Problem Found

[mid79]

I bought my X in Sept 2012, drove it for a few months, and noticed a deteriorating coolant/overheat condition. I parked it in early 2013 and it's been languishing in the garage ever since.

This past weekend I recruited some expert help (my brother, who has owned half a dozen X's over the years) and we pulled he head.

I wasn't completely sure it was a head gasket problem, but suspected it was since the coolant was being forced out of the coolant cap on the expansion tank. I felt, based on the experiences and noise, that the cooling system was being over-pressurized and that over-pressure had to come from combustion gasses.

We got the cam tower and head off with little trouble (the head studs will need to be cleaned and lubed prior to reassembly, however). A careful look at the pistons and bores showed them to be in decent condition. A look at the head gasket showed this at #1 cylinder.



Found it! There's a break in the sealing ring of #1 cyl in the lower right quadrant.

The head/cam has been sent to Steve at Progressive Automotive in Tacoma, WA for refreshing. A new cam, larger intake valves, intake and exhaust port/manifold work and then everything will be ready to bolt back on.

I will use my new straight edge to check the block deck and then I'll begin the rest of the work: cleaning the engine, replacing the 'while I'm in here' bits like the water pump and timing belt/tensioner, replace the clutch slave and refresh the fluid in both the clutch and brake systems. Bob's nifty aluminum radiator is waiting as are the dual DCNFs. The Bayless SS expansion tank and Vick's adjustable cam gear will roll in just in time, I hope.

A long list, for sure, and one I hope won't keep the car in the garage the entire summer.

 

[Red Bull 78]

Number One Rule of Aluminum Engine Parts

Never let them Over Heat. They Warp way too easy. Iron block with Aluminum Heads are even worse, as they don't expand & contract at the same rate/temp.
You need to "True Up" BOTH surfaces before you put them back together, unless you just like spending your Driving Time, changing head gaskets.
Even something as simple as this might mean taking 10/1000th's of an inch off the Aluminum head but only a light sanding on the Iron block.
Lots of work, but when you're done, that 10 thousandth of an inch off
all 4 cylinders, just gave you a little more Giddy-Up, if you did it "right"?

Neat trick I'll bet NONE of you have tried.
All a Timing Light does is tell you when a certain Cylinder Fires, Right?
Use that to look for "leaks", all around the engine compartment. You'll have to deal with Radiator & Alternator cooling fans, creating turbulence in the engine room
But working in a dark room and hooking the lead to all cylinders, the strobe will show you cooling & fuel system leaks, you could never eyeball.

 

[jvandyke]

after 4 head gaskets in one season I've done some research and gotten some help, conclusion: blocks rarely need anything beyond good cleaning, heads should be checked and trued up, as you're doing. Installation and proper retorque regime is 95% of the battle, IMHO, why it failed is always interesting, overheat or a lame gasket or preignition…. I still don't know why mine kept failing.
What's going on between 1 and 2? Looks a little odd, is that just gasket torn up/stain/discolor from removal or was it failing there too?

 

[Dan Sarandrea (Phila)]

Take a closer look at the water jacket passages in the deck around #1, in the pic you posted it does appear as thought they are somewhat blocked.

If that's a fair representation of the actual condition, you'll want to take advantage of the head being off to use some sort of solution to dissolve the build up in the water jacket. You may want to poll the membership as to what to use....cooling system cleaner or something stronger like CLR, pool acid, or what have you. If you use something stronger it will do a better job but might attack the gaskets that seal the front and rear water jacket access plates on the block.

Since you have plans to remove the water pump, remove the housing as well which will give you more insight into the water jacket on the backside of #1 and #2.

 

[mid79]

Update & Question

The head is being worked on and the preliminary report back is that it is in good condition. There are no obvious (to the trained eye) areas of damage. I will get a call when there is news and I'll post the news.

Meanwhile, I'm working on the block. The plan is to keep the bottom end untouched as much as possible. I'm replacing the ancillary stuff - water pump, T-belt, tensioner, etc. and cleaning everything else.

Dan - I agree, the water passages do show signs of (impending) blockage. I'm giving that a thorough cleaning as well as the pipes to the (new) radiator. Thanks for the cleaning agent ideas. I want the cooling system to be as close to factory fresh as possible without stripping and boiling the block. New hoses and, of course, the new M-B stainless tank are going in when everything is ready.

Jeff - We looked carefully at the head gasket and both mating surfaces and feel the 1-2 spot is just discoloration. I'll pay close attention to that area (and all the between-cylinder areas) as the block surface is cleaned and checked. Thanks for the suggestion, please offer anything else you care to. I read your saga with interest and compassion, there were times when the frustration oozed from the page as I read.

Question - should I remove the five head studs from the block? If so, how?

I have a '79 1500 carb'd engine with the 10 bolt head. Actually, there are five bolts and five studs. Removing the studs will make cleaning and checking the block deck much easier.

I was able to double-nut one stud out (don't even start with the jokes), the rest are stuck in solidly. I have them soaking in PB Blaster penetrating oil and will try them again tomorrow.

Any suggestions on how to remove them other than by using two nuts locked together?

Bonus question - can/should the studs be replaced by appropriate head bolts when I reassemble the engine?