impala 3.4 vs 3.8

[toptech69]

Both engine are great, I like the 3.8l. But other than the intake gasket issue the the 3.4L is also a winner. The car is a good choise.

[sarotara]

Originally Posted by phewop118

As for the comment about taxis, I believe any Impala that was ordered with the Taxi or Police package included the 3.8 and an HD transmission + HD suspension, despite having the base Impala looks.

You are only half correct. The 9C1 and 9C3 Impala police packages do have the HD suspension, including the tubular rear trailing arms, but they do not usually have the 4T65E-HD transmission. As far as I know, the only difference between the regular Impalas and the police packages, transmission-wise, is that most police packages include the 3.29 transmission drive ratio. The supercharged Impalas (Impala SS) do have the 4T65E-HD transmission however. One way to find out which transmission the car has is to look at the RPO codes in the trunk. M15 means 4T65E, MN7 means the 4T65E-HD.

As far as the 3.4 versus 3.8 engine goes, I would probably suggest going with the 3.8. My fiance's 3.4L 2002 Oldsmobile Alero (79k miles) is currently experiencing the dreaded lower intake manifold gasket leak, while my 2004 Impala (9C1) (81k miles) with the 3.8 engine does not have that problem. Additionally, that extra 400 ccs of displacement will get you a bit more power with a fairly insignificant drop in fuel economy. As someone already mentioned, however, the LIM gasket issue was fixed in 2004 I believe. If you still decide to go for the 3.4 engine and the gasket does fail, it's not that difficult to replace if you are somewhat mechanically inclined and have a decent set of tools (especially torque wrenches). It will set you back by about $150-200 and 6-12 hours of your time.

[wafrederick]

Fel Pro has the fix for the intake gaskets,came out with ones made out of metal instead of plastic and are more money if you want to do it once.I have done this once and I do not torque the intake bolts.I run them down with a 3/8" impact wrench and there is one problem with torqueing the intake bolts.Most over torque them and do the job all over again.The 3.8 series II is a bullet proof engine and the only problem is with the upper plentuim.It is made out plastic and will fill the intake with anti freeze and will cause a no start if not caught in time.I read in my local paper about one mechanic hating the Impalas as police cars putting in more money for repairs putting in transmissions,axles and other suspension parts.

[vando002]

I purchased a 2002 impala LS with 250,000 miles on it. Last week it rolled over 260,000 with no problems at all. I'm very impressed with the power this engine still has with all of those miles. And it doesn't burn or leak any oil. A very good car.

[threewide]

Great forum! Buying 2004 Impala 3.4, 50K on it New tires and brakes (rotors too). What type of maitenance should i look to do at this point coolant, tranny. What about intake gasket? Can I check it? Runs great... I took it on trade at work and hit the trip computer said 31.8 mpg, to me that is great for such a large car. Looking for any pointers as to what I should look to do to it. Driving to FL. from OH in a month want it in tip-top shape.

[playerk12]

i own a 2002 impala 3.4 and my buddy has a 3.8 impala ls and we have the same mileage almost 180,000 miles! all you have to do is maintain your vehicle like your suppose too i have never had a check engine light he has 4 codes on his check engine light! we have raced each other at gateway track at and open and we stayed neck to neck until his car wouldnt let him go any faster. we both get 29 mpg on the highway. the only differences with the engines are the the 3.4 engine are mostly aluminum so if you do not maintain up to date you will have problems but its that same with every vehicle! i am not an impala enthusiast but i am telling you that i love cars and hondas and other "long lasting cars" cant compare you end up putting more money into it! the only reason they do not make the 3.4 or 3.8 anymore is because they could not keep up with emissions, i also know multiple people with impalas with 250,000 plus with both engines they are pretty much the same engine besides bracket and and cooling set up. all you have to do is flush your coolant change your oil flush your transmission fluid change your thermostat and timing chain and you will be fine!

[rkvons]

Originally Posted by playerk12

i own a 2002 impala 3.4 and my buddy has a 3.8 impala ls and we have the same mileage almost 180,000 miles! all you have to do is maintain your vehicle like your suppose too i have never had a check engine light he has 4 codes on his check engine light! we have raced each other at gateway track at and open and we stayed neck to neck until his car wouldnt let him go any faster. we both get 29 mpg on the highway. the only differences with the engines are the the 3.4 engine are mostly aluminum so if you do not maintain up to date you will have problems but its that same with every vehicle! i am not an impala enthusiast but i am telling you that i love cars and hondas and other "long lasting cars" cant compare you end up putting more money into it! the only reason they do not make the 3.4 or 3.8 anymore is because they could not keep up with emissions, i also know multiple people with impalas with 250,000 plus with both engines they are pretty much the same engine besides bracket and and cooling set up. all you have to do is flush your coolant change your oil flush your transmission fluid change your thermostat and timing chain and you will be fine!

