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TSB Mysterious Coolant Leak

JohnBChef said:
    I used dino oil for 65,000 miles and switched to Synthetic at the 70k mark... so needless to say Dinosaur oil sucks... I got the pictures to prove it.
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John,

I don't recommend any folks who have used conventional oil for that long and that many miles to ever switch over to synthetic. It has been proven to cause the crud that builds up from using conventional to well...get loose and do not so nice things  :E: I've used synthetic in all 3 of my AV's, but that's because I only broke them in on conventional and switched over after I knew the valve seals were seated...blaa..blaa... I've seen engines side by side that used conventional for over 100K and one that used synthetic for over 100K, they were like night and day in terms of the difference. That convinced me of the value of the cheap insurance with synthetic.

Just glad to hear you repairs are not costing you anything other than your time and trouble  (y)
 
I have an 02 Z71 Avalanche and I had the same slow coolant leak problem.   The saga started about a year ago when I noticed that the coolant level would require about a gallon of DEX Cool every month or two. I took it in and they replaced the water pump which they said was bad. That was covered under the extended service warranty at around 70,000 miles. A few months and 5000 miles later the coolant level was low again. They didn't find any leaks but they didn't do a PRESSURE CHECK!! They said it must be an exterior leak somewhere since the engine ran fine and no computer messages.

After about 6 more months of this (going thru a gallon of Dex Cool every two months or so) I went back to the dealership and said there has to be something wrong. THEN they did a pressure check and they said "yep, you have a slow internal leadk" Must be the gasket. That'll be $1300 to replace due to labor mostly. I then went to a couple of mechanics I knew well and they printed off the TSB from GM about the leak on the 5. 3 Vortec. If you have an engine with Castech heads then there is a good chance there is a leak in the head.

So I went back to the dealership armed with the TSB and papers showing I was the original buyer of the truck. Well the dealership just announced they were being sold. BUT the service manager did go to GM and presented my case. In the end we settled for 30% my cost and 70% to them since by now my truck was 5 years old and had 90,000 miles. My issue was that when they did the initial repair they should have checked the pressure to diagnose the coolant leak WHEN IT WAS STILL UNDER THE EXTENDED WARRANTY! :E:

It took some bitching but GM will replace the heads AND the lifter set. It'll cost me about $500 or so but that's better than $2500 or more.

I think that GM is "quietly" settling this issue with original owners who have castech heads which when they removed the cover the heads were in fact made by castech.

Still cost me some $$ but at 90,000 miles $500 is better than $2500.

Get this. . . when the service clerk first told me of the issue he told me to "seriously think about trading the truck as the engine is ok for now and the problem isn't noticeable. . . " So in essence they wanted to buy the truck and PUT IT BACK INTO CIRCULATION KNOWING IT HAD A PROBLEM!! (n)

 
WOW what a coincidence.  I am looking at 100K so I decided to have the coolant flushed and some other work done a few weeks ago.  Ever sine then I am losing coolant on a regualr basis and as of last Friday one of my lifters is ticking. 
My research thus far has all pointed to intake gaskets leaking so I am planning a tear down this weekend to replace the lifters and intake gaskets.  Now it looks like I will be looking for some markings.  Man I hope I dont have these markings. 
Thank You very much for the thourough post. 
Mike
 
Well Well Well -

This whole thread explains what has been happening with my 2003 Z66 since 30K miles.

I lose 1 gal of coolant every 8000 miles like clockwork.  No leak, O2 sensor fine, no smoke, no odor.

My dealer would never give me the time of day on this.  My local dealer sucks, and I hate GM.  Another story altogether there.  I used to be one of their suppliers.


Of course it was obvious the coolant was being consumed, but I didn't relate it necessarily to lifter noise (see other thread in this section).

I will look for the Castech logo and take pics.

98K miles.  Love the truck, hate the company.
 
Just a thought, you can pick up heads from an LS1 or something else mildly used for pretty cheap. I'd go with LS2 heads, some guys sell them low mileage with springs on them already since they go bigger. Just a suggestion to save you some cash, and give you a little something more.  :cool:
 
More INFO and a QUESTION:


Question on identifying Castech logo.

The graphic from the GM TSB on this listed at gm-trucks.com (thread below)

http://www.gm-trucks.com/forums/index.php?showtopic=57746&st=25



castech%20logo.jpg



Is DIFFERENT? :eek: than the logo in the picture that JohnBChef took.

normal_CL1small.jpg



We need to get some clarification on this.


The more I try to decide what to do, the more I like the idea of putting on LS2 heads and changing out to a mild cam.  Will I have to reprogram the PCM if I change the cam?



 
Well I based my decision off of the first posted picture so as of this past weekend I now have a set of LS1 heads installed.  I picked them up at a local spped shop for $350.00.  The sad part is that the headset (gaskets), headbolts, and lifters cost more than the heads.  Go figure.


