My mother n law has a 98 malibu with the 3.1 v6 it had been losing coolant for about 3months?So after adding fluid and idiot light coming on I starting looking for leaks and low and behold leak located at the intake manifold gasket!!!! This is a issue with this specific eng and dexcool is the PROBLEM.This car has 41k and this is NOT uncommon problem.Another story stepdad 01 gmc sonoma had radiator replaced last wk due to dexcool, problem radiator cannot be repaired new radiator, and flushed system cost 280.00.Dexcool is a issue with engines with aluminum and engines like cadillac that use iron do not have this problem.I thought I would share this info since this ? comes up alot here and if anything I said is incorrect please correct it ,I am not perfect by any means.If I had anything with dexcool I would flush it out, and go green regardless but ,my rides are way old and do not hv that issue and may this help those with the what if's and do I change dilema.

that doesn't prove the problem is dexcool, the upper intake gasket on the 3x00's is a design flaw, and the fact a rad can't be repaired also doesn't point to the coolant, there can be alot of reasons for that. With that said, im not saying that dex-cool is definately not the problem either, its just your statement provides absolutely no proof that dex-cool is the issue. My car is now 8 years old, 205,000 km's (120k miles) and still has the orginal rad, water pump and any gaskets to do with the coolant

YA i haven't have any problems with Dexcool either. The cars you mentioned all had known problems with dexcool because of a design flaw.

I havn't heard any issues with using dexcool in the Jbody setup.

Malibu's - yes
GMC/Chev s10 - yes
3.1-3.4 engines - yes



Ryan1

my fathers friend who is a mechanic for Pickering Saturn says there is not enough rust inhibitors in Dex cool. im not sure if hes right or not, my 05 cavalier is the only car ive used dex cool in. my other cars it was changed to green coolant.

i have 90,000KM on mine now and no problems.


http://registry.gmenthusiast.com/images/my2005cav/my%20car%20the%20bash.jpg

Repairing radiators is almost a thing of the past. When brass and copper were commonly used, removing the tanks and having the core boiled and rodded was a viable option. Now, with radiators being plastic & aluminum, replacement is typically the only option when issues arise. And $280 for a radiator and a flush, if that includes installation, is MORE than reasonable.

As for the Malibu, I'm sure Dexcool was a contributing factor, but even though the car had only 41,000 miles, it is going on 10 years old. With that age, a problem like a LIM gasket failure is not out of the realm of possiblity, low miles and dexcool aside.

That being said, I still think Dexcool is a joke, and if you plan on keeping it in your system (like I do with my g/f's Grand Prix), it had better be flushed every 2 years, regardless of mileage.




1989 Z24 Convertible - Dust Covered
2006 tC - Dust Covered, but driven more

My Sunbird used to just use regular Prestone antifreeze...rebuilt the engine, changed to Dexcool....thing leaked like crazy. Leaked from the radiator and leaked from the thermostat housing like freaking mad. Every day Id go out and there would be a small orange puddle on the motor mount directly underneath the housing...

the intake manifold failing early on the gm 3100 and 3400 from the mid and late 90s to early 2000s are quite common and this has nothing to do with dexcool but rather a design oversight by gm. this is not to say that all of them will fair but it is a well known problem. gm issued revised manifolds that basically fixes the problem. in the newer 3500 and 3900 engines, which are a derivative of the 3100 and 3400 designs, gm uses a different design that won't leak. if you mix dexcool with other coolants you will run into trouble. use dexcool only if it says so on your engine compartment/owners manual to use dexcool. otherwise use the regular silicated anti-freeze.

My mom has a 98 Lumina with the 3100 and it had to have the intake manifold gaskets changed at 78k miles. She also had the low coolant light come on and the sensor was replaced due to buildup. I know she never flushes the radiator and it was probably on original coolant till the intake manifold repair unless the shop didn't change the coolant then. Who knows?

I've never heard dex-cool to be a problem. GM would be in major trouble if they put it in cars and it knowingly caused problems. There is a reason they switched to it from ethylene glycol based antifreeze and it obviously because they deemed it appropriate.

Even the 4.3L truck motors pop intake gaskets. My co-worker has 2 4.3L trucks, one S10 and one Jimmy. Both had gasket leaks. He put on felpro's and made the end gaskets out of silicone and it was fine.

I wouldn't run dex-cool 100k miles like it's suggested but I over maintain my vehicles anyways. Coolant change every summer. No way for electrolysis to start and corrode the internal aluminum parts that way.


Scott
2002 Audi S4, black
1996 Z24 auto, red

Yerp had to change mine in my 99 grand am 3400. Most likely coolant will slowly start leaking a little not too long after its done and will have to be done again down the road, unless you use the updated metal gaskets.

Just as an FYI, there is a class action lawsuit pending against GM in reference to dex.

Although dex is not the problem with the upper manifold failure, it is not innocent. Anyone with a GM V6 built in the late 90's early 00's would probably cry if they saw their lower intake manifold gaskets. The dexcool eats them. GM has redesigned the gaskets to be more dex friendly, but those are only in newer cars.



"The Blue Bullet"

Felpro made newer gaskets which are metal and are 3 times thicker around the ports. They are around $120 I believe but are worth it.