jherrman@zoominternet.net wrote:
> On Sat, 31 May 2008 23:51:40 -0400, "Brian" <hskr@cox.net> wrote:
>
>>When you opened the hood and saw fluid all over the engine, that should have
>>been the first sign that you might need to top off the coolant system. Then
>>when you noticed there was no water in the radiator hose when you replaced
>>the radiator cap, that should have been the next sign that you might be low
>>on coolant. Then the first time you overheated, and you said the upper hose
>>felt cool, then once again, here's your sign. If there's not enough water
>>in the block to let the water touch the thermostat, then the thermostat
>>isn't going to open.
>
>
>
> Ok, I feel like an idiot, and rightly so. It really didn't look like I
> had lost a lot of fluid, compared to the 13qt it holds, and I didn't
> know it would fail to use the overfill reservoir if the radiator got
> too low, and that I should look past its "full" reading. When it began
> to overheat I cranked the heat control up, and I wonder whether that
> drained more coolant into the heater core and aggravated the problem,
> since there's no sign the garage bothered to turn on the heat or use
> the bleeder plug when they refilled.
I'm assuming the radiator cap on your truck is not mounted on the
overflow tank - based upon your descriptions. If you have a radiator
cap mounted ON the overflow TANK itself, than its not really an overflow
tank. Its pressurized with the radiator and directly part of the
coolant system. Fords have had this for a while now.
With a traditional system the radiator cap has two functions... mounted
on the radiator... its designed to vent excess pressure and draw in
coolant when low.
As with anything - heat expands and cold contracts. Ever seen a boiler
system on a home heating furnace? Theres an expansion tank for the
water... thats the same princpial with engine cooling systems. The
level in the "overflow" tank will go up and down with normal driving
conditions. As the system heats - the coolant expands - excess coolant
in the system is pushed into the resevior via a valve in the radiator
cap. When the system cools down - the coolant will contract, causing a
negative pressure - or vaccum. Opening the other valve in the cap,
sucking coolant back into the system from the resivore.
You stated that even though you saw a bunch of coolant leaking out over
time, because the tank was still full. This is because you discovered
the cap was not tight on the radiator. Without the cap tight, there
could be no vaccum to suck the coolant back into the system, as it got
low. Notice where the tube to the resevore tank goes? Usually Right to
the neck on the radiator where the cap attatches... on in the case of
cars with thermostates located in water outlet housings... the resevore
tank hose attatches to the water outlet.
As for cranking up the heater - that may have saved your engine... it
would not "use up" more coolant. What it would do is provide a way to
bleed of some heat from the system. So that was a good thing to have done.
>
> I guess I can only hope and pray I didn't cause more extensive engine
> damage. When it started to overheat I was literally "in the
> neighborhood" on a residential street going 20 mph or less, and pulled
> it over to cool within 30 feet of the "check gauge" lights, and then
> drove a few blocks home very slowly with my eyes glued to the temp
> gauge. It never got all the way up to the redline. Serves me right:
> I've taken the time to learn how to do all the maintenance (other
> fluids and plugs) myself up to now; this is the first time I've
> trusted a mechanic with any sort of work. Time to find another one.
>
pulling over and shutting down was the right thing to do... you probably
did not damage the engine. The most common thing would have been to
blow a headgasket with overheating.. or warping or cracking a head. The
warning lights are there to tell you to shut down NOW... and thats what
you did.... had you continued to drive without letting it cool down...
well then you might have been posting here looking for a used engine
instead :) I think you'll be fine. Just make sure you know why the
coolant leaked out. It might just have been that the cap was loose and
that was it... or the shop mighta done something.
ALSO - be sure you use the right coolant in that truck. There are lots
of "all makes all model" antifreeze on the market - I sell it at work
too - but I try to recommend the original stuff to my customers before
selling them the all makes stuff.
Chryslers use whats called G05 thats "Gee Oh Five" antifreeze - its an
extended life antifreeze - almost a pinksish color... different from the
GM DexCool antifreese. G05 is used by imports, fords, and chryslers.
Be sure you use a 50/50 water/coolant mix. Zerex makes G05 and you
should be able to find that at your local NAPA, Carquest, Autozone,
Advanced, O'Rileys etc etc
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