Grizzli Diesel Performance

Mechanic in Carol Stream, IL

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About This Shop

Providing reliable, high-quality auto repair services in Carol Stream, NY, this shop specializes in general maintenance and diagnostics. Delivering high-quality workmanship, dependable diagnostics, and honest service is our standard. From regular maintenance and tune-ups to complex mechanical repairs, this shop features the expertise and equipment to handle it all. This listing is part of the WrenchConnect directory. Claim this profile to manage reviews, update hours, and receive direct customer inquiries.

Expertise & Specialties

General MaintenanceDiagnostics

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Brian Petersena year ago

★★★★★

Met John and his guys after having an intermittent turbo issue. Naturally the dealer just wanted to replace it. John spent the time to thoroughly run through the pinpoint diagnostic tests to rule out all other possibilities before recommending turbo replacement. He was quick to get the parts and had the turbo swapped in about a day and a half. We had a few computer bugs to chase out after the swap, but John and his team remained committed to getting the truck perfect for me. Very passionate about his work and cares to get it right. Pricing is reasonable and on par with what you might expect. Be patient when he is busy, I assure you it’s worth it if you can wait a bit. I would recommend him without hesitation. Bp

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Zeke Velazquez5 months ago

★★★★★

I took my 21 Denali L5P to the crew at GDP and they did an awesome job “upgrading” it with a trans tune and SOTF tunes. It been 27k miles now since the work was completed. I’m happy to report that everything is working flawlessly. Thank you so much for great work. I’m also getting some awesome fuel mileage as a result. Edit: 1/15/2026 I started having a misfire from cylinder 3. It was quickly diagnosed as a fuel injector going bad. He replaced it with a new GM part and a new pig tail. My new mileage is over 453k miles and it’s been achievable by the quality of work performed at Grizzley. Currently driving east of Topeka Kansas headed to Northern New Hampshire with a 47ft 3 axle goose neck toy hauler and running great.

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Ray Beyer5 months ago

★★★★★

Needed a diesel mechanic close by and found Grizzli Diesel. The owner John is a super nice guy and very knowledgeable. As soon as you walk in you know they mean business. John’s been going through a truck I recently bought and working out all the kinks and has delivered a really reliable truck to me. He always answers his phone, answers questions, and is there to help you out. Very few mechanics care as much as he does. He is my new go to diesel mechanic and will be the only hands that work on my truck. Highly recommend!

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Thomas Trujilloa year ago

★★★★★

An absolute pleasure working with John. I have a 2001 f350. And John’s only the second mechanic to work on my truck, and the last one at that. Had my truck a week and reached out 3 times with updates. Price and Quality are on point! All future work/upgrades will be done by grizzli. Thank you!

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Fidel Loyaa year ago

★★★★★

Really bad experience with John. He took a year to finish my truck. Had to keep calling him. To give me an update on my truck and he will never answer. I called during work hours and he was never there. I took my Duramax there so he could swap out my engine. I took the truck and he was saying that the new engine needs a head gasket but it wasn’t that he did not install my injector cup right and broke my cylinder head I do not recommend the shop at all !!!

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Shop address

25w658 St Charles Rd Unit 3, Carol Stream, IL 60188, USA

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Business HoursOpen Now

Monday9:00 AM – 5:00 PM

Tuesday9:00 AM – 5:00 PM

Wednesday9:00 AM – 5:00 PM

4.3

Providing reliable, high-quality auto repair services in Carol Stream, NY, this shop specializes in general maintenance and diagnostics. Delivering high-quality workmanship, dependable diagnostics, and honest service is our standard. From regular maintenance and tune-ups to complex mechanical repairs, this shop features the expertise and equipment to handle it all. Open weekdays 7:30 AM – 6:00 PM. This listing is part of the WrenchConnect directory. Claim this profile to manage reviews, update hours, and receive direct customer inquiries.

General MaintenanceDiagnostics

Carol Stream

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