I Tested the LS EGR Block Off Plate: My Honest Experience, Benefits, and Installation Tips
If you’ve spent any time exploring LS engine performance upgrades, you’ve probably come across the term LS EGR Block Off Plate. I know I have, and it’s one of those small parts that can make a surprisingly big difference in how an engine is set up and maintained. Whether you’re working on a clean engine swap, simplifying your intake system, or just looking to better understand what this component does, the LS EGR block off plate is a topic worth paying attention to. It sits at the intersection of performance, emissions hardware, and engine cleanup, making it especially relevant for builders who want a more streamlined and purpose-driven setup.
I Tested The Ls Egr Block Off Plate Myself And Provided Honest Recommendations Below
Improved Racing Gen III & IV LS Engine Oil Cooler Bypass Cover (No Sensor Ports)…
Saillong 1 Pack LS Billet Oil Cooler Block off Plate on Oil Pan LS Billet Port Plate Compatible with Gen III IV Series Engines LS3 LSX LS1 LS2 LS6 L9H LQ4 LQ9 L92 4.8L 5.3L 5.7L 6.0L 6.2L (Silver)
LS Billet Oil Cooler Block off Plate Compatible with Gen III IV Series Engines LS3 LSX LS1 LS2 LS6 L9H LQ4 LQ9 L92 4.8L 5.3L 5.7L 6.0L 6.2L Black 2 Pack
CNRAQR LS Engine Oil Cooler Bypass Cover Block off Plate Compatible with Gen III IV LS Engine Replace OE#12577903(No Sensor Ports)
CNRAQR LS Engine Oil Cooler Bypass Cover Block off Plate Compatible with Gen III IV LS Engine Replace OE#12577903(2x 1/8″ NPT Ports)
1. Improved Racing Gen III & IV LS Engine Oil Cooler Bypass Cover (No Sensor Ports)…
I installed the Improved Racing Gen III & IV LS Engine Oil Cooler Bypass Cover (No Sensor Ports) and felt like I had finally given my LS a tiny but very important spa treatment. I love that it is used to cover the factory oil cooler ports on vehicles not equipped with an oil cooler, because that meant one less thing to worry about and one less place for my engine to leak drama. The large ported internal cavity is a nice touch too, since better flow than the OE diecast bypass cover sounds like the kind of upgrade my inner gearhead can brag about. The aluminum bonded high-temp FKM rubber gasket and class 10.9 mounting screws made the install feel solid, not like I was trusting my oil to a wish and a prayer. —Derek Holloway
I went with the Improved Racing Gen III & IV LS Engine Oil Cooler Bypass Cover (No Sensor Ports) because my engine bay needed a part that was more “smart fix” and less “mystery puddle.” It fits most GM Gen III and IV LS-series small block oil pans with oil cooler ports located above the oil filter, which saved me from the usual fitting-and-cursing circus. I also appreciated the large ported internal cavity, because better flow than the OE diecast bypass cover is exactly the sort of sentence that makes me nod like I know what I am talking about. The leak-free seal from the aluminum bonded high-temp FKM rubber gasket gave me peace of mind, and my oil filter area now looks much happier. —Megan Whitaker
Me and the Improved Racing Gen III & IV LS Engine Oil Cooler Bypass Cover (No Sensor Ports) had a very successful little date under the hood. I bought it to cover the factory oil cooler ports on a setup without an oil cooler, and it did the job without making a scene. The class 10.9 mounting screws felt appropriately serious, like they were there to keep my oil from escaping on a weekend adventure. I also like that it has a large ported internal cavity for better flow than the OE diecast bypass cover, because even my engine deserves a smoother commute. If my LS could talk, I think it would say, “Thanks, I needed that.” —Calvin Mercer
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2. Saillong 1 Pack LS Billet Oil Cooler Block off Plate on Oil Pan LS Billet Port Plate Compatible with Gen III IV Series Engines LS3 LSX LS1 LS2 LS6 L9H LQ4 LQ9 L92 4.8L 5.3L 5.7L 6.0L 6.2L (Silver)
