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Please tell me this isn't a heater core issue? (Pictures included)
Background...2000 C5, 21,000 miles, auto trans, "manual climate control".
I bought the car last summer with 18k miles. Noticed an anti freeze/moldy smell when turning on AC/heat (and even very very faint anti freeze/moldy smell when AC/heat not turned on). It turns out it had a leaky water pump. Water pump replaced last fall. Still noticed anti freeze/moldy smell after water pump replaced. Mechanic overfilled coolant was my thought, as coolant level well above "fill line". Removed excess coolant. Never smelled anti freeze/moldy smell again for the last 6 weeks of fall driving!
Car sat in garage all winter connected to battery tender. Suddenly pulled car out of garage for spring...Noticed a circular/oval almost clear haze on windshield developed over winter/spring while car sat parked (it was started a few times to let fluids move but AC/heat not used). Here is a picture, but tough to see. It's concentrated on passenger side...starts halfway up windshield from top to bottom and ends where black factory line comes across windshield. From left to right, about 18", starting directly over passenger "dash grab bar" and ending 1/3 way over dashboard heating A/C vent.
I drove car for first time this season last week. A very, very faint anti freeze smell after driving for over an hour (didn't notice until almost an hour of riding). Windshield "haze spot" doesn't get bigger or smaller when driving...just stays there. I didn't touch it as I wanted to get pictures. Coolant level still high...I recall reading it should be pretty well filled in these cars for one reason or another.
Am I smelling excess coolant draining somewhere through a safety valve of some kind when it heats? Or dreaded, horrible heater core? What are tell-tale heater core signs? I can tell you the passenger side foot well is bone-dry, the windshield haze doesn't get better or worse with driving--it's just there and suddenly appeared after sitting during the winter, and the heat and A/C system seems to work fine.
Thanks for any help.
Last edited by Slo Yelo C5; 05-28-2017 at 11:23 AM.
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'23-'24
Your overflow tank appears to still be overfilled but I don't see how that is related to a fogging of the windshield inside the car.
Do you run the car in recric or fresh air? I've noticed sometimes when I run it in recric the window will fog up but it never does when I run it fresh air.
Your overflow tank appears to still be overfilled but I don't see how that is related to a fogging of the windshield inside the car.
Do you run the car in recric or fresh air? I've noticed sometimes when I run it in recric the window will fog up but it never does when I run it fresh air.
1.) Overfilled tank could cause the very faint antifreeze smell when antifreeze gets hot maybe? Kind of separate issue from windshield haze.
2.) Fresh air or recric air? What do you mean? Sorry, I'm confused.
I would definitely lower the level of the coolant tank (cold engine) to the full when cold mark on the end of the tank. Then drive the car and see if you still have the coolant smell after a somewhat lengthy drive. If the tank is over filled the expansion of the coolant when the engine gets to operating temp could cause the coolant to be pushed out through the pressure cap.
On your comment in post #1 about a "safety valve", no such thing exists on the C5. Unlike many cars that do not have pressurized coolant in the "surge/overflow" tank, on the C5 the surge tank does have pressure when the system is at operating temp. The only means for over flow is at the pressure cap which could open and discharge excess coolant/pressure in the system. If this has happened then there are usually tell tale signs of the coolant on/near the surge tank.
Thank you.
Now this may sound like the dumbest question in the world but...I wanted to see how high the coolant was and the color of the coolant. So to view it, I removed the cap that said "15 psi". I've never seen a coolant tank that had a "psi" number on it...normally just says "Engine Coolant". I'm obviously assuming the "15 psi" label on the cap is because the system is pressurized.
Therefore, when I twisted and removed the "15 psi" cap, is that bad for the engine coolant/cooling system since I'm allowing more air in? Since the system is pressurized, is that cap not supposed to be removed without doing something else? I just pulled it off and removed it for a minute, then put it back on...very tightly. I did not see any coolant residue around the cap.
Removing the cap will not introduce air into the system, but you don't want to remove it when the coolant is hot. It is under pressure (only when hot) and hot fluid can spray out.
