Dirty Coolant

[jimlevin]

Hello, new here but hopefully you can help.

Got a 6.5 turbo (center mount-H1 Hummer).

Primarily, began loosing coolant, low coolant light. Added water and notice coolant is nasty brownish greenish foamy gritty water. So flush, 6 times, new coolant. Now getting some erradic weird temp fluctuations, sometimes almost like themostats are sticking. Once warm and temp is up, is fine. Temp stays pretty stable at 190ish.

Not smoking, no white steam, No start up clouds of smoke, no puddles on the ground, runs great. Oil is beautiful jet black. No foamy milkshake. CDR valve clean, only oil. Uses just a bit of oil between changes.

Coolant now looks kinda ok but still has small brown lumps in it. Still loosing coolant. Constant pressure on coolant overflow tank, even immediately starting from cold. Constant bubbles and foam from upper bleeder screw and radiator bleeder.

Took it to a shop and they said, hey we're not comfortable repairing it and just replaing the head gasket but we will sell you a new engine--I said no thanks, engine has 60,000 on it, new in 2007.

New shop says, gotta pull the heads and look, if you got head warping, good sign, we replace. Also said, no head warping or no head cracking, bad, maybe worse problem. Confirmed some pressue loss in a couple cylinders. They want to check the radiator and head gaskets.

Any thoughts? Am i missing something?

 

[great white]

Hello, new here but hopefully you can help.

Got a 6.5 turbo (center mount-H1 Hummer).

Primarily, began loosing coolant, low coolant light. Added water and notice coolant is nasty brownish greenish foamy gritty water. So flush, 6 times, new coolant. Now getting some erradic weird temp fluctuations, sometimes almost like themostats are sticking. Once warm and temp is up, is fine. Temp stays pretty stable at 190ish.

Not smoking, no white steam, No start up clouds of smoke, no puddles on the ground, runs great. Oil is beautiful jet black. No foamy milkshake. CDR valve clean, only oil. Uses just a bit of oil between changes.

Coolant now looks kinda ok but still has small brown lumps in it. Still loosing coolant. Constant pressure on coolant overflow tank, even immediately starting from cold. Constant bubbles and foam from upper bleeder screw and radiator bleeder.

Took it to a shop and they said, hey we're not comfortable repairing it and just replaing the head gasket but we will sell you a new engine--I said no thanks, engine has 60,000 on it, new in 2007.

New shop says, gotta pull the heads and look, if you got head warping, good sign, we replace. Also said, no head warping or no head cracking, bad, maybe worse problem. Confirmed some pressue loss in a couple cylinders. They want to check the radiator and head gaskets.

Any thoughts? Am i missing something?

does sound like a head gasket issue. Could be a cracked valve land into the coolant passage. A good shop should be able to get close with coolant pressure tester or cylinder leak down test.

2007 replacement engine should be a GEP/Navistar casting so head crack is less likely but still possible. I would bet on head gasket failure as a likely cause.

Still going to require you to have the head pulled off to confirm though.

Cheers.

 

[WarWagon]

Remove the water pump belt. Remove the coolant crossover that has the thermostats in it. Fire it up. The side that is bubbling gets the extra attention for a bad gasket or crack.

Recommend ARP head studs with the block side sealed in blue locktight.

Where you located? - some members can help you locally in person or with known good shops.

 

[FatFut]

Hey WW, will the new locktight blue tape work? or should it be the liquid?

 

[WarWagon]

Hey WW, will the new locktight blue tape work? or should it be the liquid?

Only used liquid. Red/blue and it works. Hate to mess with success. The one with the red will likely take the studs with to the scrapyard when the block gives up...

 

[Will L.]

Jim, welcome to the truck stop! I pull my engine myself its a chore but not to the worst. You have to pull engine to get heads off, at least on mine. Follow war wagons recommendation. You are better off fixing it while fix-able.

 

[jimlevin]

Thanks guys, that is good info.

I wish I hade time to do this myself but the mechanic I have now seems to be well versed. In fact, we already discussed the ARP blots and Felpro mls gaskets. He also said to go ahead and make some other "while you're in there repairs/replacements" just to be safe (water pump, some hoses, wants to reseal the radiator, etc.). In good ole AL.

