fj40 carb cooling fan...do you run yours? (2 Viewers)

[michaelharrisco]

I just fixed my carb cooling fan and my FJ is now cranking (warm cranks) much better and I'm sure it is due to the carb fan fix. Do most FJ drivers have a functioning carb cooling fan? I have a 78, but I'm not familar with the story behind the fan...it seems like a design flaw fix and I wonder if they later fixed it where a fan isn't needed.

Is there anyone out there that has a carb cooling fan that doesn't work and they just let it go, but still don't have any cranking issues? I've searched the forum around for topics and one helped me find the fuse which was behind the heater duct (such a weird place to me), but no comments about the history behind it and if people still run theirs today.

 

[IH8Wood]

It's there in the FJ60s. Mine hard starts when the engine is warm if the fan isn't working.

 

[Fast Eddy]

I ran around for a long time before I got it working without really noticing. I don't think I've ever seen another one that was working.

 

[kurtnkegger]

Mine works in my '77. I've been told it's design is to help prevent vapor lock, and fuel from boiling in the bowl in extreme conditions. I like the fact that it runs for a while after the truck has stopped to help it cool. Put your hand at the vent after you stop, and feel the rush of hot air coming out...thats got to be good for your motor.

 

[GarageRat]

Mine works in my '77. I've been told it's design is to help prevent vapor lock, and fuel from boiling in the bowl in extreme conditions. I like the fact that it runs for a while after the truck has stopped to help it cool. Put your hand at the vent after you stop, and feel the rush of hot air coming out...thats got to be good for your motor.

The air circulation does nothing for the motor when it's not running, just keeps the stagnant hot air from boiling the fuel in the bowl so it starts easier because you don't have to refill it. Ideally with iron, steel, etc etc you want as slow of a cooling cycle as possible due to the crystalline structure of the material. It doesn't help it by any means with that fan going but it doesn't hurt it either since it doesn't cause any thermal shock with the small amount of added cooling it provides. Now it might help the mechanical fan a little with reducing underhood temps while driving, my 16" electric cooling fan from a third gen f-body moves enough air to do that by forcing the hotter air out through the hood vents.

My friend's 2F rig doesn't have the fan, had an issue once with slow, high load crawling on a high 90s low humidity day where it vapor locked.

 

[mano002]

My canadian spec '78 doesn't have the fan, and its always started fine when warm, but it doesnt really get that hot up here either.

 

[michaelharrisco]

interesting...now that I have fixed mine and it is working again it seems to have fixed the vapor lock issues I was having.

It just doesn't seem like a lot of people have them / have them working yet they don't seem to have any cranking issues (warm). I had ~3 out of 20+ warm cranks that seem to be vapor lock symptoms so it seems to have helped because I have not had any issues since the fix.

Just curious...thanks

 

[Eric_S]

When I bought my 78 JF40, it was not working. I ended up just hooking up a toggle switch to the fan and running it when I felt like it. I have since removed the cooling fan to make room for other modifications.

 

[surfpig]

Mine works. I had it out for a while when I pulled my radiator to get it repaired and I did have some hot start issues...

 

[1911]

Mine still works; here in Texas it runs every time I turn the engine off.

 

[myquestoyota]

Interesting information. Mine has the fan, it works, and is hooked to a toggle switch on the dash. I haven't run it yet in warm weather. Bought it last winter and immediately started cleaning it out which led to stripping the bed which led to rebuilding the heater, etc etc etc
I was wondering what conditions to run the fan and whether it was once wired a different way. What is the correct (factory) way this should be wired? Curious about the running after shut-down operation.

 

[Robert LaDuke]

Mine works. Occasionally when I park get people telling me " Hey... you left something running" .

 

[bsevans]

When I bought my '78 FJ40 in 1986 the fan did not work. In my first summer with the high temperature consistently over 100 degrees I had the same issue time in and time out. I would drive to a store and upon returning to my 40 it would start and I might get 2/3 hundred yards and the vehicle would start surging and then shut off. It would not restart for at least 5/10 minutes. Obviously, this got old real fast. I pulled the module that controls power (and duration) to the fan based on the input from the thermocouple located under the intake manifold. I refloated all the discrete solder joints and two things happened. The issue completely disappeared and the cooling fan has worked ever since. That would be over 20 years. The fan may not be needed in cooler climates, but here in Southern Arizona, I see it as a necessity.

 

[Bodean]

Mine works only on the hottest days here in MS. Worked a lot before the header installation. I guess the sensor for this if further away when running a header???? No hard starts though.

 

[John Smith]

Mine works only on the hottest days here in MS. Worked a lot before the header installation. I guess the sensor for this if further away when running a header???? No hard starts though.

Your sensor is probably hanging somewhere not touching the header. When I installed my header I had to bend and modify the mount bracket to get it to contact the header flange. My carb fan kicks on every time I turn off the 40, even in Winter. On 100 degree days my truck has zero issues with restarts.

 

[MoCoNative]

To clear things up, fan should only run after shutdown to reduce vapor lock issues, doesn't really need to run while driving.

I have the fan on my fj-60, works perfectly, vehicle always starts perfectly, no issues, cold or hot, fan always runs for some duration whenever the engine has gotten up to full operating temp. Sometimes it will even kick back on if it is really hot out.

The fans were present on even the FJ-62's with fuel injection. But I think the 60 series hood was a tad tight and trapped alot of heat.

My 40, a 73 did not have a fan, those ddin't come around till later, later in the 70's. I have the exact same troubles that bsevans talked about for the most of the summer, on days over 80 degrees. It is very agravating. But mine is kind of a mix of engine parts too. Running stock intake and exhaust, but my exhuast flapper is removed with a permanent aluminum peice bolted in to direct flow away from the intake. Running 2F carb and aircleaner.

I don't know if the stock carb was a suseptible to the vapor lock as the 2F carb I have now or not. I ran a Holley with headers and then with stock exhuast for several years, it too would vapor lock.

Hooking the fuel return line up helped alot, that helps fuel circulate and stay cooler, but does not solve the sitting and heating issue during a short stop in the store.

I am going to next try insulating the fuel line near the manifolds to help this condition.

 

[mloudy]

Mine used to work and now that it doesn't it is slow to start when hot and will stall if I don't run it for a bit before I take off. The fuse is good and the fan is good. I haven't looked any further to fix the problem.

 

[antFJ]

now that its upper 90's mine runs every day when i shut the truck off - it gets hot in there with the headers so I like having it up and running.. im very tempted to do a test one of these days.. don't let the fan run and start the truck up within a couple of min after running it for about 30 min (the point where the floorboards are hot) and then try it again with the fan and see if there is a difference

 

[fj40notajeep]

mine doesnot have a cooling fan where can i get one

 

[fj40notajeep]

anybody have a picture where it is mounted in the truck . thanks