Now this may sound like the dumbest question in the world but...I wanted to see how high the coolant was and the color of the coolant. So to view it, I removed the cap that said "15 psi". I've never seen a coolant tank that had a "psi" number on it...normally just says "Engine Coolant". I'm obviously assuming the "15 psi" label on the cap is because the system is pressurized.
Therefore, when I twisted and removed the "15 psi" cap, is that bad for the engine coolant/cooling system since I'm allowing more air in? Since the system is pressurized, is that cap not supposed to be removed without doing something else? I just pulled it off and removed it for a minute, then put it back on...very tightly. I did not see any coolant residue around the cap.
Not to worry! The pressure builds up as engine heats up.
The system is ONLY pressurized when the coolant temp is above about 212* F. The pressure cap is a two way device. As pressure in the cooling system increases due to the heat of the engine it closes a small port in the cap and allows pressure to build to as much as 15PSI for your cap. Newer caps for the C5 are 18PSI. The pressure is necessary because a 50/50 coolant/water mix boils at about 218*F. For each lb of pressure the boiling point is raised about 3* so the boil point at 15lbs is about 263*.
When the coolant temp drops below about 212 * the cap opens a port inside it to allow atmospheric pressure back in on top of the coolant. If this did NOT happen then the inside of the cooling system would develop a negative pressure that would suck in the sides of the coolant hose(s) and eventually ingest air into the cooling system rather than JUST on top of the coolant. You would know this because the engine temp would rise abnormally high within just a few minutes of starting a cold engine.
Your removing the cap did not hurt a thing. Just be careful in the future if you try to remove the cap and coolant is above 212. You could be seriously burned by the hot coolant.
Well slow hunt and peck typist that I am, you got the condensed info from other members while I was still hunting and pecking.
Did you feel your interior carpet to check for dampness?? Check around where the heater core is...
I did!
Last time I drove the car for an hour (a week ago), engine was hot (I want to say 220-230℉). That's when I smelled a very, very, very faint antifreeze smell. Far from overwhelming. I felt carpet on passenger side floorboard. Bone dry.
A/C blows cold air...heat works when turned on and blows hot air. When I turn A/C or heat past level 2 (again--manual climate control with levels 0-4), system makes a very weird sound. Almost a sound like it's struggling to work. It sounds like my old Cavalier fan before HVAC stopped working entirely (like a bad fan blower). If AC/heat stops working, I'll possibly live without it (Targa top and I don't drive it past November so heat isn't necessary).
My concern is...what's causing that haze on windshield? Like I said...car sat all winter, heat/AC wasn't turned on (but engine was started 7-8 times throughout winter for 5-15 minutes each time), then I noticed haze on windshield a few weeks ago. If it is AC evaporater and/or heater core, can car be driven if I'm willing to not use AC or heat? Or it'll still damage the car? Or is this haze something else entirely? I'm afraid to remove it for the time being because I want a friend or mechanic to see it if I need to bring it in for repair. But I've never seen a haze just suddenly appear like that on a windshield and not get better, or worse...just appeared and stays there.
I admit my car technical knowledge stinks...I'm trying to learn. I know "of" cars and general maintenance...but you guys are super knowledgeable and I'm trying to slower absorb more and more so eventually I'll be somewhat knowledgeable. I've learned a tremendous amount from the forum over the past year ( ) but I'm still very much a beginner.
Can you guys see that haze smudge from the picture? It's super hard to get a great picture of it. It's like a large oval if you can make it out.
If it makes a difference, when you first turn on AC or heat on any given day, the system emits a musty smell for 1-3 minutes, then it just goes away. Not sure if, like the haze, that's indicative of a bad heater core or evaporater.
Last edited by Slo Yelo C5; 05-28-2017 at 02:32 PM.
A bad cap could be the cause of the smell. It will leak out coolant. It then runs down a little channel on the top of the tank. Hard to see. Let the car come up to temp then look closely around the cap for coolant. It will not leak out until the car is at operating temp.
