was on there. I don't have it to compare since it is with my mechanic. We are really remote here in the west Texas desert so I can't just run across the street to compare the blade size. I did a search on OEM parts, versus the Dorman blade I purchased through Autozone that stated that it would fit my 4runner. They are two very different sizes. The Dorman blade is 17" x 17.3" whatever that means and the OEM part measures a considerable !4" in diameter. Does anyone know the inside clearance of the fan shroud? Since my fan shroud is in several pieces and missing others I can't compare it. Would it accommodate such a large difference between the two fan blades? Thanks for any assistance.