I am curious, I see a lot of people having their heads machined but, for the cost, trouble, future problem potential, and just the labor, I can't understand why new heads are not used.

I am deathly afraid that this was the dreaded block crack but since the engine was replaced in 07 I just figured 'no way' but after talking to numerous other 6.5 owners, maybe 8 of 10 people say "ooo, probably a cracked block, you need an engine". Which has caused me to question myself. I am hoping most people just don't know and also are giving me the worst news it could be and I know that some are just eager to spend my money on a $14k engine!

At any rate, thanks already guys.

 

[great white]

Thanks guys, that is good info.

I wish I hade time to do this myself but the mechanic I have now seems to be well versed. In fact, we already discussed the ARP blots and Felpro mls gaskets. He also said to go ahead and make some other "while you're in there repairs/replacements" just to be safe (water pump, some hoses, wants to reseal the radiator, etc.). In good ole AL.

I am curious, I see a lot of people having their heads machined but, for the cost, trouble, future problem potential, and just the labor, I can't understand why new heads are not used.

I am deathly afraid that this was the dreaded block crack but since the engine was replaced in 07 I just figured 'no way' but after talking to numerous other 6.5 owners, maybe 8 of 10 people say "ooo, probably a cracked block, you need an engine". Which has caused me to question myself. I am hoping most people just don't know and also are giving me the worst news it could be and I know that some are just eager to spend my money on a $14k engine!

At any rate, thanks already guys.

If it was replaced in 07 it is probably an Optimizer. All service replacements after about 2000 were GEP optimizers as GM sold the rights to GEP and stopped making them "in house". If it is the #8 cylinder crack, it would only be the second one I've ever seen on an Optimizer, very unlikely.

Those you are talking too are probably familiar with the GM 506 casting problems, but not with the GEP improved 506 castings. All optimizers have 506 in the valley. The key is to look for the Navistar "endless roads" casting mark. Looks like two triangles back to back on the long run.

Again, HIGHLY unlikely it is the cylinder crack if it's a GEP/Navistar...

 

[jimlevin]

If it was replaced in 07 it is probably an Optimizer. All service replacements after about 2000 were GEP optimizers as GM sold the rights to GEP and stopped making them "in house". If it is the #8 cylinder crack, it would only be the second one I've ever seen on an Optimizer, very unlikely.

Those you are talking too are probably familiar with the GM 506 casting problems, but not with the GEP improved 506 castings. All optimizers have 506 in the valley. The key is to look for the Navistar "endless roads" casting mark. Looks like two triangles back to back on the long run.

Again, HIGHLY unlikely it is the cylinder crack if it's a GEP/Navistar...

YES! I can see the valley and "506" with dots that make up the numbers. Three horizontal lines with dots that make up the lines on each side. Almost like it was printed with on old dot matrix printer, only a dot matrix printer that prints on steel. Not quite sure what the "long run" quite means...can you elborate a little?

The engine was installed by a GM dealer and the bill for engine item alone was $7,500

 

[jimlevin]

Looks like I found where the engine came from. Its an AM General motor.

https://www.real4wd.com/zedSuite/catalog/partdetail.aspx?PartNo=5744918

Part No.: 5744918

I spoke with them, they said all their stock comes from AM General directly.

 

[great white]

Looks like I found where the engine came from. Its an AM General motor.

https://www.real4wd.com/zedSuite/catalog/partdetail.aspx?PartNo=5744918

Part No.: 5744918

I spoke with them, they said all their stock comes from AM General directly.

Likely a head gasket if that's the case.

The block and heads were redesigned and the materials changed when GEP took over production, making cracking events nearly unheard of.

Notice I said "nearly".

All engine castings have a possibility of cracking. Ford, GM, Chrysler, Navistar, caterpillar, etc.....

My money is on a head gasket though.

If they do get it apart and need to surface the head, make sure they remove the precombustion chamber when they do it. A good machine shop should know this.

My optimizer 6500 has around 50,000kms on it right now and some hard towing miles in there. Not a hiccup or hitch. Sounds like you just got a bad hand dealt, but it's a relatively easy fix if it's just a gasket.

