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Derale Fluid Control Thermostat Kit w/ 1/2" NPT Ports

Derale Fluid Control Thermostat Kit w/ 1/2" NPT Ports

Item # D15719
Our Price: $64.59
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Shipping Weight: 1.18 lbs
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Derale Thermostat Accessories and Parts - D15719
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Warm your engine faster with this thermostatic bypass system. At temperatures below 180 degrees, an inner valve opens, allowing 90 percent of the oil to bypass the cooler, thus heating faster. Great for cold climates! 1-800-940-8924 to order Derale accessories and parts part number D15719 or order online at Free expert support on all Derale products. Great prices and Fastest Shipping for Derale Fluid Control Thermostat Kit w/ 1/2" NPT Ports. Accessories and Parts reviews from real customers.
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  • Reviews (4)
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Derale Accessories and Parts - D15719

  • Engine Oil Coolers
  • Thermostat
  • Derale
  • 1/2 Inch NPT Ports

Warm your engine faster with this thermostatic bypass system. At temperatures below 180 degrees, an inner valve opens, allowing 90 percent of the oil to bypass the cooler, thus heating faster. Great for cold climates!


  • Allows your engine to warm up faster
  • Includes inner valve that opens and closes according to oil temperature
  • Maintains system pressure
  • Prevents air pockets
  • Eliminates cold-oil shock
  • Increases flow, moving up to 20 gallons per minute
  • Can be used with either engines or transmissions
  • Has an ultra-bright finish
  • Includes brass fittings and hose clamps
  • Made in USA


  • 1/2" NPT inlet/outlet ports
  • Rated up to 200 psi
  • 1-Year warranty

When fluid temperatures exceed 180 degrees, the thermostat's interior valve closes so that 95 percent of the oil will be directed to the cooler. When the temperature falls below 180 degrees, however, the valve opens, allowing 90 percent of the oil to bypass the cooler and head back into either your engine or transmission. Preventing that fluid from entering the cooler will help to raise its temperature faster so your vehicle will be ready to go sooner - no more long waits, no more cold-oil shock. When valve is in bypass mode, 10 percent of the oil is still allowed through to the cooler to maintain constant system pressure.

Mount with Mounting Bracket Kit for Derale Fluid Control Thermostats (D25793).


15719 Derale Standard Series Fluid Control Thermostat Kit

Installation Details D15719 Installation instructions

Customer Reviews

Derale Fluid Control Thermostat Kit w/ 1/2" NPT Ports - D15719

Average Customer Rating:  4.0 out of 5 stars   (4 Customer Reviews)

Warm your engine faster with this thermostatic bypass system. At temperatures below 180 degrees, an inner valve opens, allowing 90 percent of the oil to bypass the cooler, thus heating faster. Great for cold climates!


Moved oil filter because the old cast aluminum (zinc) part had cracked. Replacement couldn't be found so I had a machine shop cut some 1/2-in. aluminum plate to cover the old mounting location on the engine, drilling & tapping it for the remote filter fittings. Bolted the relocated oil filter piece to the firewall and woo hoo! Much easier to change filters now!
Had 3 incidents--stock filter, metric, blew off driving down the road. Hafta use the Fram filter that the instructions call for, not the one your engine manufacturer recommended.
Months later the pressure hose, one carrying oil from engine to the filter, blew off. Had to double-clamp it to get it to stay on.
Finally, noticing an oil leak a few months later, I found a 3mm long slice or break in the pressure line, parallel to the flow and located 2 or so inches back from the engine-side fitting. Replaced line and, so far, OK


Don't confuse this 1/2" NPT model with the smaller 3/8" NPT ported Derale or clones. This is a full-sized thermostat with enough flow for a racing engine.

Purpose of this device is to block oil to your oil cooler until the engine gets to and above operating temp. The smaller 3/8" device is better suited to transmission coolers or stock to mild air-cooled VW engines.

We bought this 1/2" device for a 2.2 litre air cooled VW road racing engine, which needs the flow.


Price and service great. Same product I saw on other websites but much cheaper.



