Help identifying 03' 5.3L V8

[KarenZ71]

Hello, reciently i had to swap out engines from my 04' 5.3L Z71 Tahoe. I went the cheaper route and bought a salvaged engine. I know of the work this mechanic had done in the past and heard they would definitely do again if needed, so i went with it. After the mechanic put the engine in i started noticing all these parts i needed to replace. I thought all my parts would be transferred over and i would be on my way. Well that wasnt the case. I guess he put in (supposedly) a 2003 5.3l LS. So my issue is how do i know what parts to buy if im not sure what engine this is. So naturally i came to the experts. Can anyone shed some light on how i can tell what engine i have? I have seen an 862 stamped on the head gasket. This was a learning experience for me for sure. I was pressed for time and thought this would go smoothly. But we live and learn i guess. Thanks in advance for any help. It is all Greatly appreciated

 

[iamdub]

Hello, reciently i had to swap out engines from my 04' 5.3L Z71 Tahoe. I went the cheaper route and bought a salvaged engine. I know of the work this mechanic had done in the past and heard they would definitely do again if needed, so i went with it. After the mechanic put the engine in i started noticing all these parts i needed to replace. I thought all my parts would be transferred over and i would be on my way. Well that wasnt the case. I guess he put in (supposedly) a 2003 5.3l LS. So my issue is how do i know what parts to buy if im not sure what engine this is. So naturally i came to the experts. Can anyone shed some light on how i can tell what engine i have? I have seen an 862 stamped on the head gasket. This was a learning experience for me for sure. I was pressed for time and thought this would go smoothly. But we live and learn i guess. Thanks in advance for any help. It is all Greatly appreciated

There are some ID/serial numbers on the upper left rear of the engine block, but they're very difficult to read even with the engine out of the truck:




With my engine on a stand, I had to brush off the surface rust and wet the area with light oil and view it from various angles with a bright flashlight from other angles to try to determine if I was looking at a "0" or "8", etc.

What differences are you finding? External parts should swap over. The easiest way is to use your original intake manifold on the other engine in question. Most, if not everything everything else should be the same.

 

[swathdiver]

Hello, reciently i had to swap out engines from my 04' 5.3L Z71 Tahoe. I went the cheaper route and bought a salvaged engine. I know of the work this mechanic had done in the past and heard they would definitely do again if needed, so i went with it. After the mechanic put the engine in i started noticing all these parts i needed to replace. I thought all my parts would be transferred over and i would be on my way. Well that wasnt the case. I guess he put in (supposedly) a 2003 5.3l LS. So my issue is how do i know what parts to buy if im not sure what engine this is. So naturally i came to the experts. Can anyone shed some light on how i can tell what engine i have? I have seen an 862 stamped on the head gasket. This was a learning experience for me for sure. I was pressed for time and thought this would go smoothly. But we live and learn i guess. Thanks in advance for any help. It is all Greatly appreciated

862 heads came on your truck, whether it has the LM7 or L59 motor. The LR4 and LM4 used them too which are also contemporaries.

Maybe one motor was FlexFuel and the other not? Not sure what the differences might be between the two years in question but there are plenty of guys on here who know. @01ssreda4

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics, please.

Other folks will chime in, but if you want to be sure, try to check out the ID/Serial numbers, as @iamdub suggested.

 

[KarenZ71]

862 heads came on your truck, whether it has the LM7 or L59 motor. The LR4 and LM4 used them too which are also contemporaries.

Maybe one motor was FlexFuel and the other not? Not sure what the differences might be between the two years in question but there are plenty of guys on here who know. @01ssreda4

You are definitely on to something. I just found out yesterday that the intake manifold gaskets are different sizes from the flex and non flex. I just dont know how to tell the difference?

 

[KarenZ71]

You are definitely on to something. I just found out yesterday that the intake manifold gaskets are different sizes from the flex and non flex. I just dont know how to tell the difference? Thanks alot for your reply

 

[KarenZ71]

There are some ID/serial numbers on the upper left rear of the engine block, but they're very difficult to read even with the engine out of the truck:




With my engine on a stand, I had to brush off the surface rust and wet the area with light oil and view it from various angles with a bright flashlight from other angles to try to determine if I was looking at a "0" or "8", etc.

What differences are you finding? External parts should swap over. The easiest way is to use your original intake manifold on the other engine in question. Most, if not everything everything else should be the same.

Thank Alot! Yeah i may have to find another way. I also have codes and i may be stressing and over thinking. These are the codes.

 

[swathdiver]

You are definitely on to something. I just found out yesterday that the intake manifold gaskets are different sizes from the flex and non flex. I just dont know how to tell the difference?

Well, we can identify your motor, if it is original. The 8th digit of the VIN, T for LM7 and Z for L59 and those "L" numbers will be on the RPO sheet in your glove box, if it's still there. A FlexFuel vehicle would also have originally had a yellow gas cap as well.

Someone around here know the 3rd generation motors well, where are you???

 

[iamdub]

You are definitely on to something. I just found out yesterday that the intake manifold gaskets are different sizes from the flex and non flex. I just dont know how to tell the difference?

This is news to me. When I refreshed my '08 5.3 (Gen4, FlexFuel), I used the same gaskets as I did on my brother's '05 5.3 (Gen3, non-FlexFuel). I literally just reordered everything from my order history.

 

[iamdub]

Thank Alot! Yeah i may have to find another way. I also have codes and i may be stressing and over thinking. These are the codes. View attachment 255182

According to that pic, you don't have any codes, just some some monitors that aren't showing as "ready" yet. Did you recently clear codes or have the battery disconnected for a while? You have to complete various drive cycles for each of those monitors to complete. Some complete much quicker than others. You currently have completed three of the seven.

...After the mechanic put the engine in i started noticing all these parts i needed to replace...

What parts do you need to replace? Are you having any problems with the engine?