1997 Bravada with Dex-Sludge and a Coolant Leak

NTL1991 · 12-20-2008, 03:49 PM

I purchased a 1997 Bravada with some "Dex-Sludge" in the radiator fill neck and coolant overflow tank... I noticed it wasn't getting up to temperature, it would just hover above 110F or so even after 20 minutes of driving... Also, there was no heat at all and when I would accelerate, I could hear a gushing in the heater core. The PO replaced the lower intake manifold and heater core, but never flushed the system after that... I opened the radiator to find low coolant in there, but the overflow tank was at a perfect level. I filled with antifreeze up to the top and drove the truck. Still no heat and the engine temp was the same. Today I replaced the brown thermostat with a new one and I filled the radiator again. Now the engine temp is fine but I have no heat. I parked the truck on a very steep hill and let it run for about 15 minutes to get any air out of the system. Still no heat.

After looking under the truck when it's running, I can see orangy coolant running off the bottom of the block. It doesn't look like it's coming from the water pump, but the pulley below the water pump at the very bottom of the engine. There's a connector there (maybe the Crankshaft Position Sensor?) and it seems like its coming from that area...

Any help would be greatly appreciated.

Nick

dropjawjimmy · 12-20-2008, 06:30 PM

I have that gushing sound too... but no thing else is wrong right now. heat was not working then one day it just decided to work.

NTL1991 · 12-20-2008, 10:20 PM

Well, after inspecting the underside of the truck, I've noticed that when the engine is running a "stream" (almost), (or maybe two streams) of orange coolant drips off the bottom of the block. It doesn't seem like its coming from the water pump, but rather, the bottom crankshaft pulley. I'm sure, though, that coolant could be weeping out of the pump and down to make it look like it's coming from the very bottom pulley...

Anyone have any ideas?

***DJDAudio*** · 12-20-2008, 10:32 PM

I hat the water sound then nothing, the heater core has clogged solid, this is the after effect of that sound. I have to reverse flush the core to get heat back again.

MikeInCtown · 12-21-2008, 12:31 PM

Most likely the water is coming out of the little hole at the bottom of the water pump. I've never seen coolant come out of the block where you describe.

As far as the heater core goes, it's either clogged or you have a ton of air in the system. Fix the leak and then back flush the heater core. When you fill the system back up, try and crack the output hose to relieve that air in the system.

NTL1991 · 12-21-2008, 01:23 PM

Great Replies, Thanks!

To do a proper flush, I need to fix the leak first, right? If the leak happens to be a bad pump and I replace it, would the crap in the system contaminate the new pump when it's being flushed, or is that a non-issue? I have to rule out any other sources for the leak first, though...

It's kinda hard to flush the system now or even put a new pump in because of the snow and 18*F weather... But I will take the truck with me to school on day and do everything in my auto class...

Any tips on flushing out the sludge properly?

D.T. · 12-28-2008, 07:52 PM

I had the same problem. Intake gasket was bad.

Aerated dexcool turns to some nasty stuff. Stains are almost impossible to get out. Hopefully my heater core won't clog. It's a PITA to replace.

Vash · 12-28-2008, 10:40 PM

I bypassed my heater core and redid the LIM (as in the guide thread) and put in a new Delphi radiator because the crust was so bad it was impossible to flush. BTW Switch to Yellow is my advice (Prestone Extended Life), it's GM certified to replace and or mix with Dex Cool.

D.T. · 12-29-2008, 09:29 AM

Quote: Originally Posted by Vash

I bypassed my heater core and redid the LIM (as in the guide thread) and put in a new Delphi radiator because the crust was so bad it was impossible to flush. BTW Switch to Yellow is my advice (Prestone Extended Life), it's GM certified to replace and or mix with Dex Cool.

You must live in Mexico or somethin', I need heat!

