Northyadams writes:
I have a 2004 GMC Yukon XL that’s developed a coolant leak that three shops can’t identify. Someone mentioned something about it on here. Does anyone have any more info—is this another GM problem?
Sajeev answers:
Much like the awful Cadillac HT4100 family of engines, I’ve heard that GM recommended the use of a stop leak for some LS-series engines. The Internet is full of reasons why, but I cannot verify. Considering the 5.3L’s infamous connection to the title of this TTAC series, no reason for your coolant leak surprises me.
If the shops used dye and never found a leak with a black light, you might be burning coolant. I’d pull the spark plugs and look for white or brown-ish deposits. I can’t think of anything else: if the heater core was leaking you’d either see it or smell it.
Back to you, Best and Brightest.
[Send your electro-mechano-technical queries to sajeev.mehta@thetruthaboutcars.com]
I believe that year of 5.3L still suffered from rampant Intake Manifold Gasket failures. But, I would have to think any half decent shop would have checked that first, would they not?
If not, check for residue where the manifold meets the engine, and check for oil in your coolant and coolant in your oil.
I need to get around to doing that gasket on my 5.7L Yukon one of these days now that the weather is warming up.
This is most likely an upper or lower intake manifold gasket leak. It is typically a hard leak to identify since so much of the manifold (especially the lower part) is obscured by the engine AND if the leak is external the coolant burns off. It could also be an internal leak related to the intake manifold gaskets which would produce the ashy deposits on the spark plugs that Sajeev mentioned. It is better to get the leak repaired, then do a full flush and fill with non-Dexcool coolant.
There is a possibility that it is the head gaskets as well, but the intake manifold gaskets are the most likely culprits.
If his is like the one in the picture, I’d blame the ugly grille, ugly wheels, knobby tires, and lift kit for the leak.
With the engine running see if you can smell antifreeze from the exhaust. If you do it’s head gaskets or worse a crack somewhere. Note also the O2 sensors are damaged by anti-freeze so it would be wise (though expensive) to replace them as well.
If his is like the one in the picture, I’d blame the ugly grille, ugly wheels, knobby tires, and lift kit for the leak.
I like the Tires and Lift, but the Grille and Rims = Pimptastic.
Cosmetic upgrades are totally out of place on an off-road vehicle.
I would get an oil analysis ASAP to see if any of the lost coolant is getting into the motor oil. This is a depressingly common problem on many GM V-6 engines, though I’m not sure about the 5.3 V-8.
Shops also have a test strip which can detect high levels of coolant contamination in the oil, but a proper oil analysis is much better and only costs around $25. I’ve used these people: http://www.blackstone-labs.com
As others have said, leaking intake manifold gasket is the most likely cause and leaking head gasket the second most. With a GM engine, don’t think that relative youth implies a well sealed motor. Ours had a leaking intake manifold gasket at only 3 year, 40k miles.
I’d check for the infamous GM intake gasket leaks before anything else, and then check all oil/trans fluid for coolant. Some GM vehicles have had trouble with the trans cooler/radiator rupturing inside, mixing coolant and trans fluid. Odds are that if this has gone on for a long time, though, you’d have noticed the tranny acting goofy.
I would chime in with the obligatory “GM quality sucks” comment that will eventually creep in here, but there’s almost no sport left in kicking that dead horse.
So I won’t mention it.
Also, agree that most like the intake manifold gasket is your likely culprit on that year 5.3L engine. These motors didn’t really have problems with head gaskets. Is your oil level increasing as your drive, due to coolant getting in there?
It is its own reward.
The problem is not in the leak you have, the problem it’s a 2004 GMC Yukon XL.
Change both intake gaskets, fill with non-dex and you will be good to go for another 16-24 months.
I would chime in with the obligatory “GM quality sucks” comment that will eventually creep in here, but there’s almost no sport left in kicking that dead horse.
So I won’t mention it.
Darn! You beat me to it. Dexcrap strikes again!
