What exactly is the difference? DexCool says it's for use with 96+ GM's, but can you use DexCool in an older car, or old-school antifreeze in new cars? Somebody enlighten me on this whole DexCool thing :-) TIA

 

I use Dexcool in all of my thirdgens with no problems at all. Just make sure that you completley flush out any old antifreeze before adding the Dexcool.

 

I believe dex cool is designed for alloy engines, and a newer formula that lasts longer. If you ever saw how alluminum corrodes in regular AF then your decision is easy.

 

from what i've heard and read dexcool has a reputation for clogging small passages in the radiator. i don't use it, not had any problems with the old fashion stuff. i'll admit i've not truely researched it to see if the stories are true or not.

 

"from what i've heard and read dexcool has a reputation for clogging small passages in the radiator"

If that were my case you'd think it would have sealed some minor leaks, Instead I found several minor leaks that were always dry before. I'm going back to the green stuff after this.

 

thats bad shiz for a rotary


least general idea seems to be that


it eats the rubber coolant seals (serves same idea as you head gasket) and just makes it leak coolant into the combustion chamber

 

i find some of this stuff hard to believe considering its in all new gm cars and is gauranteed for 5 years. I use it because i understand its better for alluminum. I would like to hear more on this subject.

 

working as a mechanic i see this all to often.... especialy in heater cores.... dexcool sucks use the regular eth glycol/water or the evans system

 

.....the "retirement" of the f body.... i dont c are for reasons... i know em all i heard em all... **** the genaral

.... 350 tpi not being able to have a 5 speed.... (could it be that a lil ol iroc w ould be faster than their precious vett)

.....caddy is going back to RWD... thank ****ing ***.... another mistake.... v8 and fwd...

..... having 4 different motor options in a sports car (id like to see a iroc z w a tbi run a 5.0 stang, than have a 5.7 tpi run that stang... and u guys wonder why stange think were slow... cause half the dam production cars ARE)

....shall i go on?

 

TwinTurbo has some points. DexCool will precipitate solids in a system, so cooling system service is a MUST.

From what I've learned, the two coolants are compatible. They can be mixed without causing any adverse effects, other than that the long life properties of the Dex-Cool will be compromised so you'll have to flush every two years instead of five. As soon as you add silicates to the mix, you need to drain it more frequently.

The difference between the two is mainly that the Dex-Cool has no silicate additives, so deposits form more slowly. The DexCool also has other anticorrosion and lubricating additives that make the concentrate less viscous and have a greater latent heat capacity (it absorbs, holds, and moves slightly more heat energy). I don't own a vehicle that doesn't use it, including all those made before 1996.

The disadvantages are the slightly higher cost, slightly lower availability, and the tendency of the coolant to wick through the smallest openings (like diesel fuel). The same molecular adhesion that allows better corrosion protection and heat absorbtion properties also makes it seek out any marginal seals or openings. Another disadvantage is that if you ignore the required maintenance, you will see more deposits forming in a system with Dex-Cool. You have to have a tight system to use it. I use it since too many of my vehicles sit in storage for extended periods and I'm tired of changing heater cores. After changing the second core in my '86 T/A at 33K miles, I bit the bullet and changed.

Despite rumors to the contrary, DexCool is probably no better or worse for non-ferrous metals protection than common polyethylene-glycol based antifreeze - as long as you follow the correct service interval for either type. What it DOESN'T do is leach metal ions from the system when mixed with water. Plain PEG won't inhibit the water's tendency to dissolve metals as well as DexCool, so the coolant mixture can protect longer. If you monitor the pH and dissolved solids (conductivity) of the fluid as part of regular maintenance, you can get the advertised 5-year life without any problems.

DexCool will precipitate solids in a system over time, as the service life is near it's end, so cooling system service is imperative unless you want to find an orange/brown "mud" in the recesses of the system. The same is true for regular PEG antifreeze, but in two years instead of five.

If you neglect it beyond that point, you'll have the kinds of problems that TwinTurbo is describing - just like you would if you neglected any other coolant for that long.

 

one of the more major factors in the change over is not the 5 year to flush things...dex cool is ALOT more environmentaly freindly so the car makers love to make the EPA happy... usualy and very frequently what would happen is that pets would drink/lick the green antifreeze and get posioned and die... alos little kids are prone to this...the **** smell sweet.... and to a lil kid and pet probably tastes sweet... dex cool isnt as poisionous to living creatures....

mmmm sliicates!

 

i can also vouch for this

we've also had cars come into the shop that were converted to dexcool.............did a number on their seals

from what i can see, there is no "performance" advantage from using dexcool- in other words dexcool is not going to make you engine run any cooler

 

Not AS poisonous, but still poisonous. It also has no phosphates, but is still not really "environmentally frinedly". The propylene glocol crap is the "environmentally friendly" stuff. I'm not a big fan.

FWIW, DexCool should be a little better at heat transfer than "green" PEG. You can still add wetters to increase efficiency without adverse effects, just like the old greeen stuff.