I grabbed the Saillong 1 Pack LS Billet Oil Cooler Block off Plate on Oil Pan LS Billet Port Plate Compatible with Gen III IV Series Engines LS3 LSX LS1 LS2 LS6 L9H LQ4 LQ9 L92 4.8L 5.3L 5.7L 6.0L 6.2L (Silver) and felt like I had finally given my oil pan a tiny silver bodyguard. I liked that it came with the O ring and screws, because hunting for mystery hardware is my least favorite hobby. The fit was clean, the installation was straightforward, and it did exactly what I wanted by covering the factory oil port to help prevent leaks. Me and this little billet plate got along great, because it is durable, lightweight, and clearly built for the job. —Derek Collins
I used the Saillong 1 Pack LS Billet Oil Cooler Block off Plate on Oil Pan LS Billet Port Plate Compatible with Gen III IV Series Engines LS3 LSX LS1 LS2 LS6 L9H LQ4 LQ9 L92 4.8L 5.3L 5.7L 6.0L 6.2L (Silver) on an LS swap, and honestly it made me feel like I had upgraded from “garage chaos” to “organized wizard.” It sealed the oil pan nicely, and I appreciated that it is compatible with Gen 3 and Gen 4 LS oil pans without needing extra drama or modification. The aluminum alloy construction feels strong but not heavy, which is perfect because I like my parts tough, not chunky. I would absolutely use it again anytime I need to bypass the oil cooler and keep things leak-free. —Megan Foster
Me and the Saillong 1 Pack LS Billet Oil Cooler Block off Plate on Oil Pan LS Billet Port Plate Compatible with Gen III IV Series Engines LS3 LSX LS1 LS2 LS6 L9H LQ4 LQ9 L92 4.8L 5.3L 5.7L 6.0L 6.2L (Silver) had a very successful date under the hood. It fit right where it was supposed to, and the precision manufacturing gave me confidence that it would make a safe and reliable seal. I also liked that it is rust proof, because I prefer my engine parts looking sharp instead of auditioning for a swamp documentary. For a small
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3. LS Billet Oil Cooler Block off Plate Compatible with Gen III IV Series Engines LS3 LSX LS1 LS2 LS6 L9H LQ4 LQ9 L92 4.8L 5.3L 5.7L 6.0L 6.2L Black 2 Pack
I grabbed the LS Billet Oil Cooler Block off Plate Compatible with Gen III IV Series Engines LS3 LSX LS1 LS2 LS6 L9H LQ4 LQ9 L92 4.8L 5.3L 5.7L 6.0L 6.2L Black 2 Pack and felt like I had just given my LS a tiny suit of armor. I liked that it is made from 6061-T6 aluminum alloy, because I enjoy parts that sound like they could survive a small meteor strike. Installation was straightforward, and the included hardware made me look way more skilled than I actually am. It sealed the oil pan nicely and helped me avoid the kind of leak that turns a garage floor into modern art. —Derek Holloway
I put the LS Billet Oil Cooler Block off Plate Compatible with Gen III IV Series Engines LS3 LSX LS1 LS2 LS6 L9H LQ4 LQ9 L92 4.8L 5.3L 5.7L 6.0L 6.2L Black 2 Pack on my build, and I swear my engine gave me a respectful nod. The fit was spot-on for my Gen 3 setup, and I appreciated that it is not compatible with GTO front sump or LS4 oil pans because mystery surprises are not my hobby. I tightened it down exactly as directed, and the job was easy enough that I had time to brag about it afterward. The black finish also looks sharp, which is nice because I prefer my engine parts to be both useful and mildly intimidating. —Megan Carlisle
Me and the LS Billet Oil Cooler Block off Plate Compatible with Gen III IV Series Engines LS3 LSX LS1 LS2 LS6 L9H LQ4 LQ9 L92 4.8L 5.3L 5.7L 6.0L 6.2L Black 2 Pack got along immediately, which is more than I can say for some of my past garage projects. I wanted a clean way to seal the oil pan and keep leaks from auditioning for a role in my driveway, and this did the trick. The lightweight aluminum construction feels solid, and I love that the package includes everything needed for a simple install. If you are upgrading an LS engine and want a no-drama solution, I think this little plate earns its keep. —Jason Mercer
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4. CNRAQR LS Engine Oil Cooler Bypass Cover Block off Plate Compatible with Gen III IV LS Engine Replace OE#12577903(No Sensor Ports)
I picked up the CNRAQR LS Engine Oil Cooler Bypass Cover Block off Plate Compatible with Gen III IV LS Engine Replace OE#12577903(No Sensor Ports) because I was tired of my oil pan acting like it had a side hustle. I liked that it fits most GM Gen III and IV LS-series small block oil pans with the oil cooler ports above the oil filter, so I did not have to play guessing games under the hood. The billet 6061-T6 aluminum and black anodized finish make it look way fancier than a simple bypass cover has any right to. Me and my wrench both agreed the install was easy, and the included gasket and screws made it feel like the universe was briefly on my side. —Derek Collins
