Antifreeze

[safety_match]

Just a dumb question...isn't the 1990 L98 an aluminum engine thus requiring an aluminum compatible antifreeze?

 

[Moonunit 451]

Use the Green stuff.

 

[tyrel]

Any old antifreeze will work, same as any other car, but avoid Dexcool if that's what you're getting at.

 

[Edmond]

The block is a cast iron block but the heads are aluminum.

The green stuff has worked for so many years, I don't see any reason to switch to the orange stuff.

 

[LT4man]

Green stuff should (must) be changed every two years. No matter what mileage.

Orange stuff (Dexcool) should be changed after five years if you bought vehicle when new. After the first five years, should be changed every three years.

My own experience: Bought my 96 CE new (ordered from factory).
Replaced Dexcool in 2001. Antifreeze looked new. No sludge or muck whatsover. Installed Dexcool and distilled water mixture.

Installed new radiator in Summer 2005. Old Dexcool still orange and looked like new. Flushed block and heads several times by removing knock sensors in block. Flushed till water ran clear. Installed Dexcool and distilled water mixture. Will replace again in 2008 or 2009.

When Dexcool was first released there were some problems with it. Mainly the Bars Leak that GM had always installed in every cooling system since forever would cause the Dexcool to thicken. Now GM does not install Bars Leak. No problemo.

The trick is to flush your system thoroughly every now and then. If you do, your cooling system will not give you any trouble.

Save The Wave!

 

[Aurora40]

Green stuff should (must) be changed every two years. No matter what mileage.

Orange stuff (Dexcool) should be changed after five years if you bought vehicle when new. After the first five years, should be changed every three years.

Just FYI for anyone thinking of going to DexCool, or who put green silicated coolant in a DexCool car. Once you have green stuff in the system, that's the end of the extended intervals. The silicates will always be there to some degree, and prevent the DexCool from having its long-life properties. You can't flush it out or anything like that. You can still use DexCool, you just need to follow an ordinary change schedule (i.e. 30,000 miles or 1-2 years or whatever).

I've had a hard time finding silicated green coolant. When I changed the coolant in the ZR1, I ended up going with Prestone's all-compatible stuff. It claims 5 year 150,000 mile changes, but I won't be doing that. It's sort of a light yellow, slightly greenish color.

 

[c4cruiser]

Ethelyne Glycol (green) coolant is the stuff to use in your '90. Most all of the anti-freeze makers now have a "generic" EG coolant that works for all-airn motors or iron/aluminum. Prestone coolant is now a yellow color and it will work fine.

Just do a complete flush of your cooling system to insure you get any old garbage out. Unless your old coolant looks very dark, I would not use a radiator flush or cleaner. Just run clear water through until it comes out clean.

Then refill with a 50-50 mix of new coolant and distilled water. This is also a good time to replace the upper and lower radiator hoses if they have not been done. Check the pressure cap for its ability to hold pressure and replace if necessary. Remove the overflow tank from the car and drain out the old coolant, clean it out and re-install. Once you have the new coolant in the system, refill the tank with a 50-50 mix.

 

[Ruby Fan]

Sorry folks, but I changed all of my vehicles to Dexcool: '77 Caddy(did over 6 years, but low mileage), 2 Mopar Neons, and of course my '85 and '93 Vettes. The red-orange stuff seems to be a gentler-kinder mixture on metal. I believe it came out because of the extensive use of aluminum in engine components. I have not had any problems with it and all the vehicles run fine. The only way to flush out your system is with just plain water, keep fill and then empty until it comes clean/clear. Don't use a flush, especially on older cars.