Sludge in Radiator

Yesteday I had th ecoolant changed in my 98 Chevy Lumina. The mechanic called me over while and showed me a large amount of sludge that had bulit up in my radiator. They said I would need a new raidiator soon. I came home and checked online and found out for the first time about all the problems GM cars have been having with Dex Cool. There seems to be no consensus on exactly what to do from the point I am at now. The head gasket isn’t leaking and the car is running cool and fine. My question is: What should I do now? Thanks.

Who changed the coolant and gave you this news? If it was an Iffy Lube or other chain store type place, you can disregard anything that they told you to try and increase sales.

While I would often agree about the Iffylubes, the Dexcool sludge problems are well known.

Did you stay with DexCool or was it changed over to something like a universal? If it was kept on DexCool I would get it out.

I would then have it flushed again in another 10K or so and keep driving it as long as the temp doesn’t become a problem.

Have it flushed and get away from the Dex Cool in my opinion. My oldest son’s 96 Camaro used to sludge up badly on DC and I got tired of flushing it every year or so. There were zero leaks in the system and it was always properly bled with not even a single drop of coolant loss or any air bubbles.

After the last DC flush I started using the green over 8 years ago and any sludge problems are total history. The radiator and overflow bottle is just as clean today as it was when converted way back when.

What engine do you have? How long was the coolant in there? DexCool itself isn’t bad unless you let it get too low or leave it in too long. Change it more frequently.

It was my regular mechanic and not a JiffyLube ripoff joint. I bought Dex Cool 50/50 mix for them to put in becuase thats what my manuel said to use, so Dex Cool is in there now. The engine in my car is a 3.1 liter. I’ve got 75,000 miles on the car and this is the 2nd time I’ve changed the coolant. Thanks for all your help.

Is there any sign of leakage from the intake manifold gaskets? That might be the place where the air got in to foul the Dexcool.

Does the engine oil dipstick still show clear oil?

If the sludge is (Dexron trans fluid) red, then the radiator has to be changed because the trans cooler is leaking trans fluid into the coolant.

Yeah, another genius “advancement” in OAT technology. Death Cool. I’ll never use the stuff.

Anyway, get your oil tested for coolant. About $25. Google Blackstone Labs. If you find coolant (high potassium w/high sodium), you need the intake gaskets replaced. You’re just seeing the coolant side of it (if that’s the source), the Used Oil Analysis will show you how much of a beat down it’s taking out on the bearings.

hat fill you had in there was subjected to air infiltration (as was mentioned). Exposure to air degraded this mockery of science/chemistry into garbage very quickly.

Flush the rad with a cleaner and get some G05 coolant or even old green. I use the PG coolants. The only thing they require is more frequent service …which as you can see, the miracle Deathcool should have had too.

Good luck.