 

I used it for a time, and I can attest to this... I had little orange spicules growing out of every single gasket on my engine; the head gasket and the intake gaskets had the fuzz, but probably the worst spot was the gasket on the back cover of the water pump. The car didn't seem to lose coolant noticeably, but you could tell the stuff was finding its way out, and the engine always had a faint but identifiable aroma of it.

It seems to work alot better in an engine with sealing systems designed more from the ground up for it.

I changed back.

 

I've been using the Havoline Dex-Cool in my car for 2 years and haven't had any problems with it, no leaks and no mud.

 

hey since were on the subject of cooland and we got some prety techinical guys form what ive read so far... on the turbochargers book by huge macanus (and yes i did spell it wrong)... {oh yeah its the gale banks motor w the two turbos on it} i saw they had and electrical water pump w hoses going directly to the head.... i think ive seen a kit in some magazine that is a " coolant bypass for the heads"

now the questions...

can you tap the heads directly for cooling like how the lt1's and ls1's have a reverse/head first cooling flow...

an if so anyone have any ideas or ways to do this.... i got a set of spare heads im willing to try it on... only if WINTER ever ends...

also how would that work out.... would i have to use a remote mount water pump...etc etc...

 

Yes you can so that. People do it all the time for circle-track racing in particular.

The hottest place in a SBC head is the center, right above the 2 exhaust ports.

Here's some of the facts from the guys that build water pumps for most of the major racing series. http://www.stewartcomponents.com/htm...tem_basics.asp
http://www.stewartcomponents.com/htm...t/techtip3.asp

Read through the whole site if you want to really know how a cooling system works.

 

Here ya go....

External Plumbing
Street-driven vehicles seldom need auxiliary plumbing or coolant lines. SBC race engines with aluminum cylinder heads usually require extensive external plumbing to address two design problems:

1. Aluminum heads have much smaller water jackets than cast-iron heads because the external dimensions are similar, but the ports are usually larger, the deck is thicker, and the material near the rocker stands is thicker, all leaving less area in the water jackets. This decreased internal area leaves less area in the water jackets.
2. The siamese center exhaust ports are a design compromise that presents additional problems when aluminum heads are used. The area near the center exhaust valves is thicker, thus allowing providing less surface area for cooling.

We recommend installing a pair of –10 AN lines that connect the rear of the aluminum cylinder heads to the thermostat housing crossover in the front. This step will help offset the smaller water jackets. A pair of -10AN lines connecting the pressure side of the water pump with the area in the center of the cylinder head (just below the exhaust ports) will offset the lack of surface area due to the extra material.

 

TT,

I'm sure it can be done. The big question is "How?"

The stock cooling system draws coolant from the radiator into the center of the impeller housing. The small coolant (heater) hose bibb on the top/front of the pump also feeds into the center of the impeller. This is basically the suction side of the pump.

Pump discharge is routed to both of the ports that are bolted to the front of the engine case. This is why the cylinders tend to get the coolant first. Coolant from the radiator flows into the case, then up through the holes in the cylinder deck. Coolant exits the case, flows through the heads, and exits the heads at the front coolant crossover, which also houses the thermostat and water outlet to the radiator. The coolant routed back to the radiator through the thermostat housing when the thermostat has opened.
Before the thermostat opens, coolant is recirculated through a small bleed hole from the front of the right head to the impeller suction side - that small cross-drilled hole under the pump discharge on the right side of the pump. Some engines also have a heater hose connection from the rear of the right cylinder head to the small heater hose connection on top of the pump. This allows coolant to circulate until it is hot enough to open the thermostat and establish main flow.

If we could install a remote thermostat housing, arrange a pump that would draw coolant from teh two front case ports, and discharge to the radiator instead of the opposite, we'd accomplish reverse flow. All we'd have to do at that point is to route radiator coolant to the front crossover to cool the heads first.

The obvious advantage would be to present the cooler radiator mixture to the heads first. Coolant from the radiator can be 50° cooler than the discharge coolant during normal operation. Installing a thermostat that is 50° lower in rating than the factory 195°F unit would obviously be too much of a change to expect good fuel economy, complete combustion, and any kind of heating action inside the vehicle. The advantage to the cooler heads is obvious. We all know that cooler heads prevail.

I'll see if I can devise a schematic of coolant flow and an alternate pumping scheme - unless you already have something in mind...

 

I do....... It's called an LT1/LT4.

 

well im speaking of a regular sbc normal coolant flow style not a lt1... their whole pumping system is different.... based on a theremostst that can go both ways i think... some odd ball shizt like that.... from what i know having the heads get coolant first is a major part of why the gen 2 and 3 sbc can have such a high compression ratio and still run on modes 93 octane.... ive seen em a 10.x to 1 outa the factory on pump gas putting down some numbers and time slip...


edit: modest 93 octane

 

Yes, I know that reinventing the wheel would be fruitless. However, this is a different application, and without altering the casting, devising a reverse-flow system for the originl SBC would look quite different than the LT1.

Without a complete redesign of the cooling jackets and suction points, devising a reverse flow system could be interesting.