MailmAn New Reader
3/8/20 12:37 p.m.

I have a 2004 Chevy Impala with the 3400 series V6 engine.  The car currently has around 172,000 miles on it.  I have been driving this car all over the place for the past 7-8 months or so with absolutely no problems.  Due to its age, mileage, and lack of maintenance from previous owner(s) when I bought the car, I have already had to replace a lot of parts on this car to keep it running and improve the ride and handling on this car.  I have already replaced the following on this car:  Front and rear strut assemblies with new coil springs, front and rear sway bars and end links, front and rear brakes (including new rotors and ceramic pads), new rear parking brake cables and adjuster, replaced all O2 sensors, complete engine tune-up (including B&B Platinum Class Laser Mag 8mm spark plug wires, Bosch Platinum spark plugs, new WIX air filter and cabin filter, PCV valve, etc.), new Idle Air Control Valve (IACV), new Throttle Position Sensor (TPS - since the engine had problems idling properly and once it warmed up, it would "idle" around 1,800-2,000 RPMs), replaced heater blend door actuator motor (which was a B-ITCH to get to, but necessary as it was blowing cold air out of the driver's side vents with the heat cranked up all the way!), and, most recently, I just replaced all of the subframe mount bushings on the car as it was making creaking and popping noises when going around corners.  (PHEW!!)  So, obviously, I have more than a few bucks invested into this car at this point...  It rides like a new Cadillac now though after all of the suspension upgrades I've done to it.

However, on Thursday evening (March 5th) while driving it back home from work, as I was pulling into my driveway, the engine suddenly started puking its guts out all over my driveway!  After I shut the engine off, I noticed there was already a pretty large coolant puddle underneath the front of the car.  I took a quick peek under the car and could see coolant dripping down from the back of the engine and down the oil pan.  On Friday morning, I tried to put some radiator and engine block stop leak pellets in the radiator and topping it off with some fresh coolant to see if I could band-aid it for now just to get me to work.  I started it up and let it idle for about 15-20 minutes in my driveway to warm up and circulate the stop leak.  However, this did not work as it was still dumping out coolant from the back of the engine and the temperature gauge in the car started heading towards the overheating mark (around 260 degrees).  I'm pretty sure this means that the lower intake manifold gasket is blown, especially since these GM engines are known for this problem.  I can see that it is pouring out coolant from the back passenger's side of the engine and steam and coolant is coming out from in-between the alternator and the power steering pump.

So, if I have to replace the lower intake manifold gasket on the engine, that's pretty involved as I'd have to take everything off from the top of the engine.  I'm sure that everything I remove will need new gaskets and/or O-rings as they will be all brittle and destroyed from age.  It is a cheap job, relatively speaking, in that the gaskets to repair it are pretty cheap (under $100), however it is a very labor-intensive job.  I'm sure if I had to take it to a repair shop to have it fixed, they would probably charge me anywhere between $600-$1,000 to replace the intake manifold gasket, which would be pretty much all labor.

Given all the other work I have done to this car already, I'm kind of already into it beyond the point of no return, I think.  I hate to have to throw in the towel and junk the car with so many new parts installed on it.  However, it is not exactly the prettiest car by any stretch of the imagination!  The car suffers from the bad GM paint problem and most of the clear coat has blown off of the car, making the paint on the car look horrible.  There is typical New York rust all over the car, especially on the rocker panels and over the rear wheel arches.  (In fact, especially on the passenger's side, the rocker panels are pretty much completely rusted away...)  At least for now, thankfully the floor pan in the car is still intact though.  I also recently hit a deer that was standing right in the middle of the road with the front passenger's side of the car.  Amazingly enough, all it did was break the headlight assembly and dent the front fender a bit!  So, now I have new headlights in the car too.  Still, this car certainly ain't winning no beauty pageants in the shape it's in!

