LA 318 cooling prob has me fretting

1986 LA roller cam 318 in an M-body, 85K, mysteriously started sucking
air (or exhaust gas) into the cooling system, causing odd overheating
symptoms. Off came the whole top end, with judicious inspection of
the heads as well as deck and head surface flatness. All looked well,
and the valves were in pristine shape. After complete cleanup, new
Fel-Pro gasket set (along with the "one size fits all LAs" head gasket
that robs you of 5 lbs of compression!), figuring it was a pinhole
leak in one of the head gaskets. Back together, with the freshly
kitted carb, new RN12YCs, new wires/cap/rotor, new O2 sensor and
meticulous reassembly, the old LA ran SO smoothly and quietly it was
eerie. However, here comes the bubbles...again! Prior to the top end
job, I had fed 125 lb. air to each cylinder, and never did get
positive sighting of bubbles in the top tank of the radiator. But, a
firing cylinder under load, even in a low compression engine like
this, produces a lot more than 125 lbs. on the cylinder walls.

I can only think of two possibilities...lip seal in the water pump is
sucking in air, or...there's a pinhole in one of the cylinder walls
that's allowing exhaust gas to pass, but not water to pass the other
way. While glaze busting the cylinders, there WAS an odd little rust
spot in #5 that I attributed to water getting in there during head
removal (don't you LOVE they way they hid those drain plugs behind the
new style motor mounts????), but it went away with a single pass of
the hone, and nothing looked unusual. However, this engine, while in
great condition overall (.0002-3 taper in all cyls...barely a ring
mark to be seen) the original owner (the know-it-all father-in-law)
didn't seem to believe that you needed to change antifreeze regularly.
Thus, the jackets were FULL of rust flakes, necessitating me taking a
pressure washer nozzle down into the block to clean it up. After the
pressure washer treatment, the walls of the water jackets were grey
iron with ocassional dark rust spots here and there. However, if by
doing this, I knocked all the rust loose, the problem should've gotten
worse, and it didn't. Actually, it improved...slightly...but it is
still there.

Prior to this, this engine would NEVER get more than 5° above
thermostat in any condition except pulling a grade when 110° out with
the AC on. Now, it gets up to 210° just putting around town at 45
MPH.

Anyone heard of any bad block castings on this vintage LA engine?
Also, anyone had a water pump do exactly what this may be doing? No
bearing noise, and the weep hole is clean, but it's a two year old
"rebuild" (the original blew the seal right out the nose on a trip to
Vegas on the hottest day of the year).

The car, an '86 M-body 5th, is a cream puff, and I've grown to love
it, even with its various faults. Strengths: comfy "rich Corinthean
leather" seating all around; low noise level; excellent handling;
excellent AC; straightforward, honest design, no engineering
"gotchas," and it has Lee Iacocca in the trunk under the spare cover.
(Ricardo Montalban is a no-show.) Weaknesses: Choppy ride at times;
A-904 TF's lockup converter locks up at 36 MPH in 3rd gear...no matter
WHAT the load...no part throttle unlock...have to downshift to second
to knock it off; the usual headliner replacement (normal in any car
this old); jiggly front sheet metal on rough roads; rather ungainly
styling; and the standard MoPar feature...HARD to work on in places,
something I think that's been a MoPar standard since the '60s. You
need every wiggle and U-joint extension you may have in your
rollaround, but if you're smart, everything comes apart fine.

Hate to trash this car for a porous cylinder wall. My wife loves it,
too (it was her mom's when new) and it hasn't even hit 100K yet, and
the paint and interior are still quite nice and draw compliments
wherever we go.

Any opinions?

Caveat: If you have an old engine with low mileage where the original
owner ran long oil change intervals with mediocre oil, and you see
crusty sludge on the rockers (or wherever,) do yourself a
favor....strip the top end, clean it out BEFORE switching to
synthetic. I didn't, thinking the syn would sort of erode the
carbonized oil and slowly send it to the filter. I got away with it,
but after my clean up after dear Dad-In-Law, I'd never chance it
again. The amount of crap loosened up and laying in the pan was a bit
scary. Oddly enough, the pickup screen was clean, but every oil
change, that filter (Fram Double Guard) was HEAVY. I changed out the
oil pump just to feel safe, and later disassembly of the original
proved me right...there was a LOT of abrasive wear in it.

To much for me to read ths early. Just curious..was the vehicle loosen
coolant before repairs? And did you get the intake manifold gaskets on
properly??? they will go on backwards and the only problem you will get is
an overheat condition if you close off the coolant passage from the head to
the intake.

