The supplement that GM has in my owner manuals for my 96 Monte Carlo and my 96 Corvette does not have metal in it. I believe it comes from a organic source.

 

Having a coolant leak prevents the system from holding pressure, that can also impact cooling. The other item to look at for cold temp problems is a failing thermostat. If it fails and is either left open or opens too early, then the car can never achieve operating temp.

But again, if you have a known coolant leak, I'd pursue resolving that before dumping coolant into the car repeatedly just to loose it on the road.

As for the gm tablets you mentioned, the organic/metallic, I would not use them. Even if nothing negative happens, it's a temporary band aid over the real problem.

 

OK thanks for all information. So I refilled my radiator today and I think I found the leak. It's leaking from the driver's side of the radiator.

So I ordered all Acdelco replacements. Got a radiator, thermostat, thermostat seal, upper and lower hoses, and a radiator cap.

Now to flush it, I just fill the system with water ,then let it run, then drain, then repeat correct?

Also for bleeding will this technique work for my engine?
How to Burp your car's cooling system

It actually looks like a GM 3.8 V6 series 1 in the photos. So I'm guessing it's a similar procedure. Thanks again guys.

Oh yeah any recommended coolant? I heard Gm dexcool turns into a gummy acid after a few years.

 

I have used DEX-COOL for over 18 years in my 1996 with coolant change every 5 years using distilled mixing water and not tap water. I never drained a gummy acid coolant. On my coolant changes over the past 18 years, the drained coolant was so clean looking I have not flushed the system, only added new coolant using distilled water. I also have always used/added the GM supplement with the coolant change according to my owners manual.

 

@1996Red

I don't know man. I don't wanna take any chances lol. I'm sure you heard about all the lawsuits and read all the forums about the coolant eating threw gaskets.

"
DEX-COOL specifically has caused controversy. Litigation has linked it with intake manifold gasket failures in General Motors' (GM's) 3.1L and 3.4L engines, and with other failures in 3.8L and 4.3L engines. One of the anti-corrosion components presented as Sodium or Potassium 2-ethylhexanoate and Ethylhexanoic acid is incompatible with Nylon 6,6 and Silicone rubber, and is a known Plasticizer. Class action lawsuits were registered in several states, and in Canada,[20] to address some of these claims. The first of these to reach a decision was in Missouri where a settlement was announced early in December 2007.[21] Late in March 2008, GM agreed to compensate complainants in the remaining 49 states.[22] GM (Motors Liquidation Company) filed for bankruptcy in 2009, which tied up the outstanding claims until a court determines who gets paid.[23]
According to the DEX-COOL manufacturer, "mixing a 'green' [non-OAT] coolant with DEX-COOL reduces the batch's change interval to 2 years or 30,000 miles, but will otherwise cause no damage to the engine."[24] DEX-COOL antifreeze uses two inhibitors: sebacate and 2-EHA (2-ethylhexanoic acid), the latter which works well with the hard water found in the US, but is a plasticizer which can cause gaskets to leak.[16]
According to internal GM documents,[citation needed] the ultimate culprit appears to be operating vehicles for long periods of time with low coolant levels. The low coolant is caused by pressure caps that fail in the open position. (The new caps and recovery bottles were introduced at the same time as DEX-COOL). This exposes hot engine components to air and vapors, causing corrosion and contamination of the coolant with iron oxide particles, which in turn can aggravate the pressure cap problem as contamination holds the caps open permanently"

Think I'ma try something else lol. Maybe Prestone

 

