Freeze plug failure common on 4.2L ?

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Old 08-10-2008, 03:59 PM
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Freeze plug failure common on 4.2L ?

Hi,
I have a '99 4.2L that has been well maintained, motor never apart. A couple of years ago, I noticed some creamy looking sludge on the two freeze plugs (both sides of the motor), that are visible when looking over the top of the front wheels. Also, sometimes I'd notice a little antifreeze odor, but not all the time (very faint, maybe once monthly). Two years and 30k miles later, I had to add about a gallon of antifreeze (never added any since new). Now, two months later, it's a couple of pints low.
I guess it's seeping around those freeze plugs. Wanted to run it by the experts before I add Bar's Leaks (the good kind, not the rabbit pellets in molasses).
Any input appreciated.
Thanks.
Tom
 
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Old 08-10-2008, 04:08 PM
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I don't think freeze plug failure is particular to any engine. I think it is more related to the condition of the coolant. Frm what you said, you've never changed the coolant or flushed the system.

Is it not possible to replace the plugs? I have never been a fan of the "stop leak" products. I think they are a temporary fix at best and can cause additional problems.
 
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Old 08-10-2008, 04:25 PM
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Thanks.
Yes, I've never changed the coolant. Here's why:
I've always owned Ford vehicles. Still have a '66 Mustang 289 that rarely had coolant changed. Original freeze plugs. Had a 1986 Mustang GT, sold with original coolant at 13 years old,147k miles. Had an '84 F250 with original freeze plugs when sold with 175k miles. I also have a 1978 Mustang that had coolant changed with motor rebuild (with Bar's Leaks OEM stuff added) in 1992. No leaks at all.
I've never had to replace a leaky freeze plug. Out of all the Ford vehicles I've owned (2.8L, 5.0L mostly), never had one fail. Probably all originals, who knows. So, I am surprised that this truck would develop leaks at 7 years and 90k miles. Must be inferior metals or poor seal, but seems odd to me.
I also have the original battery, belts, hoses and rear brakes at 120k miles. But, I expected to, as my '86 Mustang had original stuff at over 10 years old. I don't abuse them, as a matter of fact, they probably get carboned up a bit from taking it easy on them.
Thanks for the reply.
 
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Old 08-10-2008, 04:33 PM
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I never used to change the coolant in mine either and always had pretty good luck with the freeze plugs, altho not as good as you have. I've had to replace a few. I do think it is a change in the metals as well as maybe a change in the chemicals in the coolant. The leaking is normally caused by rusting pin holes.
 
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Old 08-10-2008, 04:35 PM
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Your 66, which body style, what color? I used to rebuild/restore them. Still have a 65 Fastback.
 
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Old 08-10-2008, 05:35 PM
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There is a good reason why Ford (and every other manufacturer) recommends coolant flushes every so often............CORROSION.
 
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Old 08-10-2008, 06:45 PM
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Jim, it's a '66 Coupe...

Been in the family since 1972. It's also been in the garage for a number of years, but still tagged. Never had any real trouble with it. It's a 3 speed, all original. Not perfect, but never abused or altered. Interior is great, except for the driver's seat bottom cracked, and carpet has faded. Thankfully, it has never been in an accident, so all of the body lines are nice and straight. Right now, I have the carb apart for it's 22 year rebuild (first rebuild was in 1986, but it didn't really need it). It was originally Wimbledon white w/black pinstripe and lower rocker molding. Was painted midnight blue metallic in 1977, but will be white again (hopefully soon).

BTW, I put the Bar's Leaks in the truck, will post results. I have had good results with it before (sealed up a head gasket leak once, and a few heater core leaks). It will not plug anything up. It is installed from the factory. Not Alumaseal, or the Bar's Leaks that looks like rabbit pellets, it's product #C16, same as our trucks got on the assembly line.
 
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Old 08-10-2008, 07:57 PM
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Sounds like a neat old Mustang. Nice when you run across on that has not been beat up and has all the proper lines to the body. Right now, the cluth in mine is frozen, I need to replace it.
 
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Old 08-10-2008, 08:38 PM
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Thanks Jim, they are good reliable cars...

Hope you get your clutch working soon. Not a bad job, did mine about 20 years ago (clutch #3).
Is your car a 3 or 4sp?
 



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