Glenn Beasley
Chrysler Tech

Since it was doing it before teardown I would look at the radiator. With
that much rust have you checked the radiator flow, Maybe the fan clutch.
Did you have the heads maged or the valves done ??? I have some LA intake
gaskets in my hand don't see any difference in the water passages Take it
to the local radiator shop & have them do a block check. or if you have a
friendly smog man he could check for exhaust gases with his analizer

OldieChrysler wrote:
> 1986 LA roller cam 318 in an M-body, 85K, mysteriously started sucking
> air (or exhaust gas) into the cooling system, causing odd overheating
> symptoms. Off came the whole top end, with judicious inspection of
> the heads as well as deck and head surface flatness. All looked well,
> and the valves were in pristine shape. After complete cleanup, new
> Fel-Pro gasket set (along with the "one size fits all LAs" head gasket
> that robs you of 5 lbs of compression!), figuring it was a pinhole
> leak in one of the head gaskets. Back together, with the freshly
> kitted carb, new RN12YCs, new wires/cap/rotor, new O2 sensor and
> meticulous reassembly, the old LA ran SO smoothly and quietly it was
> eerie. However, here comes the bubbles...again! Prior to the top end
> job, I had fed 125 lb. air to each cylinder, and never did get
> positive sighting of bubbles in the top tank of the radiator. But, a
> firing cylinder under load, even in a low compression engine like
> this, produces a lot more than 125 lbs. on the cylinder walls.
>
> I can only think of two possibilities...lip seal in the water pump is
> sucking in air, or...there's a pinhole in one of the cylinder walls
> that's allowing exhaust gas to pass, but not water to pass the other
> way. While glaze busting the cylinders, there WAS an odd little rust
> spot in #5 that I attributed to water getting in there during head
> removal (don't you LOVE they way they hid those drain plugs behind the
> new style motor mounts????), but it went away with a single pass of
> the hone, and nothing looked unusual. However, this engine, while in
> great condition overall (.0002-3 taper in all cyls...barely a ring
> mark to be seen) the original owner (the know-it-all father-in-law)
> didn't seem to believe that you needed to change antifreeze regularly.
> Thus, the jackets were FULL of rust flakes, necessitating me taking a
> pressure washer nozzle down into the block to clean it up. After the
> pressure washer treatment, the walls of the water jackets were grey
> iron with ocassional dark rust spots here and there. However, if by
> doing this, I knocked all the rust loose, the problem should've gotten
> worse, and it didn't. Actually, it improved...slightly...but it is
> still there.
>
> Prior to this, this engine would NEVER get more than 5° above
> thermostat in any condition except pulling a grade when 110° out with
> the AC on. Now, it gets up to 210° just putting around town at 45
> MPH.
>
> Anyone heard of any bad block castings on this vintage LA engine?
> Also, anyone had a water pump do exactly what this may be doing? No
> bearing noise, and the weep hole is clean, but it's a two year old
> "rebuild" (the original blew the seal right out the nose on a trip to
> Vegas on the hottest day of the year).
>
> The car, an '86 M-body 5th, is a cream puff, and I've grown to love
> it, even with its various faults. Strengths: comfy "rich Corinthean
> leather" seating all around; low noise level; excellent handling;
> excellent AC; straightforward, honest design, no engineering
> "gotchas," and it has Lee Iacocca in the trunk under the spare cover.
> (Ricardo Montalban is a no-show.) Weaknesses: Choppy ride at times;
> A-904 TF's lockup converter locks up at 36 MPH in 3rd gear...no matter
> WHAT the load...no part throttle unlock...have to downshift to second
> to knock it off; the usual headliner replacement (normal in any car
> this old); jiggly front sheet metal on rough roads; rather ungainly
> styling; and the standard MoPar feature...HARD to work on in places,
> something I think that's been a MoPar standard since the '60s. You
> need every wiggle and U-joint extension you may have in your
> rollaround, but if you're smart, everything comes apart fine.
>
> Hate to trash this car for a porous cylinder wall. My wife loves it,
> too (it was her mom's when new) and it hasn't even hit 100K yet, and
> the paint and interior are still quite nice and draw compliments
> wherever we go.
>
> Any opinions?
>
> Caveat: If you have an old engine with low mileage where the original
> owner ran long oil change intervals with mediocre oil, and you see
> crusty sludge on the rockers (or wherever,) do yourself a
> favor....strip the top end, clean it out BEFORE switching to
> synthetic. I didn't, thinking the syn would sort of erode the
> carbonized oil and slowly send it to the filter. I got away with it,
> but after my clean up after dear Dad-In-Law, I'd never chance it
> again. The amount of crap loosened up and laying in the pan was a bit
> scary. Oddly enough, the pickup screen was clean, but every oil
> change, that filter (Fram Double Guard) was HEAVY. I changed out the
> oil pump just to feel safe, and later disassembly of the original
> proved me right...there was a LOT of abrasive wear in it.

Did you check the timing case? I had a 273. After 200,000 miles, some
pin holes developed in the casting right behind where the water pump
impeller sits. I didn't notice any bubbles, but coolant was getting
into the oil.

