'02 Impala 3.4L, 185k: Running HOT !

Colt Hero
01-04-2015, 06:00 PM
'02 Impala 3.4L, 185k: Running HOT !

Full Disclosure: This thing has had a coolant leak for a few months now, and without both time and energy to get to it, I've been just filling with mostly water, but enough coolant to prevent freeze damage (although this car is in the Carolinas where freezing is not much of an issue). Leak seemed to be coming from firewall side of engine, but I haven't been able to determine exactly where. Water *sometimes* comes down like a waterfall with more than one stream, but then other times, it doesn't appear to leak at all! Really weird.

Anyway, while I was away for 10 days, wife *claims* car "overheated" on a short 2 mile trip to place where she runs. "Overheated" means engine temp went to the far right, but she shut off the engine and never saw any "steam" coming out of engine compartment. Car had plenty of water in it at the time.

So I just checked it out and here's what I found:

1.) On short neighborhood test drive, Engine temp rose quickly to 225 F.

2.) Popped hood and heard loud "SHHHHhhhhhhh" noise coming from cavity between Alternator and Power Steering Pump, but couldn't see any obvious liquid leaking anywhere. Top of engine *does* have sooty 'blemishes' on aluminum intake, which is something that seemed to be getting more noticeable lately, but that's it. Also some damp stains on "V" seal on side of block where intake gaskets are, but no liquid oozing out.

3.) LOW COOLANT Message appearing in cluster, but this might be dirty sensor (seen this before). But this was also symptom of intake gasket failure previously.

4.) Radiator cap reasonably clean underneath. No 'sludge' or 'muddy' residues.

5.) Top radiator hose got HOT during short drive, but bottom hose was STONE COLD. This means bad radiator, right?

6.) Intake gaskets replaced in May 2008 @ 104,980 miles. I used Felpro 'metal-framed' gaskets, also replaced all lifters, all disturbed o-rings (injectors, fuel rail, coolant bypass, oil pump drive, t-stat housing pipe), both valve cover gaskets, T-Stat, plugs, wires). Re-used old intake bolts, using blue threadlocker.

7.) Engine sounds and runs OK otherwise.

8.) Plenty of water in overflow tank.

9.) Radiator was replaced 4 years ago, Nov 2010, (Advance Auto, ReadyRad) at 140,700 miles. Might be able to get 1 free replacement if it turns out it has failed internally.

10.) Computer Codes: P0102, P0442

Tech II
01-04-2015, 09:11 PM
Sounds like you have created an air pocket, due to a loss of coolant......when you have an air pocket in a closed system, coolant does not flow, therefore, it overheats....at the same time you will not get any heat out of the registers either.....

If you have an external leak, you should be able to see it....have you tried a pressure tester?

You can add coolant dye to the radiator, run the vehicle, let it cool down and repeat......then use a black light to find the leak.....

Colt Hero
01-05-2015, 02:45 PM
What do you think of this?


Would this work well enough, or should I purchase something more substantial?

Tech II
01-08-2015, 08:35 AM
Looks fine, but you spend that amount and may only use it once in your lifetime, unless you are a tech....

I would just rent one from places like autozone.....it actually costs nothing once you return it....they will charge you for the full price on your CC, and then give you a credit when returned......

01-11-2015, 01:57 AM
maybe its your radiator cap or the line going from the radiator to the overflow bottle.

Colt Hero
01-31-2015, 03:39 PM
OK - I've got some glacial 'progress' to report. Before ripping anything apart, I decided to do a compression test today. Figured it was good information, right? Keep in mind that this engine starts right up and runs like a clock with no unusual noises (other than the hissing and water seepage noises coming from between the alternator and power steering unit at the very top of the engine, which I've yet to find the source of):

Here are the compression test results (BTW: each cylinder was 'cranked' for *about* 5 seconds, and each pressure was timed for at least 5 minutes afterwards to see if it held):

Front side (Right To Left):

Cylinder #6: 185 lbs/in2, and held solid

Cylinder #4: 190 lbs/in2, and held solid

Cylinder #2: 185 lbs/in2, and held solid

Firewall side (Right to Left):

Cylinder #5: 185 lbs/in2, and held solid

Cylinder #3: 190 lbs/in2, and held solid

Cylinder #1: 180 lbs/in2, but *seemed to* leak very slowly down to 175 lbs/in2 after about 1 HOUR

So - what does this mean? Is my head gasket probably OK? I was worried about cylinder #1 - that's why I did it last, and was surprised to see the pressure reading seemingly OK. Although there *does* seem to be *some* leakage there, does this warrant a head gasket job?

Forgot to add:

Coolant recovery tank was bubbling like a fish tank (~3 big bubbles per second), and the plugs all came out intact with the center electrodes all looking just fine, BUT - there was whitish residue on the "elbows" ... but we already know there's a coolant leak, so these symptoms just verify that, correct?

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