Fox T-Bird/Cougar Forums

Technical => Engine Tech => Topic started by: dw85745 on October 20, 2007, 05:36:51 PM

Title: Help ID Cooling Leak
Post by: dw85745 on October 20, 2007, 05:36:51 PM
1984  Cougar, 3.8L, 157,000 miles, original owner

I've got a small cooling leak I've  been trying to find over the last 6 months.  The leak appears on the drivers side and pan evidence shows it to be 1/2 way between the driver's side inside tire and the driver side transmission housing. 

Crawling under vehicle I cannot see any evidence of leaking from the engine, or visible freeze plugs.

The leak shows up after running about 20 miles.  Overflow bottle needs to be filled about ever 100 miles.

Have pressure tested cooling system cold and holds pressure for good hour when I remove tester.

Radiator rodded about 2 years ago and new water pump, hoses (upper and lower), thermostat and both heater hoses that attach to X-over tub replaced.  Heater core never replaced, but no evidence of leakage in cab.

I do have a small oil leak from the head gasket (Passenger side), but coolant shows up as pure coolant -- no mixture coolant/oil.

Freeze plug was a possibility, but no seeping that I can see.

================================

Any suggestions appreciated.

Thanks
David
Title: Help ID Cooling Leak
Post by: vinnietbird on October 20, 2007, 08:09:29 PM
Does the car have any idle issues at all?I had a 3.8 that was losing coolant,and idled a little off.Not too badly,though.Turned out to be a head gasket.
Title: Help ID Cooling Leak
Post by: HAVI on October 20, 2007, 08:56:41 PM
Quote from: vinnietbird;183530
Does the car have any idle issues at all?I had a 3.8 that was losing coolant,and idled a little off.Not too badly,though.Turned out to be a head gasket.

mine too, drove it for quite a while before the gasket blew completely, thus the white smoke billowing from the tailpipe.  Also, fwiw, my windshield washer fluid tank had a hole wore into it from the tire, and caused a leak that had me guessing for a short while.  this is on my 88
Title: Help ID Cooling Leak
Post by: SLEEPER T-BIRD 87 on October 20, 2007, 09:10:54 PM
Go to autozone and get some UV dye and follow the instructions with it and then you will see your leak.
Title: Help ID Cooling Leak
Post by: dw85745 on October 21, 2007, 01:00:20 PM
Thanks for ALL responses.

Have never used coolant dye but will kept under consideration.

RE:  Head gasket, car runs great and no white smoke from tailpipe.
      You would think you could see the yellow coming from the head
      gasket (if this is the source), but maybe the dye will highlight it !!

David