"pkurtz2" <pkurtz2@cox.net> wrote in message
news:ka%yf.23842$0G.17919@dukeread10...
> OK here is a new one for yall....
> I have a '00' Ford Ranger 3.0L Flex-Fuel 97,000mi, 5spd, 3.71 rearend.
> Suddenly I noticed one cold morning when I started my truck that it
> sounded like it had a miss. It also vibrated what I would consider harshly
> (compared to normal). What I dont get is that if you rev the engine real
> quick a couple times it will go away. Or if you let the truck sit and run
> for like 2min it goes away?? I havent pulled the plugs yet to see if they
> are fouled, but its only got 97000 and I changed the plugs at 50,000mi,
> and they looked great when I did it. I was just stuck in the mode of my
> old vehicles. I am a ASE mechanic myself, and we have another one in the
> family. I asked him what he thought the problem might be, and he couldnt
> even remember working on the internals of a 3.0L engine.
> NOW, to add to that issue, at the same time I noticed my coolant seems
> to be disappearing into the thin air. I was driving along one night and
> noticed my temp gage just bottomed out. So I checked my radiator and it
> was almost bone dry. It took a full gallon of antifreeze to refill the
> radiator, at the same time I looked at my overflow tank and it was almost
> full. Now, correct me if I am wrong, but isnt that tank for expansion
> during hot engine run, and its supposed to pull coolant BACK into the
> radiator when it cools down? When I pulled the cap off the radiator to
> refill it, it was under a strong vacuum. I thought there was a valve in
> the cap that is supposed to allow flow back into the radiator when it
> cools down??
>
> Now here is what I think the problem is, you tell me if I am barking up
> the wrong tree. I think the two problems are interlaced. I think that the
> rough idle when I start the truck on cold days is due to head gasket
> shrinkage. I also think this shrinkage is causeing air to escape into the
> coolant system. I think that this is causing my truck to spew coolant out
> of the expansion tank.
>
> Let me know what you think. Respond to pkurtz2@cox.net . I appreciate it
> if anyone has had this issue and found a resolution for it.
>
I think you figured it out. Sounds as though you have a bad gasket --
intake, exhaust, or most likely a head gasket. The gasket likely has a
crack in it -- the crack is allowing air to be sucked into the cylinders,
thereby making the air-fuel mixture more lean than it should be and this is
causing the engine to run rough. When the engine gets warm, the gasket
expands and seals itself, thus, the engine runs normally when warm.
The disappearing coolant is the result of coolant running out through the
crack in the gasket. It may be that coolant is being pulled into one or
more cylinders where the heat of combustion turns it to steam and it goes
out the exhaust -- or -- the coolant may be blowing out through the crack in
the gasket -- or both.
Of course, this diagnosis is not definitive -- just the opinion of an old
shade-tree mechanic.
