Antifreeze

69z28rsss · July 28, 2009

I would like to drain my antifreeze and replace both radiator hoses. My question is, Do many people switch back over to the old green fluid. I have heard bad things about dexcool. I have a 99 gmc 5.3 with 165k on it. Dont have any records on it. Previous owner said he would send them to me but never did.

txab · July 28, 2009

If you had Dex, then I'd stick with Dex. There's nothing wrong with it. It still needs to be changed before it wears out. It's best not to mix other AFs with Dex. My .02 worth.

Change ALL your hoses, not just the upper and lower radiator hoses.

Zembonez · July 28, 2009

If you had Dex, then I'd stick with Dex. There's nothing wrong with it. It still needs to be changed before it wears out. It's best not to mix other AFs with Dex. My .02 worth.

Change ALL your hoses, not just the upper and lower radiator hoses.

+1 Make sure you change the heater hoses too. If Dexcool made it 1o years, why change now? If you DO change, make darn sure you flush all of the old coolant out of the block and heater core. You don't want to mix them.

2COR517 · July 28, 2009

Personally, I would dump the dexcool and go green. There are drains on the block that make it much easier to get the coolant out. Drives side is just a pipe plug, easy. Pass side is knock sensor. They can be trouble, so take your time. This time of year you can run straight water for a day or two to get all the old stuff out. Run for a couple days, empty, do it again.

Zembonez · July 28, 2009

Personally, I would dump the dexcool and go green. There are drains on the block that make it much easier to get the coolant out. Drives side is just a pipe plug, easy. Pass side is knock sensor. They can be trouble, so take your time. This time of year you can run straight water for a day or two to get all the old stuff out. Run for a couple days, empty, do it again.

Is there a reason for this? If you're gonna start spouting those old wives tales about the horrors of Dexcool I suggest you go read up and rethink your position. That was nothing more than a bunch of old school geezers that didn't want to change or were too cheap to buy Dexcool and mixed it with the cheaper green stuff.

Draenor · July 28, 2009

Flush,replace all hoses, and refill with dexcool.

There are drains on the block that make it much easier to get the coolant out. Drives side is just a pipe plug, easy. Pass side is knock sensor.

'Yer thinking about the 'ol 350's. The sensors are on top of the block now, not the sides.

WaterGuy · July 28, 2009

The trick with DexCrap is to be sure that air never gets into the system.

That was where most of the problems came from.

Keep the overflow tank at the proper level all the time.

2COR517 · July 28, 2009

Just my opinion. Sorry if I upset you.

Spurshot · July 28, 2009

Steve,

When you replace the upper and lower radiator hoses, change all of the little ones. They include the two heater hoses, which you'll need a quick disconnect tool (available at most autoparts stores). One of those hoses has a Y connector in it and it has a hose from the Y to the coolant recovery tank. The other hose you should replace is the return hose from the tank to the radiator. That heater hose with the Y connector is some rediculous price like $180 at the stealer. Shop it online at places like GMpartsdirect.com, etc..

I've been using Dexcool in my 99 2500 for 215,000 miles without any cooling system component failures/replacements and only changed it once at 55,000 miles and just recently. But I highly recommend the 50,000 mile interval. When I flushed the radiator last summer at over 200,000 miles (about 150,000 since a flush/change) it had a lot of crud in it. I changed the waterpump and thermostat as a precaution/maintenance rather than wait for it to fail on the road somewhere. Flush it first if you're going to change the pump or thermostat.

Zembonez · July 28, 2009

Just my opinion. Sorry if I upset you.

No worries. We are both allowed to post our opinions.

Dexcool got its initial bad reputation because old school guys were stubborn and mixed in the green stuff instead of sticking with Dexcool (because the green stuff was cheaper). The two products don't mix well and problems cropped up. Of course, it was immediately because Dexcool was a bad product... All I was saying is that it isn't a bad product if you use it as intended.