"DANGER": Sweet smell in the car = one possible answer:
Heater core or cooling system is leaking into passenger cabin = breathing it can damage or KILL you.
Allergies in your family may make the affects worse.

Ethylene glycol intoxication
http://www.nlm.nih.gov/medlineplus/ency/article/000774.htm#Symptoms

Ethylene Glycol Intoxication
Symptoms & Signs
http://health.allrefer.com/health/ethylene-glycol-intoxication-symptoms.html

Material Safety Data Sheet
Ethylene Glycol
http://www.sciencestuff.com/msds/C1722.html

Toxicity, Ethylene Glycol
http://www.emedicine.com/emerg/topic177.htm

GLOSSARY Acute Exposure -- Exposure to a chemical for a
http://64.233.167.104/search?q=cache:rkP0LzHF8nMJ:www.atsdr.cdc.gov/toxprofiles/tp96-c9.pdf+Ethylene+glycol+neurotoxicity&hl=en

Applied Toxicology
http://64.233.167.104/search?q=cache:M3dkYbb4apsJ:aquaticpath.umd.edu/appliedtox/organics.pdf+Ethylene+glycol+neurotoxicity&hl=en

Metabolic Acidosis
http://health.allrefer.com/health/metabolic-acidosis-info.html

Treatment of Ethylene Glycol Poisoning
http://www.aafp.org/afp/20020901/807.html

Ethylene Glycol
http://www.mnpoison.org/index.asp?pageID=155

Material Safety Data Sheet
Ethylene Glycol
http://avogadro.chem.iastate.edu/MSDS/ethylene_glycol.htm

Edit new data:
Hazard Summary-Created in April 1992; Revised in January 2000
http://www.epa.gov/ttn/atw/hlthef/ethy-gly.html

__________________
ASE Master Mechanic
https://whunter.carrd.co/

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
2003 Volvo V70

https://www.boldegoist.com/