 
Mike or Geo -

Can you tell me whose heads they are and  where to go to get them.  That's about what I can afford to spend right now.

Thanks
 
I would tell you to start with Craigslist, I always find good stuff locally on there.

Second choice I would tell you to call SMC Performance, 248-276-0483. I've bought a pretty lot of stuff from him, specializes in everything LSx platform.
 
I got lucky.  It just so happened that the shop I called had just removed the heads from a vette that as being upgraded.  He even wanted to give me an LS6 cam but I was not willing to take the project that far.

If you would like I would more than happy to call him and see if he has any others.

And of course Summit is always an option too.

Mike

 
SgtSchultz said:
More INFO and a QUESTION:


Question on identifying Castech logo.

The graphic from the GM TSB on this listed at gm-trucks.com (thread below)

http://www.gm-trucks.com/forums/index.php?showtopic=57746&st=25



castech%20logo.jpg



Is DIFFERENT? :eek: than the logo in the picture that JohnBChef took.

normal_CL1small.jpg



We need to get some clarification on this.
Click to expand...

? ? ?Sgt. I know it was a month late. But one day someone will come to this post and I wanted to update it. Take a look at this picture...
index.php

? ? ?This is the Castech logo that was on my heads. I posted the wrong picture. This Battery shaped logo is the Castech logo. I admit that I posted the wrong picture in the thread. I did go back and correct it. You sent me a PM and asked me for all of the part numbers. Well today I found the invoice, and I am posting the information. It is my hope that this will help someone in the future.

JB

The work code is "J0517"Head Cylinder Both Banks Replace
? ? ?I did not pay for it but this is what GM was billed Since it didn't cost me a dime I can't tell you how much it cost off the invoice All I have is the part names, Numbers, and quantity....

? 5 each? 12558840? ? ? Bolt
? 1 each? 15077362? ? ? Seal
? 1 each? 15035747? ? ? Seal
? 1 each? 12346290? ? ? Gallon Dex-cool Coolant
? 2 each? 12578925? ? ? Head
? 5 each? 12558840? ? ? Bolt
? 1 each? 89017252? ? ? Gasket kit
? 1 each? 12482062? ? ? Seal kit
? 1 each? 12482063? ? ? Seal kit
16 each? 11588291? ? ? Bolt
? 4 each? 12560745? ? ? Bolt
 
thanks for the info. i have an 03 avi z71 i  replaced the pump and watched over the next couple of days and i still have to fill it with coolant i drive at least 100 miles a day and i see a drop of 1" in my reservoir i stop driving my truck, i guess next its time to check my heads. thank you  :(
 
Though GM would never say it, that slow steady loss of coolant mixing with your oil actually helps keep the engine internals clean and is good for keeping small oil passages open that feed the bearings.  As long as you change your oil frequently the coolant loss is really no big deal.  Just make sure you are not overfull in the oil pan.  Lucky for me my oil burn rate is about equal to my coolant leak rate into the oil pan.
 
Yes I know the thread is almost a year old but I am still glad I found it. This coolant leak is the exact reason I joined this club I just bought a used 04 av about a month ago and have added a mix of coolant and water in it just to keep coolant in the tank. Used dealer gave me a 5000 mile 3 month warranty on it and I had him look at the loss of coolant and he said that they did two pressure test on it and found nothing. Man I am glad I found this thread gonna save me a lot of $$$$.
 
Has anyone managed to get any results out of GM on this? What are they required to do, if anything?  My 04 started losing fluid about 5 months ago, I had the coolant system pressure tested, it tested ok.  It uses about a gallon every couple months. (no leaks anywhere)  This truck has been serviced exclusively by the Dealer since i bought it with 31000 miles on it. (95000 now) It's been driving me crazy trying to figure it out.  I plan on taking it for an oil change on Saturday.  I am going to print this bulletin and take it with me. 
 
First off, this thread was very helpful. Thanks much. Now to the good stuff. I bought my 04 AV less than 2 months ago. I have noticed the white puff of smoke on cold starts and every week I have to put an inch or two of coolant in the reservoir.  I took it to a local mechanic, he put it on the pressure pump for 2hrs and said everything was okay. I believe he said it was staying around 15psi. I told him about the thread about the Castech heads and asked him to take the valve covers off and see if he could see anything. So, he took both valve covers off and he said there was coolant in both. He took the heads off next, it ends up both heads have cracks. GM is not offering anything and neither is Castech. A $1,700 bill and I haven't had the Avalanche for 2 months yet! I went by the dealership and they are offering to get the heads and give me around $200 cash, basically cutting my cost in half. I have also had to replace the battery and the hydro-brake booster. The dealership also forked out $500 for the brake booster, with me just paying $160 labor. My luck hasn't been to great with the AV yet, maybe that will change.
 
