On my last nerve - more SC troubleshooting

Roboplex

SCCoA Member
Sorry I haven't been more active on the forums lately, back in school now and managing some health problems, so dealing with this car has sorta gone on the backburner. Pardon the long post, I'm just sorta thinking out loud here.

So I just took it in to the mechanic due to running out of freon, fearing it was my evaporator core. He traced down the leak to the new R-134a adapter fittings on my new AC lines. Apparently I installed it incorrectly to where the schrader valve was always being depressed, leading to a slow leak. So now it blows ice cold, but whenever the car is warmed up and the AC is on "norm", I still get this horrible smell that makes me lightheaded. Thankfully putting it on MAX makes it go away in the cabin, but after I park, I can smell it in the engine bay, most potent to the immediate left of the radiator, in front of the high side AC service valve.

One would think that it's antifreeze since it's slightly sweet, but the mechanic pressure tested my radiator and said it was perfect. I haven't used any chemical cleaner of any kind in months, anywhere in the car. The car was also sitting at his shop for about a week after he recharged the AC with the new fittings, and it hasn't leaked one bit.

My gut is really telling me that this smell isn't AC related (even though I can't think of anything else that would smell like that) since I distinctly remember smelling it when I was driving around with no AC (no charge in system), but ONLY when the radiator fan would cycle to cool the radiator. My theory is that it's something around the radiator, but when I run the AC the cooling fan is constantly running, circulating the odor throughout the engine bay (into the AC intake), thus producing the smell in the cabin.

I'm really on my last nerve with this car. It seems like every time I fix something, another thing pops up. I know, it's just par for the course of daily driving a 27 year old Thunderbird, but once in a while I just wish I had bought a Civic or something for my first car like everyone else xD.

Thanks for listening to me...again xD
Joseph B.
 
Last edited:

KMT

Registered User
I've had engine compartment odors migrate into the cabin via the fresh air intake below the pass. side cowling.

Bit if a pain, but if you can block the intake long enuf to check, you can at least determine if it is coming from the engine bay. And yes, sweet usually means anti-freeze. Have you been able to tell where the level in the expansion tank has been riding? Been adding any?

Might just be mold inside the air channels in the dash and/or on the exchanger where air is forced over it behind the dash, in which case a good dose of Lysol spray should help clean things up, but that smell is hardly described as 'sweet' ;)

Another possible cause is if the condensate drain from the cabin into the engine bay is blocked and that moisture has been collecting inside the exchanger box, inside the dash. Can you verify it's working/not plugged? Do you see moisture under the car in that area when the A/C is on? If you can get to it, you can check it for debris at the exit, I think...
 

MadMikeyL

SCCoA Member
Well if you smelled it with no refrigerant in the car, that completely rules out the AC system being the cause of the smell. Are you loosing any coolant? I have seen radiators that only leak at certain temperatures, but will pass a pressure test every time if tested cold. If you are losing coolant but it passes a pressure test, that would be my guess. If you aren't losing coolant, then it has to be something else. As for the smell going away on max, all that does is block off fresh air coming into the car causing the air in the car to recirculate, so that proves that the smell is coming from outside the passenger compartment, and not in the HVAC ducts.
 
Last edited:

Roboplex

SCCoA Member
I've had engine compartment odors migrate into the cabin via the fresh air intake below the pass. side cowling.

Bit if a pain, but if you can block the intake long enuf to check, you can at least determine if it is coming from the engine bay. And yes, sweet usually means anti-freeze. Have you been able to tell where the level in the expansion tank has been riding? Been adding any?

Might just be mold inside the air channels in the dash and/or on the exchanger where air is forced over it behind the dash, in which case a good dose of Lysol spray should help clean things up, but that smell is hardly described as 'sweet' ;)

Another possible cause is if the condensate drain from the cabin into the engine bay is blocked and that moisture has been collecting inside the exchanger box, inside the dash. Can you verify it's working/not plugged? Do you see moisture under the car in that area when the A/C is on? If you can get to it, you can check it for debris at the exit, I think...
Oh I've already determined it's definitely coming from the engine bay. I can smell it ALOT more under the hood than in the cabin, and the smell virtually vanishes when I put it on recirculate. I was sort of sniffing around the different areas of the engine bay, and I think I tracked it down to the front passenger side of the engine bay, in between the intake air handler box and the radiator. I put my nose right in there and it immediately smelt (and felt) like I was huffing spray paint xD. Smelled EXACTLY like paint thinner or nail polish remover.

But like I was saying, i don't think it's connected to the AC, but moreso the cooling fan turning on and pushing the smell towards the intake below the cowling. Like when I was running the car without any freon in the system, the fan would only cycle occasionally for a moment or two and then turn off (like it should), I noticed a little whiff of the smell every time it cycled.
 

