Looking For Opinions....

I'm working with a 225 V-6, with heavy cooling fan and no fan shroud, and new 3 core aluminum radiator.

OK....When I changed out my radiator I removed the spacer between the fan and the water pump pulley. This set the fan back off the radiator about 3-inches. The temp ran at 180 at idol and same running down highway, (this was during the winter when the temps were in the 60's-70's). Before summer I put the spacer back in to gain some clearance between the fan and HEI distributor, (about 1-1/2-inchs off the radiator). Now the temp is running about 185-190 down the highway and hitting 195-200 at extended idols, (outside temperatures between 90's-100's).

I have made sure radiator is full and timing is set where it needs to be. The fan is drawing enough air that it will suck a piece of paper to the grill and hold it there.

Question: Should I build/acquire a fan shroud? Or back the fan off the radiator again to see if i can bring down temperatures? Or do you think that the temp spike is due to outside temps being higher? Does the fan need to be a specific distance from the radiator to work properly?

 

90-100 degrees and you're at 190-200 degrees?
Don't change a thing you're doing great!

 

X2
Don't see any need for alarm.
It's hot and it's summertime.

 

To me, the main question is - which thermostat are you running? If you have a 180 or 195 in it, that's your set point. The thermostat should keep you quite close to that temperature. If the coolant temperature rises with the conditions, then you have no cooling reserve.

 

With no shroud the air could just be recirculating. With a shroud most if not all the air is pulled through the core of the radiator.

 

X2 on what Tim said above .

 

Is your fan a flex fan or a solid fan?
I am running a 3 core aluminum radiator, solid 6 blade 15" about 1.5" off the radiator no shroud, stock water pump and a 180 thermostat. at 110 degrees outside my jeep will idle all day at 190. I started off with two different flex fans but had heating issues. Solid fan makes allot more noise but its worth it.

 

I’ll say this without a shroud watch your fingers and or hand if you ever adjust your distributor

 

I have the stock solid 5 blade heavy duty fan, 180 thermostat.

 

Im going to see if I can find a shroud or plans to build one to see if it helps.
I know it's hot outside and temps are not that far off, that's why I was looking for y'all's opinions. Thank you!

 

I agree with adding a shroud. Makes the fan as efficient as possible in conjunction with the radiator.

 

When it was hot outside, around 100°F, the temperature was higher than during cooler weather. First time I saw the needle near 200°. Usually near 170.

 

I have never had a shroud in the 40 years I've been driving this Jeep. I wish I had one but I'm not too worried, obviously.
The jeeps coolant temperature does is usually around 180-200 in summer when ambient is in the 100's. I do flush my cooling system occasionally to keep things flowing correctly.

 

I have the 225, a 165 thermostat, the largest aluminum rad I can fit and a 14" electric fan set up to pull with the switch at 185. In 95+ it will run at 190 and often make me very nervous and sometimes creep to 200. It takes quite a while for the rad and the volume of coolant to reach full temperature, so when it creeps above 190 I have been generally driving at least 10 miles or stuck in stop go traffic for some time. I have never over heated it though, so maybe our nervousness is unwarranted?

 

I've had mine go well over 200 without overheating on a sustained climb in low range on a hot day.

 

You guys understand that this is a controlled system? It's controlled by negative feedback from the thermostat. The hotter the coolant gets, the more the thermostat opens. The rate at which the stat opens is the gain of the system. Finite gain means that the temperature will only approach the set point; a well designed and properly functioning cooling system will react to demand but should still maintain a temperature in some reasonable neighborhood of the set point.

If the temperature rises much above the set point in response to load or ambient temperature, then the system is no longer under control and the conditions are determining the coolant temperature. So, the question is, which stat is the OP running? If it's a 180, then the temperature is out of control and he needs to look at why.

The OP also says that he moved the fan and the characteristics of the system changed for the worse. This points to some loss of efficiency due to the change. Maybe the fan shroud will correct this, maybe not.

Also, Chris' 165 stat does nothing, since he never operates in that range.