I'm wondering if it is worth it to fix the engine in this car to keep it going or if I should cut my losses and just get another car?  I hate to throw away all the new parts that I have installed on this car, but even if I fixed it and got it running again, I'm sure I would have a hard time selling the car for much more than maybe $1,000 as it is, if for no other reason than the body is pretty shot on the car!  (It's sad that a pretty looking car with no rust that mechanically needs everything replaced will still sell for more money than a mechanically sound car that looks like a rusted POS...)  It's probably not the most difficult job to replace the intake manifold gasket, but it would take me probably a weekend to do the job in my driveway.  (I'd also need to invest in a torque wrench to be able to properly torque down all the engine bolts as I do not own one right now...)

Also, if I have to tear the engine all apart anyways just to replace the intake manifold gasket, I'm wondering if I should also swap out the stock camshaft and lifters that are in it?  I have heard stories of people having broken the camshaft in their engine after they had the same issue of the lower intake manifold gasket blowing.  Coolant can leak into the oil and the cam bearings seize up and the cam gets destroyed.  But can I actually remove the cam from the engine with the engine still in the car or do you have to pull the engine (or, conversely, drop the cradle) in order to do that?  How difficult is it to replace a camshaft, cam bearings, and lifters in one of these 3400 series V6 engines anyways?  (Plus, I figured if I'm going this far with the engine anyways, I could upgrade the cam to one of these to make this Impala a bit more fun to drive:  Not really sure if there are any other options for a performance camshaft for the 3400 V6 or not?)


I'd appreciate any help or suggestions with how to go forward with my Impala at this point.  Thanks!


John Welsh
John Welsh Mod Squad
3/8/20 1:40 p.m.

Does the 3400 have the plastic coolant elbow (that cracks) like the 3800? 


Knurled. GRM+ Memberand MegaDork
3/8/20 1:54 p.m.

In reply to John Welsh :

No.  Completely different species of engine.

MailmAn New Reader
3/8/20 2:24 p.m.
John Welsh said:

Does the 3400 have the plastic coolant elbow (that cracks) like the 3800?


John:  No, it does not.  That is an issue that is specific to the 3800 Series engine only.  The 3400 Series has the coolant bypass tube that goes around the front of the engine and under the air intake snorkel and connects to the heater core with rubber hoses.  Here is a picture of the engine that is in my car:

(The red arrows are pointing to the coolant bypass tube on the engine.)


Curtis73 GRM+ Memberand MegaDork
3/8/20 2:42 p.m.

Given the fact that the parts are cheap, I'd fix it.  THEN figure out if you want to keep it, or sell it with all those new upgrades as a selling point.

MailmAn New Reader
3/8/20 3:18 p.m.

Also, since I didn't include any in my original post and people generally seem to like to see pictures, here are some pictures I took of the coolant leak.  First up are a few pictures I took Thursday evening after I got home and the engine was already shut off:


Then, these were the pictures I took Friday morning after running the engine for a while with the stop leak added to the radiator:

You can see a little bit of steam coming from the bottom of the engine while it was running:

Then, oddly enough, the steam seemed to start pouring out of the engine even worse after I shut the engine off! surprise frown

You can see that the steam is coming out of the side of the engine between the alternator and the power steering pump:


After I shut the engine off and let it cool down, I removed the coolant overflow tank to try to get a better look at the lower back side of the engine.  You can clearly see there is a ton of coolant leaking out of the engine while it is running!



Also, in case you were curious how bad of shape the bodywork is in on this car, well you can judge for yourself.  I was trying to find a few pictures I had taken of the car, but most of these are from a while ago (before I replaced the headlights on it):


(Actually, I did find one recent pic of the car with the new headlights on it, but it was dark outside, so kind of hard to see much:)


volvoclearinghouse PowerDork
3/9/20 6:49 a.m.

What these pictures don't show is the rocker panels.  Or, more specifically, the lack thereof.  Mailman's my brother, and I've seen this car in person.  New York State doesn't fail cars for holes in the bodywork like some states (*cough* PA *cough*) do; if it did this car would have been scrapped years ago.  

"Given all the other work I have done to this car already, I'm kind of already into it beyond the point of no return, I think. "

This is a common fallacy, not just in the automotive world, but for people and stuff in general.  All the money you've spent on something, all the time you've devoted to it, and all the work you've put into something have exactly two (2) measures:

1) How much is this thing worth to you?

