Diesel Diagnostics Service in Houstin, TX

Our mechanics use the best tools on the market to ensure accurate readings.

+1 832-707-8577Send A Message

We know diesel engines backward and forward.  Our mechanics are prepared to do a full diagnostic and provide you with the best advice on how to fix your truck.

Everything is done locally and in-house, and we use only top of the line products for all services offered.

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Have a pressing issue and need to talk to someone right away? Give us a call and we'll help you walk through your problem and find the right solution.

+1 832-707-8577
2019 F350 getting ECM tuning serviceFord and GMC getting oil changes in the shopFront view of Longhorn Diesel in Texas with 2 lifted diesel trucks out frontFlatbed Ram 3500 HD getting suspension service

Customer Reviews

"Longhorn Diesel was suggested to me by another service provider that didn’t have the equipment needed to perform the repairs my 3500 Dodge needed. First let me say they kept me informed, were fair on price and got my vehicle back to me in a timely manner. They were professional and had my truck back to me in pristine condition while finding other issues that were not identified. They also sent me video of the issue showing me the required work done and new issue identified."
William Rogers
Dodge Ram 3500
Easily the top diesel mechanic in Houston.  Denmar and Longhorn Diesel have serviced my truck (2015 Duramax) for 2+ years, and the work, service, communication and pricing are excellent.  This is the only place I trust with my truck.  I highly recommend Longhorn Diesel!  Many thanks to you and your team, Denmar!
J. Wayne Ballew
Dodge Ram 3500
These guys do awesome work, Denmar is a honest gentleman & takes time out with each & every one of his customers. They went above & beyond of what I paid for, to make sure my truck was in safe & good operating condition at no additional charge! As I'm not looking forward to any more repairs, when that time does come again I will definitely be right back at Longhorn Diesel👍🏼!
Jay Lampkins
GMC Sierra
After about 10 shops telling me no or giving me an unrealistic price. I came across Longhorn Diesel. I called Denmar and he was very down to earth and you can tell by how he talks that he isn’t your typical diesel mechanic. He genuinely took the time to get my truck right as well as him and I having a great conversation sharing what we both love to do. I would 110% recommend him to everybody I know of. Down to earth guy. Great business. Fair pricing. All around great business and I will be back.
Cole Heferle
Dodge Ram
After about 10 shops telling me no or giving me an unrealistic price. I came across Longhorn Diesel. I called Denmar and he was very down to earth and you can tell by how he talks that he isn’t your typical diesel mechanic. He genuinely took the time to get my truck right as well as him and I having a great conversation sharing what we both love to do. I would 110% recommend him to everybody I know of. Down to earth guy. Great business. Fair pricing. All around great business and I will be back.
Cole Heferle
Dodge Ram

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