I had some issues with my trucks fuel sending unit, I talked to andy about him doing the repair and doing some upgrades to my truck while it was In his shop. I gave him a $2,000 deposit he told me truck would be completed that next weekend. I got a rental car. Andy finally finished the fuel sending unit after 10 days, but said he would do the upgrades at a later date on a friday/Saturday. He has spent the next 4 months dodging my calls and lying to me. I had given up on him doing the upgrades and just wanted to get my parts I had paid a deposit on... he dodged me evertime i was traveling through and could pick up the parts. He then offered a refund on my deposit two and a half weeks ago and said he had mailed it I am still waiting and when i do get ahold of Andy he never gets back to me. I have never dealt with a more dishonest business or individual. I would stay away from this business, and definitely dont give him any money for a deposit, you will never see the work or the money again read more

This guy owes me $1200.00 for a supposedly transmission, my truck needed. He not only says he's keeping my deposit , but the tranNY was not even the problem. He could have stung me for another $4800.00. Just for the tranny. All told around $8,800. I had it towed away , at my expense. My 2001 Dodge diesel is running fine. Differential fluid change, pint of tranny fluid , cclutch replaced. Trfuck got a 50 point inspection. Total $1208.12 36 k warranty Jim Mallett Formerly of Tucson This creep Andy I am reporting to the. Attorney Generals office. I'm a senior on a fixed income. TURNS OUT HE HAS BURNED LOTS OF PEOPLE... BUT A SENIOR. .SHAME ON THIS CON. FORGOT : He had my truck for 41 days. Mechanic in Cottonwood said : Nobody touched the tranny, see the mud on this label. Oil on bolts. This was NEVER inspected. STAY AWAY ! FROM ANY AND ALL BUSINESS IN FLAGSTAFF, EXCEPT NAPA AUTO PARTS. Also COCONINNO AUTO REPAIR . Pat gave me very very good advice. He was too busy to do my work. Busy because he's a good honest business man. If it's High Mountain or Andy's diesel repair....run read more

Traveling through Flagstaff my truck had a hiccup and went into limp mode. I called left a message a few minutes later a received a call back asking me to bring it in keep in mind it was 20 minutes to closing. I took it in first thing in the morning 9am and was fixed by 10:30 read more

Called on a Sunday and Andy, the owner, made a special trip to help out with a bad axle. Solid citizen!

We were in a real jam when we called Andy. We were at the Flagstaff KOA and were supposed to check out, and the engine of our 1996 motor home wouldn't start. The engine was turning over but not igniting. It was the day after July 4th, and every roadside assistance service was slammed and many of the RV repair shops were closed. Andy came out quickly and diagnosed the problem in minutes. He was friendly and kind, and clearly very knowledgeable. He had us on the road in just a few minutes. His fee was $200/ hour, but it was worth it and cheaper than a tow! read more

These guys are the greatest! I was on my way from LA to Nashville in my RV and the generator stopped working which meant no A/C or more importantly, no XBox for the kids! Andy totally stayed open 40 minutes late AND fixed the issue for free! They deserve 10 stars. read more

I rarely leave reviews for any businesses, but felt I need to with this one. My RV was having troubles overheating and we were only passing through Flagstaff, so we didn't have much time to wait to have it looked at as he's a very busy guy. He was able to fit us in and told us he'd give us a call in a couple hours after looking at it. He did indeed call us and never tried to sell us something we didn't need, only said our radiator needed cleaning badly and that he could take care of it. About a half hour later he said his pressure washer broke, so he wouldn't be able to do the job he normally would so he wasn't going to charge us, but he did the best he could with what he had. Since then it's been running great. If you're having any problems, call Andy at High Mountain. 5 stars is not enough!! Thanks Andy!! read more

Broke down while on vacation and the local Ford dealer could not even look at it for 2 weeks. Luckily the Internet lead me to Andy who offered to tow it from the dealer to his shop. He took care of us and fixed up our turbo getting us back on the road as quick as he could. Called to check in with us and kept us up to date. Great service and hospitality. read more