2) How much is it potentially worth to someone else?

Going out of order; regarding #2: Approximately 0.1% of all of the potential buyers of a $1000 beater will care about all the maintenance and work you've put into it.  It will make it sell Easier and Faster, but nobody, even in New York where this sort of rust isn't an immediate death sentence, is going to even bother putting eyeballs on this car if you list it for sale for more than $1500.   

Which brings us to #1.  I will say that the point at which most people will throw in the towel on a car is far, far too early.  Fixing engine issues, or even replacing the engine or transmission, can be worthwhile if the additional utility gained exceeds the cost of the repairs.  Even a very modest new or used car, at $300 per month, quickly eats up a $3000 repair bill.  That said, the car in question here is a 16 year old GM product, with one of their lesser engines, rusted badly, with nearly 200,000 miles on the clock.  It's honestly not even worth the time it takes to drive it to the junkyard, nor the cab fare home.  Especially when you have somewhere between 2 and 4 other functional vehicles in your fleet, so the immediate loss of this one won't be a gigantic punch in the face in terms of being forced to quickly go out and find a new car.  

Take this as a lesson learned from me: at some point throwing money at a car past its expiration date is like plugging holes in a dike.  Eventually you run out of fingers.  Scrap the Impala, bro.  

Gearheadotaku GRM+ Memberand UltimaDork
3/9/20 10:04 a.m.

Scrap value on the car probably isn't much, call around and get a number. (Let's say it's $250)

If you can fix it yourself for $100 or so and a weekend of wreching, it's now worth about $1000.

Fix it and sell it. You'll make $600 or so more for a weekends work vs scrapping it.

John Welsh
John Welsh Mod Squad
3/9/20 10:11 a.m.

In reply to MailmAn :

I see an Uber sticker.  

Get rid of the Impala and replace with 2004-2009 Prius.  Never look back.  

wspohn Dork
3/9/20 10:25 a.m.

Edmunds says it is worth less than $500 running. Might be time to walk away or sell to someone looking for an engine to rebuild.

I guess it depends on how much your time is worth to you.

volvoclearinghouse PowerDork
3/9/20 10:33 a.m.

In reply to John Welsh :

Good eye, I missed that.  Uber ages out cars older than 15 years anyway, so the Impala in question is no longer a valid Uber-mobile anymore.  A buddy of mine who does the gig-driving thing has a Prius of the generation you mentioned, does all his own maintenance, and manages to eek out a few bucks on the deal.  Ubering with something that uses 2 or 3 times as much gas (not to mention lower statistical reliability) is arguably an exercise in futility.  

EDIT: a quick search in my area shows 2009 Priussssses with under 200k on the clock for $4000.  With under 150k on the clock for about $5000.  

John Welsh
John Welsh Mod Squad
3/9/20 10:43 a.m.

In reply to volvoclearinghouse :

2013 Chevy Sonic, cheap in Ohio and Amtrack will bring you right to my town.  

volvoclearinghouse PowerDork
3/9/20 10:57 a.m.
John Welsh said:

In reply to volvoclearinghouse :

2013 Chevy Sonic, cheap in Ohio and Amtrack will bring you right to my town.  

IIRC Uber has a restriction that cars may not have a Salvage title.  

John Welsh
John Welsh Mod Squad
3/9/20 1:32 p.m.

I knew there was at least one reason I didn't like Uber. devil

MailmAn New Reader
3/9/20 10:56 p.m.
wspohn said:

Edmunds says it is worth less than $500 running. Might be time to walk away or sell to someone looking for an engine to rebuild.

Did you look up the trade-in value or something?  I thought that seems awfully low for this car, even in really bad condition cosmetically.  I looked up the Kelley Blue Book value of the car for a private sale (since a dealership won't give you E36 M3 for it and I'd be lucky if they didn't charge me a "disposal fee" to get rid of it for me... angry)  Even with 172,000 miles in fair condition (which the car isn't in "poor" condition REALLY, except for the bodywork on it...), Kelley Blue Book says the private party sale value of the car is a lot higher than a measly $500!  (Hell, the tires alone on it are worth more than that!!)

