Hello all monte carlo gurus, I wanted to know if the 3.8 engine found in 98-99 monte carlo z34 more reliable than the 3.4 DOHC, I plan on buying another Z34 maybe a 98 or 99 but I want to know what problems are common on these cars. I love these cars and want another one. I also like the idea that the market for performance is wider.
Please help in my decision. I know that the alt. is a PITA in the 3.4 DOHC, I would like to know anything that is as hard to do on a 3.8L.
thanks

 

Well, owning several 3.4 DOHC's myself, I have never had a serious mechanical problem with any of them. Now, if you have a distribuor o-ring leak in the 3.4, well, thats probably the worst possible thing that could go wrong since you have to remove the rear head to fix it properly. There are workarounds to that however. Is the 3.8 a bullitproof motor...pretty much...can it have problems like any other engine..YES The key here is maintenance, oil changes, coolant flush/fills etc etc. In terms of power, you will find the 3.4 DOHC has a fairly good pull in the upper RPM range where I found my 2001 Monte with the 3.8 to be a little lackluster....but gobs of low end torque!

The 3.4 can be a fun motor, just keep up with the maintenance and if you hear any strange noises under the hood, get them looked at ASAP!

 

Thanks for the info., Performance wise I can work around that. I have always kept up the maintenance of all my cars, oil changes, filter, PCV valves, etc. The thing is that I don't want to worry about my timing belt snapping in the worst time like I have heard in most forums. I heard that the 3.8 has the timing chain which is an advantage. I have a good understanding of the DOHC but it is just to tempermental. My current car is a 95 MC Z34, had it for 2 years now and had nothing else than the starter going out in front of my in-laws house. But I am really interested in the newer model with a 3.8L engine, I heard that these engines rarely give problems, is that true.

 

The 3.8 is a die hard engine... keeping up with maintainance and the things seem to run forever. No known problematic components with them. The L36 takes mods nicely as well.

 

thanks, i see a 3.8 monte carlo z34 in the near future. any years that are recommended besides the 98-99.

 

I've owned both and the 3.8 is light years more reliable. The 3.4 takes a buttload of maintenance to ensure it's survival.

 

to be honest both the 3.4 and 3.8 require the same maintenance! i get agrivated when people say that these engines require a lot of maintenance! as like said above they need the normal routine that any engine needs. if you cant do or have std maintenance done just give up performance as a hobby.

the one think i fear about the 3800 is its lower intake manifold. GM's FWD v6's have a bad prob of these gaskets leaking be it a 3100 3.4L DOHC or 3800 they all leak. the 3.4L is much easyer to fix the lower gasket then the push rod 3100's and 3800's where you ahve to pull the push rods and make sure you get them back in the same spots later.

but other then that, the aftermarket is much nicer for the 3800 and the 98-99 monte Z34 is the best platform for the 3800 GM made. a 3800 5th gen is about 150-200lbs lighter then the later 6th gens! combine that with the mods out there and the ability to retrofit a SC or the existing turbo kits... and you will have one hell of a car! i love my DOHC but if i had to replace my Z i would get a 98-99 Z34

 

Well I don't know what you're talking about but they do not require the same maintenance. The 3.4 requires the timing belt to be changed at 60K if not sooner which is almost $500 at the dealer. A simple plug & wires is almost $400. The timing chain on a 3.8 almost NEVER has to be changed. So I'm not sure what you are talking about. If you don't believe me about the 3.4 maintenance just check out some websites about it. And it has the same problem with the lower intake gasket. I've owned two different 3.4's and both required the lower intake to be fixed. I've NEVER had to replace one on a 3.8.

 

Thank you all for this great information, I have mad up my mind and will go with the 98-99 Z34, I see them alot, I will just check its on board dignostics with my scanner, check the intake gaskets for any leaks and also check if it has been well maintained. Thanks again to everyone that helped in my decision, I will just use my current Z for work which like 9 to 10 miles from home. I will just keep up maintenance. I also wanted to ask, I am leaking little oil spots from behind, I had a mechanic check it out and he said it was a rear valve cover, it is not the o-ring seal since someone changed it and put jb weld on it, don't know why. But I would like to know if anyone experienced this, I plan on changing my timing belt and would like to get this leak fixed and would like to know what else to do while thats being serviced, I have 112k mi.

 

It could be the rear valve cover, however I'd look at the o-ring too as this is a common problem with the 3.4 DOHC. I know I had to replace mine when I replaced the lower intake manifold gasket & the timing belt. The 3.4 is a nice engine but it requires a ton of maintenance and they were very problematic which is why GM got rid of it.