2001 +/- GM V6 4.3 Coolant Leaks

[ARCHINSTL]

Does anyone else here have or had an S10 or any other of the many GM models of the late '90s-early '00s vehicles with this engine?
I bought a honey of an '01 2WD reg cab with only 50K miles almost two years ago, and now have 53K on the clock.
But - it has now developed a coolant leak at the rear of the engine.
Apparently the 4.3 Vortec V6 of that era is notorious for leaking at the intake manifolds due to cheesey gaskets used by GM; I was, naturally, unaware of this.
This is a lot more involved than working on a Terc and way beyond me (at my dotage, anyway).
Has anyone else had similar probs with that V6?
I've received "ballpark estimates" from several shops of from $500 to $900 on this. At this point the oil does not appear to have coolant in it.
Gotta save up for it, so am not looking to have it fixed until possibly July.
Thanks,
Tom M.

[keith]

The water pumps on all truck V-6 and V-8 engines of this era are prone to leaking. The GM 3.8 engine has a history of leaking intake manifolds because half of the manifold is plastic. I've heard that its the gaskets themselves and I've heard that the plastic half is known to crack. Have not heard of this with the 4.3 though.

BTW, never got another T4WD. Instead I got a 2007 Silverado extended cab 4WD Z71 with a 5.3 engine. Talk about one extreme to the other.

[Petros]

if the leak is not a hose or something easy to replace, I would try dumping Barr's Leak (or something similar) in and see if it works. might save you if only use this truck occasionally. More than a few older cars I have used the stop-leak for years, and sold it that way after years of service.

It does not always work, but consider the amount of effort it saves, I always give it a try.

[splatterdog]

<t>That's what I call the "Vortec maintenance package". It applies to 96+ V6 and 96-99 V8's. There are updated gaskets with metal vs. plastic carriers that are worth the extra $. Just about any V6 or 8 for a lot of years had intake issues. All those prices are in the ballpark, best to use who you can trust the most. The 900 seems a bit high if it doesn't include some "while your at it's". That list should be minimal at that low mileage though. The job should entail a full teardown of upper and lower intake and maybe a pre-emptive fuel pressure regulator(inside upper intake). Cleanliness is crucial during engine work. I have seen a truck still under new warranty get the quickie. If it wasn't for the fresh rtv sticking out from under the front edge of the filthy intake, you would never tell it just got gaskets. Valve covers do not need to be disturbed on the V6 and their gaskets are not very prone to failure. But they are easier during an intake reseal..<br/>
<br/>
They mostly leak externally, especially in the beginning. I did see one completely blow internally, but it looked like it had been dribbling inside for a quite a while. The summer heat and highway speed driven steam shot the oil dipstick out and sprayed crappuccino all over the place! The engine ended up stalling from plugs wetted down by crappuccino blowing in from both sides of the PCV system. Went straight to an engine quote on that one.. Underside of your oil cap will tell if it's getting wet.</t>

Don't stop leak such a low mileage truck! Emergency/total turd use only please.

If that truck still has the factory belt tensioner, check for lateral play. They ALL got it eventually. No need to remove the belt, just push/pull from the front of the truck and see if it's loose. Easy to replace too.

[ARCHINSTL]

Thanks for all of the advice, guys.
What you've said mirrors what I found on the "S10 Forum," but I trust the T4WD Guys more!
Will adv when repairs effected.
Tom

[Petros]

Don't stop leak such a low mileage truck! Emergency/total turd use only please.

lots of good info there Splat, but you should know that all manufacturers deliver all new cars and trucks with stop leak in their cooling systems. It saves them money of having to track down every little leak before they can deliver them. Do not fear the stop leak, there are no passages small enough to cause it to plug it up, it stays in suspension in a properly working cooling system, and only plugs up tiny seeps or porosity in the metal castings.