Cheers

 

[jimlevin]

Likely a head gasket if that's the case.

The block and heads were redesigned and the materials changed when GEP took over production, making cracking events nearly unheard of.

Notice I said "nearly".

All engine castings have a possibility of cracking. Ford, GM, Chrysler, Navistar, caterpillar, etc.....

My money is on a head gasket though.

If they do get it apart and need to surface the head, make sure they remove the precombustion chamber when they do it. A good machine shop should know this.

My optimizer 6500 has around 50,000kms on it right now and some hard towing miles in there. Not a hiccup or hitch. Sounds like you just got a bad hand dealt, but it's a relatively easy fix if it's just a gasket.

Cheers

Well, if you were a betting man, your money would be on part of the right chips.

So far: two blown head gaskets and both heads are cracked. Cracked right between the valves.

Block, so far, seems ok. It does have those triangles touching each other and the casting number looks like 04 26 and then an "M" or an "H"?

 

[jimlevin]

Obviously, we are replacing the heads but gonna need some suggestions on the "while you're there" parts.

Dynamic balancer? Water pump?

Injectors?

Gonna us ARP bolts and Felpro mls gaskets.

 

[greenmeanh1]

Hey!! welcome!! Glad to see you signed up over here. I was going to ask about your head gasket question regarding the pin hole restrictions in the water flow. Someone here will have an answer for that.

 

[jimlevin]

Hey green, yes, I've tried to keep the title and posts as similar as I can so we can cross reference, this was a terrific suggestion, thanks again.

This may well show my ignorance here but am I the only one who is seeing that they may have used the wrong gasket in the last install?

Look at the head and deck and then look a the gasket. Look specifically at the rusty orange area, those are blocked by the gasket, there was no water flow through there, is that right?!?

Why would there be a water passage and it be blocked by the gasket? Again, I am no mechanic but there is rust on both sides of the gasket and there appears to be a water port from the block to the head that is not allowing water to flow.

Anybody else notice this in the pics?

 

[great white]

That passage is normally blocked off by the head gaskets. The pinhole is there to allow air to escape the block and by cycled out of the cooling system. I believe Jim over on thedieselpage had an article on it IIRC....

 

[WarWagon]

How hot are you running the engine? This looks like the engine was run without coolant to the overheat point. just saying it has overheating written all over it. Running a tune?

I would make sure the radiator, condenser, and oil coolers are cleaned. Absolutely do the water pump and check the fan clutch for proper operation. Also may want to check the exhaust specifically for a kitty that may be plugged. I don't know if Hummers have a kitty.

It is possible they reused your old heads and did just a short block. This would explain the cracks without overheating. Post a pic or two of the head casting numbers.

The coolant sitting in the cylinders is disturbing. That needs to be removed ASAP.

 

[jimlevin]

Normal run temp is 195 but I was loosing coolant and getting strange temp swings which is why we found this. Never overheated under my driving but can't speak to previous owner. I started this journey by finding the nasty coolant.

 

[great white]

The heads are potentially salvageable: http://www.aera.org/ep/EPQ3-2011/pdf/87726877.pdf check out page 40.

It also offers a potential explanation as to why your heads might have cracked in that particular location (which is oh so common on these engines, although usually less so on optimizers)

You'll also want to closely inspect the "mouths" of the precombustion chambers for cracking. They take quite a beating in even normal use. It's hard to tell from pictures, but yours appear "crack free". There is a service limit for cracks, although I prefer to just replace if they are cracked at all....I don't see the point of returning cracked chambers back to service if I've already got it torn down that far. Kind of like replacing a clutch and not doing the throw out bearing...

 

[great white]

View attachment 39596View attachment 39597Normal run temp is 195 but I was loosing coolant and getting strange temp swings which is why we found this. Never overheated under my driving but can't speak to previous owner. I started this journey by finding the nasty coolant.

Those are also the Optimizer heads. You can see the Navistar "endless roads" symbol in the casting:

Have a look at your glow plug tips also. Burning (IE: melting) or swelling is good reason to swap them out now. Much easier than when the engine is assembled.