I own a 1995 F150 with the 3.9Lt I6 engine and 174,000 miles. Yesterday I noticed the coolant and water has over-flowed from the over-flow.

I checked for leaks in the radiator but there wasn't any and I could tell that it had come out from under the over-flow lid. It's just snaps down.

Also the water was muddy brown. So I flushed the radiator. At first I couldn't get the water to flow through the drain plug, but I kept spraying the water into the radiator until it finally broke free.

I used a commmercial flush and followed all directions. When I run water through it appears clear, but when I let the flow slow down it starts to get dirty again.

I can't say how many gallons I have ran through it. I even ran water while the engine was running, then shut it off, etc. But when the radiator nears the end of draining the water get's murky again.

I filled it up with coolant and distilled water and I am thinking of having it professionally flushed. I just didn't want to go that route.

Anyway, I was wondering if it's just rust still in the bottom of the radiator or is the head gasket cracked?

 

Hard to know from what you've indicated so far. Even a compression test won't tell you for sure, though it's not a bad idea. I had an engine with two broken head bolts, but the compression was fine. I was going to do a leak-down test, but I killed the engine in the mean time and just replaced it (found a good running engine for $100).

Have you checked under the oil cap for "dirty mayonnaise" which would indicate coolant leaking into the oil?

 

I did check under the oil cap and the oil was fine.

 

That's good, you're in better shape than I was.

It was suggested to me to use Arm & Hammer Washing Soda as a flush agent. In my case it may have worked so well it flushed out the copper gunk that had been poured in as a "head-gasket fix". Just as well I got to the bottom of my problem sooner rather than later.

 

I am driving it and letting it idle and it stays at its normal operating temp as always. It's not leaking water and no over-flow, over-flow, yet. I have a gasket fix and will use that if it ends up being that.

I have drove this truck since 1997 and it's like my horse. I just don't want to part with it. So I hope I don't need to go the new engine route. I don't have the place or the tools to do that.

 

Are you talking about the magic gunk in a bottle or an actual replacement head gasket? I would never use any of that stuff in a bottle other than as a last resort to get home or something like that. I knew it had been used on the engine that came with my truck, and I just had no confidence in it as a result. I sorta went out of my way to kill it - ironically enough, I did kill it on the way to get the replacement engine - got flat-bedded home with an engine in the back of a truck with a bad engine.

 

Yeah, I am talking the stuff in a bottle. It seemed to make sense as long as the gasket isn't blown. Heck, I am no mechanic so I wouldn't do anything crazy before talking to the mechanic.

 

If you believe the advertising, you might think that stuff cures Herpes! From my point of view, that stuff almost never makes sense. It preys on people in desperation mode looking for an easy, cheap, magic fix.

 

I bought it at Advanced Auto Parts. I read the label and the lenghty instructions and thought if it's just dry rot then why not? I don't think it's the head gasket. I have drove it around town all day and nothing leaking or over-flowing. I even let it sit an idle for over 10 minutes at operating temp. Thanks for your input.

 

It sounds like you cleared the blockage when you flushed the cooling system. I'd just run it as usual and fix anything else that comes up.

 

I just did mine and changed out the stat and gaskets all that good stuff, got a ton of junk out of it like you. Mine is working fine as of now and clean"er" all the crap is still in it to an extent you could say. someone must have used copper stuff I am guessing.

 

I think you're correct. I am going to flush it again this week and keep an eye on it.