KMT

Registered User
Have you been able to tell where the level in the expansion tank has been riding? Been adding any?
 

Roboplex

SCCoA Member
Well if you smelled it with no refrigerant in the car, that completely rules out the AC system being the cause of the smell. Are you loosing any coolant? I have seen radiators that only leak at certain temperatures, but will pass a pressure test every time if tested cold. If you are losing coolant but it passes a pressure test, that would be my guess. If you aren't losing coolant, then it has to be something else. As for the smell going away on max, all that does is block off fresh air coming into the car causing the air in the car to recirculate, so that proves that the smell is coming from outside the passenger compartment, and not in the HVAC ducts.
Yep exactly! I don't recall having lost any coolant (if so not very much), that's what's really stumping me. I can't think of anything else that would smell like that besides PAG oil or antifreeze. I suppose it could a heat-sensitive radiator leak since I really only smell it when the car is warmed up, but again, I haven't noticed my coolant dropping. I'll have to mark the reservoir with a sharpie or something and keep an eye on it to be precise though.

The mechanic did just fix a leak I had in my transmission cooler lines and around my transmission pan, but there's no way that smell is ATF.
 

BeerGarage

Registered User
This is odd.

If you take off the radiator cap (engine cold of course), and smell the coolant, is that the same smell? You said it, "Smelled EXACTLY like paint thinner or nail polish remover." My coolant does not smell like that.

Good luck.
 

Roboplex

SCCoA Member
This is odd.

If you take off the radiator cap (engine cold of course), and smell the coolant, is that the same smell? You said it, "Smelled EXACTLY like paint thinner or nail polish remover." My coolant does not smell like that.

Good luck.
That's what I've been thinking! It DOES NOT smell like straight up antifreeze, but antifreeze is the only thing the smell even remotely comes close to. I sorta just assumed it took on a different smell once it was vaporized after dripping on the exhaust or something. Really the only thing I can compare it to is acetone.

I would think that it was ATF since I did just have the trans cooler lines redone, but there's no way that smell is transmission fluid!
 

sam jones

Registered User
Good afternoon

I believe the paint thinner smell at the engine bay passenger bay location might be a indication of an accidental A/C flush solvent-based solution spill. I would check the smell at the accumulator, evaporator inlet/outlet connectors at the firewall and the cowl air vent area. A soap wash down should clear the problem.
 

BeerGarage

Registered User
Solvent spill...

There is foam all around the condenser between the rad and condenser. That could be a big sponge and soak stuff up.

But acetone... Acetone will evaporate and be gone quickly. Even in a sponge it will not hang around.

What is this mystery substance?

What about let a tiny squirt of the AC refrigerant, out of the low pressure side, with ac off, and give that a whiff. Is that the smell? OK, don't shoot that into your nose, but into a rag or something.

Pull your Trans dipstick and smell that. Is that the smell?

Open your PS reservoir and smell a drop of that stuff.

Open your rad cap and smell that.

Are the AC lines tightly connected, between the radiator and the air filter box are two fittings. Right there where you smell the smell. Give those a twist and a push and see if they click together more tightly.

What about unhook the fan and start the AC. Then smell that same spot. Then the refrigerant will be pressurized and the fan will be off.

Or just let it get hot till the fan clicks on and leave the AC off. Then if you smell it that proves nothing, but it is in the area of the fan somewhere.

Acetone?

I hate it when I can't even figure out what needs fixing.
 

DrFishbone

SCCoA Member
Could the vacuum canister be retaining some junk solvent from something? It's mounted below the air filter in the fender well area.

Seems like if it were an external spill and a solvent, the smell would dissipate after a little while.
 

aroot1

SCCoA Member
Could the vacuum canister be retaining some junk solvent from something? It's mounted below the air filter in the fender well area.

Seems like if it were an external spill and a solvent, the smell would dissipate after a little while.

Maybe even old gasoline up in the vent lines/canister? It smells sickly sweet and awful, like turpentine. Once you smell it once you'll never fail to recognize it! AND it WILL give you light headedness/headaches.

Adam
 

DrFishbone

SCCoA Member
Right - gasoline fumes are what I had initially thought of...there are a few different ways the could get down there....it just seems unlikely, since the tube is so small.
 

Mike Puckett

SCCoA Member
In my old 35th Anni Edtn the PCV valve popped out of its hole once and I was getting a strange smell that didn't smell like oil or something burnt. It was weeks before I found it. Can you smoke test it? That would show up a leak in the plumbing.
 
Top