The myth
There's a huge myth out there that's been making rounds on the Internet probably since the Internet first started. Go to almost any car forum out there, and you'll find a slew of members who like to push the idea that making your engine run cooler is a good thing.
Often times they'll suggest getting low temperature thermostats, converting the cooling fan to an electric one, and even spending big money on aftermarket "large capacity" aluminum radiators. All of this is supposed to make your engine run cooler than it does from the factory. Truth be told, those can in some circumstances help your engine run cooler at times but that's not always a good thing.
Why do you want your engine to run cooler?
First off, ask yourself this, "Why do I want my engine to run cooler?". Seriously, can you answer that with any sort of technical knowledge? Most people will probably answer something a long the lines of, "Well, if I make my engine run cooler, it will perform better.".
Will I gain anything from a cooler running engine?
No, you will not. The engineers who designed your TJ built the engine with an optimal range of operating temperatures in mind. That "optimal range" is there for a reason. When your engine runs within those temperature ranges, it's going to get the best performance, fuel economy, emissions, etc.
What about really hot days?
Do you really think that the engineers who designed your vehicle didn't take into consideration that a god majority of the population lives in hotter climate states such as Texas, Arizona, and the Southern states as well? Do you think that those same engineers don't realize how hot it gets there when you're sitting at a stop light with the AC on, 120 degrees outside, etc.? Well then, if you think the engineers didn't account for that, they must be real idiots.
What happens if I make my engine run cooler?
If you fall sucker to one of these myths and decide to make your engine run cooler, you'll be doing more harm than good. As stated above, your engine (and your ECU) are designed to run in an optimal temperature range. When you dump money into all these parts that make your engine run cooler, you're reverse engineering something that was already engineered well to begin with. By making your engine run cooler you'll be wasting money, possibly worsening your fuel economy, and potentially doing damage to certain sensors (i.e. O2 sensors) that are designed to work in conjunction with the ECU and an engine that is running the way that the ECU wants it to.
Conclusion
Please do not fall victim to this myth. There is absolutely no reason at all that the majority of us need to make our TJs run cooler. Take guys like @Jerry Bransford for instance, who are wheeling in the extreme conditions down there in Johnson Valley. Jerry is slow crawling along as he climbs rocks, and he's using a stock cooling system. If Jerry had any issues with overheating, don't you think you'd have heard about it by now?
The only reason I can see for running an aftermarket cooling system on a TJ would be if you have some sort of an engine swap (i.e. a V8, Cummins, etc.), where the stock TJ cooling system simply won't work. It might also be an exception of you had an extremely high horsepower 4.0 stroker engine (but even then, you'd need to find someone to properly tune your engine for it). But again, this is likely less than 1% of us that own TJs.
So please don't go wasting your money on foolish things like low temp thermostats, electric fan conversions, and "high performance" radiators. It's all a waste of money that will yield no positive gains whatsoever. This is one of those internet myths that continues to float around, but should be shot dead.
This is my attempt at shooting it dead!
There's a huge myth out there that's been making rounds on the Internet probably since the Internet first started. Go to almost any car forum out there, and you'll find a slew of members who like to push the idea that making your engine run cooler is a good thing.
Often times they'll suggest getting low temperature thermostats, converting the cooling fan to an electric one, and even spending big money on aftermarket "large capacity" aluminum radiators. All of this is supposed to make your engine run cooler than it does from the factory. Truth be told, those can in some circumstances help your engine run cooler at times but that's not always a good thing.
Why do you want your engine to run cooler?
First off, ask yourself this, "Why do I want my engine to run cooler?". Seriously, can you answer that with any sort of technical knowledge? Most people will probably answer something a long the lines of, "Well, if I make my engine run cooler, it will perform better.".
Will I gain anything from a cooler running engine?
No, you will not. The engineers who designed your TJ built the engine with an optimal range of operating temperatures in mind. That "optimal range" is there for a reason. When your engine runs within those temperature ranges, it's going to get the best performance, fuel economy, emissions, etc.
What about really hot days?
Do you really think that the engineers who designed your vehicle didn't take into consideration that a god majority of the population lives in hotter climate states such as Texas, Arizona, and the Southern states as well? Do you think that those same engineers don't realize how hot it gets there when you're sitting at a stop light with the AC on, 120 degrees outside, etc.? Well then, if you think the engineers didn't account for that, they must be real idiots.
What happens if I make my engine run cooler?
If you fall sucker to one of these myths and decide to make your engine run cooler, you'll be doing more harm than good. As stated above, your engine (and your ECU) are designed to run in an optimal temperature range. When you dump money into all these parts that make your engine run cooler, you're reverse engineering something that was already engineered well to begin with. By making your engine run cooler you'll be wasting money, possibly worsening your fuel economy, and potentially doing damage to certain sensors (i.e. O2 sensors) that are designed to work in conjunction with the ECU and an engine that is running the way that the ECU wants it to.
Conclusion
Please do not fall victim to this myth. There is absolutely no reason at all that the majority of us need to make our TJs run cooler. Take guys like @Jerry Bransford for instance, who are wheeling in the extreme conditions down there in Johnson Valley. Jerry is slow crawling along as he climbs rocks, and he's using a stock cooling system. If Jerry had any issues with overheating, don't you think you'd have heard about it by now?
The only reason I can see for running an aftermarket cooling system on a TJ would be if you have some sort of an engine swap (i.e. a V8, Cummins, etc.), where the stock TJ cooling system simply won't work. It might also be an exception of you had an extremely high horsepower 4.0 stroker engine (but even then, you'd need to find someone to properly tune your engine for it). But again, this is likely less than 1% of us that own TJs.
So please don't go wasting your money on foolish things like low temp thermostats, electric fan conversions, and "high performance" radiators. It's all a waste of money that will yield no positive gains whatsoever. This is one of those internet myths that continues to float around, but should be shot dead.
This is my attempt at shooting it dead!
