Coolant Loss !!!!

[joe k]

I have a 2003 H2 that has a coolant loss problem. Started to use a small amount of coolant at around 24k miles. Problem has escalated to a loss of about 1/2 gallon every 1500 miles. Have taken the H2 to the dealership several times to address this as a warranty concern, no external leaks have been found. The techs at the dealership have inspected system for gases in the coolant system (dye test / black light), along with pressure testing, ect. It also looks like the rest of the component fluids are clean (engine oil, transmission, ect). Have had 2 dealerships and 2 outside shops look at this problem and no one has a definitive response other than " the coolant is going somewhere." Also had a engine light come on at around 36k miles, turned out to have most of the ceramic insulation missing off of the #2 spark plug (rep at the dealership stated that I needed a fuel treatment before I demanded a plug inspection), have a question in the back of my mind if the 2 problems may be related.
Anyone out there have any thoughts on this? Willing to listen to any thing at this point.

[joe k]

I have a 2003 H2 that has a coolant loss problem. Started to use a small amount of coolant at around 24k miles. Problem has escalated to a loss of about 1/2 gallon every 1500 miles. Have taken the H2 to the dealership several times to address this as a warranty concern, no external leaks have been found. The techs at the dealership have inspected system for gases in the coolant system (dye test / black light), along with pressure testing, ect. It also looks like the rest of the component fluids are clean (engine oil, transmission, ect). Have had 2 dealerships and 2 outside shops look at this problem and no one has a definitive response other than " the coolant is going somewhere." Also had a engine light come on at around 36k miles, turned out to have most of the ceramic insulation missing off of the #2 spark plug (rep at the dealership stated that I needed a fuel treatment before I demanded a plug inspection), have a question in the back of my mind if the 2 problems may be related.
Anyone out there have any thoughts on this? Willing to listen to any thing at this point.

[Klaus]

Well, they are right - The coolant has to be going somewhere!

It's either leaking on the ground or in the cab (heater core), leaking internally into the engine oil or the combustion chamber, or leaking into the transmission fluid. The only other possibility I can think of is that the throttle body has a coolant line running to it to keep it from freezing. If the throttle body got cracked somehow I suppose it could be leaking coolant into the intake charge.

Given you've already had a problem with the spark plug, I'd say that was your first clue. I'd pull the new spark plug out and take a look. Compare it to another plug pulled on the other side of the engine. If the plug looks bad again I'd say you either have a blown head gasket (if you're lucky) or a cracked head or block.

[KenP]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Posted by Klaus:
Given you've already had a problem with the spark plug, I'd say that was your first clue. I'd pull the new spark plug out and take a look. Compare it to another plug pulled on the other side of the engine. If the plug looks bad again I'd say you either have a blown head gasket (if you're lucky) or a cracked head or block. </div></BLOCKQUOTE>Can you say, "Bingo"? After reading the post that's exactly what I was thinking. Not good and not normal. You should be able to tell with an oil change. Another thing you can do is put the dye in the coolant, run it and blacklight the oil.

Don't let them screw around with you on this.

[joe k]

Thanks for the feedback, we checked the new plug on #2 and it looks good (compared to the originals, new plug has been in for around 6000 miles) As far as it going onto the ground, I think that would have been found with the dye and black light test. Still looking.

[PARAGON]

I'm guessing two things that could be done to check is to do the coolant bypass on the throttle body and see if there is a loss if they are unwilling to inspect the throttle body.

Also, I would guess you could do an extended compression test on each cylinder to see if there is a slight bleed of pressure back into the coolant passages.

[LasVegas]

Everyone here is dead on. If it's not showing up inside the cab (heater core) or outside (on the ground) and not appearing in the oil or transmission or other fluids it's just about having to be "consummed" by the engine. If it were me, I'd let it idle for about an hour in the driveway to check for external leaks. If none, it's dealer time.

[Hummertech]

Look real good at your trans fluid. We have seen several coolers in the radiator split. Usually you get more trans fluid in the radiator though, but check it out. Also, it's common for water pumps to leak slowly from it's gaskets. Take your front skid plates off and look very closely with a bright flashlight. It usually runs down the edge of the front cover and may be a little hard to see. This should be the first place your dealership looks, but they may be a bunch of morons. Did they pull the skid plate when they were looking for the leak? Bring it back to them. It's under warranty. It's their job to find the problem. Not yours. Good luck and let us know what the morons find.