-KM

OldieChrysler wrote:

> ...Caveat: If you have an old engine with low mileage where the original
> owner ran long oil change intervals with mediocre oil, and you see
> crusty sludge on the rockers (or wherever,) do yourself a
> favor....strip the top end, clean it out BEFORE switching to
> synthetic. I didn't, thinking the syn would sort of erode the
> carbonized oil and slowly send it to the filter. I got away with it,
> but after my clean up after dear Dad-In-Law, I'd never chance it
> again. The amount of crap loosened up and laying in the pan was a bit
> scary. Oddly enough, the pickup screen was clean, but every oil
> change, that filter (Fram Double Guard) was HEAVY. I changed out the
> oil pump just to feel safe, and later disassembly of the original
> proved me right...there was a LOT of abrasive wear in it.

There are those here who will adamantly disagree about synthetic
dissolving and breaking loose deposits, but I agree with you that it
definitely does and that those that suddenly switched over without a
problem were just lucky.

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

On Tue, 15 Aug 2006 05:59:30 -0400, "damnnickname"
> wrote:

>To much for me to read ths early. Just curious..was the vehicle loosen
>coolant before repairs? <snip>

No, but gas bubbles would be escaping into the reserve tank after
shutdown.

> And did you get the intake manifold gaskets on
>properly??? <snip>

Of course. The problem existed BEFORE the teardown.

>they will go on backwards and the only problem you will get is
>an overheat condition if you close off the coolant passage from the head to
>the intake. <snip>

Only an idiot would install LA intake gaskets backward. I'm not one
of those.

On Tue, 15 Aug 2006 07:41:55 -0400, "sqdancerLynn"
> wrote:

>Since it was doing it before teardown I would look at the radiator. With
>that much rust have you checked the radiator flow <snip>

Backflushed core, got some particulate rust out, now flows fine,
minimal deposits.

>Maybe the fan clutch. <snip>

Negative...works as new.

>Did you have the heads maged or the valves done ??? <snip>

I personally magnefluxed those heads...no cracks anywhere. To
confirm, I took them to the local grinder shop and had them Zyglow
them....same thing, no cracks.

>I have some LA intake
>gaskets in my hand don't see any difference in the water passages <snip>

One this particular application, both sides are the same. However on
many earlier LAs (and As) the BACK water passage is active and has a
metering hole. If the numbnuts installed the gaskets backward, there
will be no flow to the thermostat.

>Take it
>to the local radiator shop & have them do a block check. or if you have a
>friendly smog man he could check for exhaust gases with his analizer <snip>

Checking for exhaust gases today with a NAPA tester I just picked up.
I'm fearful that there are these, because after running a couple of
days, the water/inhibitor takes on a "rainbow sheen" when exposed to
light. However, I've been told that also could be water pump bearing
grease being sucked into the system from the bearing, presaging a pump
failure. I'm putting a new Cardone pump on after checking for exhaust
gas presence. If there ARE exhaust gases, I'm afriad the block
porosity problem is real.

On Mon, 14 Aug 2006 23:43:56 -0700, OldieChrysler
> wrote:

>1986 LA roller cam 318 in an M-body <snip>

Update: Exhaust gas presence negative. Water pump goes on as soon as
it gets here, stay tuned.

Meanwhile, three wrenches I know have warned me about shops using
"cheapie" rebuilt pumps from schlock vendors like Poop Boys or Auto
Bone, and they ALWAYS have seal and/or bearing failure within two
years.

Looks like this might be the case, since the car had a "rebuilt" pump
installed when on a trip to Vegas. The original blew the lip seal
right out the nose on that one.

OldeChrysler wrote:
> On Mon, 14 Aug 2006 23:43:56 -0700, OldieChrysler
> > wrote:
>
> >1986 LA roller cam 318 in an M-body <snip>
>
> Update: Exhaust gas presence negative. Water pump goes on as soon as
> it gets here, stay tuned.
>
> Meanwhile, three wrenches I know have warned me about shops using
> "cheapie" rebuilt pumps from schlock vendors like Poop Boys or Auto
> Bone, and they ALWAYS have seal and/or bearing failure within two
> years.
>
> Looks like this might be the case, since the car had a "rebuilt" pump
> installed when on a trip to Vegas. The original blew the lip seal
> right out the nose on that one.

When you remove the pump, inspect the condition of the pump housing in
timing case. Please see my earlier post.

-KM

On 15 Aug 2006 10:59:00 -0700, "
> wrote:

>When you remove the pump, inspect the condition of the pump housing in
>timing case. Please see my earlier post. <snip>

Will do. I've been told it could be possible that the front cover
suffered corrosion damage due to poor cooling system maintenance early
in its life, and if the perforation is near the center of the hub,
crankcase blowby could be getting sucked into the water stream.
However, one would think that if this were so, the hole would be big
enough to leak water into the pan, and I'm not seeing that.

More later, and thanks.