'02 Impala (3.4L) Intake Project Complete, but...

'02 Impala (3.4L) Intake Project Complete, but...

It's done and seems to be running fine - smooth idle, heats up to about 185-192, new T-Stat appears to be opening OK ... BUT I drove it 30 miles to work today and could smell a very faint whiff of coolant inside the car with Outside Air flowing throught the vents. I've looked several times for leaks but so far cannot see any. You'd think that if there was a leak while driving that you'd still be able to detect it after pulling over and shutting off the car. Maybe I need to leave the car running after stopping ...

Also, I haven't been able to get more than, say, 6-7 quarts of antifreeze/water mix into the car (a jug and a half) - even after bleeding at the T-Stat and leaving the radiator and tank caps off (and trying to fill after the T-Stat opened)! I could've sworn the system was bone dry when I opened it up - never saw any coolant spill out anywhere after emptying the radiator. When I started it up for the first time, I was getting the Low Coolant messages, but as I bled and filled it those went away and haven't returned (I DID remove and clean the radiator sensor). I also overfilled the plastic tank (at, or even slightly above, the HOT line) thinking that I'd be pouring in AT LEAST two full jugs and it would bubble down, but it hasn't gone down much. Pretty weird! After the drive to work today I tried to pour more in at noontime, but same thing - just a few tablespoons until the filler neck started to overflow. So I guess it's full!

So should I flush and fill the coolant again - like I will be doing with the oil in a couple of weeks - since there apparently is contaminated coolant still inside?

I did my gaskets a few K-miles ago. They're a pain to get all the air bled, but doesn't seem to cause overheating issues while occurring. About 7 quarts is right, and the level will be about 3/4" below the cap neck when cold. I wouldn't overfill the tank too much because you don't want to create too much pressure on the overflow part of the cap. It may not "burp" the air into the tank. DO put a new cap on it, though. The system is dependent on the cap pressure being correct. Also, look at your A/C condensate drain on the firewall for coolant...maybe you need a heater core. I put a half bottle of Prestone stop-leak in and the (exterior-only) coolant smell and small leak went away. There are rumors that GM and others use the stuff in new cars to clear minor issues. Also, I switched to the green coolant, and it works fine. And I have never flushed it...everything is still clean.

PAman,

I've got the green stuff in my Impala, too. I flushed the Dexcool out about two years ago. I'm going to give it another flush in a couple of weeks, then hopefully that will be it for a while.

I don't think I have a problem with the heater core. The whiff of coolant has seemed to go away and the wife has the car now. If she complains about it, I'll investigate further.

Still no leaks that I can see anywhere. I'm keeping my fingers crossed...

Potentially bad news regarding my intake gasket replacement work:

After replacing the gaskets and driving the car for 3-4k miles in the local geographic area with no apparent problems, I recently gave the car a "stress test" by driving it 500 continuous miles. Well, it drove fine and made it to its destination OK, but after parking and re-starting, the dreaded "LOW COOLANT LEVEL" message reared it ugly head again! At first I thought it might've had something to do with the parking spot (because there was a drain grate there that caused the nose to dip down quite a bit from level), but I've driven the car an additional 1900 (mostly highway) miles since and the message is still there (off an on, but mostly on). When cool, I've checked the level in the radiator and it's just low enough to be out of sight, so I've added a couple of ounces to it so far. As far as the plastic tank, there's plenty of liquid in there, but it's almost impossible to tell if it has dropped by such a small amount because of it's shape and orientation. I might have to yank it out and mark it, then go back and check it later.

Has my gasket fix failed under stress, or could there be another explanation here? There are no external leaks anywhere as far as I can tell - the gasket seams all look very dry - but it could still be leaking internally.

One question though - when you remove a radiator cap, shouldn't there always be a bead of coolant connecting the filler neck to the overflow tank? Could it be possible that there is a break in the flow of liquid between the two such that the two reservoirs are now islands?

Could be a break, but if this is just not a freak thing like replacing an air pocket with coolant and you continue to loose fluid, suspect a head gaskets. There are tests to confirm that condition before just jumping in.

I sure hope not it's not a head gasket problem. What I'm hoping is it's:

1.) residual air in the system, or
2.) A leaking cap, or
3.) A re-gunked up (or otherwise faulty) level sensor.

Seems to me that the radiator should be sucking all the fluid from the tank before it starts telling me there's a LOW COOLANT LEVEL. The fact that the tank still has plenty of coolant in it and I'm getting the message may indicate that the cap is sucking air instead of coolant. Also, the sensor could be dirty (again) or faulty. I was thinking the sensor could still be gunked up (again) by residual oil still in the in the system. After all, even though the gaskets are new, there's still got to be residual gunk inside the system from the previous leakage that may never go away.

Correct, so repalce or test the cap for starters, then keep your on things.

Well, the LOW COOLANT LEVEL messages continued off and on over the last three weeks during the "stress test", so this past weekend I removed the level sensor on the radiator and found it to be fouled with oil once again! Nothing like before the gaskets were replaced, but nonetheless apparently soiled enough to cause the messages to appear. On the brighter side, the underside of the radiator cap was almost completely clean - just a few specks of oil, once again - nothing like before the gasket replacement when thick fudgicle sludge routinely appeared (and re-appeared).

So the question is: is this oily residue NEW residue (ie: the new gaskets are now leaking), or could it be residual residue still inside the system that just got stirred up by 2+ weeks of very heavy driving? I mean - isn't it virtually impossible to get the oily residue from the original leak completely out of the system (without replacing the radiator, for example)?

I would say residual as you never get it all out unless a coolant flush machine is used, even then some clings to the inner block surfaces.

One other thing I've noticed recently: After driving the car, the frame of the car (and the black cross-brace bars) inside the engine compartment get pretty hot to the touch. Is this normal?? I know the engine heats up and some of this heat will transfer to the surrounding metal inside the engine compartment, but I just never noticed this level of heat before.

I'm concerned that this could be an indication that the engine heat is not being dissipated correctly (through the radiator). Is it normal for the cross-braces and frontal metal (the long color-painted metal section along the front where the hood latches) to get pretty hot?? Doesn't seem right to me...

Bad news today: Looks like my gasket repair job is failing. Checked for leaks again today like I've been doing pretty regularly since doing the job 7k miles ago. Looks like I've got some wetness under the throttle body toward the front side of the engine (or maybe it's right in the middle at the base of the V-seal "valley").

The original leak was on the other side - behind the power steering pump.

What do you think I did wrong? Bad torque on the short angled bolts? Re-using the old bolts? Maybe the gasket moved on me as I dropped in the Intake? Bad sealant used on the ends (I used Permatex black, and a pretty healthy bead of it).

I don't think I'm going to do anything about it right now. I'll just go back to what I was doing before: keeping track of how much fluid I need to add and what the radiator filler neck/cap and overflow tank look like (greasy). I'll probably be buying a new car at the end of this year or the first quarter of next year, so I need to rip it apart again, I'll do it then (unless it starts hemmoraging fluid).