Heater Core Flush? - Page 2

chembrad · 01-20-2005, 02:02 PM

From a chemistry standpoint Dexcool is propylene glycol and is mixable with water at all concentrations. Old green antifreeze is ethylene glycol and is also mixable with water at all concentrations.

Dexcool (propylene glycol) apparently polymerizes under certain conditions *my guess is a small amount of engine oil mixed with iron oxides* (which is the sludge observed in the heater core).

They switched to propylene glycol (Dexcool) from ethylene glycol (old green), primarily for environmental concerns (cats like the taste and it crystalized their kidneys... it also harms dogs and humans in high enough concentrations).

Ethylene glycol has better properties (regarding raising boiling point and lowering the freezing point of the coolant) than propylene glycol at the same concentrations.

So to make Dexcool sound better, they increased the concentration of the rust inhibitors and pH buffer and gave it a longer listed operating value (ie. 150, 000 miles vs. 30,000 miles for old green).

This is all my opinion as a chemist and I am willing to debate my conclusions.

BlazerLT · 01-20-2005, 04:30 PM

Quote:

Originally Posted by CSR44

Just a reminder when I say "Green" I am referring to the new Prestone "Geen" that is compatible with Dex-Cool. If you don't completely eliminate the Dex and add the "old" green Prestone, you will get a sludge problem after time.

Just my $.02

From my knowledge, the compatible stuff is yellow.

Anything green is non compatible and has a silca based formulation.

blazee · 01-20-2005, 04:58 PM

Yeah, the new prestone that is compatible with everything is yellow.

CSR44 · 01-21-2005, 05:12 PM

You guys are right, it is yellow... I know I read Dex compatible and the stuff was $9.50 a gal!! I guess the $3.99 days are long gone..

chcknugget · 01-21-2005, 05:29 PM

Yeah I bought a gallon of the yellow for 8.99 when I flushed out my heatercore. I didn't need it though, because I had more than enough in my reservoir. Now I can't find the reciept.

BlazerLT · 01-21-2005, 05:57 PM

Yea, stick to the proper coolant for your truack and don't experiment with the new stuff.

blaz'd · 01-22-2005, 06:33 PM

96 blazer...same deal...heater blows cold and engine runs hot, now i seem to have a pinhole leak just under the a.c. motor in the engine compart.(drivers side). sometimes i hear a gurgling under the dash and the temp goes down for a while,but pegs quickly after. flushing my heater core will fix it long enough to get it to the shop(in a couple days)
right?

blazee · 01-22-2005, 06:59 PM

Quote:

Originally Posted by blaz'd

96 blazer...same deal...heater blows cold and engine runs hot, now i seem to have a pinhole leak just under the a.c. motor in the engine compart.(drivers side). sometimes i hear a gurgling under the dash and the temp goes down for a while,but pegs quickly after. flushing my heater core will fix it long enough to get it to the shop(in a couple days)
right?

No, you need to do a complete flush. I sounds like you neglected your cooling system and your dexcool has turned to sludge. Judging by the problems you described the problem is larger than just your heater core your entire system is affected. I usually recommend doing the flush yourself, but in your case I would recommend a shop if your intake gasket is leaking, ( the leak near tha A/C) connecting a water hose to backflush could cause lots of damage. (you system leaks with 16 psi, usually a water hose has around 40 pounds of pressure just think of the damage....water in the cylinders, water in the oil. You will also need to change out your Radiator Cap with one not made by AC Delco, perferably a Stant (sold at Advance Auto for $5-$6).

You need to investigate to see where the leak is first, if it's not the intake gasket (maybe the water pump) you can safely fix this yourself without a shop.

FYI the gurgling in the dash is air in your heater core...a sign of a bad cap.

BlazerLT · 01-22-2005, 07:06 PM

Yes, take it into the shop and have them perform a heater core and engine cooling system flush.

Also, are you saying the heater core is leaking in the passenger compartment?

blaz'd · 01-22-2005, 08:42 PM

Took it to the shop to get a complete system flush, said they couldnt do it because I had a leak. Needless to say I was quite "PO'd", because I just spent $1200 getting it registered...,new cat, tune up...etc, anyway I get it home tonite thinking I'll take it to the car wash and do it myself and I fill the radiator with water and notice now that it leaks ALOT underneath by the tranny but I cant find the actual leak. Me thinks I may have blown it!?

blaz'd · 01-22-2005, 08:51 PM

.... by the way, I've always loved the blazer post 93 body style and I just got this about two months ago....I'm getting slightly discouraged, but remain optomistic that my initial cost of purchase, $0, and the $1200 I spent to make it legal, I figure I'll go another $1500 or $2000, after that its not such a good deal anymore

capttrob · 01-23-2005, 12:32 AM

excellent forum you guys have here. im having the same problem as most above on my 99 ZR2. Think i may bring it to jiffylube for a full system reverse flush.

Heater is blowing cold air, and gets luke warm at high idle. Im thinking it just needs a good flush. 56k miles. Any comments on bringing it to jiffylube? I'd do it myself, but i havent picked up a Haynes yet for the truck and i dont really have any place to dispose of the used antifreeze. Thanks for any help in advance.

blazee · 01-23-2005, 06:03 AM

The procedure is easy enough that you don't need a haynes book I can give you step by step directions and tell you what to get, it is cheaper to do it yourself and you can do a better job, but it is messy.

BlazerLT · 01-23-2005, 06:46 PM

Although doing it yourself is ideal, changing coolant and doing the flush on your own in the winter is just messy as hell.

Seeing you only do it every 3-5 years, I recommend having a shop do it since they will collect the mess, and they have all the proper fitting and proper cleaners.

capttrob · 01-24-2005, 05:06 AM

took it to jiffylube.... they did the full flush for 54 bucks... heat was still blowing cold air... made "buddy buddy" with the mechanic... showed him how to flush out the heater core.... we pulled both hoses off the block.... did reverse flush and forward flush a few mins each....heat is hot as ever.. .all fixed.... gave him a nice tip....

Im grateful to this forum for its insight.... thanks everyone...

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