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Got serious about cooling issues

good flush and water wetter.....

btw, make sure to backflush behind the thermostat, otherwise all your doing is flushing the radiator, not the block....

i had same issue this summer, went from 210 freeway to a hair under 200 with the a/c on max fans blasting.

easily a 15 degree difference... can't even break 210 anymore, even if i try, 3 row rad, 185 thermo, 40/60 mix with one water wetter... (redline)

107 f. 4 hours of crawling around sweet home oregon, never got above 195...
 
you have to create a vaccum under the hood or all the fans in the world will do nothing.

front to back is the rear higher or lower???? if it's higher good, the front end needs to be just slightly under the rear to create a good vacuum, also is the bumper scoop gone???? the flashing that guides the air under the bumper back up into the radiator??? all these things will make a difference... i ran a strip of corner molding and experimented with placing under the xj and then hitting the freeway to see how the temp changed.... amazingly small changes can have drastic effects on temp.... i also found that blocking air from access under the xj was the ticket for me, helped create more vacuum in the compartment, forcing air to be sucked in through the rad/fan assembly, vs. the fan fighting to compete with windspeed at 65 mph.
 
UDATE-

I got the fan from UPS last night, so I mounted it up and ran some temporary wiring, since I need to leave town today and don't have time for getting it "perfect" yet.

The 10" fan sitting over the heater core on the hood-
P1050356.jpg


New routing of the hoses. this core works out perfect because of the angle of the IN/OUT lines, I cut about 3" off each to give it a side-directed hose connection and left a good loop out over the valve cover. It now has plenty of room to open the hood without any hose in the way, and there are no kings in the lines.
P1050360.jpg


Here is a mounting plate I made for the fan, theplate sits on the core about 1/4 inch all the way around, and 4 #10x3" bolts hold the mounting plate to the hood. I was very concerned about movement or vibration of the fan under the hood, so the plate is doubled up. The bolts that mount it have nuts at about 2" to keep from over-tightening the plate onto the core.
P1050362.jpg


Here is the fan mounted on the plate, under the hood.

P1050363.jpg


Right now this is controlled my a variable temp controller from NAPA, the same controller as my main electric fan. The controller sucks though because it ony has the one on/off point, I'd like it to turn on at 220 and off at 190, but this controller turns it on at whatever temp you set it at (trial and error before you get it to 220) and it turns off as soon as it's below your set temp, so it constantly turns on and off. The new controller will control the main fan, and this small fan will be run on the single point controller at a higher temp. Right now the fan is configured as a puller, pulling air into the engine bay, but only because that's the way it was sent and I forgot to change it until after I had mounted the whole thing up.

Hood scoops haven't come yet but when they do I'll update this thread again. I'm headed to southern Utah today and should be able to give a good indication of how it's going to work by the end of the trip.
 
very interested to see how this turned out and what became of the cooling problem
 
selarep said:
very interested to see how this turned out and what became of the cooling problem
Click to expand...

I don't have pics right now because I took it all apart- NOT because it didn't work, but rather to re-work my mounting brackets. But I screwed up, and need to re-do it on a new hood after warping the living hell out of the first (original) one. Because of this I didn't mount the scoops yet, although they are now sitting here waiting for me to finish the new hood, mount the scoops and get it painted before it gets installed.

Some thoughts-

Heat dissipation was phenomenal. I couldn't hold my hand over the core when the fan was blowing because of the heat.

Mounting it well enough for off-road use is problematic (at best). In the next phase I'll weld studs to a backer plate and reinforce the mounting area as best as I can. The problem is that the core and fan act as a pendulum below the hood and over bumps on a trail it really gets to shaking.

Hose routing has been re-done as well. I now run the hose to the stock heater control valve, out to the new core, and then back to the radiator. This allows me to have normal heater function and the added heat dissipation. Best of both worlds.

I have used it going over mountain passes and I don't even get close to overheating now, great mod IMO. I'm a little concerned about having the scoop over the top and still getting good airflow, but it is still far better than stock.

The biggest problem I'm having now it making a strong mounting bracket that isn't heavy. I don't want to make a heavier pendulum under the hood nor do I want to make it heavy to lift the hood for service. That's really the bottle-neck right now, building a decent bracket for the core and fan.
 
I have been thinking of doing something similar. Except I've been thinking of mounting my trans cooler on my hood and mounting a fan on it. Maybe get the one B&M sells.

I wonder if your trans cooler is blocking too much air flow into your radiator, as I suspect mine is. I wonder if moving the trans cooler up there would have much of an affect?
 
my tranny cooler(s) didn't go on till after. I decided that I'd like to keep my trans fluid a little cooler during the summer and since I have the additional "radiator" space, I can handle some loss in airflow through the radiator. Now the trans stays at about 170* around town and the radiator is always about 210*. As the weather cools I'll pull one of the trans coolers to keep the tranny temps at about 170-180*.

I really think there isn't enough radiator area, and the core in the hood is basically adding about 48 sq in, in addition to improved airflow through the compartment. Cooling the tranny further won't keep the engine cooler if your at the limits of the cooling capacity, but I think a hot tranny could make things worse by not letting things cool enough in the radiator.
 
Hey I've got an adjustable Zirgo fan controller, pm me if you want to take a look at it, I never used it.

I'm running the 91+ style aux. cooling fan plus a Zirgo 14" and have no cooling problems. The Zirgo is the main fan and I found a slick way to hook it up. On my 89 the temp sender is on the rear of the head so I got a newer t-stat housing with the port. I can't remember the pn# for the fan control sender I put in that but I know it was a GM part for a front wheel drive car. Comes on around 215 and shuts off about 185-190. Doesn't kick on and off very much at all.
 
AJsArmor said:
Hey I've got an adjustable Zirgo fan controller, pm me if you want to take a look at it, I never used it.

I'm running the 91+ style aux. cooling fan plus a Zirgo 14" and have no cooling problems. The Zirgo is the main fan and I found a slick way to hook it up. On my 89 the temp sender is on the rear of the head so I got a newer t-stat housing with the port. I can't remember the pn# for the fan control sender I put in that but I know it was a GM part for a front wheel drive car. Comes on around 215 and shuts off about 185-190. Doesn't kick on and off very much at all.
Click to expand...

Which model Zirgo fan did you get. I think there was 4 models of the 14"
 
AJsArmor said:
Hey I've got an adjustable Zirgo fan controller, pm me if you want to take a look at it, I never used it.

I'm running the 91+ style aux. cooling fan plus a Zirgo 14" and have no cooling problems. The Zirgo is the main fan and I found a slick way to hook it up. On my 89 the temp sender is on the rear of the head so I got a newer t-stat housing with the port. I can't remember the pn# for the fan control sender I put in that but I know it was a GM part for a front wheel drive car. Comes on around 215 and shuts off about 185-190. Doesn't kick on and off very much at all.
Click to expand...


Clean out your inbox :D Better yet, when you join NAXJA you get a lot more storage space....

I'm interested in the controller- [email protected]

Shane
 
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