Pulled the head...

geekdaddy

X1/9 Learner's Permit...
OK for those of you following along at home, I've been trying to diagnose a problem where air was getting into my cooling system. http://xwebforums.com/forum/index.php?threads/24950/ After a lot of testing and evaluation I determined the air was building only at high RPMs (over 3-4K) and very slowly. I suspected a potential head gasket leak but wasn't certain.

Following the directions and advice of others here, I pulled the head. I initally borrowed a head wrench (thanks Docpan) to remove the nuts/bolts but the head wouldn't budge. Got the head-removal-tool from Mirafiori (thanks Jeff) and removing the head was easy-peazy -- except for the fact that it's awful darn freezing cold in my garage right now!

While removing the manifolds and other bits I noticed some coolant drips when I removed my Allison's header. This kinda surprised me because I installed a new gasket and had that header very tight when installed last Spring. Now that I've pulled the head, the gasket looks pretty good to me. I don't have much experience with this, but don't see any problems with the gasket. So mainfold drips + good head gasket suggest loose manifold + exhaust gases pushing into the coolant ports.

Anyhow, would appreciate fdbk from those of you with more experience on anything good, bad, or ugly about the condition of my piston tops, head, etc. Since I've pulled everything apart, I will probably splurge on one of Matt's rebuilt perf heads before I put things back together and will of course double-check the flatness of the block beforehand...

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Looks pretty typical Greg

I see no issue with the gasket either. Pistons show a usual build-up of carbon deposit.
Looks like you might have found it with the exhaust port. Got a better photo of that?
Maybe you can ask Matt to plug them while it's there. (if you're sending it to him)

Nice work so far. You're a better man than me 'cause it's way too cold for me! :excited:
 
Nothing obvious, but....

Overheating over 3500 RPM is almost always a head gasket.
Both #2 and #3 combustion chambers on the cylinder head have rust deposits, and the #2 combustion chamber has a cleaned area near the intake valve which is very close to the water jacket port right there.

The surface of the head between the combustion chamber and that jacket port does not show any evidence of passage there, so maybe the leak was between the gasket and the block? You didn't show a pic of the block alone.

A minor head gasket issue can lead to the erratic overheating problem you describe, without spewing loads of steam out the exhaust.

Be sure to use a machinist's straight edge and look for low spots in the deck of the engine block, I suspect you might have one (or a bad cutter "swirl" mark) near that water jacket hole between #2 and #3 in the block.

It is extremely unlikely that the overheating was caused by the header or manifold gasket. Those little water ports are between the intake ports. The exhaust ports are no where close, and that's how you get air into the system, from either compression in the cylinders being pushed into the coolant system, or exhaust gasses being pushed in.

The moment you loosen any of the manifold studs, the coolant will start moving out of those center passages and pissing all over, so I think you got a bit of a false positive there.

One tip for others: Before loosening the manifolds, always open the block drain and get the coolant out of the head, that way you don't flood the intake ports. Once you have the manifolds off an FI head for any reason, it's always good practice to tap and plug those ports (they do nothing on an FI app) so you don't have to do that again.

Good luck!

-M
 
false positve...

yeah, but Matt, he saw dripping from his exhaust manifold before he loosened it (I remember his previous post) this really rings a bell with me, because when I first got my car (20 short years ago) I kept having overheating problems, and leaking from the intake /exhaust, so much that I kept tightening the nuts, till i stripped out one....so the question is: did you see coolant leaking BEFORE you loosened the manifold, or while doing it?
I finally figured it out- previous owner must've put a used exhaust manifold on the car, and it's mating surface was extremely corroded with rust, making the exhaust manifold mounting THICKER than the intake, and therefore the intake wasn't getting the crush it needed to seal the gasket...ironically, later I got a header, and noticed the mounting points were different thicknesses....anyways, i noticed he has an aftermarket header. There are supposed to be thick washers on the nuts that equalize the pressure between the intake and exhaust...might want to make sure those are there, and make sure the header mounting points aren't "thicker" than the intake
I solved my problem by having a machinist "skim" the surface of my exhaust manifold, so the intake would get more gasket crush.
Not arguing that you might still have a head gasket leak- just sharing my baffling experiance
 
I found the coolant leaks before I loosened and pulled the manifolds. I also drained the coolant beforehand. I detected the leaks based on a trail of dried coolant which had dripped down the side of the block and puddles a bit near the flange at the bottom where the oil pan mounting screws engage.
 
