Is this 100% a blown head gasket?

[428Marauder]

So, years ago I purchased a used 428 that was running and according to the guy that sold it to me (in a car) it had less than 1000 miles on it. I've had lots of problems with it, finally replaced the carb with an aluminum holley, and the car runs great! There's just one problem. Over 180 degrees and the car starts to knock and gurggle. So, I was thinking that it was a good idea to burp the radiator. Since I replaced the radiator myself with a brand new aluminum radiator a couple years ago, I never have burped it, but I also have not driven it much. Anyway, my green coolant has turned into a more chocolate milk color. While trying to burp it, I noticed it was foaming up. I did not notice any abnormal smell.

I've ran a couple tanks through it with 91 octane, so that is eliminated. I just did an oil change and it looks clean, nothing weird coming out the tail pipes. Car runs and drives great, for about 5 minutes. At 70 MPH it will cruise just fine, and then you go up a hill and it starts to gurggle and knock.

So, I think a coolant flush makes sense, with fingers crossed and then I found these Thermagasket kits that is supposed to fix head gasket problems doing a coolant flush. Anyone ever tried this?

http://www.rxauto.com/products.php?cat=8

[cjshaker]

I'm not really a fan of gasket fixes that include sealers put into the engine, so can't really comment there.
HOPE that it is a head gasket though. The alternative may be that the internal oil tube leading to the deck surface is rusted through and allowing oil under pressure into the water jacket. They're fixable, but the entire engine must be dismantled.

[428Marauder]

FWIW, I not need to drive the car every day, and I am pretty broke. I would hate to waste the money on coolant flush and still have the same problems. If it costs me $115 more and it solves the problems, that would be a good thing.

I have a complete (seized) 390 in another car that would be correct for the car (the 428 is not). It might make more financial sense to have that motor rebuilt, but I would have to hire a good mechanic.

Pull one motor and trans, do complete rebuild. Pull other motor and and trans, put in other car, install rebuilt motor. What are we looking at here, $5-7K?

[428Marauder]

Im going to flush it several times with water, and once it has clean water in it, I will get back to you guys.

[66FAIRLANE]

Get someone to put a 'head tester' on it.

[Heo]

Put some dishwasher detergent in the radiator and run
It for a while then flush it out with a hose till
All the mud is gone

[428Marauder]

OK, so I opened up the valve on the bottom of the radiator and surprisingly the coolant looked fairly clean, not milky at all. Drained it out, ran some water through it. Put in some dish soap, ran water through it. Drained, ran water, drained, ran water. Still each time there would be some foam, but eventually I got it fairly clean. Ran it for about 5 minutes with the cap off, put the cap on, took it out for a test drive, right away when accelerating, "gurggle, gurggle, knock".

Going to flush it a few more times and try again tomorrow.

[428Marauder]

When engine is off and cool, it the water looks clear. Here is a video of the water with the cap off:

https://m.youtube.com/watch?v=7iFybx1vRcc

[machoneman]

Ouch! That vid of pulsating coolant is a textbook case, unfortunately. Once hot again, rev up the engine to say 2,000 rpm. Near 100% sure you'll see the pulsing increase rapidly....and then slow again as the revs drop to idle.

If not a head gasket, it could instead be a crack one of the cylinder heads (possible) or a cracked bore (less likely). With that much pulsing btw, a compression test should show a suspect cylinder down on PSI a lot or even two adjacent cylinder low (like 1-2, or 6-7, or any pair).   

https://www.youtube.com/watch?v=5zpNjYmmiYY

[428Marauder]

Welp, I'm not the kind of guy to sell the car and not be honest about the problems, so I guess I need to find a good mechanic.

[428Marauder]

I added some Bar's Leaks metallic block seal. Says "permanent" repair. $10. Should be good now. Phew!

Ok, the real reason is, like I said, the car runs fine. No water in the oil, no white smoke out the tailpipes, no weird smells, and the bubbles are very fine and foamy. I hope, that means it's a small leak, and a head gasket leak. My guess is, if that's the case, this will temporarily fix it. If it's a cracked cylinder head, or block, I don't expect this to do anything.

Will report back in a couple of days.

ETA: Also, I didn't put any in the overflow, or run the heater, as directed (so it didn't get into my heater core) and I am not going to leave it in, as directed. Ran it with just water, gonna drain it one more time, fill with coolant. Still have a little left, may add that at that point if I am still having the same issue, or it seems slightly improved.

[428Marauder]

Slight, weird question.

I have a pair of 390 4 barrel heads. Is there any difference between 428 heads and 390 heads?

Also, could be interesting, this motor has the 1U crank, externally weighted flywheel, webbed block, pretty much meets the requirement for a cobra jet, despite the fairly standard heads. Have not found a vin on it, I think it was a service block. I've pulled the top end off a 390 before, I could get this all the way down to the block, myself. The problem would be putting it back together, but it's not rocket surgery, right? The reason for doing this, would be to instead of spending money on a mechanic, maybe I can replace the heads with something better. Also, maybe I can do the job myself if I purchase a torque wrench. Watch a couple youtube videos, I'm there, right?

ETA: As long as I break it down carefully, bag and tag, actually that might save me some money on mechanic time, even if it means towing the car in, right?