I'll go with the possible plugged A/C drain line option.
Drive around with the radio turned off and don't accelerate too hard; you may hear water sloshing around in the box, especially around turns. If the drain line is plugged, the water will eventually overflow and drip onto the computer in the passenger footwell, then all sorts of mean nasty things start to happen.
The drain hole is low on the firewall a couple feet in from the passenger side of the car. (Awkward to get to, in other words.)
THere is a pic of it in another thread about resolving water leaks....
I'll go with the possible plugged A/C drain line option.
Drive around with the radio turned off and don't accelerate too hard; you may hear water sloshing around in the box, especially around turns. If the drain line is plugged, the water will eventually overflow and drip onto the computer in the passenger footwell, then all sorts of mean nasty things start to happen.
The drain hole is low on the firewall a couple feet in from the passenger side of the car. (Awkward to get to, in other words.)
THere is a pic of it in another thread about resolving water leaks....
So awhile back, I thought I heard liquid sloshing around. I never thought anything of it...I thought it was just engine coolant or windshield washer fluid I was hearing.
I'm going to take it to my mechanic tomorrow. I'll ask that he clean out the A/C drain line. Any idea how much time is "reasonable" for him to charge me to clear out A/C drain line? Do you reasonably believe that could potentially be the cause of that odd haze on the passenger side of the windshield?
So awhile back, I thought I heard liquid sloshing around. I never thought anything of it...I thought it was just engine coolant or windshield washer fluid I was hearing.
I'm going to take it to my mechanic tomorrow. I'll ask that he clean out the A/C drain line. Any idea how much time is "reasonable" for him to charge me to clear out A/C drain line? Do you reasonably believe that could potentially be the cause of that odd haze on the passenger side of the windshield?
Thank you.
As an aside, if too much water builds up in the box, I think it is capable of impeding the fan (think of a gerbil exercise wheel partially submerged).
I had the car in the shop for other reasons, so I added the clean that drain line to the list. Forgot how much they charged me to clear it.
It could easily cause the haze. There is a direct path from the box to the defroster vent, so excess water in the box plus enough temperature difference to cause condensate...and you have haze on the inside of your windshield. You have to run the defroseter to make it go away, which heats up the water, which releases more condensate (and aroma) into the interior...shutdown the car, roll up the windows.... now you have warm water, releasing humidity into the enclosed cabin....which condenses on the windshield. (Lather, rinse, repeat)
There's another direct path from the box to the vents in the (passenger) door. It runs almost directly above the passenger footwell (and computer.)
This is the escape route the excess water takes when the drain is plugged.
Believe the joint is a compression fit, so water leaks through, dripping onto the CPU connectors.
Update
First off...thank you for all the great responses!
I took the C5 to my mechanic.
First he inspected the haze and agreed with me...it wasn't "oily" feeling.
He checked A/C drain line...it was completely clear and working perfectly.
He then ran a test on the A/C and heating system (pressure test?) to check for leaks, just to be sure A/C and heat system and components weren't leaking or otherwise bad. Results came back that system has proper pressure.
I'm at a loss regarding what happened. With that said, A/C and heat system are running perfectly, so I'm thankful I have no issues, and dont need a heater core or A/C evaporater or any other expensive and/or labor intensive repairs. On the down side, driving home, I got caught in a rain shower...First time that car has ever been driven in rain in 17 years. It didn't melt ( ), my johnson didn't fall off ( ), and the car still seems to be working.
It did take me 2 hours to give her a bath to get the dirt-rain (that nasty "wash" from the tractor trailers full of dirt and dust and grime ) off her.
05-28-2017, 10:47 AM
Please tell me this isn't a heater core issue? (Pictures included)
I know "of" cars and general maintenance...but you guys are super knowledgeable and I'm trying to slower absorb more and more so eventually I'll be somewhat knowledgeable. 
) but I'm still very much a beginner. 
It didn't melt (
), and the car still seems to be working. 
) off her. 