See what our Experts say about this Derale Accessories and Parts

  • The Derale Fluid Control Thermostat Kit Fit 2011 the Honda Odyssey Touring Elite
    Fluid Control Thermostats, including # D15719, are not vehicle specific. I recommend you to visit a local Honda dealer to ask them for the inner diameter of the transmission lines on your Odyssey to know for sure. or you can inspect the fitting on your van yourself.
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  • How to Route Supplemental Transmission Cooler with Factory Cooler on Chevy Silverado
    The ideal setup is to run the fluid from the factory cooler, to the supplemental cooler, and then back to the transmission. This will keep the fluid as cool as possible. If you are worried about it being too cold like in the winter you would need to just let the truck idle to warm it up and then you will be good to go. Or the ideal solution is to use a thermostatic bypass that allows the cooler to be bypassed till the fluid reaches 180 degrees. For that you would need # D15719. Running...
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  • How Does the Derale Fluid Control Thermostat Kit # D15719 Install
    To plumb a Derale Fluid Control Thermostat Kit # D15719 is actually pretty easy. All you do is run both the send and return line of the transmission to one side and then run both the send and return lines of the cooler to the other side of it. I attached a picture that shows how this will look. You would just need to use the send line after the factory cooler so that the fluid will still run through the factory cooler first. I also attached a link to the install instructions for you to...
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  • Dual Oil Filter Mount and Relocation Kit for a 2005 Ford F-150
    The Engine Oil Filter Relocation Kit, # D15749, that you have referenced should fit your 2005 Ford F-150. The specs for the engine threads and o-ring diameters are listed on the product page and this kit covers all of the most popular sizes. The filter that will fit will have to have 3/4-16 threads. You can use Fram PH8A or equivalent filters. This is a flow-through device. This means the oil pump pushes the fluid through it and will only pump oil through it if the truck is running. You...
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  • Can Transmission Fluid Be Cooled Too Much on a 2005 Dodge Durango
    First, transmission fluid cannot be over cooled so you would not have to worry about that. In the winter time, it would just take longer to warm up. Or you could use a special thermostat adapter, # D15719. This will only allow 10 percent of the fluid to get through until the temperature reaches 180 degrees. You would also need mounting brackets # D25793. For a supplemental cooler, go with the largest one that will fit in the space you have. The most popular cooler for a 2005 Dodge Durango...
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  • Thermostat To Use with the Transmission Cooler Portion of the D15902
    The thermostat unit to use with the # D15902 that you have planned on installing is the part # D13011. If you check out the install video I attached you will see both of these products being installed on a similar Toyota vehicle. The difference is the diameter of the threaded portion of the barbs and not the actual barb itself that the hose attaches to.
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  • Recommendation For Transmission/Engine Oil Cooler on 1995 Ford Ranger V6 Towing 2750 lb Trailer
    An engine cooler and a transmission cooler are always good items to have on your vehicle when towing a trailer. Even though you mention the outside temperatures will be cold, the strain that towing a trailer will put on the engine and transmission of your vehicle will still increase the temperatures of the oil and fluid in your vehicle. The coolers will help keep those temperatures at their best operating levels for optimum life and performance of the engine and the transmission I recommend...
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  • Transmission and Engine Oil Thermostats for a 2013 Ford Explorer XLT Adding Tow Package
    I can help you protect your Explorer XLT, even in the cold climates of Wisconsin. The Derale # D15902 you were looking at is a great choice for your 2013 Ford Explorer XLT. This kit already includes an engine thermostat adapter, so all you will need is the transmission thermostat to complete your setup. The Derale # D15719 is the transmission thermostat kit with fluid control you are looking for. Since you will have to cut the return line as well as the input line, you will need the...
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  • Recommended Fan-Powered Transmission Cooler For 2003 Toyota Sequoia
    The transmission cooler kit I recommend for your 2003 Sequoia is the Derale Hyper-Cool Remote Cooler kit, part # D15960. This kit includes the hardware to connect the cooler and the mounting hardware. This cooler is a stacked-plate cooler with a 500-CFM fan to make sure your transmission fluid stays as cool as possible. The great thing is this is a remote mount kit that can be mounted anywhere you have room under the hood. The cooler measures 13-inches wide x 10-inches tall x 5-5/8-inches...
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  • Recommended Transmission Cooler for a 2013 Chevy Tahoe
    I have the perfect transmission cooler option for you. Generally speaking, the best transmission cooler to use would be the largest one you have available space for. The best place to install a transmission cooler is in front of the radiator/condenser behind the grill on your 2013 Chevy Tahoe. I recommend using the Derale 25-Row, High-Performance, Stacked-Plate Cooler part # D52508 because the plate and fin technology incorporated into this transmission cooler is far more efficient than...
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Info for this part was:

Employee DeAnne T
Updated by:
DeAnne T
Employee Daron K
Updated by:
Daron K

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