[428Marauder]

I've actually never had the valve covers off on this car, and even though the oil is clean, at the very least, I have some Mercury pentroof valve covers I want to use anyway, so I will buy a torque wrench and check the head bolts torque next. Video to come.

[428Marauder]

Pretty much what I expected, made a temporary seal. I try and make it sound cool. And for $10 ... if it works for a day, I get a clearer picture. Gonna hafta get out there, put my foot in it, oh darn ... Will report back though.

https://m.youtube.com/watch?v=M9VkWKHhEnk

[428Marauder]

Post removed by author. Off topic.

[428Marauder]

Update: I decided, with this kind of major surgery, it would be a good idea to have a guy that is not gonna screw me over, but also do a complete job. So, I called some guys at the oldest machine shop in town, they said they don't do head gasket jobs, I said, "I figured, but can you suggest someone for me?" and they did.

So, I take her in Monday. Fingers crossed it costs me less than $1K. At least I finally get to put on the valve covers that I want.

[428Marauder]

Update:

Compression checks at 155 on all cylinders, mechanic said it looks like the head gasket did not fail. Heads are in the machine shop getting checked now.

Fingers crossed.

[428Marauder]

Quesion:

The mechanic said to me today that the problem might have been just that I hadn't properly burped the radiator. Then he said the compression check was fine, and then he told me that the heads were at the machine shop. Our initial discussion was to do a diagnostics first, compression check, etc. and then go from there. Too late now, right?

I'm not sure how upset I should be that perhaps the top end was torn down and all it needed was a burp. $100 bill vs. $1500 bill. I've decided something needs to be said, but not sure how to word it. Any suggestions?

[My427stang]

Well, it's tough to say.  If all the diagnostics go pretty well, but you had already temp-sealed it using a block seal, he likely took it down to see if he could find a marginal head gasket or a crack.  Once he went in there, he saw it wasn't a gasket, but the machine shop could still find a crack or warped head.

As much as there are shady guys out there, if I understand the posts, you had it sealed but didn't trust it.  So he started looking at it, found it sealed, so went deeper to see what was going in so you could trust it.  It sounds like he is trying to make sense of what he sees before the heads get back.

BTW how did you fill it with coolant, did you let it get hot with the cap off and let the thermostat open and add more?  Did you drill a small hole in the thermostat (not required but surely helps)    I am not a guy who "burps" any cooling system unless it has a bleed valve by design, but you have to add more after the thermostat opens.

As this point, if it were me or my customer, I'd do a good valve job with modern valve seals and if marginal, cut the head surface and if needed the exhaust flange surface.

I could be wrong, but my hunch is he is doing it right to make the car reliable

[jayb]

+1 on what Ross said, and to me it is hard to believe than an air pocket in the cooling system could cause the problems you were seeing.  Drill that small hole in the thermostat and install it at the top to eliminate that possibility.

[428Marauder]

It's not that I think the guy is shady, I just wish he had consulted with me after doing diagnostics and before taking the heads off. I feel like he may have jumped the gun.

It was his words that it might have just been air in the system.

[428Marauder]

I do not know if he did a Co2 check. He didn't say anything about doing one. I clearly need to replace a radiator hose, but I told the guy, because I am broke, that I have a spare and I will do that myself.

[428Marauder]

Could a crack in the intake manifold cause this?

[428Marauder]

Update:

I wont go into the whole thing with my opinion that the mechanic MIGHT have prematurely, without my authorization, tore the top end off. I'm putting in those Mercury pentroofs, there has been a lot of bead blasting and repainting and it's going to look real nice.

I'm upset that the mechanic and the machine shop made decisions without talking to me first.

Final bill, $1406.

I wrote all about it on my poker blog. If it fixes the problem, as the mechanic says he thinks it will, phew ... Only $1400. If we still got a problem ....

ETA: Intake has a crack in it. Photos to come. I have not seen them, but when the guy said $600 for a aluminum intake I said no.

[jayb]

Where is the crack in the intake?

[428Marauder]

I have not seen it yet. The mechanic took a photo of it.

[428Marauder]

Ok, so here is the crack:

http://imgur.com/DzLdXU3

I got the car back today and it is still knocking. Also I just looked at it and my radiator hoses were almost flat. I guess now that the system does not leak I need hoses with springs in them?

[jayb]

If that crack goes all the way through into the exhaust crossover passage, you can suck oil through the crack and into the intake port.  You can burn a lot of oil that way.  Did they fix that crack?

I would say yes on the spring in the lower radiator hose.

[428Marauder]

They did not fix the crack. The mechanic said it would not cause any problems besides maybe some blowback and any oil would go back into the crankcase. He said out here in AZ those ports can actually be intentionally blocked off as they help warm the carb at startup and are not needed.

I think now I must have a clog in my overflow hose. The mechanic did put a new radiator cap on it.

[Drew Pojedinec]

428 Marauder, where do you live?

$1400 for the work done is nuts.

[428Marauder]

Tucson, AZ.

If it didn't still gurgle/knock I would be happy paying $1400, but it does.

[428Marauder]

Ok, the collapsed rad hoses was being caused by the overflow being plugged up. Still knocks though, once it gets up to temp.

[428Marauder]

Could that crack in the intake be causing it to knock?

It really only does it at temp when pulling.