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Discussion Starter #1 (Edited)
After a complete flush we used several coolant pellets on our 94 Deville with 4.9. It turned the fluid to an ugly brown muddy look. Is this normal? I know this has been covered before, but is there any engine damage that can occur if we chose not to use the pellets next time? I tried to search other threads but only found that most suggest using the pellets. We couldnt find any info suggesting that the lack of using them could cause serious problems like head gasket failure. There is no mention of using pellets in the factory service manual (at least no reference that I could find).
 

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1993 SedanDeville (RIP), 2006 CTS (current)
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If the coolant is brown, that means that the sealant tablets have mixed, and your coolant is now protected.
 

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95 Fleetwood Brougham / 01 DTS / 11 CTS Lux / 11 DTS Platinum
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I keep hearing this but have not seen it happen yet.

I personally drained the factory fill in my DTS and the coolant was bright orange. I refilled with Dex and added 4 pellets. The coolant is still bright orange.

I'm not saying you're wrong because it sort of makes sense and I've heard more that one person say it but it's definitely NOT my experience with Dex-Cool and the sealant tabs. Now, I did use genuine GM seal tabs, maybe that matters?
 

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White Diamond '03 DHS (with DTS floor shift)
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Yes, it is normal. The 4.9 used green coolant and thus the discoloration is more evident than with Dex. Our old Guru said that the tabs are mandatory in the 4.9 and recommended on the Northstar, though GM has stopped using them (and so have I).

The tabs WILL NOT prevent head gasket failure, nor cause it by not using them. They're only purpose it to seal porous aluminum castings and seal small nuisance leaks. If I remember correctly (and I may be wrong here) the 4.9 can leak coolant into the crankcase if the intake manifold develops a leak. Bearings do not get along well with coolant. On the 4.9 I would use them and don't worry about the color. Just change the coolant every 2 years.
 

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1994 sedan deville
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hello all....I also have a 94 deville with a 4.9 in it. My problem is that the person who owned the car before me used just water in the radiator and for a while. The water in the system is rust brown I wanted to know should I just drain that it and add new coolant and tablets and will this clear up the system or should i do something else as well?

Please help!!
 

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White Diamond '03 DHS (with DTS floor shift)
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In your case I would flush the system first. Then refill with coolant and tabs. Then lick the previous owner right square in the nuts for being STUPID!

Yes, your ISC motor is failing.
 

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99 Seville STS, 08 STS4 N* 1SG F55
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After reading these forums I went and flushed my Dodge pickup this summer, N* is next but was done last January. The Dodge is a 97 and was on original coolant. I drained it, refilled with distilled water, ran it up to temp to pop the t-stat and circulate, let it cool (that's important) and drained again. Did that cycle once more until what I got out wasn't nasty. Then refilled with coolant and distilled water (compensating for the water left in the block).
 

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99 Seville STS, 08 STS4 N* 1SG F55
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The radiator drain petcock should be at the bottom of one of the side tanks facing the firewall. Usually twists out by hand or you can use a pair of pliers for a little extra leverage - but be careful if you do because it is all plastic. You can also probably put a length of fuel line or other rubber hose on the drain if you want to direct the flow better.
 
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