Ok i have 72 240z and there is this really weird smell in AND out of the car when its warm. Its not gasoline for sure. Its more like sugary smell or something. My whole garage smells like it after car has been run warm (outside) and brought inside. My Z is not leaking BUT the rear end is literally covered with crap.

I think i smell it more inside if i switch heater options to hot.. Please help, i want to get rid of that. Ive sealed tail light and all the possible holes from the rear end and also my muffler tip is 2" extended to keep out the fumes.

Is this a sudden onset condition?

Have you done anything , service-wise recently?

If yes and yes, perhaps something got left in the engine bay, under the dash or near the exhaust.

In my opinion, coolant has a "sugary" smell. It would correspond to the heater set to 'hot'. Check/monitor coolant level.

Coolant for sure, you have a leak.

I know that odor well, it smells like Maple Syrup. Yuck. Dealing with coolant over the years has ruined oatmeal for me forever!!

On the bright side of things it is a great time of year to deal with this issue. Have you discovered where the leak is??? I would remove the Pass Carpet and feel around the Firewall and Trans Tunnel. If your carpet is soaked, you can hose it out and let dry in the sun.

While you are at all of this, you might go ahead and replace the Thermostat and flush the Radiator.

Good Luck!

Hiya. Thermostat has been replaced and the radiator flushed. Twice. No leaking coolant and no moist inside car. Got to triple check all the hoses though.

I'd check the heater core. I wouldn't take it out but right after you run it open the floor panels and with a flash light see if you see anything shiny. Also take a rag and see if you have gunk on the bottom of the box. The heater core contol valve should be checked they over time might let little amounts of coolant when moved, while the car is running play with and see if you can get some coolant.

When you flushed the car maybe you got some coolant under the cowl, your heater air intake is their. Try flushing some water in the cowl, be careful the drains have a rubber hose that gos inside the cab make sure they are not leaking otherwise you will have a wet interior. This might be a good excuse to take the cowl off and clean it out, check for rust, lube the joints on the wiper system, and if your really ambitions check on the wiper-motor, and give a good coat of a protestant.

I'd check the heater core. I wouldn't take it out but right after you run it open the floor panels and with a flash light see if you see anything shiny. Also take a rag and see if you have gunk on the bottom of the box. The heater core contol valve should be checked they over time might let little amounts of coolant when moved, while the car is running play with and see if you can get some coolant.

When you flushed the car maybe you got some coolant under the cowl, your heater air intake is their. Try flushing some water in the cowl, be careful the drains have a rubber hose that gos inside the cab make sure they are not leaking otherwise you will have a wet interior. This might be a good excuse to take the cowl off and clean it out, check for rust, lube the joints on the wiper system, and if your really ambitions check on the wiper-motor, and give a good coat of a protestant.

There is indeed small leakage inside car on the passenger side. I dont know where it leaks but its not leaking much, few drops. Suggestions?? BUT it does not explain the odor from outside car. Its 10 times bigger than inside.

and give a good coat of a protestant.

... but don't forget to ask the protestant for his cloak too. It's sort of an ask for one, get the other free sort of deal, as I understand it.

To the OP: Turn on your heater, and smell the hot air coming out of it. It might have that same strong smell. I suppose if you have enough of that smell flowing through the interior of the car and then to the exterior, you might smell it there too.

If the smell is more than that, you might have a tiny radiator leak.

How often do you change antifreeze? Old antifreeze loses its corrosion inhibitors and can leave your radiator, heater core, and engine internals susceptible to corrosion. That might be the source of small leaks.

There is indeed small leakage inside car on the passenger side. I dont know where it leaks but its not leaking much, few drops. Suggestions?? BUT it does not explain the odor from outside car. Its 10 times bigger than inside.

I'd start with a known leak antifreeze is great at rusting things, it eats paint . . .

Smells on the outside of the car and you see no sines of leaks look look at the radiator see if you see any discoloration that would be a hint of a leak.

Also do you get moisture in the exhaust, or a white smoke? Signs of coolant

Is the overflow be dumping more than you expect? this could be caused by excess pressure, air-lock, blockage, or bad radiator cap

Is the radiator cap working at the right pressure?

Is the car engine getting hotter than normal?

... but don't forget to ask the protestant for his cloak too. It's sort of an ask for one, get the other free sort of deal, as I understand it.

That is a good one it sounds like a topical drug or something. It's funny how I make mistakes like that and I just don't see them. I write a lot of technical document, most of the ones for my department, and we get a kick out of some of my mistakes when we proof read my stuff. Well that is why I have a person at work that specializes in proof reading, because my supervisor is as bad as I am.

I'd start with a known leak antifreeze is great at rusting things, it eats paint . . .

Smells on the outside of the car and you see no sines of leaks look look at the radiator see if you see any discoloration that would be a hint of a leak.

Also do you get moisture in the exhaust, or a white smoke? Signs of coolant

Is the overflow be dumping more than you expect? this could be caused by excess pressure, air-lock, blockage, or bad radiator cap

Is the radiator cap working at the right pressure?

Is the car engine getting hotter than normal?

When i start the car, exhaust is white but when it warms up its colourless. It does dump a little water when starting to move. Dont know about the cap.

Water temperature rises 3/4 and returns to normal, everytime when i drive it. But i think thats normal.

So even tiny radiator leak smells that bad? There has been a very small amount of water (like few drops) in the engine side but not enough to fall to the ground.

It sounds like a heater core issue (leak). The odor will vent outside through the air vent system.

JLP