2003 Chrysler PT Cruiser Intermittant Antifreeze Odors

Hi there,

Thank you for the donation,

The first thing that must be done it to prove the integrity of the entire cooling system and the heater system, to do this you will have to get a cooling system pressure test done, this hould be done hot with the heater on full heat, this will prove any small external leaks, clear this first and if there are no problems we will look further.

Mark (mhpautos)

OK - Just had the shop call me to say that they've pressure tested the coolant system and could not find any leak. They asked if maybe the engine had been overheating as that could cause some odor to bubble through the coolant reservoir under the hood and into the passenger cabin - but the engine has not been overheating.

They suggested a flush, but couldn't say that would do anything.

This is a bizarre problem - what do the smart guys think could be going on?

Hi there,

The coolant does have a particular smell and you can't really mistake it for something else, the only other sweet smell can be a fuel leak on a warm surface, from past experiences i have had similar problems with coolant type smells in the cabin with no apparent leak, and it was a tiny weep from a heater core barely enough to drip, but enough to form an culmination of dried coolant that emitted an odor with the fans on, also have seen this after a hear has been repaired and the heater box has not been cleaned and dried coolant residue has been emitting odors into the cabin with the fans on, but not all the time and more predominate with the air direction low to the foot wells.

Mark (mhpautos)

Thanks Mark. To pressure test, the shop used a pump device that attached to the radiator to generate pressure. A gauge on the device monitored the pressure. The mechanic indicated the gauge is very sensitive, but do you think it could/should detect such a small leak?

Also, do you know of a way to visually check the core without a major disassembly?

I drove the car several miles today and could only generate faint whiffs of antifreeze in the cabin as I worked over the vent controls - nothing like the overwhelming smell I experienced two days ago. The smell was stronger when i checked under the hood - especially around the radiator cap.

When the pressure tests is done, you normally only use the gauge as an indication of the system pressure you have induced, normally a leak of any magnitude will show up as a pressure loss, but with small leaks you must do a visual inspection as the loss of pressure may be quite small, they can check the cap with the tester as well, but if in doubt a new cap is quite cheap, the problem is a very small leak in the heater core will be hard to detect as the coolant may dry up before it shows as a leak in the cabin, but this is often the smell you can have, do the cap next and have a good visual inspection under pressure around the engine first.

Mark (mhpautos)