My cracked head, see lower post *pictures*

Orange/brown colored coolant in a new radiator, running extremely hot and missing/shaking engine on acceleration most likely means I have a blown head gasket, right?

Maybe. Can also be a burnt vale or two. To help pin point it you could do a compression check a blown gasket shows up as two weaker cylinders right next to each other with low or no compression.

Just pulling the plugs and looking at them will give you some indication. Sounds like you have a bunch of buildup in the cooling passages too. Need to clean that out before it clogs your new radiator.

I don't think dirty coolant + poor running = blown headgasket.
If chunks of debris in the head loosen up and stop up a coolant passage that might account for overheating, But the overheating could be something else, like timing.
And a vacuum leak/incorrect timing can cause the poor running you describe.
As has already been stated, compression test on a warmed up engine will tell the tale.

usually a blown head gasket will cause a significant loss of coolant along with turning it ugly colors. i've never heard of one that mucked up the coolant without consuming it.

bubba22349":3fsz1bq8 said:

blown gasket shows up as two weaker cylinders

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Not necessarily. Only if the gasket is blown between two cylinders. It could instead have a leak to the coolant.

JackFish":3fsz1bq8 said:

compression test on a warmed up engine will tell the tale

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Compression tests are good and I would recommend he do one but it might not show the problem.

The Plankster Prankster":3fsz1bq8 said:

significant loss of coolant along with turning it ugly colors

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A small leak would take time to suck up enough coolant to be obvious.



I would recommend

1. Stop driving the car until this gets sorted out.
2. Check the oil for any signs of water.
3. Remove and inspect the plugs.
4. While the plugs are out due a compression test for completeness.
5. While the plugs are out due a pressure check of the radiator.

one thing we haven't mentioned yet is that you should idle the engine with the radiator cap removed and look for any bubbles in the water. if any are present, theyre coming from somewhere (and the HG is the likely place)

The oil should be floating on top of the coolant; just look at the Gulf. If the brown is mixed in with the coolant it might be crud from the cooling jackets.

So I finally had time to do some testing today (a death in the family really delays things)

Did a compression test, results were pretty good.
cylinder:
#1-140psi
#2-155psi
#3-155psi
#4-150psi
#5-160psi
#6-160psi

Here's the situation: My transmission + rearend is geared really low, thus my engine revs really high on the freeway. It does stay cool (more like cold) at the high revs though.
A few weeks ago I drove about an hour on the freeway to visit my friend. I drove back later that night, doing about 75-80mph. I normally max at about 70mph but I wanted to go the same speed as everyone else. It was also really windy and I could tell the engine was really working. I pull off the freeway and hit a red light. It immediately overheats (I wasn't too surprised), however, the car was running terrible. I drove it home 2 minutes away and parked it.

The next day I fill the radiator with water. I noticed there was a rust coloration on the inside of the radiator. The engine starts and has a noticeable stumble at idle. Also, there is a bad stumble while accelerating.
I changed the spark plugs and it did help but the problem is still there. Currently: Idle is less smooth, under moderate acceleration it is smooth for the first 500 rpm increase, then there is a stumble/the engine shakes for the next 1-2000 rpm, then in the upper rev limits the engine is smooth again (though it does feel to be down on power, even though it is smoother at max revs)
-It is not overheating
-It uses minimal coolant, possibly none (it boils over sometimes when I get off the freeway and immediately park it)
-THERE WERE GRAVEL SIZED PIECES OF IRON IN THE RADIATOR, which didn't show up until the shake occurred. Also, the coolant had always been clean before that night.
-SOME creamy colored spot in the valve cover and breather cap. Multiple dipstick checks appeared fine. Good color and oil level not dropping.
-Took off the valve cover and everything appeared fine. Nothing broken or bent. No gunky buildup.
-Distributor cap pickup points were a bit burned, however they've always been like this so I would dismiss it.
-Oil pressure has been just slightly higher.

http://i47.tinypic.com/j9c747.jpg
(coolant on right side)
http://i46.tinypic.com/33c3dqs.jpg
http://i49.tinypic.com/2istf7t.jpg
(had no orange color before that freeway drive)
http://i50.tinypic.com/2jays0l.jpg
http://i45.tinypic.com/wjyvkn.jpg
http://i50.tinypic.com/1191cox.jpg
(Not great but no worse than usual)
So something's definitely fishy with my coolant system, but that doesn't tell me why I have a miss.
Suggestions?

Sounds like it’s a blown head gasket from what you are describing what happen. You could probably pull head clean it up check the surface with straight edge or do re-surface with a fresh valve job and be good to go again. Flush that block, head, and rad out too.

Added pictures to previous post.

But with the decent compression numbers could it still be a head gasket?

Have you changed the oil?
Do you have coolant in the oil?

Do you know what the compression was before it was overheated? Short answer is yes a blown gasket could be leaking only slightly at first and it will get worse as you keep driving it. You could try some K&W block sealer before it get too bad if you don’t want to tear it down now. I have fixed more than a few temporally that way when needed to keep using a car or truck.

350kmileford":1nu9c16d said:

A few weeks ago I drove about an hour on the freeway to visit my friend. I drove back later that night, doing about 75-80mph. I normally max at about 70mph but I wanted to go the same speed as everyone else. It was also really windy and I could tell the engine was really working. I pull off the freeway and hit a red light. It immediately overheats (I wasn't too surprised), however, the car was running terrible. I drove it home 2 minutes away and parked it.

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the fact that it went that far before it got too hot indicates that the leak is still small. i've seen (and driven) much worse. there's a chance that you would be able to cheat as bubba suggested.
my guess from the numbers is that #1 is starting to leak against the water jacket

when you changed the plugs, how did they look? did one look cleaner than normal, as if someone took the steam cleaner to it?

Each plug looked nearly identical as far as color and tint goes.
1-2 years ago when I did have a blown head gasket, I remember the pistons were also 'cleaned' from the water that was getting into the cylinder. I peaked at every piston through the plug hole and each also looked similar.

Only other thing can think is you might have burnt an exhaust valve or wiped a guide.

Just for craps and giggles, check your idle screw to see if it came out, I recently went on a road trip that included dirt road, although the road wasn't that rough the idle screw mixture moved and described what your experiencing...

My distributor cap does the same thing, why? is it not seated right?

another thing might be the heater core gunk came loose... when's the last time that has been replaced...

sorry for shooting blanks, but it might be simple... at least we hope so.

Richard

you thought of a pin hole in a bore, sounds the same symptoms mine had. drove me nuts, several head gaskets later i discovered a tiny little hole in the "front" wall of #6 bore.

gravelrash":21nprvx5 said:

you thought of a pin hole in a bore, sounds the same symptoms mine had. drove me nuts, several head gaskets later i discovered a tiny little hole in the "front" wall of #6 bore.

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thats a strange one!! let me guess, the block had been bored out as far as possible? thats still quite a bit to rust through, probably was run on straight water instead of antifreeze for some time?

turning my wastegate off and running 20+ psi every now and then didnt do it any favours though. but FARK ME it went hard.