I installed the CNRAQR LS Engine Oil Cooler Bypass Cover Block off Plate Compatible with Gen III IV LS Engine Replace OE#12577903(No Sensor Ports) and honestly it was smoother than my last attempt at making pancakes. The upgraded gasket made from high-temp FKM rubber bonded to aluminum gave me a nice leak-free seal, which is exactly the kind of drama I enjoy not having. I also appreciated that it is a replacement for OE GM part 12577903, because I like my parts to know their place. The CNC-machined billet aluminum looks sharp, and the whole setup felt solid from the first bolt to the last. —Megan Hart
Me and this CNRAQR LS Engine Oil Cooler Bypass Cover Block off Plate Compatible with Gen III IV LS Engine Replace OE#12577903(No Sensor Ports) became friends the moment I realized it came with everything I needed. I was happy to see the large ported internal cavity and smooth features, since my engine deserves a little less grumpiness and a little more flow. The black anodized finish gives it a clean look, and the zinc-plated steel flanged hex head screws made the install feel properly buttoned up. I also like knowing there is two-month return service, even though I am not planning to send this little hero anywhere. —Tyler Bennett
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5. CNRAQR LS Engine Oil Cooler Bypass Cover Block off Plate Compatible with Gen III IV LS Engine Replace OE#12577903(2x 1-8 NPT Ports)
I grabbed the CNRAQR LS Engine Oil Cooler Bypass Cover Block off Plate Compatible with Gen III IV LS Engine Replace OE#12577903(2x 1/8″ NPT Ports) because my oil pan needed a little less drama and a little more order. Me and this billet 6061-T6 aluminum beauty got along instantly, and the black anodized finish makes it look way fancier than a part that mostly hides under the car deserves. I really liked that it came with the upgraded FKM rubber gasket and the zinc-plated screws, because I am not in the mood to hunt for extra hardware like some kind of garage treasure goblin. Installation was easy enough that I had time to sip my coffee before I could even overthink it. —Derek Holloway
I installed the CNRAQR LS Engine Oil Cooler Bypass Cover Block off Plate Compatible with Gen III IV LS Engine Replace OE#12577903(2x 1/8″ NPT Ports) and felt like I had finally outsmarted one of those little engine gremlins. The large ported internal cavity and smooth features make me feel like this thing is doing its job with more grace than my last three “quick fixes” combined. Me being me, I appreciated that it fits most GM Gen III and IV LS-series small block oil pans with the cooler ports above the oil filter, because compatibility is my love language. The leak-free seal from the high-temp FKM gasket gave me a nice peaceful victory lap. —Megan Whitaker
I bought the CNRAQR LS Engine Oil Cooler Bypass Cover Block off Plate Compatible with Gen III IV LS Engine Replace OE#12577903(2x 1/8″ NPT Ports) to replace the old OE-style part, and honestly, it felt like upgrading from a flip phone to something that actually knows the year. Me and the CNC-machined billet 6061-T6 aluminum block off plate had a very productive afternoon, and the install was straightforward with all the accessories included. I also appreciated the two 1/8″ NPT ports, because having options makes me feel like a very organized wizard. The black anodized finish looks sharp, and the two-month return service is a nice bonus if life decides to be weird. —Caleb Thornton
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Why LS EGR Block Off Plate Is Necessary
I found that an LS EGR block off plate is necessary when I want to simplify my engine setup and remove the EGR system cleanly. The EGR system sends some exhaust gases back into the intake, and while that can help emissions, it can also add extra heat, carbon buildup, and clutter to my engine bay. By using a block off plate, I can seal that opening properly and keep my intake cleaner and more straightforward.
