Head gasket - but now totally confused- Help!

[riazoo]

Hi - I have a 2005 Chevy kodiak LLY bus and after reading the forums I was convinced I needed head gaskets. I had the hard upper hose and pressurized overflow tank symptom. No oil in water mixing and no white smoke. I did the combustion test and the fluid turned yellow. There were no visible leaks of coolant anywhere near or under the engine.
I was going to change the head gaskets but before I could the belt broke. Here is where it gets interesting.
The workshop was 30 miles away and the driver drove the truck back to the shop with the temperature around 220. Next morning we opened the overflow tank expecting the coolant to blow out - instead we find the hose soft, the coolant at the correct level and no pressurized overflow tank.
So now I'm totally confused - what's wrong with this truck?

 

[catman3126]

Still bet its the head gaskets.

 

[Devon]

Yeah, head gaskets for sure! My 06lly had a hard radiator hose, it would get soft but it took forever to. I would relive pressure and I would be good for a day or so. Then it would get hard again. Ended up being the passenger side head pissing internally. Chances are you won't get coolant in the oil or white smoke even.


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[riazoo]

I would think so too. Especially after the fluid test changed color. The truck has 120k miles.
However before it broke the belt, if we drove it for a mile and came back the system was pressurized and the tank would remain pressurized even 3 days later.
Just surprised that after the belt broke there was no pressurized tank and no loss of coolant.

 

[Stingpuller]

Water pump

The water pump is gear driven and would not be affected by a broken belt. Maybe he run it easier thinking to not over heat it or something. I'm not sure why there would be a differance. I have seen more problems with LLY head gaskets than any other at my shop. Not sure why but they seem to be more problem. I had one that had a broken head bolt in the back on the drivers side. That was fun to get out and not mess the block up.

 

[riazoo]

Could it be the thermostats were stuck and they finally opened up at high temp?

 

[Stingpuller]

Water pump

I would guess it to be a lack of coolant. Air will not let a stat open up. Was the coolant full?

 

[SBCNX20]

I've just got to chime in on this one. So several months ago my truck developed a strange leak. It was coming from the pass side in the rear. We couldn't really find it, but some times it leaked pretty bad (a steady drip,drip,drip flow that left puddles) and other times only a few drops while it was parked. Funny thing was it didnt seem to correlate to how aggresive i drove or the coolant temp??????????? So since ive kinda grown tired of [her] these days and really didnt feel like f*cking with this thing for the 100000000000000 time i threw some stop leak in it. Well the leak stopped. Since then, i now have these Large and quick temperature changes directly related to engine power output/load so the truck runs about 185-190ish cruising but clime a hill, or accelerate hard and within 10 seconds it will climb to 205-210. BUT it NEVER goes above 210 ever. It seems to me that with a bad head gasket with that quick a temp rise that it should...... just keep rising and over heat. I dont know just bummed out. I de-tuned it after the first motor went bu-bye and now again............:giveup:

 

[riazoo]

Yes and no as far as the tank being full goes. It used to eat up coolant about a gallon every hour. Well here goes. Today we removed the intercooler and cleaned it out on the surface. The radiator was really dirty and so that was also hosed down. The egr was deleted with a sinister kit. The egr looked okay but I took the whole thing out. Changed the serpentine belt because one of the pulleys was rubbing up against the adapter below the second alternator. I replaced all the pulleys, the tensioner and started up the truck and took it for a spin and no leaks out of the overflow tank. I'm keeping my fingers crossed. Tomorrow I have a long trip with the bus, so i will let you know if anything "springs" up! For now - it appears like it was a dirty radiator. If that was the case - that's a huge saving! If it works maybe all these headgasket issues are due to blocked radiators! The overflow tank was really oily and full of black soot. Tried to clean it out with little success. So if thats the condition of the overflow tank one can only imagine whats going on inside the radiator. I should have used a gun to measure the temperature variations across the radiator but it was getting late. If there is an improvement I might change out the radiator and the waterpump and see what happens before we dig into the headgaskets. In any case even if we do the heads I would have to change out the pump.

 

[riazoo]

Maybe its the heater hoses going into the firewall on the passenger side

 

[RKTMech]

Where do you think the black soot in your coolant bottle came from? RHETORICAL question.
Hope for the best, save for the worst.

 

[DAVe3283]

My LB7 has never had head gasket problems, but my coolant bottle is covered in some black soot or something. It was that way when I bought it, and I can't get rid of it. Coolant itself has always been nice and clear (well, reddish clear).

When I researched it (years ago) I was told that when you overheat DexCool, it turns black and leaves that residue. I believe the previous owner overheated it.

Maybe that is where the black residue came from? Though with the strip test result, I would still suspect a bad HG.

Good luck!

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[riazoo]

Well the results are in! The bus ran like a top and no overflow from the radiator tank. The pipe is still hard but the level is the same and has not changed.
IMHO maybe the head gasket is leaking - who knows till its taken apart. However the coolant loss has stopped and the bus is fine. The soot in the tank was probably due to the egr being blocked. The bubbling in the overflow tank due to a clogged radiator.
All I know is that I've saved some serious dough - for the time being!
We had a Lincoln sedan and it had a radiator bubbling over symptom and $85 at the dealership it was diagnosed with a possible head gasket issue. That was at 100k miles. Changed the radiator and still running with 475k on the odometer!
Hard to believe a head gasket on a diesel with only 120k!

 

[riazoo]

Also the radiator is a crappy plastic tank type probably made in Taiwan - not that there is anything wrong with that! But for heavy duty application it's probably all crapped out internally.
For all those head gasket issues with no visible sign of coolant - i'd recommend changing the radiator, deleting the egr, doing the water pump, changing the thermostat and clean that overflow tank! I soaked the coolant tank in diesel and liquid tide mix for a few hours and then added some crushed ice and shook the heck out of it. Looks pretty good!

 

[RKTMech]

:thumb: the good thing about diesels is you can milk a head gasket issue for quite some time, and no its not hard to believe head gasket issues at 120k. Lowest mile set i've done were at 76k on a daily driver non-tow'er LLY, Vehicle had absolutly no issues at all he just wanted to know why he had a black ring around the inside of his coolant bottle. Found both gaskets failing at rear most cylinders. Although this example is the exception the rest of my experience with failing head gaskets does range from high 80's to high 100's.

 

[riazoo]

I believe you're correct about me milking the head gasket! Situation appears to be under control. Will keep you posted

 

[riazoo]

Well it's been a couple of months and the overflow tank is puking coolant. Temp is still low and no overheating. No viable leaks but upper hose is hard. I'm going to do the head gasket change and bite the bullet. It's a kodiak so I will be pulling the engine. In addition to changing the head gasket kit and water pump what else should I change? Also it sometimes knocks on idle but the knock goes away when it warms up. It also idles up and down when cold. Thanks in advance.