My 2002 LB7 is currently at the dealer having the injectors replaced. I called this morning to see how everything was coming along. The service manager informed me that they found 3 bent pushrods on 1 side of the motor and they were going to take a look at the other side. I don't trust this dealer %100. They have been caught by the state overcharging and fixing things that don't need to be fixed. I was wondering if anyone has had this problem associated with the injectors, or what might cause the rods to bend. The crankcase had quite a bit of fuel in it. Could the engine have hydrauliced? Any help or insight would be greatly appreciated!

my only experience with bent pushrods was due to the lifters sticking but it was a 64 chevy not a dmax.

Thanks for your time. I had a 350 small block that was submerged in water. The pushrods were bent a bit from the motor hydraulicing.

More than likely you had a hydro-lock

Even if there is more damage it should be covered by the 5yr/100000.

What is a hydro-lock? What are the chain of events that produce a hydro-lock? Thanks

Problem is, the truck has 138,000.

yeah, but the injectors are covered untill 200,000 and if an injector(s) caused fuel to leak into the cyl's and caused a hydrolock, all damage related to the bad injectors should also be covered.

I had the same thing happen on mine ! Its Hydrolock ! Fuel in the crank case and such. Have them show you the damaged parts they have to by law !

I drove to work 2 months after i got my truck , it was -37c , very cold i started it up every couple of hours but the last time i started it up it took awhile and it took 3 trys. when it would turn over it would shake violently , the third time i tried to start it it ran the whole truck was shaking till it warmed up it sounded like a locamotive , it was a bent pushrod

You should fill in your signature with all your truck information so that we can help you better.

there is no reason they should have found those unless they are bent horribly bad. Ask to see them. I'm not buying it.... but then again i am going on limited info... why was the truck brought in? If you had bent pushrods that are visually noticeable during injector replacement then you would be missing a lot of power.

Yeah I hear ya. Between the injectors and the pushrods, the thing sounded and ran like one big piece of junk. I also found out there are 3 bent on the other head as well.

If you get a stuck injector it will fill the block with fuel and the cylinders with it too. All that oil and fuel creates a vast amount of un moveable pressure, called HYDROLOCK !

What is a hydro-lock? What are the chain of events that produce a hydro-lock? Thanks
instead of compressing gas you are compressing liquid. one of two thing will happen it will not roll completely over or you WILL bend something.


secondly you can require that the deal keep the replaced parts and give them to you when the job is done. easy test roll the push rod across a flat surface and see if it is bent

How can a hydrolock cause bent pushrods? I can see how it could cause a bent rod or cracked piston. It would take an awful lot of fuel to hydrolock a dmax. I've seen failed injectors that cause so much smoke and fuel knock so bad that you dont even want to start the engine, but those engines didn't hydrolock.
I want to know what the tech was doing inspecting the pushrods when he was doing the injectors.

I want to know what the tech was doing inspecting the pushrods when he was doing the injectors.


that is exactly what i wanna know too. When i go in to do injectors, i will glance over for discoloration or SEVERE abnormalities, but thats it. Injectors don't pay much as it is.... get in and get out...

Something fishy is brewing here. It just does not sound right, find out what prompted them to pull the push rods. When you get there ask them if your 02 sensor showed any signs of unburned fuel....


:eek: :muahaha:

After I found out about the pushrods, I posted the thread. After I learned alittle about hydro-lock, I called the dealer. The service manager (SM) said the injectors could'nt have caused the hydro-lock because there was no fuel inside the cylinders. I knew there was fuel in crankcase. Well today, the SM and I were talking about this mess and He mentioned that they are going to pull the heads to find out what caused the hydro-lock. I wonder how he knows about the no-fuel in cylinders with the heads still on. If I,m wrong, someone tell me. I will ask about the 02 sensor and the rest of the dtc's for that matter today. For what it's worth, I was on the freeway going about 75mph when I heard a small pop, felt a slight loss of power and noticed smoke coming out of exhaust. Thanks guys. I'll post later.

After I found out about the pushrods, I posted the thread. After I learned alittle about hydro-lock, I called the dealer. The service manager (SM) said the injectors could'nt have caused the hydro-lock because there was no fuel inside the cylinders. I knew there was fuel in crankcase. Well today, the SM and I were talking about this mess and He mentioned that they are going to pull the heads to find out what caused the hydro-lock. I wonder how he knows about the no-fuel in cylinders with the heads still on. If I,m wrong, someone tell me. I will ask about the 02 sensor and the rest of the dtc's for that matter today. For what it's worth, I was on the freeway going about 75mph when I heard a small pop, felt a slight loss of power and noticed smoke coming out of exhaust. Thanks guys. I'll post later.


just so we are on the same page your truck does not have an 02 sensor. it's fun how i will talk to other techs over the phone and i'll ask the same question and they always answer that it seemed fine. I hate it when hole in the wall shops call and ask how to work on a dmax. That question will let you know if the tech has a slight clue of what they are working on... It may offend them too though, so be careful.

Well, I just got off the phone with the service manager. Good news for my bank account, GM is covering pushrods and the filter housing along with the injectors. I almost fell out of my chair when He told me. I still have to change the water pump, it went out, before all this other stuff happened. I bought a brand new in the box GM water pump on e-bay for $81.00 and was going to put it on myself. How much of a headache is that? Thanks guys for the help!

GM absolutely should cover it. No way would I pay for any of that when the truck is still under injector warranty which caused all of this to begin with.

Good news regardless.

I agree, but the headache and the frustration of fighting with them was something I was not looking forward to. I know this thing isn' over till the truck is fixed and I have the copy of the work order in my hand. (work order with WARRANTY written on the face). I'll keep posting as things develope. I appreciate the time and effort on your part. Larry

I just picked up my truck from GM. They replaced all 8 injectors, pushrods and the line that feeds the heater core. All was covered by warranty except the water line to the heater. The thing I find funny is the line to the heater was the "waterpump" the same dealer told me was out during the warranty fuel filter change. I bought on e-bay and was going to install myself. They wanted $900.00 to change waterpump. Anyway, thanks to all for the help and take care. Larry Fraser.