The 4.3L engine in this 2003 S-10 LS has 150k miles and has low compression on cylinders no 4 and no. 6. The shop says it is not a blown head gasket and that it is a serious mechanical problem.. They advise me to buy a used engine and get it installed in this S-10. My old 2003 Blazer LS was recently wrecked and totaled. Can I pull out the Blazer engine and transmission together as a unit or do I have to remove the engine and then the trans, separately? Both Pickup and Balzer 4.3L are 2003, both are the LS model, X in VIN, auto trans, and stock. Will the old Blazer 4.3L V6 fit and work in the S-10 Pick up without any modification ? That is: without any mod's to the PCM /ECM ? Will the mechanical parts and electrical harnesses all connect ?
Although I have done basic maintenance on this SUV and simple repairs such as new water pump, alternator, brakes, and wheel hubs, I have never done an engine swap in this vehicle or any vehicle for that matter. I won't be doing this work, but will contract it to an independent mechanic. Even though these questions are basic to those of you who have done this type of work, it is important that I understand the process an can plan to do it in an logical format. TIA for your help, It is greatly appreciated. Jim in SC

 

I am in need of your help on this engine swap. Please take a look at my first post above and help me go in the right direction. I need your expertise and knowledge on 4.3L swaps. I am negotiating with several mechanic shops and the wrong move would possibly change my new S-10 truck project to an expensive disaster. My beloved 2003 Blazer WAS my primary transportation---it has been TOTALED by the insurance company--- and I live 13 miles from the nearest town. So I am trying to say this 'new' truck is crucial to my quality of life to say the least. If you read these two posts, please see if you can help steer me in the right direction so there will be a happy ending. My black lab Abby and I are counting on your advice. We both thank you in Advance. Jim in SC midlands.

 

Other than steer you in any direction I'll give you my take on this. If it were me (I'm more than capable of doing it myself) I'd pull the Blazer motor and put it into the S10 if they are both 2wd or 4x4. Engines would match so all the sensors and motor mounts should be the same and you don't have to swap oil pans, this is assuming neither is a ZR2 model. I don't think there would be any issues with the ECM but don't quote me on it.. There is a difference in transfer cases though the way I understand it, 4 button versus 3 button, I'd investigate that to see if it would cause any issues for the swap. I mention it because the ECM controls the shift points in the transmissions depending on what range the transfer case is in. It may be a non-issue though. Hopefully some one else will chime in. You may want to look at exhaust manifolds to see if they match also because the exhaust is more than likely different.

 

If both are 2003 4.3 auto, then the only difference you need to worry about is if it's 3 button transfer case or 4.

Everything ive read along this forum, and google, points to this being a direct swap. As long as the transfer case is the same, or if both are 2wd, won't make a difference between blazer/jimmy/s10/sonoma...

 

Both my Blazer and the 'new' S-10 pick up are 4WD ** and both are LS models with auto transmissions. Neither are ZR2. My Blazer is a 2 door with very basic equipment----- Only PS, PB, auto trans.... no power windows, door locks and no Cruise control. The S-10 LS pickup with Extended cab has Cruise and I am not sure about what other options it may have. Thanks for your responses. I go this afternoon to pay for it. The S-10 owner has purchased a new truck and is excited to get some cash. I am excited to get a 2003 Pick up. Win --Win.

** I will have to check if both are 3 button or 4 button. I should know this answer later today.

 

It shouldn't mater as of zr2 or not.

I used an 03 zr2 engine in my none zr2 99 4door. Only things i had to do was the egr and knock sensor, because I went from a 99 block to an 03 block.

But because you are going for same year and same shift. Your only issue should be the transfer case(3 button to the 4 button or vise verse).

Speaking out of experience(as no experience), the only difference should be the transfer case....

 

Hey so could you explain the 3 button 4 button thing? I’m swapping my motor tomorrow and the donor was an Astro of the same year. Am I looking at some headaches?

 

DonL, both my old 2003 Blazer 2 door and the 'new to me' S-10 pick up are 4.3L with Auto Trans and --I just checked last night-- both are the 4.3L with the Three Button 4X4 control. Both have the big 'X' as the eighth character in the VIN.
The 4.3 L in my Blazer had no PVC and no EGR. I didn't think to check that in the S-10 pick up. It was getting dark so I had to get home to feed and walk my rescue lab Abby.
The history of the S-10 pick up is slowly coming out. The present owner's father was the original owner. Then the son inherited it when his father died. When the S-10 pick up got too small when his family started growing, he realized he needed a full size crew cab to transport his 'crew' around. He got a brand new, blue 2021 crew cab Ram 5.7L Hemi. Maybe someday one of his sons will inherit that Hemi. Meanwhile It now has the place of honor in the enclosed garage. That's where my S-10 was sheltered for years. The torch has past. Life moves on.
Now I have to focus on getting a good, used 4.3L V6 into my blue S-10. At 400 AM eastern in the midlands of SC, Jim

 

Romeo, the 4X4 control panel on the dash will have either a three button device or a four button device. These are the push buttons that select the 4X4 mode: My three button choices are from top to bottom---no. 1=2 HI, no. 2=4 HI, and no. 3=4 Low. Ideally you want them to be the same.

 

Today I had the S-10 moved by Roll Back to an Indy repair shop. They are going to look at the 4.3L V6 and see what is wrong with the no. 4 and no. 6 cylinders with no compression. They will evaluate if it is a repairable problem or it requires an engine swap. If it is a serious problem and requires an engine swap, will I use my old Blazer engine or go to a salvage yard that sells 4.3L V6 with a 6 months guarantee.