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Design Engineering

Design Engineering Fuel Rail & Injector Cover Kit | Jeep Wrangler & Cherokee 1997-2004 4.0L | Reduces Heat Soak & Vapor Lock | Reflective Heat Shield | Made in USA

  • Based on 1,187 reviews
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Availability: In Stock.
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Arrives Saturday, Jul 18
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Features

  • HEAT SOAK & VAPOR LOCK SOLUTION Reflective heat shield material blocks radiant engine heat, reducing fuel rail and injector temperatures to prevent vapor lock and maintain performance.
  • HIGH-QUALITY FUEL RAIL & INJECTOR COVERS Aluminum-skinned, glass-fiber backed covers protect fuel rails and injectors from excessive engine heat for long-term reliability.
  • PERFORMANCE MANIFOLD COVER Dual-sided aluminum barrier with high-temp insulation sandwiched between provides maximum thermal protection for inline-6 engines.
  • COMPLETE KIT FOR EASY INSTALLATION Includes manifold shield, fuel rail cover, six injector covers, 12 OE replacement O-rings, and detailed instructions for professional-grade results.
  • DIY-FRIENDLY INSTALLATION Hook-and-loop design allows easy mounting in your garage with basic tools (10mm socket, ratchet, flathead screwdriver, fuel rail disconnect tool).
  • Made in the USA

Description

Design Engineering, Inc. Fuel Rail & Injector Cover Kit for Jeep Wrangler and Cherokee (1997–2004, 4.0L Inline-6) is a professional-grade heat protection system designed to reduce heat soak and prevent vapor lock. The kit includes a manifold heat shield, fuel rail cover, six fuel injector covers, and 12 OE replacement O-rings, all constructed from high-temperature glass-fiber-backed aluminum to block radiant engine heat. Installation is simple with the included hook-and-loop design and instructions, requiring only basic tools. By lowering fuel rail and injector temperatures, this kit protects critical fuel system components, maintains fuel stability, and improves engine performance under extreme conditions. Made in the USA by DEI, it delivers durable, high- performance thermal protection for Jeep owners.

Brand: Design Engineering


Color: Silver


Material: Aluminum


Exterior Finish: Design Engineering Fuel Rail & Injector Cover Kit


Item dimensions L x W x H: 6.25 x 1.88 x 15.38 inches


Brand Name: Design Engineering


Model Number: 10378


Manufacturer Part Number: 10378


OEM Equivalent Part Number: 10378


Manufacturer: Design Engineering, Inc.


UPC: 607078103789


Global Trade Identification Number: 89


Manufacturer Warranty Description: DEI warrants to the original retail purchaser with proof of purchase for warranty determination that its products are free from defects in material and workmanship while purchaser owns the vehicle upon which such product(s) were originally installed. DEI’s obligation under this warranty shall be limited to the repair or replacement of parts that are determined by DEI to be defective, or refund of the products original purchase price, at DEI’s option, of the alleged defective product. We pledge that if at any time you encounter a problem with our products, we will strive to correct the problem in the most timely and efficient way possible, subject to the terms, conditions, and Limitations contained herein.


Included Components: Fuel Rail & Injecter Cover


Unit Count: 1.0 Count


Item Type Name: Fuel Rail and Injector Cover Kit for Jeep (1997 - 2004, 4.0L Engine)