John
DEXCLOG-the silent killer of GM gaskets!
As much as I know I should not try to diagnose a vehicle over a medium, here goes….
I worked for GM for many years and generally the 5.3 is a very good unit but any motor can have a failure no matter what brand it is. If the shop cannot identify the leak it is almost definitely a cracked head. Herein is the problem. Which head is it? Well, then you replace both of them. But what if it isn’t an head? Well, it is a cracked block. Therefore, probably the best action is a 5.3 litre long block installation in prevent huge diagnostic and installation charges, which may not work.
Before you do this, take it to a GM dealer. Certain vehicles have certain “issues” and the dealer is best equipped to know what they are.
And another piece of bad news: this is a five year old GM vehicle. Confuscious say “This when GM problem start.” Do you really want to spend $5000 minimum on a motor for a five year old GM truck or do you want to buy something else? Can you be assured you are not going to buy a transmission soon, a rad, new a/c compressor, steering shaft, O2 sensors……
Yes this a common GM problem… Google LS1 and “cup plug” early LSx engines in the 4.8 5.3 5.7 6.0 sized had these “plugs” in the heads… The problem is that as the head expand and contract over use the plugs get loose and they leak.
Drain coolant, Remove plug, apply sealant and install new plug… and Bob’s your uncle…. LSx’s are NOTHING like HT4100 or Northstar who are NOTORIOUS for head gasket leaks… The LSx Family of engine have some issues (like the one I posted above), but head-gaskets are not a common problem.
Oh and the TSB for the plug issue is:#PIP3018 – (Jun 17, 2004) Good luck!
“Truth” webs site won’t let me edit my post… any way GM removed these plugs in all LSx engines made after 2007.
Dexcool isn’t the problem, its the AutoZone employees who insist you can mix and match that are.
Only use Dexcool and you’ll never have an issue.
Here’s a forum thread that may interest you.
http://www.gm-trucks.com/forums/index.php?showtopic=89050
Talks about “porosity cracks” in the heads.
Those rims hardly qualify as pimptastic. They’re what, 15″ or 16″? If they were 22″ then I’d buy pimptastic.
Dexcool isn’t the problem, its the AutoZone employees who insist you can mix and match that are.
Only use Dexcool and you’ll never have an issue.
Here’s a forum thread that may interest you.
http://www.gm-trucks.com/forums/index.php?showtopic=89050
Talks about “porosity cracks” in the heads.
That’s wrong, plain and simple. DEXCOOL is incompatible with GM’s silicone gaskets and has been directly implicated in their failure. (check http://www.dexcoolsettlement.com/ among many internet sources on this) Switch to standard-issue green coolant and there’s no problem.
The major issue with DEX-COOL is that the 5 year, 150,000 mile life is not accurate. If you flush it every 2 years, you should not have a coolant related problem. However, this raises the question that asks, why would you use the more expensive DEX-COOL, if the regular stuff lasts as long? For this, I have no answer.
The comments about leaking intake manifold gaskets are a likely possibility, but at least one of three competent shops should have been able to find a leak there. You may have a leak in the cylinder head due to casting porosity. Please refer to TSB 06-06-01-019B. Yukon models 2001 to 2006 with 4.8 and 5.3 engines are covered. This TSB describes how to check for leaks and recommends replacement of the heads if leaks are found.
Here is my experience and theories about Dexcool, and I believe Dexcool is the root of the problems in this truck.
There are three basic coolant/antifreezes on the market today.
the classic Green antifreeze
the Hybrid OAT
and Dexcool
the original, green antifreeze/coolant has been around for decades and works very well. It is actually a byproduct of gasoline production and was discovered because Standard Oil was dumping it into a river in New Jersey and they realized that the river that froze over every year quit freezing in the winter. And they realized, wow… what a great antifreeze…we can actually SELL this stuff. Anyway, its main downfall is that it has silicates which can wear out water pumps faster and should be changed fairly regularly, every two years or so. General knowledge about it is that it is alkaline in nature. Keep it in your older cars and change it often.
