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- USA
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Ships within 48 hours · Estimated delivery Jul 10 - Jul 15
For Your Every Summer RSVP, with Code: SUMMER15
Description
Fleece Performance Coolant Bypass Kit W/Stainless Braided lines 03-05 5.9L Auto Trans CumminsHelp eliminate the possibility of scored rear cylinders and blown freeze plugs in your Cummins with this Coolant Bypass Kit from Fleece Performance! The Fleece Coolant Bypass with Stainless Lines solves the problem of excessive coolant pressure before it becomes a problem. The integrated secondary thermostat locates at the back of the block and allows coolant to flow freely when at normal operating temperatures ensuring consistent temperatures across
Help eliminate the possibility of scored rear cylinders and blown freeze plugs in your Cummins with this Coolant Bypass Kit from Fleece Performance! The Fleece Coolant Bypass with Stainless Lines solves the problem of excessive coolant pressure before it becomes a problem. The integrated secondary thermostat locates at the back of the block and allows coolant to flow freely when at normal operating temperatures ensuring consistent temperatures across all six cylinders and eliminates excessive pressure. The kit comes with high quality AN o-ring fittings and AN hose connections with braided hose to ensure a leak free installation and installs in two hours or less!Increased Coolant Flow, Decreased Coolant Temperatures
The rear cylinders on the 24 Valve Cummins suffer from a lack of coolant flow, and therefore, experience the highest coolant temperatures. This can cause excessive pressure to build in the cooling system, especially the rear of the block and blow out freeze plugs externally, or the smaller diameter plugs under the valve cover, leading to a failure. Fleece's coolant bypass kit adds a secondary thermostat, that unlike other brands, works based on temperature instead of excessive pressure. This solves the problem before pressure becomes an issue by ensuring consistent temperatures across all six cylinders.
Why do I need a Fleece Coolant Bypass?
One of the biggest issues on the 24 valves is the coolant flow problem to the rear cylinders. This can cause catastrophic failure or blow outs of the freeze plugs in an over-temperature / over-pressure condition. The Fleece Coolant Bypass is one of the most important additions you make to improve the reliability and longevity of the Cummins platform.
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4.5 ★★★★★
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Product Reviews
★★★★★ 5
Great socks!
Size: Large, Color: (001) Black / Black / White
These fit true to size. Good socks.
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Reviewed in the United States on February 23, 2026
★★★★★ 5
Great for walking all day at work as well
Size: X-Large, Color: (001) Black / Black / White
I walk approximately 10 miles a day at work, in a manufacturing setting. On concrete with steel toe shoes. My feet have been begging me to change from the socks that I have worn for years. I have worn these other name brand socks for probably 10 years. So, change was obviously something I had to be pushed into. I got on Amazon and searched for training socks. I read the description. Glanced at the reviews. I decided to move forward with purchasing these. I could not have been happier. My feet began feeling better immediately. And the priced was very reasonible.
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Reviewed in the United States on April 12, 2026
★★★★★ 5
You have one pair of feet. Treat them kindly with a pair of UA socks
Size: Large, Color: (100) White / White / Black
Soft and tough. Easy on the feet. Nice fit prevents sore spots and blisters.
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Reviewed in the United States on December 3, 2025
★★★★★ 5
I stay on your foot they don’t slip in your shoe
Number of Items: 3, Color: White/Neutral (3-pairs), Size: Medium
This is the only socks I wear Under Armour because they stay in place I wear a size 8, but they’re more comfortable with a large instead of a medium, but I wear both because I have them already and you can pull them to stretch them out a little bit
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Reviewed in the United States on May 12, 2026
★★★★★ 5
Great fit, truly doesn’t slide off heel
Number of Items: 3, Color: White/Neutral (3-pairs), Size: Medium, Number of Items: 3, Color: White/Neutral (3-pairs), Size: Medium
I’ve scoured all the lands looking for a no-show sock that was 1) thin, 2) quality, soft, breathable material, 3) didn’t dig into my feet/heels, 4) doesn’t shrink, and most importantly 5) stays on the back of my heel without a bulky non-slip rubber piece and these check all the boxes! Perfect for low profile women’s work shoes like Keds, etc. Not low enough for most flats though. I wear a women’s size 9.
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Reviewed in the United States on April 19, 2025