Yellow is the Hybrid Organic Acid stuff. I was wondering why not use this instead? It's the G5 stuff isn't it? Looks like most of the imports use it.

blazer346ls1 · 12-30-2008, 08:05 PM

More then likely it is the intake manifold gasket. I'm in the process of changing mine now. GM's wisdom of using a captive o-ring in a plastic retainer is crap. The plastic corrodes over time and then there is nothing to support the o-ring and you get a leak. Mine was leaking in the front of the intake where it meets the block and the heads and was seeping down and dripping by the balancer. Fel-pro has a fix gasket that is a metal core covered in rubber that solves the problem for good.

NTL1991 · 12-31-2008, 12:41 AM

Well, I back flushed the whole system using very hot tap water about 4 times and then flushed the rad... Now I get perfect heat, but I'm still leaking a bit. The truck has to be inspected, so I will have them look at the leak then. I'm pretty sure it's the water pump because the PO replaced the heater core and intake manifold gasket... I could tell he replaced the heater core because he forgot a few dash mounting tabs that were sticking out of the bottom...

Nick

PimpingA1997Jimmy · 01-04-2009, 10:46 AM

jsut wondering i know what a flush is but this is the first time i have ever heard the term back flush what is the back flush ?

THank you

NTL1991 · 01-04-2009, 09:16 PM

Back flushing is when you flush in the opposite direction of normal flow. For example, when you back flush your heater core, you would flush water into the OUTLET instead of into the INLET. This reverse of direction allows particles of crap to be blasted out rather than just getting packed deeper and deeper into your heater core.

BTW, Still a slight leak but I have great heat!

Nick

PimpingA1997Jimmy · 01-04-2009, 10:11 PM

ah ok im going to ask the Mechanic to do that when i do get the rad flushed

Calvin51 · 01-07-2009, 02:42 PM

On a lot of the S-10's, Jimmy' s, etc, when you see that black sludge, it's time for a new radiator. The oil cooling side of the tank has developed a leak mixing oil and coolant. The oil cooler is low pressure so it sucks oil into the sode of the tank but will not suck coolant back into the engine. I've replaced three radiators because of this on different vehicles. And BTW....the sludge is very hard to wash off from the engine bay. I had to use a few cans of degreaser and powerwash.

NTL1991 · 01-13-2009, 04:21 PM

Well, I brought the truck to the shop for an inspection and I also told them that there's a coolant leak, so the water pump might need to be replaced.

I picked it up today, and to my surprise, the bill was $38. $38 for the state inspection and zilch for tightening "Looses Coolant Hoses"...

I haven't seen a shop bill that low in years.

Nick

***philntx*** · 01-20-2009, 07:04 PM

Too bad you didn't know about this:

Claim deadline expired on 10/27/2008

http://www.dexcoolsettlement.com/

12-20-2008, 03:49 PM	#1
NTL1991 Registered User Join Date: Sep 2007 Posts: 208 Location: Rhode Island User is: OffLine	1997 Bravada with Dex-Sludge and a Coolant Leak I purchased a 1997 Bravada with some "Dex-Sludge" in the radiator fill neck and coolant overflow tank... I noticed it wasn't getting up to temperature, it would just hover above 110F or so even after 20 minutes of driving... Also, there was no heat at all and when I would accelerate, I could hear a gushing in the heater core. The PO replaced the lower intake manifold and heater core, but never flushed the system after that... I opened the radiator to find low coolant in there, but the overflow tank was at a perfect level. I filled with antifreeze up to the top and drove the truck. Still no heat and the engine temp was the same. Today I replaced the brown thermostat with a new one and I filled the radiator again. Now the engine temp is fine but I have no heat. I parked the truck on a very steep hill and let it run for about 15 minutes to get any air out of the system. Still no heat. After looking under the truck when it's running, I can see orangy coolant running off the bottom of the block. It doesn't look like it's coming from the water pump, but the pulley below the water pump at the very bottom of the engine. There's a connector there (maybe the Crankshaft Position Sensor?) and it seems like its coming from that area... Any help would be greatly appreciated. Nick
	[Reply w/Quote]