2004 Chevrolet Impala Sedan 4D Private Party Values | Kelley Blue Book

(KBB estimates the private party median value around $1,300...  So, could probably get a bit more than that given tons of new parts on it...?)


Vigo MegaDork
3/9/20 11:16 p.m.

I really dislike doing that job. There's just enough about the way the car is put together that annoys me that pretty much every step of the job i think "this would be so much easier if they had made this bit just a little different" and that gets old. 

If your alternative is selling it for $200 and you have some free time and patience, you can fix it. Just depends how much you care about the value you'll be adding through the effort and annoyance. 

volvoclearinghouse PowerDork
3/10/20 6:36 a.m.

In reply to MailmAn :

Does KBB discount the median value for disappearing rocker panels?  devil

You keep conflating how much you've "invested" in the car vs. how much it's actually worth.  Those things are not the same.  

I'm not sure what sort of magic bullet you're expecting here, but you basically have 4 options, outlined here:

Fix and Sell, you'll spend around $100 in parts and a weekend in work, and maybe be able to get $1000 out of the car.  

Fix and Keep, spend $100 in parts and a weekend in work, and you'll end up with a rusty, 180,000 mile, 16 year old Impala you can't use for Uber and a question mark as to what will fail next

Don't fix and sell- you'll get maybe $250 for it as-is, spend an hour or so dealing with selling it or driving it to the junkyard, and you can go buy that 2009 Prius you've always wanted.

Don't fix and don't sell - and have a lovely, Impala-shaped lawn ornament your neighbors will be sure to comment on - or you'll pay $600 per year to store somewhere.  

The difference between selling fixed and selling broken is about $600 and a weekend's worth of your time.  And that's assuming you fix it and it works.  Figure 16 hours in a weekend and the lost opportunity to do something else you'd rather be doing than wrenching on a dillapidated, oxidized, Chevrolet built when a Bush was in the White House....

Scrap the Impala.

MulletTruck HalfDork
3/10/20 10:31 a.m.

The EX has a 2001 Impala that had a recall on the intake gaskets. Maybe the same for yours. 


Jusst after the recall was done the main computer took a dump. go figure.

wvumtnbkr GRM+ Memberand UberDork
3/10/20 11:26 a.m.

Iirc, this isn't that bad of a job.


Remove 6 bolts from upper intake.  Remove 3 spark plug wires.

Unbolt coil setup.

Disconnect air intake at throttle body.  Unplug iac, and tps.   

Unplug map sensor.  Remove upper intake manifold.

Unbolt about 8 tty bolts on lower manifold. 

Unplug fuel injector main plug.  

Disconnect fuel line(s) to injector rack.

Remove valve covers.

Remove lower Intake manifold.

Loosen rocker arms

Remove pushrods(long ones are exhaust)

Put on new Felpro gaskets.  

Put pushrods back in.  Tighten down rockers to correct torque.

Everything is the opposite for reassembly.

Get new bolts for intakes (they are tty).


Change the oil.


Start up and have no issues. 


I just did this (with an engine sitting on the floor).  Took about 45 minutes.  I would say that engine in car should be about 3 hours tops.


MailmAn New Reader
3/13/20 11:22 p.m.

In reply to wvumtnbkr :

Thanks for the helpful comments.  I've been researching the job and watching several different YouTube videos on how to remove the intake manifold on this engine.  It really doesn't look too bad and I have replaced intake manifolds before, but that was on 1970's era V8 engines, which are a breeze to work on.  I've never actually disassembled the top end on a modern, fuel injected, transverse-mounted engine before.  I suppose the concepts are identical, really, but it does seem like a more daunting task in a newer front-wheel drive car.

Also, if I'm going to attempt to fix this myself, I'll need to invest in one (possibly two?) torque wrenches, which I do not currently own.  The rockers, intake manifold bolts, and valve cover bolts all need to be properly torqued down to spec when reassembling this engine.

Gearheadotaku GRM+ Memberand UltimaDork
3/15/20 3:44 p.m.

The cheap one from harbor freight are good enough. Or get one from the auto parts store tool loaner program.

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