Muddy Radiator

[rmurphy5]

Just purchased a 2000 GP GTP with 81,000 miles on it. I have owned a 2001 Bonniville W/SC in the past and have regreted getting rid of it ever scence. the GP was bought knowing it has a problem, It has What looks like mud around the radiator cap, and was loosing coolant. I found a cut from the belt in the overflow hose and have repaired it. Just not sure wich direction to go. After looking at alot of posts i am guessing intake gaskets. The car runs good, has some noise from the front of the S/C, sounds like a bad bearing, and a little of the rock grinding noise that is always talked about. Not sure if just the coupler will take care of that or do i need to do somthing else in addition. Thanks for your help.

[SlowNA06]

Are you burning coolant (sweet smell from exhaust)? Is there coolant creating a wet spot around the LIM gasket? The cut in the hose is likely what caused your sludging (air = rust = sludge). Unless you just feel like doing the LIM gasket (it'll have to get done someday, though) I'd do a coolant flush first with fresh dex and see if that's all you need. That's probably 12 year old coolant in the car. I think it's only good for 5 years.

[rmurphy5]

Thanks for the reply. What radiator flush would you use. Also should it be filled with 100% dex-cool or 50-50??

[SnowFlake]

Flush the dex outta there and use something else (full strength) and mix with water.

[Explicit_Spade]

Dex cool gums up if it isn't routinely changed, which is what you are seeing as "mud". Dex cool is perfectly fine to use and is highly reccomended by GM, but requires changing annualy if not more frequently.

[SlowNA06]

Flush it with water.
Fill it 50/50 with dex.
Change it at the intervals recommended on the bottle, or before.
No need for an annual flush, though there's nothing wrong with it if you've got the money and time to burn.

Videos of how to do a coolant flush should be pretty readily available online... too lazy to find you some (sorry).

[kevins]

The problem is that once the radiator is sludged its hard to get clean. I always ditch dexcool and go with traditional green coolant. It doesnt gum up and cause sludge. Just pers pref. Ive seen the amount of damage dexcool can cause when left un checked.

[SlowNA06]

Ive seen the amount of damage dexcool can cause when left un checked.

Leaving something un-checked on your car, regardless, is begging for problems.

[cool98gt]

I didn't know you had to change Dexcool annually (or more often) and let it go for 5 yrs. I got the same rusty brown gunk/sludge in my radiator. I eventually had to replace the radiator as the flush didn't really do the job. My mechanic recommended going with regular Prestone Green which I did and the motor is running at proper temps without the sludge and gunk. Also, I did check with a mech at the GM dealership and he said, unofficially, if it was his car he'd dump the Dexcool!

[kevins]

Leaving something un-checked on your car, regardless, is begging for problems.

Correct but unlike dexcool, traditional green coolant doesnt react to air and sludge up radiators and heater cores.

[SlowNA06]

Correct but unlike dexcool, traditional green coolant doesnt react to air and sludge up radiators and heater cores.

I seem to remember that dexcool does not, in fact, react to air. Because dexcool does not stick to the sides of internals when you let it run low, rust quickly forms. The rust reacts with the Dexcool to cause sludge.

[kevins]

OK. But you're still going to end up sludge. Switch to green and no sludge