Here's what I can say about Dex and gaskets.
- Early Dex was found to be corrosive. After the class action lawsuit, it was re-formulated. Not sure when that took place, but I know any 2000+ car has re-formulated Dex.
- GM still uses Dex today. Not saying GM is perfect (none of the car manufacturers are). But honestly, after the spanking they got from that lawsuit, would you want to continue using a fluid if you did not believe it was good? It's 2014, Dex was introduced in the early to mid 90's. Days of "death cool" are LONG gone.
- The problem with the 3100/3400/3800 LIM gaskets is not Dex. The problem is nylon! Those gaskets were made with a material that just breaks down from hot fluid and pressure, period. I have changed those nylon gaskets on cars that NEVER ran Dex (always good ol' green). They failed in the same spots. They last normally 80-120K miles, then, they are done for. My old '94 Grand Am, 3100, great example. Per the owners manual, from the factory, used green coolant. I bought it with 86K on it, sold it at 215K. During my ownership, never had Dex. Yet, the LIM gaskets failed twice. Also, the factory heater core inlet/outlet tubes on that car were also nylon/plastic. I'm amazed, at exactly 200K miles, those tubes burst (aftermarket core had metal tubes).

- Any anti-freeze and honestly any fluid in the car, needs changed or flushed periodically. It's regular maintenance.

You are welcome to run Dex or old green in your car. My point is don't look at pre-2000 information and feel it is still valid. There is no reason today to run away from Dex cool, it's not the cause of LIM gasket failures these days, it's nylon, that's the failure. If your LIM gaskets need replaced, get the metal core Fel-Pro gaskets (they don't cost much more and completely worth it).

 

Apparently the cars covered are between years 1995-2004. And the case was settled in 2008.
GM Gets Close To Resolving Dex-Cool Settlement | GM Authority

I highly doubt that this Monte was maintained correctly so I'm sure its gonna have the gasket problems soon enough. I don't think I'm brave enough to attempt to fix it myself. Lol

I'll update you guys when I get the parts and install them.

One more question, the transmission problems I'm having do you think they're related to the undercooling?
The transmission stays in each gear longer and doesn't go into overdrive until the temp gauge passes 140. I'm sure it's to late to change the fluid and filter with 131,000miles.
I don't know if it was done before. Doubt it.

 

Hey Guys, I got all my parts for my cooling system. But how do I remove the transmission cooling lines? My new radiator has the bolts in the radiator so i have remove the disconnect lines

When I remove them is a bunch of tranny fluid gonna leak out?

 

To remove the transmission lines, you have to slide back the plastic covers from the fitting. You will see ears of a spring clip sticking out from the fitting. Use a dental pick to remove the clip and the line will pull right out and only drip minimal fluid. Maybe a few drops. Those fittings have an O-ring in them that seal the line when it's installed. The old, used O-ring will not reseal. You must replace the line fittings on the radiator with new ones to insure a proper seal. I just replaced my radiator for the second time in 197k miles and I speak from experience. My new radiator came with two new fittings for the trans lines. Check your new radiator box for fittings before you buy some. And if the spring clip flies away when you remove it, don't worry about it, the new fitting comes with clips.

And now to address your other problems;
I have the '03 LS Monte with the 3400 engine. At around 100k miles, my radiator tank was cracked and leaking. The water pump's impellar blades were completely corroded away and literally not there. At the same time and mileage, the intake gaskets started leaking. I ran the car with the gaskets leaking until 134k miles and finally changed them.

As for your car not reading normal temps, it may be due to low coolant levels. I had an '87 chevy truck with a 350 that exhibited the same symptoms as your car and it was because the coolant was low and apparently there was an air pocket at the sensor, causing it to give a false reading.

With that many miles on your car, I suggest you change the water pump and the thermostat as maintenance and insurance. They're both cheap and easy to do.

good luck and let us know your outcome.

 

Thanks for the advice with transmission lines. I got an Acdelco replacement for the radiator that had the bolts built into the radiator.I'll replace the quick release fitting on the transmission line too. Might as well.

The water pump was replaced by a mechanic at around 100,000 miles. So that's good

Ughh, I'm dreading the day that these gaskets go. If they haven't already. Might have to take it to the shop for that one. I have the Haynes manual but it's pretty confusing for a layman.