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Increased Coolant Flow, Decreased Coolant Temperatures. The rear cylinders on the 5.9/6.7L 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.
Our 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.
Benefits:
Why do I need a Fleece Coolant Bypass?
One of the biggest issues on the 5.9/6.7L Cummins 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.
Application Notes:
We can ship to virtually any address in the world. Note that there are restrictions on some products, and some products cannot be shipped to international destinations.
When you place an order, we will estimate shipping and delivery dates for you based on the availability of your items and the shipping options you choose. Depending on the shipping provider you choose, shipping date estimates may appear on the shipping quotes page.
Please also note that the shipping rates for many items we sell are weight-based. The weight of any such item can be found on its detail page. To reflect the policies of the shipping companies we use, all weights will be rounded up to the next full pound.
Items with weights ove 100 lbs will be subject to a freight and handling fee.
You may return most new, unopened items within 30 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
These items are not returnable or refundable. Please be aware of this when purchasing
-Opened or Damaged Packages
-Truck Freight items
-Special order items (Any Non Diesel item is Special Order)
-Powder Coated / Custom / Painted Products
-Tuning
-Programmers and Related
-Products containing electrical components.
-Emissions Defeating electronics or equipment (No Exceptions)
Products that ship direct from the manufacturer may have delayed tracking upto 2-3 days or more..
If a product is out of stock or shipping direct from the manufacturer, we will send a notifacation email.
Frequently Asked Question.
Fleece Performance
Increased Coolant Flow, Decreased Coolant Temperatures. The rear cylinders on the 5.9/6.7L Cummins suffer from a lack of coolant flow, and therefore, experience the highest coolant temperatures. This...
Fleece Performance
The Fleece CLNTBYPS-CUMMINS-VP Coolant Bypass Kit is a must have on any high performance Cummins Engine. The Cummins engine cooling system was designed to adequately cool a 300-350hp engine. When
Fleece Performance
Increased Coolant Flow, Decreased Coolant Temperatures. The rear cylinders on the 5.9/6.7L Cummins suffer from a lack of coolant flow, and therefore, experience the highest coolant temperatures. This...
Fleece Performance
Increased Coolant Flow, Decreased Coolant Temperatures The rear cylinders on the 5.9/6.7L Cummins suffer from a lack of coolant flow, and therefore, experience the highest coolant temperatures. This...