For some reason I throughly that all 4.0 has a drain plug. May be in different location?
Improving the cooling on our TJs
- Thread starter TexasTJ2004
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For some reason I throughly that all 4.0 has a drain plug. May be in different location?
Early (pre-HO) definitely did not. I'm not sure about the HO series (1991-95?) From early reading I thought that all TJs had a plug but I guess not. According to Wikipedia one way to break down the major changes is 1996-2001 and then 2001-06. What's mysterious is that my block is in the latter group and I would expect that it would have the drain.
MountaineerTom
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My ‘06 has one. Drivers side, sorta kinda between the area where the pre cats are. An 8mm (if I remember correctly) square drive adapter to remove it.
MountaineerTom
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I think that they show the location of the drain plug. I have the drain plug in my 2004 in that specific location
I just figured out those two red squiggly lines I couldn't figure out self-identify as an arrow.
It’s the drain plug for the coolant in the block. It takes a 8mm square head… I switched to a recessed hex key plug to make the installation much easier (bc plug doesn’t fall off a hex bit when feeding the ~12” extension between the pre-cats).
Edit: @jamespwsullivan I’ve drained my 2005 many times. I couldn’t get the plug out of the 99 that I had for a little bit, so I left it alone when flushing the system.
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The drain plug is 8mm square. This is the way to drain the block.
I also used it monitor he level of rust inside the block.
You can see one before thermocure and the other after.
Finally got to install the Hayden 2791 fan clutch and Derale 17918 Heavy Duty Fan Blade.
It is a proper 6 blade fan with a proper clutch.
Previously I was running the stock fan and the Hayden 2771 fan clutch.
It is a proper 6 blade fan with a proper clutch.
Previously I was running the stock fan and the Hayden 2771 fan clutch.
When you live in Houston area, the concept of winter is very different that what it is let’s say in New York
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MountaineerTom
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What do you think of it so far? I imagine it’s loud.
I tried the 2791 with the stock fan and later of the Derale 6 blade with the Hayden 2771 (I think that’s the HD one). Both setups were loud and stayed engaged for a long time. Felt like some drag with both also. I’m back to the stock fan and 2771 again.
Do you know the CFM difference between stock and the alternatives? I was under the impression that stock was as good or better than the Hayden clutches and Explorer fan, but I can't remember if the Derale 6-blade was discussed.
It is a little louder and it definitely works better than 2771 and stock fan combo.
But not significantly louder.
My original problem was that I am using my TJ as my preferred daily, and plenty of times I have to idle for prolonged periods of time with AC on in Houston 100+F heat.
This is why all this work is needed.
Yes, @Davidtj did the comparison.
Here is his observations (copy pasted):
I found Derale sold a 18 inch reverse rotation 6 blade steel fan
Pt# 17918 I ordered one and Hayden HD clutch pn#2771
Before removing my old fan I did some testing for comparison
When I received new fan was impressed by quality of part made in USA very nice and looked heavy duty ( I have used Derale trans coolers before consistently have a good product)
In comparison to my 5 blade noticed besides extra blade new fan had less pitch, began to wonder if would make a difference, called Derale while they didn't have fan curve data, they did tell fan me was designed to produce 500 to 750 cfm more then stock
This is my test data before and after using Fluke 922 airflow meter
orginal idle 450 cfm 0.21 static
1200 rpm standing 700 cfm 0.35 static
6 blade idle 635 cfm 0.36 static
1200 rpm 1020 cfm 0.48 static
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