2001 Pontiac Montana, 2550 miles, Supertech 10W30

[Colt45ws]

Horrid.

After the repair, I ran it maybe 50 miles at most on some ST. I changed the oil and filter and ran that load 1000 miles. After that was this, with ARX. I am a little hot under the collar right now. Im going to be more so if it truly is still leaking coolant in to the oil. I am having to add coolant, but I have an external leak I cannot get to seal, so I have not paid attention to it.

Does anyone think 7.62x54R will penetrate a 3400?

 

[Drew99GT]

Originally Posted By: Onmo'Eegusee

Does anyone think 7.62x54R will penetrate a 3400?

I've wondered the same thing about our 3.8L and 4.3L GM engines.

Sorry to see this report. Was it done at a garage, or did you do it yourself?

I wouldn't give up just yet. Do another sample in about 500 miles.

I know. I know. Been dealing with these stupid [censored] GMs and their leaky intake gaskets for the last 10 years. What a PITA.

Good luck.

 

[Colt45ws]

DIY. I used new bolts, the Felpro kit, torqued in multiple stages, etc, etc. I do not see where I could have f it up at. Certainly possible, but I was sure it was correct.

 

[Drew99GT]

When you pulled the lower intake, did a lot of excess coolant dribble down through the lifter valley into the oil pan?

 

[Colt45ws]

Probably. Thats why I did multiple changes before this one. Getting just a sample at 500 would be a PITA. I might just pull the plug at 1500 and see whats up, as opposed to just changing the filter.

 

[FZ1]

You'll need an AP round for that.

 

[Colt45ws]

Well, they are steel core, though not technically AP.

 

[Colt45ws]

Is it possible to tell different coolants apart possibly? It had DexCool OE, of course. When I did the LIM, however I switched to G05.

 

[OVERKILL]

.50 BMG.

 

[Colt45ws]

Originally Posted By: OVERK1LL
.50 BMG.

FTW. Sadly, I do not know if that is an option.

 

[Coogles]

I hate the GM 60*V6 with a passion. All of the 3x00 motors fail at some point, some as early as 20,000miles.

I'd resample again in 500-1,000 miles. Also...make a line on the coolant resevoir at its current level while the car is cold, and check it every week or so. If you see the level dropping you know you have a leak somewhere. That doesn't mean it isn't external, but your UOA suggests it probably isn't, at least not exclusively.

 

[JohnBrowning]

It will crack the block but no gurantee it will penetrate depends on where it hits. My 44 magnum can crack a Chevy small block!

If you want to make sure best get a 600-900 grain 50BMG round and then you will know it will penatrate 100%!LOL

I always like to run a quart of MMO after a coolant leak and Ihave found it works great to get rid of the left over stuff fromt he leak as long as the leak was not going on for a long long time. Seafoam also works good to get rid of coolant and water traces in the block. The Auto_rx is more of the answere to getting rid of sludge that was the result of a long term coolant leak it as far as I am aware is not going to grab hold of the coolant or the water that is in the system it is just going to work ont he sludge. If the leak is still on going then even ARX will not work to clean it!

What type of external coolant leak do you have that you can not stop? I have never heard of or seen an external leak that was not easy to get under control? They make test strips that can detect combustion by products in the coolant since you have an external leak still you can not go by the consumption because it might all be going outside of the engine. If the repair internaly was done properly then their should not be any combustion byproducts in the coolant.


As far as the GM 60°V6's are concerned they always have been junk! Even with the updates to them they remain a cheap design that is just dreadful when compared to all of the other modern V6's used by most automotive companies. Compare GM's 60°V6's to Nissian VQ engine or the Buick 3.8 or Toyota's current V6's or Audi's etc.........No matter how you slice it they are outdated low grade crudely built junk! It is a price point engine in every way. I used to have a bunch of failed pistons on my desk as paper weights and candy dish's when I worked at GM. I can honestly say that the piston in a Brig's and stratton lawnmower is not only better design but is built to higher levels of quality control and with better materials that is the sad part. If someone sent me pistons like the Mahl built pistons that GM use's in the 60°V6 for a rebuild on any engine I would reject them right away. Those engines have had piston issues, rod bearing issues, intake gasket issues, oil drive unit,lifter issues you name it! I have never seen an engine with more problems stay on in production for so long with so few upgrades. GM went so far as to claim that rod knock was not considered a durability issue based on their 3 year 36,000 mile validation testing!!! Here in Michigan the knocking of a 60°V6 is so common that no one even pays it any attention!LOL

 

[Colt45ws]

Its at the upper connection to the radiator. I changed most of the hoses when I did the repair. Well, this one does not want to seal. Whenever I noticed it was low, I would start it up and let it idle until it got really hot, maybe around 220 and look for the leak. I'd see it coming out of that connection so I tightened it down then a week or two later it is back at it. I have pulled the hose a couple times now thinking the bullshiska plastic had cracked and it ends up being fine. Where are these test strips for combustion byproducts in the coolant?

 

[Camu Mahubah]

I see GM cars for sale all the time with the V6's that have the Dexcool problem and think to myself what a great 2nd car they would be if they didn't have these issues.

Mah! Saddens me the most is I know used car dealers are selling these things to people with little money and even less knowledge of the defect!

Think of all the little ol' ladies buying these cars!

 

[Rabbler]

My guess is you did the intake job correctly but also have a cracked head gasket.
It's happened to me...Twice!

 

[Colt45ws]

I checked the compression in this not long after I did the repair. It was around 175psi across the board. Is it possible it has a direct coolant to oil leak in the HG?

 

[oilmaven]

I bought a 2008 Impala with the 3.5L V6 Flex-Fuel. From what I understand, this engine has some improvements over the 3.1, 3.4 and 3.8L engines...particularly the coolant routing and associated gasket issues that GM claims should avoid any problems. At 34,000 miles, the engine is quiet (no piston knock...know what you mean here...very common in the 3.1L particularly) with good power and highway mileage from 30-34 mpg. I know I took a chance on this car but I couldn't deal with any more 7-8 hour stints in the Yaris (although dead reliable and 40mpg). I admit I caved and bought the extended warranty out of concerns regarding anything GM. So far I love the car...comfortable and economical. I'm changing the PP 5W30 at 5,000 mile intervals.

 

[Colt45ws]

I didnt know they were still making this engine design. I thought it ended with the 3400. Shows how much I know.

 

[caprice_2nv]

Not to say they are the best engine out there, but we just sold my girlfriends 98 Grand Am, with the original 3100 and 4T60E trans, with 246k on it still running good with lots of power and average amount of piston slap noise. It had the intake gaskets done around 190k for the first time. Not only that, the local cab companies love the Buick Centuries and Chevy Lumina's with the 3100/4T60E in them. Maybe it's cause they know how to fix the intake issues, but my point is I don't think they are as junky as people think they are. Lot of them are lasting a lot of miles. Also 190k on my mom's 99 Alero with the 3400 and its still running well too.

 

[Bill in Utah]

Let's get back to your *possible* leak....

If you had coolant in the engine it WILL take more than a couple of oil changes to get it out no matter what oil or additive you put in.

When I had my 2 head gaskets go (on a FORD so its not just a GM problem) I did TWO 500 mile ocis, a 1000 mile one then 3000 miles. At the end of the 3000 miles I did a UOA and it was good to go.

The 2nd time I did a UOA on the 1000 mile run and still had a trace of coolant show up.

Coolant is bad and hard to get rid of in a engine. FREQUENT oil changes is the ONLY way to get rid of it completely IMB.

Bill