"Joe S." <anon@mous.com> wrote in message
news:oL2dnabhcL3kTFHeRVn-uw@comcast.com...
>
> "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.
>
>
Your diagnosis sounds good to me but what if it runs rough at start-up but
is not losing coolant? I have a '92 Explorer 4.0 V6 OHV with a mere 275,000
miles on it and it runs rough at first then smooths out after a minute or
two (or if I rev it up a little at first). I also have not pulled the plugs
recently but could leaking valve seals cause this? I recently replaced the
radiator because it was dumping coolant out of the reservoir and it had
white smoke coming out the tailpipe (burning coolant?). I added some
(GASP!) stop leak that is supposed to seal cracked heads and leaky head
gaskets and the smoke went away but it still runs rought at startup. I also
recently replaced the water pump and have cleaned the MAF and the other (?)
sensors. The intake manifold gaskets have also been changed. I realize at
this many miles it could be more than one problem. Could a clogged radiator
also cause pressure build-up and coolant loss and contribute to a head
gasket leak?
