antifreeze eating intake gaskets

Diamondpilot · Mar 25, 2010

carpenter383 said:
Yup 3.1's and 3.4's in ALL '96 to 2002ish? gm vehicles. Fel pro sells a metal replacment gasket set for like 85 bucks, it comes with valve cover, intake, egr valve gasket, and even a new oil pump drive o-ring (where the distributor used to be). It's the only way to go for a permanent fix.
Lifter noise is the other issue, spray some carb cleaner in the lifters (while you have the intake off) and replace the oil with rottella t and it should be quiet as a kitten.
I just did a 3.1 intake gasket change in a '98 cutlass, took about 4 hrs. so 800 bucks is kinda steep for this job ( maybe not in a minivan though) I charged $375 for the whole nine yards You're right about the 3.8's being good engines, so are the 3.1's and 3.4's overall.

Yea, Mini Vans are not easy to work on, especially GM's. My aunt had a early 90's era all wheel drive Astro Van. It was a major ordeal to change the passengers side spark plugs on that 4.3L. If I remember right you had to remove the fender and it was a common maintenance item. The motor set off center to the passengers side to make room for the master cylinder, steering box and shaft, ect. Not sure if it was worse or not being all wheel drive but I am sure it did not help.

I had a 89 4X4 S-10 Blazer at the time with a 4.3 and it was much easier to work on. I tried to change the plugs for her and had no problem with the drivers side but could not get the passengers. My dad though I was a idiot so he came over and just scratched his head. She was a single lady so the next day my dad called around and found out it was something like a 4 hour job just to do a plug change.

Chris

ModMech · Mar 25, 2010

Dirty little secret.....

DexCool was developed BECAUSE of intake leaks with geeen antifreeze that would occur under warranty.

How are those related? Simple really, EVERY new vehicle leaves the factory with some amount of "Stop leak" product added to the cooling system. This is why you almost never have "cold water leaks" on a new vehicle, but will after some time and especially after cooling system "service".

Well, you can only get so much stop leak in with green coolant before it starts causing problems with chemistry and clogs. You can get MORE stop-leak product into the system "safely" with ELCs (extended life coolants) like DexCool. This is *just enough* to get the vehicles past warranty and make it the customer's problem. Nice!

PH is a big factor, proper cooling system maintenance is critical to reducing your risk of problems like these but aside from improving the quiality of the Aluminum casting (intake) there really isn't a "fix".

Also, NEVER EVER add "DCA" or "SCA" products to ANY engine with DexCool or the commercial equivelants, it will ruin the cooling system. They are designed to be used with GREEN type coolants (in some rare cases also with yellow coolant).

Diamondpilot · Mar 25, 2010

Quick question ModMech.

My Fords of late have all had a gold color coolant. I am familiar with DexCool but this stuff looks different. What is it?

Also I noticed on my Nissan Titan they use a blue coolant. I checked the manual to make sure they did not service it with WWF but its blue. Never seen that one before. Any idea with what it is?

Chris

workinallthetime · Mar 25, 2010

over the years as a gm tech i have hung hundreds of intake gaskets on everything from a 2.8 to a 454. people have blamed dexcool for years for leaking intake gaskets and a load of other problems. th2 2.8 had a bad design on the intake gasket that would allow coolant into the oil but on an 86 s-10 dexcool was not even around yet. we grew into the the 3.1 and that into the 3100/3400. they changed from a paper gasket to a hard plastic one, the same material that is used on the v8's. i have seen what people are talking about around the coolant ports, they look like they are disolving. Gm came out with a new design intake gasket a few years back that is supose to be a final fix. Most people just drop the instructions in the trash with the bag the gaskets came in, if you dont follow these directions you will be hanging another set in 30-40k miles. torque spec, and lock tite on the bolts is key to the life of these "plastic" gaskets.
dexcool is great stuff as long as you dont contaminate it, additives, mixing it, and even dirty water can lead to major problems.
anyone remember how often you were required to change the green stuff? 2 years/24k miles from what i remember. dexcool 50k-100k depending on your climate and driving conditions.

workinallthetime · Mar 25, 2010

ModMech said:
Dirty little secret.....