Back in the 1996, GM and Texaco rolled out a brand new antifreeze/coolant called Dexcool. They put it in EVERY new car they made, even models that had regular coolant in it the year before. It is acidic in nature, and is called OAT antifreeze. OAT stands for Organic Acid Technology. So they suddenly flipped all of their engines from alkaline to acidic coolant overnight without any other modifications and said Hey, dont change it for 5 years or 150,000 miles! WHAT?!? Dexcool, as an OAT coolant is similar, but not the same as coolants that BMW and Mercedes uses in their aluminum engines. Why? It is my guess, that after the HT4100 disaster and other problems GM had with aluminum engines and iron block/aluminum head combinations, they figured that they would leapfrog (GM never tries to do that) other peoples tried and true innovations. But the thing is, not all of GM’s engines has aluminum components, most are old legacy designs from the sixties. GM, with one broad stroke just changed coolants, with what I believe was very little testing (GM would never rush anything into production, right?!?)
Anyway, that leads me to the third coolant. The Hybrid OAT. Hybrid OAT coolants are used by EVERY OTHER MODERN AUTOMAKER TODAY EXCEPT GM. Mostly it is yellow in color. Chrysler, Honda, Toyota, Ford, BMW, Mercedes, etc, uses Hybrid OAT coolant. There are small secret variations. Toyota has it’s own factory coolant called “Toyota Red” BMW swears that you should use BMW coolant in their vehicles, etc. But in reality, they are all Hybrid OATS. Two interesting stories. In 1999 Ford used Dexcool in one model car they made. The 1999 Mercury Cougar. It was a complete disaster. They switched back to green the next year. Ford started using Hybrid OAT yellow coolant in 2003 models and actually has “NO DEXCOOL” illustrations on all of their radiator caps now. Chrysler tested Dexcool and supposedly said no way. They went with Hybrid OAT, under Mercedes leadership. Another interesting story is that of the Pontiac Vibe. It is the only GM vehicle that leaves the factory without Dexcool. It is filled with Toyota Red, because it is made in the NUMMI plant and is basically a tall Corolla Wagon. Unfortunately I am sure Dexcool is mixed and used when they are serviced at Pontiac Dealers. I would really not advise this practice.
How and why do I know all of this crap? Because I have owned and currently own several GM cars with cooling system problems that are the result of Dexcool. How do I know this? Only on a low mileage, well maintained GM dexcool car you open the radiator cap and see orange mud and rust that is nearly impossible to remove. This coolant does not play well with old iron block engines. It seems to cover everything in a thick coating of rusty goop. It attacks the seals of the intake manifold and they all will eventually leak. It is a major problem on all 1996 and up 3.1, 3.4, 3.8, 4.3 V6’s and 5.3, and 5.7L V8’s.
What I did on my 5.7L Suburban, after loosing a Radiator, Intake mainfold gasket #1 and subsequently engine #1, water pump #2 and intake manifold gasket #2 was change to a Hybrid OAT coolant that EVERY OTHER MAJOR AUTO MANUFACTURER IN THE WORLD uses. Since then, I have had no other cooling problems. The only clue that Dexcool was there at one time is a stained orange coolant overflow tank (just TRY to get that thing clean… not gonna happen) and Radiator #2 has a scary rusty orange coating that is not getting any worse since I have been running the Hybrid OAT coolant.
I would suggest you find and fix your coolant leak (intake mainfold gasket) and refill with the coolant that EVERY AUTOMAKER IN THE WORLD USES. (except the super successful automaker with the huge stock price, and so many customers that they need 12 different brands, General Motors)
Me and my dexcool filled GM car will be fine. I never believe internet claims and complaints anyway.
Regarding Dexcool:
I have it in my 1995 Chevy C1500 truck. I know it’s use was “officially” started with the 1996 models, but apparently there must have been a transition phase at the very end of the ’95 model year. My truck was manufactured in July 1995-likely one of the last ’95’s before ’96 production started-and it left the factory with Dexcool.
