SKU: 40351058994

Fleece Performance Coolant Bypass Kit 03-07 5.9L Manual Trans Cummins

Sale price$170.55 Regular price$189.50
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Description

Fleece Performance Coolant Bypass Kit 03-07 5.9L Manual Trans CumminsHelp eliminate the possibility of scored rear cylinders and blown freeze plugs on your 5. 9 Cummins with this Coolant Bypass Kit from Fleece Performance! The Fleece Coolant Bypass 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

Help eliminate the possibility of scored rear cylinders and blown freeze plugs on your 5.9 Cummins with this Coolant Bypass Kit from Fleece Performance! The Fleece Coolant Bypass 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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SKU: 40351058994

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4.2 ★★★★★
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Matthew Ericksen
Port Orchard, US
★★★★★ 5
Looks good
Color: Light Grey, Size: Large
Good quality and comfy lol baggy but looks good
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Reviewed in the United States on May 19, 2026
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Curt Briscar
Pawtucket, US
★★★★★ 3
Decent Suit, But the Sizing Is Way Off
Color: Black, Size: XX-Large
I really wanted to like this suit because the material and overall look are actually pretty decent for the price. The jacket and vest fit about how I expected for an XXL—no complaints there. But the pants? I swear they could fit a small horse. I ordered the WULFUL Men’s 3-Piece Slim Fit Suit in Black, XX‑Large, and the pants that came with it were massive. They’re supposed to be part of a “slim fit” set, but the waist and leg width are so oversized that I have no idea what size they were aiming for. It honestly feels like they just toss in whatever pants are nearby. If you’re buying this suit, be prepared for a trip to the tailor… or to exchange the whole thing. The suit itself is okay, but the sizing consistency is terrible.
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Reviewed in the United States on January 26, 2026
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Verified Purchase
R. Wilkerson
Boise, US
★★★★★ 5
Good quality suit, but size up.
The suit seemed was very good quality. It was too small, so size up. We had to send it back, but the refund process was very simple and easy! Thank you for the easy transaction!
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Reviewed in the United States on February 22, 2026
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Tina Howell
Bozeman, US
★★★★★ 5
Fit
Color: Black, Size: X-Small
This suit is perfect. I was worried because we were running out of time to prepare for prom. We got it the day before and it was perfect. Highly recommend this suit!!
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Reviewed in the United States on April 24, 2026
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Paniz Ameri
Draper, US
★★★★★ 5
Super cute
Size: 7 Toddler, Color: Glitter Clear/Pink
Looks cute and smells good.
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Reviewed in the United States on March 4, 2026

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