More than just a coolant flush.. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**scotts62** · 12-12-2010, 10:01 PM

Ok i have a question.. i have looked around in the search but didnt really find what i was looking for. I was helping my dad out on his '98 Bravada earlier because its not heating up like it should and we flushed it out really good a few weeks ago and got a bunch of nasty out of it and figured all was good but its back to acting up again, i let it warm up and pulled the cap and noticed that the flow of the coolant wasnt very good and it wasnt pouring out of the cores like it should when its at its best. Looks to me like the people before didnt take care of it and let some rust and gunk build up in there and now its stopping it up.. So my question is, is if there is some stuff out there that will give it a good flushing and help open it all back up or if i should just buy a new radiator and heater core and go about it that way?

Thanks,

Jonboy · 12-13-2010, 11:07 AM

Did you use any additive in the coolant, or just flush it out with water? Prestone used to have a coolant flush additive, that you could add, drive it a little, then wash out. One of the guys I work with was having similar problems in a S-Blazer. I thnk it ended up popping a head gasket.

**scotts62** · 12-13-2010, 04:41 PM

The additive popped the gasket??
It needs something because I'm afraid it's going to block up the flow too much and really cause a headache later on.. I'll check out the additive and give it a shot. Thanks
Posted via Mobile Device

ofnaman · 12-14-2010, 02:45 AM

When I run across a car with a heater core plugged problem I usually backflush the coolant system with several gallons of water (I usually put a hose in our machine and flush it until it runs clear for a little bit), then I forward and backwards flush the heater core itself. The only problem with that is if the heater core (or any other coolant component) has been weakened by corrosion/rust they usually start leaking in a couple of weeks. The upside to that is that you really don't have anything to loose, if it works great, if it starts to leak it needed to be replaced anyway. I have personally had terrible luck with flush chemicals (on any system, not just coolant). I believe they cause premature seal/gasket failure.

68C15 · 12-30-2010, 08:35 AM

ahh, the joys of DexCool. it coagulates when it meets hot air.

do a GOOD back flush of heater core and then the whole system with the thermostat removed (keep the seal in there though). then drain system and pour in 1 cup (8oz) of Cascade dish washing machine soap (the gel type stuff), fill system with water and run to operating temp plush half an hour. back flush with water, pull both block drain plugs, drain radiator and fill with 50/50 water and GREEN coolant.

finally plan on doing intake gaskets in the near future along with possibly having the intake manifold welded and milled where it pits up around the coolant ports.

**scotts62** · 12-30-2010, 09:04 AM

I did just that the other day, i got the T that you install in the heater hose to back flush and i took the thermostat out and put straight water in and drove for a bit to get hot and then flushed all the junk out. Did that about 8 more times over a couple of days and a friend told me to use cascade so i poured a nice fair amount in and have been driving a few days now since i drive more than my dad but the temp stays where it is suppose to now but there is no heat at all coming from the core, it has to be plugged up really good...

That Dexcool crap sucks! My wife drives an '06 Avalon and when we first bought it i drained that junk and flushed the system and put the good ole green in it.

68C15 · 12-31-2010, 06:08 PM

that flushing T will leak in the near future.
try removing heater hoses and back flushing the core by itself.
the hose that comes from the intake is the feed, you want to hook your garden hose to the other one (the one that leads back to the water pump via hoses and an aluminum pipe)

**scotts62** · 12-31-2010, 07:01 PM

Quote:

Originally Posted by 68C15

that flushing T will leak in the near future.
try removing heater hoses and back flushing the core by itself.
the hose that comes from the intake is the feed, you want to hook your garden hose to the other one (the one that leads back to the water pump via hoses and an aluminum pipe)

Thats fine its going to be sold when its all working right anyways

I have flushed and flushed but its finally getting better slowly..