Well said. The problem with maintaining vehicles is many people are lazy. It's work to do all that stuff year after year. I have a '98 Pontiac Montana with the original 3.4 and it is very reliable. I did the intakes before they failed. It will easily go 200K and beyond. I believe the engine behaves the same now as it did the day I bought it. The trans is solid. I love flooring it every now and then and watching passenger's eyes light up.

[BeautifulNightmare]

i have a 03 3.4 impala and i really dont like it. i have had it a little over 3 years and still paying for it. i have had nothing but trouble out of it. it has been maintained well it just doesnt do well for me. within a month of having it i figured out it vapor locks. yes i've been told its impossible for it to vapor lock but that's a load of bull. i've figure ways around it like not tightening the gas cap but after awhile it throws my check engine light on. it seems like everytime i fix something on it something else goes wrong. like now i have to change the timing chain on it... always something going wrong with my car=( BUT anyone that i know that has one does good for them. so maybe i just got a jacked car lol idk.

[SierraK1500]

I had a 2005 Impala with the 3.4 motor in it. It made it to 170K miles before it started leaking oil and the sweet smell of coolant. Had the original serpentine belt and the oil changed every 5000 miles. Never had a tune up and I had the car since 19200 miles. It served me well. I now have a 2012 Impala with a 3.6 engine. 300 horse and runs like a dream.

[johnnyjohnny]

never knew about the impalas but mechanic had one to replace another car of mine that went out. i knew there were 2 engines for the 2002 and hoped for the larger one, but it had a 3.4.

when i took it for a test drive i was pretty stunned at the quickness. the difference was 20hp less than the 3.8, but the 3.8 had 300 more pounds, so it wasn't that much of an advantage.

in calif you can't do any real engine mods, but i put lower profile tires on and then lighter wheels that saved 10lb per wheel (unsprung weight) for 40lb.

this would definitely beat a stock 3.8 2002 impala now, and beats anything else on the road except plain out muscle cars. has 195,000 on it.

not saying it's the most amazing car in the world, but way up there in speed over anything i've pressed the pedal on in the other lane, or that i was driving. not to mention the handling is nice with 55 profile tires. not a street racer, but when i want to punch it, it wins, so i'm happy.

[ctesla]

johnny,
Welcome to Automotive Forums.. just a little heads up/reminder; kind of watch the date/timeline (i've missed it once too), but you a replying/responding to a ten plus year old posting..
but your post is VERY correct: that power-to-weight ratio helps in every way, shape, and form.. by dropping the OEM steelies with the satin covers you actually probably shed closer to 14lbs. per corner with the weight of wheel+rubber+psi/air; and the lighter rotating mass the trans has to push..the lower profile is also assisting with mpg and drag coefficient, with a lower center of gravity..
plus you are also right about the bigger engine means nothing, if it weighs the nose (and overall total) down more w/o more HP and TQ to pick-up the same vehicle..
as far as being in cali (a VERY restrictive state for modders), that is still the home of speed/racing.. many aftermarket performance companies make E.O.CARB exemption components.. plus; even if not going all out, you can custom build your own CAI for less than brand names, or just buy better than AC/Delco for your regular maintenance items: wix, purolator1, or mobil1 instead of fram; plug wires: AC are good for 75-85K, but Taylor makes a great 8mm that fits in the GM 7mm wire holders and deliver more spark, so more hp or mpg (depending upon which way you use your pedal), etc.etc..
i have an 06 MAXX with the 3.5, and it is at 180k and still getting 32mpg; so you could easily see 275K on your impala with minimal maintenance..
and hey, at least L.A. is still above freezing and two feet less of snow than here!ha..
enjoy the streets and the Forums..

[johnnyjohnny]

thanks ctesla...appreciate it.

for information, should i not have made a comment due to the age of the thread? if so i would have missed your input, which i appreciated. wish to know for the future. thanks

[ctesla]

hey JJ,
i do not know if it is a rule, but i did see a moderator or administrator comment on something like "...45 days is considered a 'dead' thread.."
still, it is great you posted, as, i saw it as a red check on a new Chevy post (but i have such slow internet, everything is new by the time it hits my computer; even stuff posted a day old, haha) and read and replied..
most common/courtesy guidelines are here:
http://www.automotiveforums.com/vbul...uidelines.html

but when you start a new thread, you can 'quote' or reference a previous thread..
and when you do start a new thread, you can always post pics of your car; or a component that needs identified, or a replacement item, etc..
and i just wanted to let you know, as starting new threads allows others to see it and gravitate to it; i hope this helps.. enjoy the forums; i just got back to them after a long AFK in a military third world deadspot... now, i'm just waiting for snow to stop falling in colorado, so i can actually go wrench on something..

[johnnyjohnny]

thanks for the info Ctesla...appreciated.

and welcome back!