Is this thing with the heads leaking coolant on certain model years or on certain engine combinations?  Would a 2005 6.0L from a Pontiac GTO have cause to be concerned?  Or is it only on the 5.3L?  Does a 6.0L have the same heads as the 5.3L?

Hang in there, the Avalanche is an awesome vehicle.  Too bad about the trouble and having to pay for much of it, but it is a used vehicle and I suppose you couldn't expect the dealer to warrant anything on a used vehicle.  I would be happy that they covered a portion of the cost honestly.

 
Not sure about your heads. I am happy they are paying for half. BUT, Right before I bought it, I asked my salesman if he would have it washed and have them put a little coolant in it because it was about 2 inches from the cold fill line. Meaning more likely than not, the heads were already cracked.


ms38w said:
Is this thing with the heads leaking coolant on certain model years or on certain engine combinations?  Would a 2005 6.0L from a Pontiac GTO have cause to be concerned?  Or is it only on the 5.3L?  Does a 6.0L have the same heads as the 5.3L?

Hang in there, the Avalanche is an awesome vehicle.  Too bad about the trouble and having to pay for much of it, but it is a used vehicle and I suppose you couldn't expect the dealer to warrant anything on a used vehicle.  I would be happy that they covered a portion of the cost honestly.
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Well, let me chime in also with my 2002 Z71. I bought the truck used in a private sale, not from a dealer. I bought it with approx. 78k and up in the 80k's I noticed the coolant tank being low and added coolant. This continued and got worse. I took it to my local dealer in Maryland and had them pressure test, tested fine, then dealer mentioned the TSB. He said that it would require the removal of the valve covers to inspect for the Castech emblem and any cracks. This all came back positive with the suggestion of replacing the heads for approx. $3000. I have an extended warranty that I bought just for this type of situation. The extended warranty company(Warranty America, Carchex, Smart Auto Warranty, all the same company) stated that since there was a TSB about the know manufacturing defect, that they wouldn't cover any cost :-( GM stated that since the truck has 93k at time of service, that would fall more into normal wear/tear and not be covered by them. I'm currently working with the Attorney Generals office consumer complaints dept. to see if I can recover through either. The extended warranty company just wrote them back confirming that they don't cover manufacturing defects, so now I need to see if GM will bend any. I ended up going with a GM rebuilt engine at the time just to get all new parts, but am looking to recoup the cost's of the heads replacement that was suggested in the TSB. If anyone has had luck getting coverage out of GM on out of warranty on this, please chime in.  Thanks
 
Well it appears as I am the next person to fall with the heads problem.  The avy is in getting a pressure test right now, I stopped in to talk with the mechanic over lunch and I saw him pulling up the TSB for the head problem.

So knowing the road that I am about to go down does anyone have any suggestions for a set of performance heads with a cam swap, reprogram and exhaust setup that is not going to break the bank but provide nice results?
 
Looks like i may be a recent victim of the mysterious coolant leak.  I have a 2004 Av with 96K miles and all the symptoms described here.  Shop appointment on Monday morning to determine if I have the Castech head. 
Can anyone tell me if they had any luck with GM post warranty?  At 96K should I just invest(?) in a new/reman engine?  Would all that leakage damage my engine & bearings to the point that replacement of the entire engine is the best alternative?  I had planned to keep the vehicle until 200K!   
Any/all advice and opinions would be appreciated.

Update: 12-29-10:  Turrns out I was one of the few fortunate individuals; I did not have a Castech head, and the coolant leak turned out to be from the water pump.  Still a costly (shop) repair, but certainly could have been worse.  BTW I have been using M1 synthetic since about 4000 miles, and the under the valve cover was virtually spotless.  Thinking of upgrading to a better synthetic like Amsoil, Lucus, or BG.  . . .  any opinions????
 
Skyview said:
John,

I don't recommend any folks who have used conventional oil for that long and that many miles to ever switch over to synthetic. It has been proven to cause the crud that builds up from using conventional to well...get loose and do not so nice things  :E: I've used synthetic in all 3 of my AV's, but that's because I only broke them in on conventional and switched over after I knew the valve seals were seated...blaa..blaa... I've seen engines side by side that used conventional for over 100K and one that used synthetic for over 100K, they were like night and day in terms of the difference. That convinced me of the value of the cheap insurance with synthetic.

Just glad to hear you repairs are not costing you anything other than your time and trouble  (y)
Click to expand...

I did the switch to Mobile 1 syn at 66k. These pics were taken today with 73k now on the rig. It looks nearly brand new. I read where it is rcommended to put 60k with regular oil before switiching or you do not break it in properly. I pulled the cover to see if I had Castech heads and if any leaking was going on. Looks OK to me but I wasn't pulling the rocker arm just to look for the symbol.
 

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