97 5.0 - coolant smell but no visual leak

[SVO LOU]

When my Mountaineer is warming up I can smell coolant from the engine compartment but I can't find a leak. No hoses, waterpump weep hole, or radiator. Better yet the coolant level doesn't seem to drop.
Does anyone have any ideas about this? Is it because the cap on the overflow bottle is not airtight?

Thanks guys.
Lou.

 

[SVO]

So you HAVE pressure tested the system?


With a pressure tester?


This will definately tell you if you have a leak or not.

It could also be the the system purging back in to the overflow causing a smell of ethyline glycol.

 

[kloadman97]

just a thought...

Although I have a 4.0 rather than the 5.0, I thought I might throw an idea out there for you based on something I recently encountered. I too noticed a coolant smell but couldn't find a leak anywhere. The smell was in conjunction with using my heater/defroster. It was so subtle and fairly well hidden that I never would have picked up on it had my friend not pointed it out to me. It turned out to be the heater control valve. A quick fix and all was well again.

 

[SVO]

And another thought, might be like my GT, where the heater core was leaking but not out of the air box onto the floor board but out the HVAC drain tube under the hood/lower part of the passenger firewall.

 

[james t]

it could have a tiny pin hole leak at the heater core. this would fill the interior with antifreeze smell. it would also be small enough so that hardly none leaks out..... only a few drops. i had one do this before in a truck and it drove me nuts. also, it wouldnt leak until the engine got up to operating temp. when cold, it would contract up enough to seal itself. very odd, but possible.

 

[SVO LOU]

Oops, should've been more specific. I'm not getting the smell inside, only from the engine compartment.
SVO, I haven't pressure-tested it yet but I was thinking along the same lines as you, that it's from the overflow. The smell is fairly strong, though. Definitely gonna have to pressure-test it.
Thanks for the tips, I'll post what I find.

Lou.

 

[410Fortune]

Umm sometimes when the waterpump is leaking it can be VERY hard to detect as well becaseu teh fan blows the dripping coolant so it nbever hits the ground.
You say the coolant level doesnt change?

It could be anything from your imagination (smell) to a faulty radiator cap, to a bad hot water bypass valve, to a shot waterpump.

No puddles on the ground?
No poor performance?
What about excessive white steam in the exhuast?

 

[section525]

Originally posted by 410Fortune
What about excessive white steam in the exhuast?

What does that mean?

 

[410Fortune]

coolant getting into combustion chamber is what that would mean.......
unless I am mistaken??? tale tale sign of a cracked head/leaking gasket....

 

[section525]

Okay. My exhaust is a little white after tearing into my motor.. but I never had the heads off. I think its just cold outside... I hope.

 

[410Fortune]

hahaha yes condensation in the exhaust is normal. EXCESSIve white smoke/steam is not. You can smell the exhaust and tell if it is coolant, dont put your head right in the exhaust, instead you use your and to grab some and pull it towards you...

Sorry didnt mean to raise any red flags