Suspected head gasket leaking.

[garion]

Hi all... I suspect that I need to change my head gasket.. Seems that my spider is turning into a basket case.. The end result is that I'm overheating.

New items changed during timing belt change (overheating also occurred before timing belt change):
- Thermostat
- front engine hoses
- fill T on the upper heater hose
- water pump
- fan temp switch
- and the usual timing belt stuff: belt, seals, bearing

After finishing the timing belt change, I burped the cooling system, letting it run until it got to temp, let it get its bubbles out. Fan came on at the appropriate time, thermostat opened and the lower hose got hot. So I believe I have the cooling system functioning properly. No external leaks.

I then took the car for a quick test drive, less than 10 miles. The temp stayed at 190 for a few miles, then started moving up, and kept going up.. Let it cool for a few hours.. checked the radiator level, looks ok.. Opened the fill T, looks dry.. Hrm.. So I start the car, with the radiotor open and the fill T open... I watch the fluid flow past, looks ok, until... It start to look foamy, bubbly. eventually its starts to overflow out of there, so i kill the engine. I figure at this point its most likely the head gasket, but want to do some more research.

The next day (today), I decide to pull the plugs. They all look ok. I then retorqued the head bolts. I loosened 1/4 turn, then tighten to 61ftlbs (at least as accurately as I can get with a cheap craftsman torque wrench). All the bolts seemed to be loose by a 1/4 turn. (in other words, I loosened 1/4, then tightened 1/2 turn).

I then ran the engine, leaving the radiator cap off.. It bubbled and gurged for a while, spitting out coolant. About about 15 minutes or so, it stopped gurgling and smoothed out. I let the car continue to run, keeping an eye on the temp. Eventually, the fan kicked on, and I could see the coolant circulating, no bubbling.

Let that go for a a few minutes, shut the car off, and put the cap on. Start the car, and go for a drive.,.. Again, within a few miles, the temp starts to rise, and just keeps going. Nurse it home again (it seems to level out just touching the red). Kill the engine, and open the hood. No leaks anywhere, but I hear the gurgling in the overflow. Seem that I'm getting exhaust into the coolant.

I'm really leaning towards head gasket at this point, what do you guys think?

[So Cal Mark]

gurgling in the reservoir isn't exhaust, it's the water boiling. Since the reservoir isn't pressurized, the boiling point is much lower than in the radiator. Tell tale signs of a leaking head gasket include, water in the oil most noticeable in the oil cap, misfire when started cold that clears up within a short time, air in the cooling system shortly after bleeding and/or water spewing from the radiator if you start the engine with the rad cap off

[garion]

I've seen no indication of oil and coolant mixing in the oil. The coolant sometimes turns brownish, could that be rust though?

Looking in the oil fill and on the dip stick, both are oil-black. No milky-ness at all.

[vandor]

Are you sure you got all the air out of the system the second time around? Did you wait until the t-stat opened before you went for a drive?

[garion]

I'm fairly sure. I waited till I could see the coolant moving through the radiator, the fan coming on, and the lower radiator hose is hot.. I let it run for a few minutes after the fan came on, just to be sure.. Only then did I take it for a drive... Maybe I'm in the early stages of failure, and it only happens once I start putting load on the car?

A few other notes:

- I also replaced the radiator cap during the timing belt replacement.(again, i was overheating before that).
- After the overheating drives, after letting it cool, the coolant level seems 'normal'. I dont think I'm losing coolant.

I plan on getting one of those 'liquid coolant testers' that check for exhaust fumes in the coolant tomorrow. We'll see what that tells us.

[garion]

OFF WITH ZEE HEAD!



Ran the block leak detector test, and got a positive result.. I had to run the test numerous times though, and it only occurred after I reved the engine a few times. But its clearly a positive result.

So.... What other stuff should I do while the head is off, and is *inexpensive*? How much is it usually to get the head resurfaced and or rebuilt? (anyone recommend someone in the Phoenix AZ area?)

And is there a trick to draining the antifreeze without creating a mess?

[garion]

Hi all... After the confirmation yesterday from the block leak detector, I went ahead and took the head off. Easier than I expected. I haven't order parts yet, so it'll be at least a week before I can get stuff back together. So if anyone would like better pictures while I have things apart, please ask.

I have a few questions about the pics..

Onto the porn!

The block:
It looks like someone used some sort of form a a gasket goop? (the orange stuff), or is that just from the old head gasket?


The bottom of the head:


Clogged passage in the head:


Another clogged passage in the head:


Looks like this passageway has been 'enlarged' in the gasket:


Another angle of the enlarge passage:


Blocked passage in the gasket:


Missing a nut on the exhaust manifold:


I know its dark, but should I block off this open port on the carb? I never knew abotu it till I took off the intake. I don't believe anything was connected to it.