Agree with Matt 100% on this, gasket (block pic) looks like it's not sealing tight between 2 and 3. Make sure you check the block with a good quality straight edge.

Exhaust gasses won't push into the inlet manifolding water jacket holes, simply there's miles of space for it to cross there... maybe air geting drawn in as the car cools thru the gasket and the inlet manifold water jacketing holes... but 100% not exhaust gasses being pushed in (not there anyway)

SteveC
 
The coolant leak at the manifold flange is very common. A lot of folks over the years have installed plugs into the 2 ports of the head to stop the issue. That does not allow water to circulate through the intake manifold for those designs with a water passage but at least it stops leaking.

As for the head gasket... It can be hard to spot a tiny leak on a tired old gasket. That said, if you think the leak is into the cylinders there should be an imperfection on the fire ring. Try running a fingernail along the upper and lower sides of the fire ring and see if you feel a little catch at some point.
 
Thanks for all of the fdbk/ideas here

I removed the gasket and wiped some of the crud and oil off the gasket and head and took some add'l photos below. I'll work on getting a precision straight-edge to check the block...

Top of Gasket
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Bottom of Gasket
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Top of Block
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Close-up of Block between 2 & 3 (odd pattern/smudge there)
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Though not obvious,

I've gotta agree with Matt that something's going on between Cyl's 2 & 3.
He has a much better eye for this than I do, but I notice a slight pattern forming here. Might be where the issue has started.

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I do not think the block is an issue. Clean it and check it but don't sweat it. I'm pretty convinced it's very rare to have in issue with the block. I don't really care to relive my drama but 4 HG in one season makes me experienced (at doing it well or doing it wrong is debatable). Skim the head, good gasket and good reassembly, careful retiming, re-torque after appropriate heat cyclings. You're good to go.:cool:

I did severely overheat a while back and did NOT blow the HG so I'm pretty happy....for now.:eyepop:
 
Well... I'm convinced! Bottom of gasket...

Look closely at your photos and the cylinder walls where the forward water jackets are and the RUST in the cylinders.

Just seeing the SPARK PLUGS alone there is evidence of RUST on 2 & 3 and maybe a bit on #1 as well. Also note how WELL a bit of water injection super-heated to STEAM can really clear up the carbon deposits!

Compare 2 & 3 piston tops and the cylinder head to #4.

99 & 44/100ths of the time our IRON blocks are OK and the ALUMINUM head and gaskets are the problem. You can see how clean and flat the block appears but do as the others say and check it to be true.

Do the same with the head and possibly mill it a bit but not so much that it becomes an "interference" engine... or... as you said, spend your Christmas money on a BVH from Matt.

Hey Greg... sorry for your trouble here but yur not driving it anyway. This CAN fix your headache of the last year or so for a few bucks, or increase your performance quite a bit with the BVH. This was probably a GOOD thing!

Hey... don't you guys have heaters, in or for your garage, at least when you are working?
 
The problem with heating your garage...

Is the same problem you have when you put an ice cold can of soda on your mother-in-law's favorite table without a coaster.
Condensation.
Your tools all condense the moisture in the air (even if the relative humidity is low) from the heat source or the humidity from breathing and has the effect of spraying water all over your tools. (and cylinder walls, etc) I've tried it more than once, and it's not worth the aggravation. Hastens brake drum rusting as well. :(
 
Let's just say my garage is well ventilated... It's hot in the summer and cold in the winter. Not worth trying to heat it up and would probably cost me a fortune. I typically get out there and work for 15-20 mins, do something indoors for awhile and then go back out. The challenge of working in a freezing garage is that it's difficult to keep your hands warm. Bulky gloves get in the way of things (and get gunked up).

But I actually enjoy living here. Winter is a good time to get big projects done on the X. ...and for me, doing maintenance and tear-down really is half the fun of owning one.
 
That's great... I'm just too damn spoiled I guess...

and its good to hear yur one of the TRUE "sportsman" that sees there are so many other facets with this car as well as driving it!
 
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