Anti-Freeze smell only when cold

[Yomie]

Ok, for the past week or so, when the truck has been sitting overnight. If i go start the truck and the temps are in the single digits, the defrost or heat has the sweet anti-freeze smell to it only untill the truck warms up, after that there is no more smell....OR if i start the truck and the outside temp is say like 30 or so and turn on the heat/defrost there is no smell? This kinda has me stummped, at first i thought it might be a Heater core prob, untill i noticed it goes away when the truck warms up and it only happens in say single digit temps..... I'm stummped

Any suggestions?

Oh yeah and i just had a coolant system check and flush in Sept. and there were no probs then, so it does have a fresh batch of coolant/water in there.

 

[BradE.]

Check your heater control valve, it might be leaking. It's on the passenger side of the engine near the back fire wall. It has 4 hoses going into it (2 inlet and 2 return) there is also a vac line attached to it.

Mine was leaking in the "Off" position and I could smell coolant very strong in the mornings. It's a pretty easy fix, the part only costs about $17 from the Ford dealer.

 

[Yomie]

You mean this piece?

http://photos.yahoo.com/bc/barneytc/lst?.dir=/Explorer&.view=t

thanks man

 

[Yomie]

how much coolant can i expect to lose when i change this out?

 

[BradE.]

Yep, that's the piece. Make sure your's is leaking before you replace it. Mine leaked in the "off" position. You would see a small drip coming from below the vac line thing. Try it in all positions of the heater, sometimes they leak in different positions but not others.

You will lose some coolant, not a ton. When you take the hoses off just hold them up and lean them against something in the engine compartment. If they face down you will are going to loose coolant.

I changed mine in about 15 minuties in 20 degree cold. Didn't lose much coolant, a few cups max. The hose clamps on the lower hoses can be somewhat of a PITA, but no biggie.

 

[IgotTwo]

I have been having the same “sweat antifreeze smell” coming from the exhaust pipe during these cold weather starts on my daughter’s car.

I started snooping around and found: “a combustion gas tester” for the radiator. aka ”block tester”

Aside from any obvious, foaming in the oil or discolorations in the coolant reservoir tank, this little thing will test for combustion gasses in the coolant.
Its a fast and easy test to isolate head gasket leaks.
Who wants to fuss with compression, leak down and back blowing air into the cylinders?

It’s about $30 with enough chemicals for 16 tests.
Could be worth a try?
I may break down and pick one up for myself.

PS. If you think coolant is getting in the oil:
Heat the thing up, pull the dipstick and drip a few drops of oil on the hot exhaust mainfold. If it "bubbles" or "fizzes" aways - NFG. It should smoke away till it disappears.