Color: Silver


Exterior Finish: Design Engineering Fuel Rail & Injector Cover Kit


Style Name: Modern


Item Dimensions: 6.25 x 1.88 x 15.38 inches


Item Weight: 9.6 ounces


Compatible with Vehicle Type: 1997-2004 4.0L Jeep models with inline 6 motor


Automotive Fit Type: Vehicle Specific Fit


Material Type: Aluminum


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Saturday, Jul 18

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Similar Products

Top Amazon Reviews

    • Looks Neat
My fuel rail was leaking so decided to replace it and saw this product and figured it to be a good idea. I’ve never had heat soak/vapor lock issues with my 4.0L but hopefully with this product I’ll never have to deal with it. Right from the box you can tell the heat shields are quality. The kit is definitely a bit pricy but well worth it because I didn’t have to modify any of the heat shields for my 02’ WJ. Instructions were clear and installation was a breeze. The only awkward part was putting the heat shields on the injectors but it all worked out. Overall, definitely worth it if your 4.0L runs hot and not to mention it looks pretty neat when installed. ... show more
Reviewed in the United States on February 24, 2026 by Justin Pagan
    • (UPDATED) I'll admit I was wrong
Well guys it finally happened. We finally got our first hot enough day in Memphis, Tennessee to require A/C and test out my new fuel rail/injector insulation. The install went okay, I put it on a while ago while it was still cold outside. The injector o-rings it came with are a perfect fit. The injector wraps are a so-so fit. The manifold shield I did not use since my factory shield (they're identical) is still intact. The fuel rail fits like a glove once you figure out where to cut the damn thing to make it POSSIBLE to wrap around the rail. Cut a hole for your schrader valve if equipped. But when it's all said and done? It looks great and fits tight. So it's gotta work, right? UPDATE: July 7, 2019, Everyone I have to admit I was wrong when I first wrote my review. I removed the unnecessary bickering and have to apologize to DEI, you guys did a good job after all. I don't know why I previously had symptoms of heat soaking on a ~70* day with this first installed but now that we are well into the 90's I haven't had ANY issues whatsoever. A/C on, hot humid days stuck in interstate traffic, stop and go, very little airflow through the radiator, yet when I get home and shut the Jeep off, change clothes, and head back out for the gym; no vapor lock. I don't have any active fault codes and the only thing I've done to the engine since this install was I also replaced a faulty Throttle Position Sensor. Perhaps the failing TPS gave me SIMILAR symptoms to vapor locking that were affected by excessive heat while still driving and I just thought this insulation kit was to blame. I don't know, but I do know that I was wrong. I'm running harder and hotter than ever in Memphis traffic and getting absolutely NO vapor lock on any cylinder. So this kit is doing great and I wouldn't hesitate to go wheeling in a desert somewhere. I'll continue to update this if anything changes but for now, I highly recommend this kit! I had to come back here to eat my words so I can keep my feedback as accurate as possible. Plus, it's terribly simple to install. I'll add pictures soon. Thanks again! ... show more
Reviewed in the United States on April 7, 2019 by Cub
    • A little pricey, but quality product A little pricey, but quality product
Review Image by Brad
Review Image by Brad
Review Image by Brad
I use my Jeep XJ to tow a small boat, so I am all too familiar with heat soak issues. I would leave it running on the boat ramp so I didn't have to shudder and shake, barely making it up the ramp. So far this kit solved the problem. I also added hood vents to keep the engine bay Temps down, but I'm sure this kit is enough to stop the heat soak problems. All the fuel rail brackets and holes lined up perfectly, except for the pressure regulator, but one cut with some scissors fixed that. My factory heat shield was totally destroyed, see photo, so the new one looks great. Top of the engine looks much better. I found it best to install the injector wraps after the fuel rail was re-installed. It was too difficult to line up the injectors with holes and connect the electrical connectors with the wraps installed. Overall a nice product. I will definitely save some fuel/wear and tear by not leaving the jeep running during stops. ... show more
Reviewed in the United States on March 28, 2022 Reviewed in the United States on March 28, 2022 by Brad
    • DEI quality DEI quality
Review Image by Liberated Seaman
Review Image by Liberated Seaman
I have ran 2 kits. The cheaper kit you get on Amazon or eBay and this kit. The cheaper kit falls apart over 2 years. Heat shield if some sort of cheap material. The DEI is new and I am giving it a go. Right out of the box I can tell it's got better material and the main heat shield has a foam barrier and not some rubberized inner like the cheaper kits. The reflection kit is also nicer. As with any Jeep project, save the money for the nice kit. This kit comes with injector o-rings. I didn't use them as I had a set already available, but as an FYI. ... show more
Reviewed in the United States on June 4, 2024 Reviewed in the United States on June 4, 2024 by Liberated Seaman
    • Working so far. Working so far.
Review Image by Nathanael
Review Image by Nathanael
Review Image by Nathanael
Review Image by Nathanael
Overall I was very satisfied with the product. I installed it on a Jeep 4.0 engine while replacing the fuel rail and injectors. Biggest frustration was installing the heat shield. It is fragile and a little tough to install without removing the wiring harness. In the end I did end up removing the throttle body to fit the shield adding to the time of the install. The fuel wrap cutouts were a little misaligned due to the release valve. When I cut around the release valve area it fit like a glove. With a little bit of modification, It is a great product and worth the hassle of installation. So far I haven’t had the same issue of the 3rd cylinder heat soak issue that is typical with the Jeep engines. ... show more
Reviewed in the United States on November 12, 2018 Reviewed in the United States on November 12, 2018 by Nathanael
    • It does it’s job and it fits great
This is definitely a well put together product, it fits REALLY well, almost too well, and it works. I was having a slight misfire issue in my XJ when I shut it down while hot and while wheeling and started it again without letting it cool down. This product seems to have helped with that a bunch. It didn’t completely fix that issue, but I’m sure there’s other aspects to that problem as well, it is a Jeep after all... The fit on the parts is really good, they definitely got their measurements right. The wrap on the fuel rail itself, though, is almost too tight. It was a little difficult to get it over the ports for the injectors on the short side by the fuel input. With some patience, it was certainly doable but some extra tolerance would have been nice. Overall, I’m very happy with it and I’m glad I did it. I was hesitant, but it’s been worth the money. ... show more
Reviewed in the United States on May 9, 2021 by Travis
    • Probably should be on these motors from the factory. Especially in Cherokees.
Spendy? Sure. Quality? Very much. I put this on a 1997 Cherokee 4.0, and I can say that vapor lock, hard hot start and the stumble on acceleration just after a hot start are greatly reduced. If it isn't, run alcohol free fuel, and replace the fan clutch. Cherokees are notorious for cooling issues when everything isn't perfect. ... show more
Reviewed in the United States on June 6, 2026 by Anthony Rose
    • Perfect Perfect
Review Image by Juz10 Mc
Review Image by Juz10 Mc
Fits almost perfect, anyone with a little sense can make it work. Great quality and keeps everything important a little bit cooler.
Reviewed in the United States on July 6, 2025 Reviewed in the United States on July 6, 2025 by Juz10 Mc

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