Talk about excellent customer service! Traveling through Flagstaff on Saturday. Noticed white smoke coming from exhaust on our diesel motorhome. Looked up rv diesel repair on my smartphone. High Mountain Diesel came up. Called the number. Of course they are not open on Saturdays. Left a message and Andy called us back in 20 minutes. Unbelievably he came to the shop and opened it to help us. He spent over 3 hours with us, test drove our motorhome, and put it on diagnostics! Talked us through how we could get a final repair done when we got home. Of course this was after he determined that we could make it home safely! We made it home safe and sound. This type of business owner is a rare species in this day and age! Thanks Andy, we will highly recommend you to every rv owner we know! read more

Andy and his crew were very personable and knew their stuff!! We limped in with our 43ft RV but got out the next day back in business. Thanks for helping save our vacation! read more

Andy was great at diagnosing and repairing my F-350. We talked on the phone about my issue and he gave me some tasks to help troubleshoot. When I got the truck to his shop, it took 2 minutes to find the problem. Got me back on the road quickly. Thanks! read more

I had accidentally put regular gasoline in my diesel Jetta while going through Flagstaff. Originally VW Findley said I had to replace my fuel system, then took my car to Andy at HMDR and he had it fixed in one day for a 10th the price. Professional and honest diesel mechanic! read more

We bought an RV and drove out from Pittsburgh to pick it up. Our vehicle needed an electric brake controller due to the size, we learned. Andy was reccomended by Rick at Flagstaff RV Service Center. Andy explained everything, and hunted down an elusive plug where the brake controller is connected behind the dash panels of our truck. He worked us in the next day, which meant a lot... This guy is honest, engaging, and very resourceful. Way to go, Andy. read more

Outstanding! Transmission went out 30 miles out of Flagstaff while towing a load to Montana, tow driver recommended Andy's shop and I'm thankful that he did! Andy worked me in to minimize my down time. Quoted me a price, kept me up to date and delivered a truck that drives better than new. Great guy to work with, fun to interact with and BS about life....just a great experience all around! You won't go wrong going to Andy and crew! read more

The owner uses Ford parts and boasts that he does because if the part fails within 2 years, Ford's warranty will cover the part and the labor. That is a good warranty but you don't have a warranty unless you have a receipt, which I do not have and never received. At the time that I had my repair work done, the owner told me that he would email me that receipt, but I never received one. A couple of months ago, I had a check engine light turn on and needed a receipt in case it was caused by one of the new parts. I checked my email and did not find an email from Andy or his company. I got in touch with Andy on numerous occasions, each time he told me that he would look for it when he got home or later and would get it to me. I even gave him my email address twice, to make sure he had it correctly. Never received it, and never received any follow-up messages from Andy. So although he got me in quickly, how good is the repair work if you can't even get a receipt? Sorry Andy, tried to avoid having to leave this update, but you left me no other option. read more

Not often do you find someone who is so customer service oriented. I found one. Andy at High Mountain Diesel is that guy. Traveling through Flagstaff and developed an engine noise. Ended up being a major issue. Didn't have great options but Andy was so honest and helped us solve the problem. Can't tell you how much he went out of his way to solve our problem. Wishing him great success as he has just recently open. We were fortunate to have gotten his name from someone who also had great success with his skills. Thanks Andy read more

Andy and bob at high mountain diesel couldn't have done anything more for our family and our horses when we broke down outside of flagstaff AZ. They were VERY fair with the price for as much work as my truck needed, they put us in touch with people locally who could take care of our horses, kept us up on everything that was happening with the truck AS they discovered it. Top notch guys running a top notch business. Couldn't ask for a better experience when dealing with them. I'm considering driving from Las Vegas back to flag staff just to have them work on my truck. Gotta say it again, TOP NOTCH PEOPLE! read more

Had exhaust issue with our RV and thought it might be a cracked manifold. Andy worked us in the same day after ordering some parts. Not only did he fix the leak and determine it wasn't cracked, but he repaired it the same day at a very reasonable rate. He saved our Grand Canyon vacation and I can't say enough good things about him. He may seem a little rough around the edges when you first meet him - don't let that scare you away. He and his staff are top notch! read more

The service, pricing, and knowledge here is outstanding! We would not hesitate to patronize Andy and High Mountain Diesel if we were in the area and needed service. Thanks for great customer support, Andy! read more