Time to replace the head gasket?

budgetzagato

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I've noticed a coolant smell from my car when driving, and thought maybe my head gasket was leaking. I tested it recently and seemed to find nothing wrong except a drip at a hose. I can't place a specific time this started since I've always been doing something to it.

Still, it seems like coolant might be leaking into one or more cylinder upon shutdown. I was running an errand today and after making a quick stop at a store I noticed what may have been steam from the exhaust at start-up, and it often has a miss that goes away after a very short while.

My question is can coolant leak into one or more cylinders when the engine warms up, and is shut down? :confuse2:

I'm thinking that I have a head gasket leak that is obvious symptom free except that coolant leaks after shutdown when the coolant system pressure is at 13psi and the cylinders are no longer under compression from running. Theoretically this could and should also leak combustion gasses into the cooling system, but I haven't noticed this, haven't seen bubbles or signs of over-pressurization of the system.

I have a head gasket and could swap it in in an afternoon, assuming everything looked good when taken apart.
 
I think I would look in other places before going directly to the head gasket. There are a fine variety of other areas I would want to look at first.

The water pump is a prime culprit along with the subsidiary connections down stream. I don't know all the plumbing in the engine bay of a Scorpion but I can imagine there are a few other connections that could be problematic.
 
Do a leak down test on the cylinders, see what those numbers turn out to be before you take apart the engine.

I'm thinking you have an external leak(s) in the cooling system. The worm gear clamps loosen over time and seals fail.

Still, checking the combustion chamber for integrity could tell you something important.
 
Look for other symptoms

Check to see if your oil has changed color (Milk), another giveaway would be that your car is running hotter. If you haven't got water in the oil or you are not running hotter then as suggested look other places.
 
Loose intake manifold or bum manifold gasket?

I've seen cases where a loose manifold (or a single pulled loose stud in the wrong spot) can let coolant from one of the two head-to-manifold passage holes to weep into an exhaust or intake port, especially at shut down when hot.

-M
 
it often has a miss that goes away after a very short while.

Classic twin cam head gasket symptom...

look at cylinder 4, there are two very small steam holes in ther block/head that are very very close to the fire ring of the gasket, the tiniest amount of corrosion to the head, or mild overheating and this is one of the first places to leak.

Use the car as normal, shut it down and let it cool as you normally would. Before restarting the next morning, pull the plugs, and wind the motor over on the starter (or have an assistant do it) and watch for couple of drops of water to issue from the plug hole... a cooling system pressure test won't always show it up, but a cylinder leak down test sure will.

SteveC
 
Pulling the head now...

Pulling the head now...

Yesterday the same situation caused a large bubble in 1.5 hours of driving. Head's almost off and will get checked by my local machinist later today. Fortunately I have all the gaskets I need "in stock". Mostly a messy PITA.

The timing is less than ideal, leaving for Mirafiori's Ore'14 in Ashland wed AM. Should be enough time to heat cycle and re-torque.

In 28 years I've never had a headgasket soft-fail like this, always been more dramatic. In this case I have no milkshake or other cross-contamination, maybe more condensation in the breather than normal.
 
Results are in...

The headgasket was certainly leaking! Check out the clean edges of the first three pistons:

IMG_20140714_123820011_zps69f2ad3a.jpg


And the corresponding crud on the head:

IMG_20140714_124128810_zpscd9f41c6.jpg


Frankly I'm surprised it ran as well as it did. Head's to be ready tomorrow morning. Cutting it a bit close! :eyepop:
 
All clean and ready for the head, which is scheduled for 10AM tomorrow.

IMG_20140714_174737554_HDR_zpsec5bb83c.jpg


If for some reason that doesn't work, I have 2 other options... pull the head off my "spare" engine, or drive the Vanagon which will allow my daughter and I to bring a canoe, bike, etc. So, no disaster.
 
number one cylinder was the problem... the fire rings on 2,3 and 4 all seem to have held their integrity, number one has been leaking from the small steam hole that's close to the bore...

clean pistons around the periphery... normal for good combustion.

SteveC
 
So is there an update to this story?

Sorry to see the head gasket was indeed the problem rather than something minor. (how wrong I was)

Hope it has all gone well.

Karl
 
Update...

Got the head back and installed, warmed up and test driven 9PM Tuesday. 5AM Wednesday I re-torqued the headbolts and changed the oil, drive 500 miles trouble free. :)

Heading back to Oly from Ashland lost injector ground pulse, trailered to local friend Andy Jossy, eventually figured it out and got home many hot hours later than planned. Corrosion on ECU plug tabs. :wall:
 
Interesting...

I assumed the clean edges were a sign of leaking. The clean center of the #1 piston is because I started cleaning before snapping a pic. I'll post more pics soon.

Both end fire rings have lots of damage. Lots of corrosion, this engine was abused in a former life (coolant mix/age etc.).

Side note: After 500 mile drive to Fiat gathering in Ashland, I checked the coolant level in the ss tank the next morning. Less than 1" from the neck. Makes me wonder about our common wisdom that the level should be 1/2 to 3/4 full. :confuse2:
 
More pics...

#4 piston top:
IMG_20140714_123922393_HDR_zps53b58346.jpg


#1 detail:
IMG_20140714_123903250_HDR_zps0097af24.jpg


#4 detail of fire ring damage:
IMG_20140714_123846105_HDR_zps092e9669.jpg


To me the fire ring in the image of #4 looks pushed into the combustion chamber. #1 was wipe-cleanable, the others required putty knife, razor blade and lots of scrubbing.

Pretty head surface, they removed 3 thousandths:
IMG_20140715_143108795_HDR_zps5357cb11.jpg
 
Update...

Got it reassembled the night before leaving for Ore'14, warmed up and test drove it, then retorqued the head bolts and changed the oil in the morning before leaving at 5:30am.

Made the trip, about 1,00 miles trouble free (not counting a little trouble leaving Ashland caused by corrosion on the ECU plug, another story with a happy ending). I got 26 mpg on the way down, not sure about the way back yet. Seemed low going down so I bought and installed a new O2 sensor so I'm curious if it made a difference.

Car ran dead-steady temp wise even in 105ºF southern Oregon valley heat, and barely rose to the right of the 9 in 190 on the gauge zipping up the hill to Howard Prairie Lake Resort.

Got home late, parked it, came back a week later to clean up and checked the coolant level:

IMG_20140731_184432756_zpsbc1e83fa.jpg


I've never seen it hold the level this well before. Very pleased. :geek:
 
Congrats. Glad the trip and the surgery went well.

Hope the get together was fun, they sound like the original FFOs from way back.
 
Makes me wonder whether or not to consider SOHC and DOHC head gaskets as "maintenance items"....for example, upon acquisition of an X1/9, 124/2000 Spider, or Scorpion, the new owner should as a matter of course replace the head gasket along with the oft-recommended for replacement timing belt.
 
a HG is one sleeping dog I'd rather not kick if it's really sleeping, they are hard to get back to sleep again :eye pop:
I wouldn't got go after one if I didn't really think I had to.
 
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