The block itself looks fine, nothing clogged... But with the various clogged ports on the head, should I be thinking about a new head? Or just clean it out? It certainly looks like the head gasket was on its way out.

--John

[131]

The orange stuff is sealant from the head gasket. If the water galleries in the head are that blocked up, chances are your block isn't real crash hot either. While your this far into it, I'd be pulling the welsh plugs (freeze plugs to your mob) and giving the block a good clean out as well. I'd pull the manifolds and cam boxes off and take the head to a workshop for a complete overhaul. Pickle, clean, guides, seals, resurface, grind valves and cut seats. I'd also be checking the condition and cleanliness of the radiator.

[So Cal Mark]

the port on the carb is for the crankcase ventilation. That hose should connect to the air cleaner. I'd like to see pics of each piston top. A leaking gasket will cause that cylinder to be clean rather than coated with carbon. I'd also like to see a pic of the bottom of the head, not just a portion of it. If the gasket was leaking, you should be able to see evidence of the leak on the head gasket. Once the head is clean, I'd check it for flatness

[garion]

Ah. I see the port on the underside of the air cleaner.. I'll hook that up as I re-assemble.

All the pistons are carbon topped, not polished like you would expected from water getting in. But I certainly had a positive result from the test. I even washed out the tester, and re-performed the test to make sure. Exhaust was getting into the coolant somehow.

Here's a link to the oringal sized version of the bottom of the head: http://garion911.smugmug.com/Cars/1978- ... J&lb=1&s=O

I'll take shots of the full gasket tomorrow.

Whats good for cleaning off the head and top of the block? Carb cleaner?

Could it be that the leak was small, and effectively 'one way'? So on the compression and exhaust strokes, it pushed out (meaning I may have fuel in the coolant too, with exhaust), and on the other strokes it sealed itself, not letting coolant into the cylinders?

[garion]

Here's some more pics of the gasket. I'll post a small pic, with a link to the full size

TOP (HEAD) SIDE:
Cylinder 1:

http://garion911.smugmug.com/Cars/Head- ... 791-X3.jpg

Cylinder 2:

http://garion911.smugmug.com/Cars/Head- ... 931-X3.jpg

Cylinder 3:

http://garion911.smugmug.com/Cars/Head- ... 010-X3.jpg

Cylinder 4:

http://garion911.smugmug.com/Cars/Head- ... 080-X3.jpg


BOTTOM (BLOCK) SIDE:
Cylinder 1:

http://garion911.smugmug.com/Cars/Head- ... 227-X3.jpg

Cylinder 2:

http://garion911.smugmug.com/Cars/Head- ... 333-X3.jpg

Cylinder 3:

http://garion911.smugmug.com/Cars/Head- ... 539-X3.jpg

Cylinder 4:

http://garion911.smugmug.com/Cars/Head- ... 751-X3.jpg

Possible problem areas (all images from HEAD side.):
Piston 2-3 (not the exhaust to coolant problem, but cylinder to cylinder?)

http://garion911.smugmug.com/Cars/Head- ... 993-X3.jpg

Piston 3-4 (not the exhaust to coolant problem, but cylinder to cylinder?)

http://garion911.smugmug.com/Cars/Head- ... 367-X3.jpg

Piston 4 (This is where I think it may be occurring)

http://garion911.smugmug.com/Cars/Head- ... 612-X3.jpg

Piston 4 (Exhaust out the back of the engine?)

http://garion911.smugmug.com/Cars/Head- ... 719-X3.jpg

[So Cal Mark]

the fire ring looks like a problem on #4. With the issue between cylinders I'd make sure to check the flatness of the head

[vandor]

FYI, it is normal that the headgasket is not fully open at all the coolant passages. It is designed to force water to circulate more toward the back of the engine. But the passages in the head should not be plugged.

IF it turns out that the head is not flat be sure to check if the camtower surfaces are flat. If not they could be binding up the cams.

Since it is this far apart I would change all the guides and valves and have the machine shop do a valve job. Also ask them to check for cracks. If you are on a budget you can ask the machine shop to check the current guides and valves, they may still be in spec, but in the long run it's better to change everything.

[So Cal Mark]

it's been many years since I've seen one of those chemical testers. Isn't the fluid supposed to turn yellow rather than green if there is exhaust in the coolant?

[maytag]

it's been many years since I've seen one of those chemical testers. Isn't the fluid supposed to turn yellow rather than green if there is exhaust in the coolant?

I was thinking the same thing.
And I was thinking that it'd sure be a shame if this motor got pulled apart to repair something that wasn't broke.

I think too many people associate overheating with head-gasket failure, without fully understanding cause & effect. I don;t yet see anything in this thread that would've made me think there was a bad head-gasket involved,
????