sludge in coolant

**gobux** · 12-02-2010

Hello,

You guys have helped me tremendously from previous threads I have read and I have a recent issue with my 99 GTP I wanted your advice on. My car runs great, but I noticed alot of brown sludge stuck to the walls of the fill tube as I opened my radiator cap last night. I also noticed a brown/orange film on the walls of the plastic fill reservoir. My low coolant light came on last week (first time after 193,000 miles), so I put in some Prestone and it went away.

Does this sound like a major problem? Could it be related to Dexcool? Ive never flushed the cooling system

, but I will after this. What do you guys think casued this sludge?

Thanks,
Gobux

**blueguy** · 12-02-2010

Get RID of the dexcool. Yes, its causing the sludge...commonly known as Dexsludge. Replace it with normal yellow or green stuff.

Probably will want new hoses, T-Stat, and intake gaskets done at the time too. Because the dexcool just eats away at it all.

**shawngtp** · 12-02-2010

THIS^^^

**NoBoost91** · 12-02-2010

I had the same problem so I Removed the drain plug and knock sensor and flushed the system about 3 months ago, but I put that dexcool garbage back in :/ , and now my water pump is going bad so now I'll remember not to use it again

**coreygnar** · 12-02-2010

just had mine flushed because of that.
apparently its caused from mixing dex and the other antifreeze stuff

**matt5112** · 12-02-2010

dex + ethylene glycol will sludge.

dex + air will sludge.

If you maintain the system well you wont have any issues with dex.

**BillBoost37** · 12-02-2010

Thanks Matt...

I wouldn't have said it quite as well.

**SlowNA06** · 12-02-2010

Read this. http://www.grandprixforums.net/dexco...ing-36656.html

I've found that keeping it all kinds of full is a good band-aid for the coolant's health until you can actually fix the problem by installing new aluminum lower intake manifold gaskets. But your coolant will still get into your oil, regardless of what color it is. Change the gaskets, flush the coolant, refill with dex, sleep soundly knowing that you've got a permanently fixed, healthy car.

**matt5112** · 12-02-2010

Originally Posted by SlowNA06

Read this. http://www.grandprixforums.net/dexco...ing-36656.html

I've found that keeping it all kinds of full is a good band-aid for the coolant's health until you can actually fix the problem by installing new aluminum lower intake manifold gaskets. But your coolant will still get into your oil, regardless of what color it is. Change the gaskets, flush the coolant, refill with dex, sleep soundly knowing that you've got a permanently fixed, healthy car.

http://www.grandprixforums.net/pitti...rts-38940.html

went from no coolant leak to having to do that repair.

And thats your godly green stuff.

**BillBoost37** · 12-02-2010

I've seen the gaskets in Series 1 motors as well as 2 and 3 motors look like hell. Some of those had green, some dex and some of the newer dex. All in all the plastic gaskets have issues and it seems to be more heat related than coolant related.

Plus..if we are saying the coolant causes the aluminum to corrod, then wouldn't we be contradicting ourselves a little if we then suggested putting aluminum frame gaskets in the motor to correct the problem?

Coolant system maintenance and the aluminum gaskets has seemed to solve the issue in all the vehicles I work on. As for the pitting, nice fix.

**rampage** · 12-02-2010

ive talked to 3 different radiator shops and they all said the same thing.get rid of the dex and put in the green.dexcool becomes corrosive after 4 or 5 years and ive seen it first hand eat the fins off of a water pump.the shops told me its the worst thing you can put in ur car and im not just talking gasgets its bad for everything,waterpumps,radiators,heater cores,etc.i got my gp with 30000 on it and the first thing i did was flush the dex and put in green and i have no sludge or mud looking crap on my radiator cap when i take it off.how many can say that that run dex?just google dexcool problems and have a field day!lol

**matt5112** · 12-02-2010

4-5 years?

I'd hope you'd change it before then.

2 years tops for any coolant imo.

Gotta keep fresh additives for best corrosion protection.

**SlowNA06** · 12-02-2010

Originally Posted by rampage

ive talked to 3 different radiator shops and they all said the same thing.get rid of the dex and put in the green.dexcool becomes corrosive after 4 or 5 years and ive seen it first hand eat the fins off of a water pump.the shops told me its the worst thing you can put in ur car and im not just talking gasgets its bad for everything,waterpumps,radiators,heater cores,etc.i got my gp with 30000 on it and the first thing i did was flush the dex and put in green and i have no sludge or mud looking crap on my radiator cap when i take it off.how many can say that that run dex?just google dexcool problems and have a field day!lol

There are radiator shops? Well, regardless, yours are full of worthless idiots and you'd be silly to pay them any money. Read the dang bottles, for crying out loud.

Flush/Fluid Swap Recommendations:
"green": 2 years
long-life "green":3-4 years
dex-cool: 5 years

**BillBoost37** · 12-02-2010

Maintenance is maintenance.

I fear of how your iridium plugs look after 100,000 miles.

**rampage** · 12-02-2010

heres the point that a few people are missing. most people are not like us and do not change thier coolant every 1 or 2 years.they read thier manuals and it says dexcool is good for 100000 miles wtf gm?like i said this stuff turns to sludge fast.so why are we having all the failed water pumps, radiators,heater cores,leaking intakes and gasgets,because gm says its good for 100000 thats why!when gm was using the green you could get away with that but not anymore.thier is or was at least a class action lawsuite against gm for this because so many people have had the same problems.

**SlowNA06** · 12-02-2010

Originally Posted by rampage

they read thier manuals and it says dexcool is good for 100000 miles wtf gm?like i said this stuff turns to sludge fast.so why are we having all the failed water pumps, radiators,heater cores,leaking intakes and gasgets,because gm says its good for 100000 thats why!

Isn't

Dexcool lasts 5 years OR 150,000 miles (GM recommends 100,000 miles in some of their manuals though (75k in '96, I think?) - still 5 years). Most people only drive 50,000 - 75,000 miles in 5 years. 5 years is therefore your limitation.

This means that if you drive a 1997 GP and you take perfect care of it, you're on at least your third radiator-full of Dex-Cool by now - the number might be higher than that, since you might have replaced LIM gaskets a couple of times before the aluminum ones came out in 2005.

Some pressure caps are faulty and do not seal out air, allowing dex-cool to evaporate, allowing iron to rust (producing iron oxide, which is what makes it chunky) since it does not coat the metal the way "green" does. This is not dex-cool's fault. It is your responsibility to constantly check your fluids to ensure that it does not get low.

**matt5112** · 12-02-2010

There is a class action lawsuit because people aren't the brightest and can't follow the two things i mentioned above.

**rampage** · 12-02-2010

u have to feel sorry for people who are not mecanically inclined.

**matt5112** · 12-02-2010

Or those who can't read where it says "dex-cool only".

If you're getting a regular oil change they check your coolant...

At least any good shop would.