12-12-2010, 10:01 PM	#1
scotts62 One day... Join Date: Apr 2008 Location: Tuttle, Ok Posts: 9,243	More than just a coolant flush.. Ok i have a question.. i have looked around in the search but didnt really find what i was looking for. I was helping my dad out on his '98 Bravada earlier because its not heating up like it should and we flushed it out really good a few weeks ago and got a bunch of nasty out of it and figured all was good but its back to acting up again, i let it warm up and pulled the cap and noticed that the flow of the coolant wasnt very good and it wasnt pouring out of the cores like it should when its at its best. Looks to me like the people before didnt take care of it and let some rust and gunk build up in there and now its stopping it up.. So my question is, is if there is some stuff out there that will give it a good flushing and help open it all back up or if i should just buy a new radiator and heater core and go about it that way? Thanks, __________________ Scott 93 crew cab build Project 62

12-13-2010, 11:07 AM	#2
Jonboy Slots go on anything! Join Date: May 2003 Location: Richardson, TX Posts: 5,957	Re: More than just a coolant flush.. Did you use any additive in the coolant, or just flush it out with water? Prestone used to have a coolant flush additive, that you could add, drive it a little, then wash out. One of the guys I work with was having similar problems in a S-Blazer. I thnk it ended up popping a head gasket. __________________ 1974 Jimmy- 5.3/4L80e/NP241

12-13-2010, 04:41 PM	#3
scotts62 One day... Join Date: Apr 2008 Location: Tuttle, Ok Posts: 9,243	Re: More than just a coolant flush.. The additive popped the gasket?? It needs something because I'm afraid it's going to block up the flow too much and really cause a headache later on.. I'll check out the additive and give it a shot. Thanks Posted via Mobile Device __________________ Scott 93 crew cab build Project 62

12-14-2010, 02:45 AM	#4
ofnaman Registered User Join Date: Aug 2007 Location: reno Posts: 397	Re: More than just a coolant flush.. When I run across a car with a heater core plugged problem I usually backflush the coolant system with several gallons of water (I usually put a hose in our machine and flush it until it runs clear for a little bit), then I forward and backwards flush the heater core itself. The only problem with that is if the heater core (or any other coolant component) has been weakened by corrosion/rust they usually start leaking in a couple of weeks. The upside to that is that you really don't have anything to loose, if it works great, if it starts to leak it needed to be replaced anyway. I have personally had terrible luck with flush chemicals (on any system, not just coolant). I believe they cause premature seal/gasket failure. __________________ A sweet 2000 Deville.....

12-30-2010, 08:35 AM	#5
68C15 blood type; Retumbo Join Date: Jan 2004 Location: next to my reloading bench Posts: 10,269	Re: More than just a coolant flush.. ahh, the joys of DexCool. it coagulates when it meets hot air. do a GOOD back flush of heater core and then the whole system with the thermostat removed (keep the seal in there though). then drain system and pour in 1 cup (8oz) of Cascade dish washing machine soap (the gel type stuff), fill system with water and run to operating temp plush half an hour. back flush with water, pull both block drain plugs, drain radiator and fill with 50/50 water and GREEN coolant. finally plan on doing intake gaskets in the near future along with possibly having the intake manifold welded and milled where it pits up around the coolant ports.

12-30-2010, 09:04 AM	#6
scotts62 One day... Join Date: Apr 2008 Location: Tuttle, Ok Posts: 9,243	Re: More than just a coolant flush.. I did just that the other day, i got the T that you install in the heater hose to back flush and i took the thermostat out and put straight water in and drove for a bit to get hot and then flushed all the junk out. Did that about 8 more times over a couple of days and a friend told me to use cascade so i poured a nice fair amount in and have been driving a few days now since i drive more than my dad but the temp stays where it is suppose to now but there is no heat at all coming from the core, it has to be plugged up really good... That Dexcool crap sucks! My wife drives an '06 Avalon and when we first bought it i drained that junk and flushed the system and put the good ole green in it. __________________ Scott 93 crew cab build Project 62

12-31-2010, 06:08 PM	#7
68C15 blood type; Retumbo Join Date: Jan 2004 Location: next to my reloading bench Posts: 10,269	Re: More than just a coolant flush.. that flushing T will leak in the near future. try removing heater hoses and back flushing the core by itself. the hose that comes from the intake is the feed, you want to hook your garden hose to the other one (the one that leads back to the water pump via hoses and an aluminum pipe)



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