12-20-2008, 06:30 PM	#2
dropjawjimmy "It was all a Dream" Age: 28 Join Date: Nov 2008 Posts: 574 Location: Maryland User is: OffLine	Re: 1997 Bravada with Dex-Sludge and a Coolant Leak I have that gushing sound too... but no thing else is wrong right now. heat was not working then one day it just decided to work.
	[Reply w/Quote]

12-20-2008, 10:20 PM	#3
NTL1991 Registered User Join Date: Sep 2007 Posts: 208 Location: Rhode Island User is: OffLine	Re: 1997 Bravada with Dex-Sludge and a Coolant Leak Well, after inspecting the underside of the truck, I've noticed that when the engine is running a "stream" (almost), (or maybe two streams) of orange coolant drips off the bottom of the block. It doesn't seem like its coming from the water pump, but rather, the bottom crankshaft pulley. I'm sure, though, that coolant could be weeping out of the pump and down to make it look like it's coming from the very bottom pulley... Anyone have any ideas?
	[Reply w/Quote]

12-21-2008, 12:31 PM	#5
MikeInCtown Registered User Age: 35 Join Date: Feb 2008 Posts: 927 Location: User is: OffLine	Re: 1997 Bravada with Dex-Sludge and a Coolant Leak Most likely the water is coming out of the little hole at the bottom of the water pump. I've never seen coolant come out of the block where you describe. As far as the heater core goes, it's either clogged or you have a ton of air in the system. Fix the leak and then back flush the heater core. When you fill the system back up, try and crack the output hose to relieve that air in the system.
	[Reply w/Quote]

12-21-2008, 01:23 PM	#6
NTL1991 Registered User Join Date: Sep 2007 Posts: 208 Location: Rhode Island User is: OffLine	Re: 1997 Bravada with Dex-Sludge and a Coolant Leak Great Replies, Thanks! To do a proper flush, I need to fix the leak first, right? If the leak happens to be a bad pump and I replace it, would the crap in the system contaminate the new pump when it's being flushed, or is that a non-issue? I have to rule out any other sources for the leak first, though... It's kinda hard to flush the system now or even put a new pump in because of the snow and 18*F weather... But I will take the truck with me to school on day and do everything in my auto class... Any tips on flushing out the sludge properly?
	[Reply w/Quote]

12-28-2008, 07:52 PM	#7
D.T. Captain DIY Age: 41 Join Date: Dec 2008 Posts: 119 Location: Moneyapolis, MN User is: OffLine	Re: 1997 Bravada with Dex-Sludge and a Coolant Leak I had the same problem. Intake gasket was bad. Aerated dexcool turns to some nasty stuff. Stains are almost impossible to get out. Hopefully my heater core won't clog. It's a PITA to replace.
	[Reply w/Quote]

12-28-2008, 10:40 PM	#8
Vash Registered User Join Date: Nov 2008 Posts: 262 Location: User is: OffLine	Re: 1997 Bravada with Dex-Sludge and a Coolant Leak I bypassed my heater core and redid the LIM (as in the guide thread) and put in a new Delphi radiator because the crust was so bad it was impossible to flush. BTW Switch to Yellow is my advice (Prestone Extended Life), it's GM certified to replace and or mix with Dex Cool.
	[Reply w/Quote]

12-29-2008, 09:29 AM	#9
D.T. Captain DIY Age: 41 Join Date: Dec 2008 Posts: 119 Location: Moneyapolis, MN User is: OffLine	Re: 1997 Bravada with Dex-Sludge and a Coolant Leak Quote: Originally Posted by Vash I bypassed my heater core and redid the LIM (as in the guide thread) and put in a new Delphi radiator because the crust was so bad it was impossible to flush. BTW Switch to Yellow is my advice (Prestone Extended Life), it's GM certified to replace and or mix with Dex Cool. You must live in Mexico or somethin', I need heat! Yellow is the Hybrid Organic Acid stuff. I was wondering why not use this instead? It's the G5 stuff isn't it? Looks like most of the imports use it.
	[Reply w/Quote]

