I purchased a 2001 Isuzu Vehicross engine from them almost two years ago and STILL do not have a working vehicle.
After paying to have my engine removed, and shipped to them, I received my supposed SIM-tested engine shortly thereafter. After paying to have it installed, the engine ran for about a month until a low oil pressure light came on, and a complete loss of power.
After paying to have it removed (again), my mechanic told me this so-called SIM-tested remanufactured engine had an oil flow problem over the crankshaft bearings, and they wore out within less than a month of driving, resulting in a destroyed crankshaft and rear seal.
I shipped this one back for a warranty replacement. It took 123engine over 3 months to receive the replacement engine.
I paid to have this NEW engine installed. Once installed, it failed to start. My mechanic tells me it's because the crank sensor isn't getting a signal. After doing some research, he found that a common mistake with companies remanufacturing this engine is that they use a 3.2l crank shaft in a 3.5l block, which appears similiar but actually has a smaller diameter timing wheel for the crank sensor. This is what happenned with this second engine. If these engines truly are SIM tested, this should have showed up and the engine should NEVER have left the shop.
After incurrring over $4000 in labor charges to replace this engine TWICE, neither Eli or Sam (the principals in the company) will consider reimbursing me anything, nor pay to have my car shipped to California (from Louisiana) where they can put an engine that actually works in the vehicle. Instead, they hide behind their warranty which does not cover labor charges.
So, basically, unless you LIVE in California, they have a very nice scam going here. They can keep sending you non-functioning engines indefinitely, because they know you will be unable to ship your car to them to have them installed, nor will you continue to keep paying $2000 each time in labor charges. Thus you can't truly take advantage of their "warranty"
I am currently speaking to my lawyer about a possible class action suit. I have asked 123engine for their legal representative's information but have not heard back from them. They will soon be hearing from me.