Rad Repair 98 Intrepid 2.7

wrote:


> I am sure that you all saw that post a few weeks ago that contained a
> link to a picture of radiator that had blown out part of it's tank. I
> would be hesitant repairing the tank after seeing that picture. I
> don't every remember every seeing a brass tanked radiator doing that.
>
> -KM

No, I've never seen a brass tank radiator fail quite like that (big
chunk gone out of the tank). HOWEVER, I definitely HAVE seen a brass
tank radiator fail by having the tank blow completely off the core at
the solder joint. Different failure mechanism, but just as sudden and
just as complete. :-/

Mechanical design and materials selections always have tradeoffs, and
even though my first reaction also was "Ewww! PLASTIC?!?!?" I've come to
realize that "plastic" tank radiators aren't so horrible after all.
Harder to fix when broken, but they do have some advantages.

Steve wrote:
> ...If you just *idle*
> an LH car to get it up to operating temperature without a cap, coolant
> will boil in the cylinder heads and send a geyser out the neck...

That's that flash boiling I was talking about. That just means
temperatures are rising well above the boiling point (the low boiling
point that accompanies little or no pressure), after which, once that
water flash boiled, there's *nothing* to moderate the temperatures
soaking thru from the even hotter metal immediately surrounding the
combustion chamber.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

a lower rating pressure cap will result in higher engine temp
the pressure spec is directly related to heat dissipation thru the raditor
get a new raditor and quit screwwing around a engine rebuild is too much money
on a 2.7

Ron Seiden wrote:

> Not that it will fix the current problem, but for the future...
> After fixing the radiator on an old car of mine, the old time radiator
> repair specialist told me that on old cars he always puts a 7 psi radiator
> cap on (regardless of what's called for by the factory) to lower the
> pressure stresses on the old systems. As long as there's an overflow tank on
> the system, it won't result in any net loss of fluid, but will lower the
> likelihood of further problems...
> To get the right 7 pound cap you'll need to go to a "real" auto parts store
> (like a NAPA) -- many places will just look your car up in their computer
> and hand you *only* the factory spec cap...
>
> "Steve" > wrote in message
> ...
> > keefee wrote:
> >
> >> I seem to have a leak Front Passenger side, drips on the horn, sometimes
> >> does sometimes doesn't. Minimum loss of fluid, no overheating to speak
> >> of. Checked hoses etc.
> >> Question is : I understand it is a plastic radiator (!!!)
> >
> > Aluminum radiator CORE with plastic tanks. Standard method of manufacture
> > these days, unfortunately.
> >
> > can this be fixed
> >> with Prestone or similar stop leak. It seems to have worked but I have a
> >> 4 hr drive next week and would appreciate anyones experience with these
> >> plastic rads.
> >
> >
> > The inevitable can be DELAYED with stop-leak, but I don't trust what
> > stop-leak does to the rest of the system. Bars-Leaks brand is pretty
> > innocuous, but even it probably reduces the heat exchange capacity of the
> > system a bit. Some of the more aggressive stop-leak compounds are also
> > known as "heater-core plugger compounds" for good reason.
> >
> >
> > The plastic/aluminum tanks actually hold up remarkably well. My wife has
> > (knock wood....) almost 250,000 miles on her '93 LH on the original
> > radiator. It has a pinhole leak right in the top of one of the tanks,
> > which I've just been keeping my eye on. Its so tiny that it doesn't even
> > drip, just makes a crusty spot where the coolant evaporates. The danger is
> > that once you have a crack in the plastic, the pressure cycles might make
> > it grow very fast and very suddenly. If you can see the leak and are
> > fairly sure its a pinhole type leak and not a crack with visible extent,
> > then I wouldn't worry much about a short 4-hour trip and back. Carry a jug
> > of water to be on the safe side.