[splatterdog]

They may have done that at one time, but I seriously doubt it happens anymore. I see little to no debris or residue in even aged cooling systems anymore, which can not happen with sealer in the system. Other than some of the low torque gaskets related with this post, sealing has greatly improved. The biggest change was just the lowly hose clamp. The spring loaded clamps work so much better and are easy to deal with when you have the proper tools. It's pretty unusual to run in to casting porosity.


As far as I know, Subaru is the only one suggesting stop leak(they call it conditioner) for obvious reasons. But I have seen pics of system clogging. https://allwheeldriveauto.com/why-you-s ... ur-subaru/


For me it will always be a last resort.

[keith]

splatterdog, your link has a major issue. It doesn't say whether it used the Subaru conditioner or some aftermarket stop leak. It also does not say when it was added or how much.

The Subaru conditioner is a liquid that remains liquid until it exceed some high temperature, 1800F if I recall correctly. It will not stop a leaking radiator or hose, it only hardens in the presence of exhaust gasses. When it hardens, it turns to glass. They only use a small amount and it is NOT for a blown head gasket.

This same stuff is sold as head gasket repair. It will work if you catch the head gasket early before you start having overheating issues. Once the gasket is completely blown, if you add this material then, this is the normal result. If your breach crosses an oil passage and this stuff gets in there, your rings and bearings will be ground to nothing in no time.

[Petros]

I would put that post in the category of fake news. there is no way if they followed the manufacturer's recommendations there should be that much sealant in the water jacket, radiator, hoses, etc. They must have been frustrated with their constantly leaking subaru and just kept adding sealant until the leak stopped.

I once owned an ancient diesel tractor that had a massive radiator, the whole cooling system leaked like a sieve from every joint. I used it on our 5 acres only about 20 to 30 hours a year, I just used water in it, kept topping it up while using it, and drained it every winter (factory manual recommendation for tractors made in 1954). I considered pulling all apart and have the rad rebuilt, replace all gaskets, etc. but you have to pull off the front loader to remove the radiator, and pull apart all of the engine cowling, etc. A big job. So I put in two bottles of "heavy duty" Barrs leak. Never had a leak after that, used it for years and than sold it. I spent more time fixing it than actually using it. 60 year old hydraulic lines were always blowing, even had one original tire, that also gave up when in deep mud of course. Cheaper and easier to hire a neigbor with a tractor to do the heavy earth moving, and now I have no maintenance issues.

[splatterdog]

Keith, that was just the easiest link. I have seen other cases on iatn(technician site) from Subaru specialists and full line shops. I can only view Subaru conditioner as a cheap fix for bad design. What about all of them with external leaks? Heat activated miracle in a bottle wont help there. I've never considered putting it in an old toyota, or needed to. Since the 80's I've used stop leak maybe 5 times.

Petros, anything remotely "ancient" had much larger passageways and now, obsolete parts making alternative repairs more feasable. Efficiency is up, capacities are down, little room for contaminates. Tom is also a fan of good heat. There is no quicker way to clog a heater core.

[ARCHINSTL]

Tom is also a fan of good heat.

HAW, Mike!
You remembered my radiator and heater musings over the years! Your comment brought a big smile to me!
Tom

[Petros]

I can only view Subaru conditioner as a cheap fix for bad design.

bad design yes, but that is the factory recommended fix. It has always struck me as odd that honda had all aluminum blocks with reliable head gaskets going back decades, now all of the manufacturers have all aluminum engines, and have no head gasket issues. I wonder why Subaru can not figure it out.

I agree that is it a short term fix, but do not be so sure that none of the manufacturers are doing it. Stop leak formulations have also been improved over the years. It should not plug up a heater core, passages are still much larger than the size of leak they are designed for sealing up. Of course, anyone can abuse their cooling system by putting too much stuff in it.

What ever caused the leak in the first place is still in your cooling system, plugging a tiny hole is like putting your finger in a dam. It does not fix a bigger problem, only delays the inevitable. Often does not even give you a temporary fix either, so it has its limitations.

All auto machanics bad mouth radiator stop leak, partly self interest, and partly desiring to provide a permanent fix. But it has its place, and its limitations.