'95 Jeep Grand Cherokee: How bad is this going to be?

(REPOST AFTER CRAP)

Hi:

Had a breakdown last night, I'm pretty worried about what might have
happened, any advice or enlightenment will be greatly appreciated. Here
is the sequence of events:

- left work at about 7:00pm in very cold weather (-20C).

- as I was entering the highway, my Jeep hesitated a bit like it was
going to stall, but then ran fine.

- within a few moments, the thermostat went through the roof, so I
pulled off the highway at the next exit. The coolant was very low
(nothing in the resevoir), so I bought a jug of coolant, topped it up
(about 2 litres to bring it to the fill line).

- the only other sign of trouble to my untrained eyes was that the rad
was still cold, and the heater was generating zero heat. No apparent
leaks, steam, smell, etc.

- tried it out again to see if the temp would come back down.

- Still bad, so I pulled off the road. While trying to get back to the
gas station, there were dieseling sounds and the engine ran very rough.
I couldn't even get to the station before the engine stalled. The
engine *would* turn, although it was labouring. I thought better of
trying to force it.

- at this point there was steam in the engine compartment, and not to
steer you in any particular direction, but it seemed to me to be coming
directly out of the perimeter of the cylinder head.

- had the vehicle towed to the only place open at almost 8:00pm: Crappy
Tire. The vehicle is there now and I'm waiting to hear.

My opinion is the head gasket is blown, and dumped coolant in the
combustion chamber(s).

So, my questions are:

- Why? Does the fact that the rad stayed cool throughout mean something
froze and caused this situation? Or is the root cause the (possible)
blown gasket, thus the coolant followed the path of least resistance,
i.e., not to the rad?


- What now? Given the high temp, possible contamination and definite
laboured engine turnover, is something totally pooched at this point?

- What is the general procedure for fixing this? Is it possible there
is no major damage? Can the (possibly blown) gasket be replaced, the
engine flushed, the oil and coolant replaced and hope for the best?

Thanks again.

 

Did you fill the external reservoir, or did you open the radiator and
add coolant directly to the radiator? If you just topped the reservoir
and did NOT add coolant to the radiator, its very possible that the
engine was still stone-empty.

A sign of no coolant in the engine, or at least not enough to circulate.
The other bad thing that happens in that condition is that the
temperature indicator will often read abonormally low until the engine
is SEVERELY overheated because the only way the sensor is heated is by
conduction through the engine block and heads, not through circulating
coolant.

By the time you hear dieseling sounds, the insides of the combustion
chamber are red hot.

Steam or smoke? Could just be oil residue burning off because the head
was so abnormally hot.

You don't say what engine, but it has to be either a 4.0 (most likely)
or a 5.2 if its a '95. Both of those engines have cast iron heads and
cast iron blocks- you have to REALLY roast either one in order to blow a
head gasket. I'm not saying it didn't happen, and the fact that it was
making diesel noises is a bad sign, but I've seen both 318 (5.2) v8s and
4.0 sixes survive overheating to the point that they sounded like
18-wheelers before.

It probably means either that, or that there was no coolant at all. A
possible scenario is that a block freeze plug popped out and when the
engine warmed up, everything drained as you were first beginning to drive.

If it was an aluminum-headed (or worse yet alumimum block and head)
engine, then it would definitely be history. But given that its either a
5.2 or 4.0, it may live many more years. It all depends on just HOW hot
it really got, and no one can tell just from a verbal description. The
fact that you didn't push it after it started rattling is a very VERY
good thing.

Fix the coolant loss or freezing problem FIRST, and then see how it
does. If there is a loss of compression or coolant in the oil or coolant
leaking at the head gasket, then the head will have to come off, the
gasket be replaced, and the block and head checked for flatness and
machined if necessary. The head should also be checked for cracking at
that time.

WORST case is if it got hot enough to wreck the piston rings, in which
case it probably will not re-start because it won't have any
compression. That should be fairly easy to rule out.

 

Damn I wish I had thought of that. You're probably exactly right.

One thing I forgot to mention: the heater in the cabin generated no
heat at all.

I assumed it was due to coolant in the combustion chamber.

I would definitely say steam, and it had that rad smell to it.

Yes, that's correct.

I'll bet that's it.

I had it towed to a dealership after my original post, and I'm sure
they'll update me. The fact that I drove until it stalled (probably 10
minutes total after refilling the coolant reservoir) worries me. I have
a bad feeling.

I appreciate the insight, that you very much.

 

It may not be that scary. Sounds like a HG is indeed blown, but I like
the freeze plug theory. Might fake you out if you don't know exactly
what you're looking at.

I did almost exactly the same sequence in my '62 Studebaker one morning
- I just got up and decided I felt like driving an old car to work.
Pulled out of my driveway and headed off down the highway. I'd
apparently blown a freeze plug before I hit the highway, but I never
noticed because the road was unlit. Once on the highway, I could see
little wisps of steam following the car, so I pulled off at the next
exit. Once I dropped below highway speeds the engine got smokin' hot,
with the associated diesel noises. I replaced the offending freeze
plug (@#$%$^%& disc plugs - ended up using the screw in rubber type as
I was unable to get the disc type to seal reliably without pulling the
engine to set them) and changed the oil, and the car still has enough
power to roast the clutch, apparently

I have much respect for both the 318 and the 4.0, they seem to be just
as basically strong as a Stude engine, so who knows, this may not be as
bad as you think (of course, it could be just as bad as you think...
you do need to have it checked out)

nate

 

My fathers 79 Dodge pick-up with a 318 blew a lower rad hose once. I had to
drive it to crappy tire ( 5 km's to get a lower hose. Drove there and back
and she was over heating and smoking like crazy. Died as soon as I drove it
into the back yard. The rad hose didn't fit as the rad originally came from
a 440 car, and the old hose was waw swollen so it fit fine when my dad put
that rad in. So as the truck was cooling, I spliced both the old and new
hose together with a piece of pipe. By the time I had it fitting, I filled
it with water and it ran fine. No problems at all. But that's a chrysler for
you! An import would have blown apart. It lasted for another 100,000 + km's.
Finally scrapped it at 286,000 km's. No floor left, burned a gallon of oil
every 25 km's, but never any work done to it except a couple of starters.
The AMC 6 is built like that also, I don't think there would be much damage
except for a head gasket (if it blew). But if something froze and caused a
freeze plug to blow, or something else gave out because of freezing, did you
not have anti-freeze in it?