[joe k]

Thanks for all of the suggestions. After some conference calls between the dealership and the GM folks, the outlook is not very positive at this point. Tried to address the options in a point by point manner. Regarding the throttle body as an area of loss, the dealership tech stated that “ any loss in this area would have been detected by the coolant / dye test ie they would have seen it. The only suggestions that were made is to first follow the #2 cylinder spark plug as an area of concern, this was replaced due to damage around 6000 miles ago. The thinking is if we switch the #2 plug(new and clean) with one of the other OEM plugs on the engine (slightly worn and dirty) and run it until the reservoir empties itself again and if the coolant is somehow going into the #2 cylinder, the old dirty plug will be washed clean by the coolant. “*#%!@” looks like another couple of weeks and another couple of bills. Anyone have thoughts if this would offer any possibility of a proper indication?
They also stated that the extended cylinder compression test along with a bore scope inspection is the next step for this problem after we look at the switched spark plugs.
Getting hosed hard down here.

[KenP]

Who's switching the plug? If the dealer is thell them to do a compression test then. They have to remove the plug anyway and it only takes a few minutes to do. It sounds like a bunch of tools at your dealership.

[joe k]

sorry, did not clarify. I live in CC and we do not have a "hummer" dealership down here, closest one is in San Antonio. Have been using a GM dealership in town to save me the drive (350 mi rt) , to preform the actions that the hummer dealership is suggesting. Good point, will ask them if they can preform the test as well.

[Klaus]

You might want to start researching the lemon law in your state. Depending on the state, they have so many attempts to fix the problem before the vehicle is considered a lemon.

How many times has it already been in the shop for coolant loss? Are you keeping good records?

[Hummertech]

Why don't you give a call to Ken Batchlor up in San Antonio. They are a very good Hummer dealership and can probably fix you up.

[joe k]

Responding to Klaus, have all of the records.
It has been to Ken Batchor 2 or 3 times, they had the opportunity to look at the truck twice in as many weeks,,, still no idea. No kidding folks, I spend at least 1 hour of my day on the phone between Hummer/ GM cust service and dealership types. I actually inquired to the cost of a replacement engine so I would not have to jack with the time / expense/ uncertainty of a very half assed approach to resolving this problem.(UFB)

[Hummertech]

Then I agree with the previous post. Start looking into the lemmon laws. Talk with your original selling dealer. If you bought it used, you're sol.

[joe k]

After a few more conversations I have an update. Looks like the lemon law does not do much for the situation, the truck now has 44,000 miles on it and it is now out of warranty (problem was initially investigated within the warranty period at Ken Bachor but they were not able to find anything at that time). The best scenario that has been offered is to “lock down” the truck at any point that the coolant system can be manipulated and observe until it runs dry again. After this point I have been told by the dealership that this will give them 0 authority to investigate the scenario further. Have already spent about a grand investigating this problem and for that we have concluded, “ It has to be going somewhere”. Have received substantially better information than that from the participating members of this forum. The good news (it is all relevant) is that I can continue to drive the truck on a daily basis and if a major component craters they (dealership and GM) may have something to talk about. Bad part here is that I really enjoy the truck (awesome platform) but my experience with this problem has just about disenfranchised me from the repeat purchase of a GM product. Many thanks for all of the information and suggestions. Someone asked how many times it had been in and I believe that Ken Batchor has looked at it twice, another shop in San Antonio once, and 3 trips to a local dealership in town. I am not going to sell the truck, cannot pass this problem on to anyone else in good conscience. Another great point here is that I believe this truck gets better mileage than any other H2 on the road (1000 MPG).

That’s Dexcool folks, not fuel!

[Hummie2]

Joe...

There was a post here that I don't see anymore( I guess it was deleted) and it made more sense about what is happening than anything else. It was about a cracked or porous intake port runner in the head to a water jacket. Coolant would find its way to the inlet valve then into the cylinder and out the exhaust. Compression would would not get back into the coolant because the inlet valve is closed then, so combustion gases won't be present in the coolant. Here is what you do to check:

1- get the engine hot (fully up to temp) then stop it.

2- pull #2 sparkplug, pull the valvecover for #2 cyl and turn the motor till intake and exhaust valves are in overlap (both valves partially open)then pressurise the cooling system to about 15lbs

3- wait and watch (you should see coolant in cyl with a borescope- wait long enough it will fill up and run out the plug hole!)

coolant is finding its way into #2, but compression is not going back into the cooling system. That is why the insulator broke on the origional plug (from water in the cyl) and why the new plug stays clean. The same could hold true for an exhaust runner also, but I would suspect an intlet leak because of the plug problem.

Don

[joe k]

Don, Thanks for the procedure, I am going to get with a third party mechanic ( I do not have the bore scope) to see how soon we can pull this off. Seems like a damn good direction to head with this as another point of verification / elimination!
I am also going to try to get a decent picture of the plug for this string. Have been told that if I can direct the GM tech to the exact source of problem (pictures, ect) I may have a leg to stand on.
Once again, thanks for the help.

[PARAGON]

Don, serious question here. Why would that cause the insulator to break?

[joe k]

Here is a pic of the #2 plug.