Anyway…I know it’s caused some nasty issues with some engines, but I’ve only had minor coolant leaks here and there for the most part, no more troublesome than any old car I’ve had with the green coolant. And I’ll admit the cooling system hasn’t been flushed for a long time. My engine is the 350 V8; not the newer Vortec, but the old one with throttle body injection (’95 was the last year that motor was used). I think that while Dexcool is problematic to some degree, I think there’s more to this issue than meets the eye…I’m just not sure what. Some engines seem to be okay with it, while others aren’t.
One of GM’s problem is that they never believed claims and complaints against them Internet or otherwise.
@big_gms
Since you have had relitively few problems with a very similar truck I am interested in your experince. (my 350 is a Vortec, though)
Since it has been awhile since your last coolant flush, and since it seems like you have had it awhile (since new?) I would be interested in how your coolant looks. Take the cap off of the radiator. Is the cap clean or does it have a sticky orange rust coating on the inside of it? Peer into the radiator with a flashlight. Does the coolant look like clear orange fluid, or like orange mud? If it is clear, can you see any orange crud on the inside of the radiator or is it clean?
If you decide to flush the system since it has been awhile, I would be interested in your impression of the coolants condition after you drain it out. Does it look like a 5 year/ 150,000 mile product to you? Just remember to collect the old coolant and bring it to your local hazardous waste drop off. Any coolant is a nasty pollutant that you dont want lingering in your front yard.
Why the switch from green in the first place? All of our high mileage cars have had water pumps that have lasted for what seems like a reasonable life. In a way it was ironic that some of our Japanese vehicles never got to be much of a test bead since I changed the pump with the timing belt service – something that most professional wrenches suggest as well. Anyway, since no coolant seems to be safe to use for 5 years, and they all are toxic to some degree, why not just keep the original? We were burned by the dreaded Dex and nothing I own will ever have that crap in it.
How many miles on your Yukon? Are you running Dex Cool? Is it the green stuff? Or worse, did you switch from Dex Cool to green or vice versa somewhere along the line? Or even worse, did you put any of those nasty Euro/Asian “rust inhibitor” additives?
@npbheights
Correction: I had a new radiator installed about a year ago; the old one was physically damaged, which had nothing to do with Dexcool. So some new coolant was actually put in, come to think of it. Suffice it to say, it went at least four and a half years prior to that with the same old coolant, and I have no idea when-or even if-the previous owner had it flushed. I bought the truck in 2003. At that time it had 83,000 miles, it now has 121,000. The current radiator looks clean inside, as you would expect, and the coolant looks relatively clear. The old radiator did have a little crud in it, but the coolant didn’t look at all like orange mud…just ever so slightly murky, that’s all. It really didn’t look any worse than green coolant I’ve seen in any of my old cars (I have in fact seen green antifreeze and radiators with it that have looked worse). There was a trace amount of rust colored sticky residue on the underside of the cap, but nothing I’d consider all that unusual. The coolant recovery tank has never had any rusty looking residue. I have noticed, however, that if I have a small leak, like I did from the recovery tank once, it leaves behind a sticky whitish-orange residue. Green coolant leaves a residue too, but not as sticky as this stuff.
I can’t help but wonder if some of the issues with Dexcool are caused by people mixing in other types of antifreeze because they simply don’t know any better. There are universal types of antifreeze now, which manufacturers claim will mix with any type, but I don’t know how good they are. My truck has warning labels to only add Dexcool, and I can only assume every other vehicle using it is so labeled, but some people aren’t too good at reading warning labels. I also wonder if people are adding rust inhibitors and other additives…perhaps some of these products don’t agree with Dexcool? I don’t know. Personally, I never use them. Then too, like I posted before, some engines seem mostly okay with it (mine), while others aren’t; I’ve read many, many complaints about it when used in the 4.3 liter Vortec V6, for example. There are a lot of variables to consider.