ejay
TJ Addict
Still unsure if I'll install a kit or not. Curious to know how much cfm an OEM clutch based mechanical fan on the TJ really pushes.
The myth: low temp thermostats, electric fan conversions & "performance" radiators
- Thread starter Chris
- Start date
Still unsure if I'll install a kit or not. Curious to know how much cfm an OEM clutch based mechanical fan on the TJ really pushes.
Wombat
TJ Enthusiast
We all should keep in mind that although a TJ may well be much enhanced by modifications with respect to oversized tires - and the obvious necessary adaptations that may be required in doing so - we all tend to tinker unnecessarily with other stuff. As has been reiterated in here time and time again, "the stock cooling system is optimum!" If your 4.0L is overheating there is most likely something else at play that's causing it.
There is of course one exception - isn't there always - when fording deep river crossings the stock fan blades can bend forward into the radiator so there may be an advantage for those running an electric fan with a cut off switch, having said that I have completed quite a few deep crossings without any such issue but then I am aware of what can happen in such circumstances and keep my reves constant and low.
I have a good mate who has a auto shop that has been specializes in cooling and air conditioning for thirty years, he owns a land cruiser and has experimented over the years with a lot of aftermarket systems on a plethora of vehicles including Jeeps and our beloved TJ's. I thought that I should think about an alloy radiator and perhaps a electric/thermo fan system and this - keep in mind he is a friend and is trying to offer me advice on that basis - is what he said... "Do you really want to spend a couple of grand on your cooling system?" He went on to say all those alloy radiators you see on ebay - and the like - are absolute crap! You would need to spend a sh&% lode to do it properly and in most cases it will be of little to no advantage. He then went on the tell me about all the cracked heads and seized motors he has replaced on account of failed thomo fans and one or two that forgot to turn them back on after fording. I know, you wouldent be that stupid right? You can imagine the excitement after successfully getting through the seemingly uncrossable river crossing? trust me it's easily forgotten.
He also does a lot of V8 conversions and that would be the only time he might recommend upgrading the cooling system.
We all need to keep in mind that just because a manufacturer make and recommend you fit whatever it might be they are peddling, doesn't mean it's better, necessary, or even fit for purpose. As a rule "Keep it simple stupid" wherever possible and simply maintain what works because in the end you will be able to fix issues without having to worry if it's got something to do with other mods.
There is of course one exception - isn't there always - when fording deep river crossings the stock fan blades can bend forward into the radiator so there may be an advantage for those running an electric fan with a cut off switch, having said that I have completed quite a few deep crossings without any such issue but then I am aware of what can happen in such circumstances and keep my reves constant and low.
I have a good mate who has a auto shop that has been specializes in cooling and air conditioning for thirty years, he owns a land cruiser and has experimented over the years with a lot of aftermarket systems on a plethora of vehicles including Jeeps and our beloved TJ's. I thought that I should think about an alloy radiator and perhaps a electric/thermo fan system and this - keep in mind he is a friend and is trying to offer me advice on that basis - is what he said... "Do you really want to spend a couple of grand on your cooling system?" He went on to say all those alloy radiators you see on ebay - and the like - are absolute crap! You would need to spend a sh&% lode to do it properly and in most cases it will be of little to no advantage. He then went on the tell me about all the cracked heads and seized motors he has replaced on account of failed thomo fans and one or two that forgot to turn them back on after fording. I know, you wouldent be that stupid right? You can imagine the excitement after successfully getting through the seemingly uncrossable river crossing? trust me it's easily forgotten.
He also does a lot of V8 conversions and that would be the only time he might recommend upgrading the cooling system.
We all need to keep in mind that just because a manufacturer make and recommend you fit whatever it might be they are peddling, doesn't mean it's better, necessary, or even fit for purpose. As a rule "Keep it simple stupid" wherever possible and simply maintain what works because in the end you will be able to fix issues without having to worry if it's got something to do with other mods.
That gets tossed out into every electric fan discussion. Has anyone ever seen it? In all the years I've been reading Jeep forums I've never seen a pic or report of it actually happening. In fact I know of 3 incidents that showed the opposite related to me by folks I trust. All 3 were similar, hood high water or water high enough to cover a fair bit of the fan blade. One in particular was highly interesting. They had to open the hood to get the winch remote plugged in and he reported that his fan had almost stopped turning in the water with the engine running at idle.
Another went through a very silty crossing and was pissy for months after due to the silt taking out everything with a bearing.
There is an article running around about what Jeep did to get the Gladiator up to snuff with regard to its tow capacity. Once you read it and see what they did to get it working, you'll understand quickly that we are the engineering equivalent of cavemen when it comes to "improving" our cooling systems.
I would say this is 99% percent true. The TJ was designed over 2 decades ago. A lot of tech available now was either unavailable, or not economical to put into the TJ at the time. So improvements can be made, but they'll be small since they will be held back by other limitations.
Wombat
TJ Enthusiast
It's a known issue with the landcruiser 100 series, down here they fit an 80 series radiator to fix the problem and I killed my GTR XU-1 radiator driving through a little creek, the fan cut a massive hole at the base of the radiator and it completely drained out, you get that if you try and ford water in a sports car, does that count?
Yep you're right it's tried and proven so why would I change out a caveman system if it works perfectly?
My 2001 OEM 4.0L would run at 100c no matter what the ambient temp and I go wheeling in temps up to 45 celsius, over 200,000 k's, never had an issue with boiling.
If anything my new 4.6 Golen runs too cold! well see how it stand up to 45 degrees this summer but I don't need it to run cooler then it already is and overheating has never been an issue for me, never!
Fitting an electric fan is unnecessary.
Wombat
TJ Enthusiast
After a second read perhaps I get your point - we are not engineers so just maintain the stock system.
I think my new 4.6 is running so chilled on account of the high volume water pump, probably shouldn't have bothered.
It should be running that low due to an improper thermostat. The thermostat controls the minimum operating temp, the system capacity controls the high side. Another way to think about it is if you had a hose fed from a large cold water lake so you could never heat up the volume. The system would have an endless supply of cold water to keep the engine cool so the thermostat would come into play to slow down the coolant circulation through the engine to maintain a minimum operating temperature.
You really need to read that article on the Gladiator.
Wombat
TJ Enthusiast
thanks @The shuggs for the link to the Gladiator article?
rebuilt one or two engines in my time so I have a vague understanding of how a thermostat works and why it's there to get to op temp as quickly as possible then open to allow the radiator to flow into the block, if you remove it, it takes too long to get to operating temp but thanks for the explanation - a good one at that.
I just got off the phone to Chad and he says it's fine, it's running the 95 thermostat but I might change it out just incase it's not opening all the way, I've had a few that have failed to work properly from new, it's common.
he also said the higher then normal oil pressure readings is what they have experienced with the stock sending unit so yeah, I'm probably concerned about nothing.
he had a laugh when I said it's running too cool lol (see above photo)
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