DexCool was developed BECAUSE of intake leaks with geeen antifreeze that would occur under warranty.

How are those related? Simple really, EVERY new vehicle leaves the factory with some amount of "Stop leak" product added to the cooling system. This is why you almost never have "cold water leaks" on a new vehicle, but will after some time and especially after cooling system "service".

Well, you can only get so much stop leak in with green coolant before it starts causing problems with chemistry and clogs. You can get MORE stop-leak product into the system "safely" with ELCs (extended life coolants) like DexCool. This is *just enough* to get the vehicles past warranty and make it the customer's problem. Nice!

PH is a big factor, proper cooling system maintenance is critical to reducing your risk of problems like these but aside from improving the quiality of the Aluminum casting (intake) there really isn't a "fix".

Also, NEVER EVER add "DCA" or "SCA" products to ANY engine with DexCool or the commercial equivelants, it will ruin the cooling system. They are designed to be used with GREEN type coolants (in some rare cases also with yellow coolant).

interesting, considering the amount of cars and trucks i see a day that have over 100k w/ nothing done but oil changes.
with your knowledge of coolant and how gm does business how long would you say dexcool is going to last before things start to leak?

kenmac · Mar 25, 2010

Diamondpilot said:
Quick question ModMech.

My Fords of late have all had a gold color coolant. I am familiar with DexCool but this stuff looks different. What is it?

Also I noticed on my Nissan Titan they use a blue coolant. I checked the manual to make sure they did not service it with WWF but its blue. Never seen that one before. Any idea with what it is?

Chris

Sounds like what I use in my dodge. Zerex G 05 HOAT.

Gem99ultra · Mar 25, 2010

I also had the infamous intake gasket failure, along with just about every item on the menu of "known problems" associated with my '97 5.7L Chevy truck. And yes, I did flush my coolant after 50K miles... but still had the failure.

I love my Chevy truck, but it's certainly been a love/hate affair. I can not, however, say that it was any better or worse than my previous Ford trucks. They all seem to have their own set of problems.

Jim

workinallthetime · Mar 25, 2010

white - (Dec 22, 2003)

Subject:4.3L L35, LU3 5.0L L30, 5.7L L31 Engine Coolant Leak at Intake Gasket

Models:.

When servicing the vehicle with the VIN you entered, the following diagnosis might be helpful if the vehicle exhibits the described symptoms.
<A href="#ss1-1417880">Condition/Concern:

Some customers may comment of a coolant leak that can be diagnosed to the intake gasket area. This may occur at 50,000 miles or higher.
<A href="#ss2-1417880">Recommendation/Instructions:

If you have completed the diagnostics and have determined the coolant leak originating from the intake gasket area, replace the intake gaskets. A new gasket material has been developed and is in production beginning with the 2004 Model Year. Service parts are currently available. The new V6 gasket kit part # is 89017460 and the new V8 gasket kit part # is 89017465.
Note: This is an external coolant leak only, it has not been a significant cause for internal engine damage.
.
Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance. This diagnostic approach was developed for the vehicle with the VIN you entered and should not be automatically be used for other vehicles with similar symptoms.
<A href="#ss3-1417880">Models:

(96-03 Chevrolet Astro M/L, Express (GMT-600) G/P , S10 Pick-up Jimmy, Envoy, M/L Vans) and (96-03 GMC Safari, M/L. Savana, (GMT-600) G/P, Sonoma (GMT-325) , Blazer, Bravada (GMT-300) S/T, Sierra, Silverado (GMT-800) C/K. M/L Vans) and (96-03 Oldsmobile, Bravada S/T)

carpenter383 · Mar 25, 2010

I believe dexcool is environmentally friendly, which is a plus.
And workinallthetime is right about the torque spec thing, you should follow the gasket makers' specs. the only problem is they (and gm) have revised the touque specs a few times, each time increasing torque. 3100's and 3400's are something like 10 or 12ft lbs on the inner, and 18 on the outer bolts now.
The newer engines with plastic intakes also have a problem with corrosion around the egr port which can leak coolant too.