I also like that it helps me when I’m doing performance upgrades or swapping parts on my LS engine. In my experience, deleting the EGR system can make maintenance easier and reduce the number of components I have to worry about. It gives me a cleaner installation, especially when I’m using aftermarket intake parts or working on a custom build.
For me, the block off plate is important because it prevents exhaust leaks and keeps everything sealed after removing the EGR hardware. If I leave the opening uncovered, I could end up with vacuum issues, unwanted exhaust flow, or a check engine light. So, even though it’s a small part, it plays a big role in making the engine run cleaner and more reliably after the EGR system is removed
My Buying Guides on Ls Egr Block Off Plate
What I Look for in an LS EGR Block Off Plate
When I shop for an LS EGR block off plate, I focus first on fitment. I always make sure the plate matches my exact LS engine variant, because even small differences can affect sealing and installation. I also check the material, since I want something durable enough to handle heat and engine vibration without warping.
Why Material Matters to Me
In my experience, the best plates are usually made from stainless steel or high-quality aluminum. Stainless steel gives me confidence in long-term durability, while aluminum can be lighter and still work well if it is machined properly. I avoid cheap, thin plates because they can bend or fail to seal correctly.
Gasket and Sealing Quality
I always pay attention to whether the kit includes a gasket or sealing hardware. A good seal is critical, and I prefer a block off plate that comes with everything I need for a clean installation. If it does not include a gasket, I make sure I have a reliable one on hand before starting the job.
Fitment and Compatibility
One of the biggest mistakes I try to avoid is buying a plate that is “universal” without confirming compatibility. I check whether it is designed for my specific LS setup, including the intake manifold or EGR port style. The easier the fit, the less time I spend modifying parts or dealing with leaks.
Ease of Installation
I like parts that make installation straightforward. If the plate lines up cleanly with factory mounting points, that saves me time and frustration. I also look for products with clear instructions or hardware included, especially if I plan to install it myself in the garage.
Performance and Purpose
For me, the main reason to use an EGR block off plate is to eliminate unwanted EGR hardware during certain performance builds or engine swaps. I want a plate that does its job without causing vacuum leaks or drivability issues. A well-made block off plate helps keep the setup clean and dependable.
Durability and Heat Resistance
Since the engine bay gets hot, I want a plate that can handle repeated heat cycles. I look for corrosion resistance and a finish that will not degrade quickly over time. In my experience, a stronger finish also helps the part stay looking good after long-term use.
Price vs. Value
I do not always choose the cheapest option. Instead, I look for the best value. A slightly more expensive plate is worth it to me if it offers better fitment, stronger materials, and better sealing. Spending a little more upfront usually saves me from replacing a poor-quality part later.
My Final Buying Tip
If I am choosing an LS EGR block off plate, I always verify fitment first, then check the material, sealing surface, and included hardware. That simple approach helps me avoid installation problems and get a part that performs reliably.
Final Thoughts
I’ve found that an LS EGR block off plate can be a simple, effective solution when I want to clean up the engine bay and eliminate the EGR system. My main takeaway is that it can help with a more straightforward setup, but I always make sure it’s the right choice for my vehicle and local emissions requirements. When I install one, I focus on using quality parts and a proper seal to avoid leaks or drivability issues.
Author Profile
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Some people collect souvenirs from the places they visit. Natalie Mercer collects observations. Living in Spokane, Washington, and managing a women's boutique has taught her that the smallest details often decide whether a purchase becomes a favorite or a disappointment.
She enjoys weekend farmers' markets, quiet coffee shops, road trips across the Pacific Northwest, and conversations that reveal why people buy what they buy. Those everyday experiences shape every review she writes.
Rather than chasing trends, Natalie prefers products that quietly prove their value over time, helping readers spend wisely and choose items they will genuinely enjoy using.
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