hi, Ive recently joined this forum, but I wanted to know if anyone had any advice, tips, tricks, and/or warnings on rebuilding a 3.4L v6 engine, my monte is currently at 242,391 miles and she's due for one soon...
sorry, Miss-read the instructions, this is in the wrong area

 

I wouldn't a 3400 they just have alot of issues, drop a 3800 in it and that will be a better option.

 

ok, thanks, what kind of issues does the 3400 engine commonly have? I always thought mine had a lot of issues because the car was not taken care of very well by the previous owners... if I go for a 3800 I will need a new wiring harness for it, correct? also If I am going for the bigger engine, why not try to find a 5.3L v8 and accompanying parts (transaxle, harness, etc.) to swap in?

 

Issues are all relative.
I have owned plenty 3100/3400 (same basic engines) and the 3800. I have also helped many friends and family with their vehicles with these engines.
Currently I have one 2004 Grand Am with a 3400 running on 190K. I also have a 2004 Monte with a 3800 and 90k and a 2000 Monte with a 3800 and 200k (original owner put those 200k miles on). Honestly, I feel all of them are great engines. The only issue ALL of them have is GM used plastic lower intake manifold gaskets. Usually those can fail 80-120k. The job to change them is intimidating but really easy. And these days it is well documented on various internet sites and YouTube.

If the engine is not giving you problems, just drive it. If it is giving you issues, dive in and see what is going on.
Maintenance is key to everything!

 

Ill also recommend the 3800 swap. If you plan on ever doing any go fast stuff, youre gonna want that 3800. Just so much more aftermarket.

The 34 can be a great engine, ive had a few but every car I had with a 3400 I wished had the 38.

 

ok, thats all good info, thanks, I think I'll leave the engine be until it starts going out and then I'll replace it, by then hopefully I'll have all the info I need on it, also I really want to try and stick 5.3L v8 in it if I am going to swap the engine out at all... (I'm trying to beat my uncle will's 2017 kia soul in a flat out race lol) but I think thatll have to wait till I have parts and time and know-how (perhaps next summer...)

 

The only thing I'd add is scrapping any thoughts of an engine rebuild. To do that properly can be very expensive (and if you wait until it fails, it could be even more expensive depending what breaks and what it takes out in the process).

Given the enormous number of 3400s (or 3800s if you go that route) that were made, you should be able to find a replacement with reasonable mileage for far less than a proper rebuild. Sure it's not going to be a 0 mile replacement, but even something with 50-100k still has plenty of life left (assuming you do your due diligence as to why the car was scrapped / how the engine appears to have been maintained).

 

I am honestly thinking about the 3800 if anything now, but I think Ill hold off for now because it is running properly for the most part, so why fix something that isnt broken? however I would like to make it run completely properly if possible

 

I had an SUV that had the 3400 in it and the headgaskets were the issue on mine, had to have those put in for the cost of 1800.00, after talking with some other folks about that they all had similar problems with that engine. all around the 100k mark. They should have been better.
The people that fixed it showed me why the difference in the stock gaskets and the new ones was night and day.
I ended up getting a new SUV and sold the other and was able to get my money back, but it took awhile.

 

It could be GM had a bad run on head gaskets. I know a lot of 3100/3400 that never had head gasket failures and made it past 200K miles and I think about two that did have failures. My daily is a 2004 Grand Am with a 3400 and over 190k miles. Original head gaskets to my knowledge (I have had the car since 120k miles). I did change the lower intake gaskets at about 174k (it now has the metal core gaskets).

Some are lucky, some aren't. I have been happy with the 3100/3400's I have had over the years.