Where oh where is my engine coolant going?

[Avispa]

Had this car two years and the coolant level in the reservoir never budged, not so much as an 8th of an inch. Was checking under the hood the other night and the reservoir was empty. Refilled it, ran it for a day, about 20 miles, and let it cool off. Reservoir was 1//2 empty.

There's pressure on the cap when it's hot. No visible leaks, no antifreeze smell from the heater, no puddles or drips on the floor after 15 minutes of idling. No visible signs of dried leakage on anything I can see.

Oil is completely clean and engine runs perfectly. No white smoke, so I''m guessing it's not a head gasket.

Anyone have any ideas?

 

[americanthunder]

I would check your plugs, coolant could be burning up In the combustion chambers in one of the cylinders even though you are not seeing white smoke.

 

[Avispa]

Thanks for that suggestion. A compression test was next on the list anyway - that always beats banging your head on the fender and swearing Fords are no good.:beer:

 

[hotcobra03]

I had cyl 7 crack up spark plug threads causing coolant leak just like this..compression test found the cyl..machine shop found crack when pressure testing head..I went with new head vs repair..

As to white smoke..mine didnt smoke while running..but after shut down wait a minute and than smoke started..I pulled mid pipe and seen coolant in header

 

[Avispa]

I had cyl 7 crack up spark plug threads causing coolant leak just like this..compression test found the cyl..machine shop found crack when pressure testing head..I went with new head vs repair..

As to white smoke..mine didnt smoke while running..but after shut down wait a minute and than smoke started..I pulled mid pipe and seen coolant in header

Will definitely pull the mid pipe and check for coolant in the exhaust, too! Thanks.

See you at the Strawberry Festival - I'll do a burnout in your driveway...lol

 

[hotcobra03]

Will definitely pull the mid pipe and check for coolant in the exhaust, too! Thanks.

See you at the Strawberry Festival - I'll do a burnout in your driveway...lol

I think burn out will be easy..I have dirt driveway..lmk when your around..festival is april.

I know shortcut to get in..I live just off hwy..that traffic is crazy..I have to drive shoulder for miles just to get to my road to turn to go home..cop pulled me over for it..no ticket after he seen I live here

 

[Avispa]

ok, plugs, perfect. compression, perfect. pressure test (2 hrs) perfect. Been driving for the last two days, no coolant loss at all. WTF?????:fm:

 

[testorossa1989]

Have you checked your petcock plug. I have had bad ones in my GT and cobra both resulting in half loss of resv over the course of 2 days sometimes over night

 

[TRQJUNKIE]

Possible crack it radiator? May not leave a puddle but could evap through the crack and cause your res to be low.

Also, may want to burp your system and see if that fixes it... just a thought

 

[Avispa]

Thanks for all the replies. Had the system pressure tested for two hours last Thursday and found....nothing. Absolutely nothing. FWIW, been driving it all weekend and the coolant level in the reservoir hasn't budged! Go figure.