Jim, that'* interesting that you say that. I'm about ready to flush my system and am still debating in my mind what to do about my aluminum 3.5....to dex or not to dex??? I am running this car into the ground so it needs to last.

Do the Northstar engines come with aluminum gaskets from the factory? The only leak I've had on my 3.5 is the valve cover gasket, the original Dex from July 2001 (when the car was built) is still in there. It'* getting grimey and needs to get changed.

Chris

I'm going to agree with everyone else and say no to the Dex cool. Just flush it out with a compatible coolant.

If you take a look in my thread in Performance & Brainstorming you'll see the LIM gaskets from my L32 with 35k on it. The Dex we eating those gaskets up, not quite as bad as the pictures above though.

Ed

Funny, i have been running the original dex cool in mine. Never had to add any coolant other than when I changed the thermostat and it isn't that grimy yet. Figure when I get out of happy land (iraq) I'll do a change on it. Not sure what to go with though. Haven't decided. Probably prestone LL.

cliff

I couldn't agree with you more, Ed. Every gasket I've ever pulled out of a non-dex engine has looked great at 100k. But a VERY high percentage of dex-soaked gaskets look absolutely rotten. The gaskets are made the same, which leaves DEX as the culprit.

I will NOT blame this on the gaskets themselves. They were designed for green, and perform flawlessly. But as DEX ages, it becomes acidic, and breaks down the plastic. Changing the gaskets to aluminum is a bandaid. Not a bad one, but the original problem isn't fixed.

Actually after a quick conversation the other day with Lash..it may not be the same gasket material. The composition on most items used for the Dex switch over changed to something that was designed to work with it. The gasket material composition may be different than that of the prior.

I have both types of gaskets at home. Every inspection method I have has shown them to be identical material.

And why does the 95 L36 use the same gaskets, but it never had the DEX? Wouldn't we assume a different part number?

There'* alot of unanswered questions.

Why do the Pre-Dex gaskets always look MUCH better? Questions, questions, questions.

I disagree. My 95 SE had Dex in it and it was a fleet vehicle, I highly doubt it had been changed to Dex from green stuff.
What is the problem, the Dex or the gasket material? In my opinion it'* both of them.
It'* not right that the coolant is eating away at the gasket, but in reverse what kind of crap material are the gaskets made of that get eroded?
This is one of those topics that will never have any sort of clear cut answer and will always be a source of contention.

Wasn't Dex first tested in fleet vehicles before the entire line got it? That might explain why this '95 had it.

There'* no logic in Dex eating through a rubber seal and eroding the plastic inside the air/fuel intake ports in most cases.

In talking further with my mechanic buddy, who spent 10 or so years at a Pontiac/Caddy dealer. He says the problem is not the dex. It is heat related, and this explains why some of us running SC'* and having a hotter air charge would have the collapse. Look at the design for what it is.. there are structural deficencies built into the cooling ports. Dead center of every flat area they put a dimpled spot. Call it X marks the spot for cracking.

You have a solid plastic frame with a rubber section and then plastic inside of that. No supporting structrue for the inside piece of plastic. Poor design.

Most other motors don't have gasket failure because they contain dex. The 3.4 and 3.1 is a poor excuse for a design.

95 L36'* also suffer the same issues....Dex or not..the gaskets are failing. What we are failing to take into account is that when we are replacing the Dex with green... we are usually changing the T stat and lowering operating temperature at the same time. We change two variables and then don't account for one?