12-30-2008, 08:05 PM	#10
blazer346ls1 Registered User Age: 41 Join Date: Feb 2008 Posts: 32 Location: North Charleston, SC User is: OffLine	Re: 1997 Bravada with Dex-Sludge and a Coolant Leak More then likely it is the intake manifold gasket. I'm in the process of changing mine now. GM's wisdom of using a captive o-ring in a plastic retainer is crap. The plastic corrodes over time and then there is nothing to support the o-ring and you get a leak. Mine was leaking in the front of the intake where it meets the block and the heads and was seeping down and dripping by the balancer. Fel-pro has a fix gasket that is a metal core covered in rubber that solves the problem for good.
	[Reply w/Quote]

12-31-2008, 12:41 AM	#11
NTL1991 Registered User Join Date: Sep 2007 Posts: 208 Location: Rhode Island User is: OffLine	Re: 1997 Bravada with Dex-Sludge and a Coolant Leak Well, I back flushed the whole system using very hot tap water about 4 times and then flushed the rad... Now I get perfect heat, but I'm still leaking a bit. The truck has to be inspected, so I will have them look at the leak then. I'm pretty sure it's the water pump because the PO replaced the heater core and intake manifold gasket... I could tell he replaced the heater core because he forgot a few dash mounting tabs that were sticking out of the bottom... Nick
	[Reply w/Quote]

01-04-2009, 10:46 AM	#12
PimpingA1997Jimmy Registered User Age: 29 Join Date: Jun 2008 Posts: 783 Location: User is: OffLine	Re: 1997 Bravada with Dex-Sludge and a Coolant Leak jsut wondering i know what a flush is but this is the first time i have ever heard the term back flush what is the back flush ? THank you
	[Reply w/Quote]

01-04-2009, 09:16 PM	#13
NTL1991 Registered User Join Date: Sep 2007 Posts: 208 Location: Rhode Island User is: OffLine	Re: 1997 Bravada with Dex-Sludge and a Coolant Leak Back flushing is when you flush in the opposite direction of normal flow. For example, when you back flush your heater core, you would flush water into the OUTLET instead of into the INLET. This reverse of direction allows particles of crap to be blasted out rather than just getting packed deeper and deeper into your heater core. BTW, Still a slight leak but I have great heat! Nick
	[Reply w/Quote]

01-04-2009, 10:11 PM	#14
PimpingA1997Jimmy Registered User Age: 29 Join Date: Jun 2008 Posts: 783 Location: User is: OffLine	Re: 1997 Bravada with Dex-Sludge and a Coolant Leak ah ok im going to ask the Mechanic to do that when i do get the rad flushed
	[Reply w/Quote]

01-07-2009, 02:42 PM	#15
Calvin51 Registered User Join Date: Dec 2007 Posts: 167 Location: User is: OffLine	Re: 1997 Bravada with Dex-Sludge and a Coolant Leak On a lot of the S-10's, Jimmy' s, etc, when you see that black sludge, it's time for a new radiator. The oil cooling side of the tank has developed a leak mixing oil and coolant. The oil cooler is low pressure so it sucks oil into the sode of the tank but will not suck coolant back into the engine. I've replaced three radiators because of this on different vehicles. And BTW....the sludge is very hard to wash off from the engine bay. I had to use a few cans of degreaser and powerwash.
	[Reply w/Quote]

01-13-2009, 04:21 PM	#16
NTL1991 Registered User Join Date: Sep 2007 Posts: 208 Location: Rhode Island User is: OffLine	Re: 1997 Bravada with Dex-Sludge and a Coolant Leak Well, I brought the truck to the shop for an inspection and I also told them that there's a coolant leak, so the water pump might need to be replaced. I picked it up today, and to my surprise, the bill was $38. $38 for the state inspection and zilch for tightening "Looses Coolant Hoses"... I haven't seen a shop bill that low in years. Nick
	[Reply w/Quote]

01-20-2009, 07:04 PM	#17
*philntx* Build them right....Mod Age: 54 Join Date: Jul 2006 Posts: 2,123 Location: Plano TX User is: OffLine	Re: 1997 Bravada with Dex-Sludge and a Coolant Leak Too bad you didn't know about this: Claim deadline expired on 10/27/2008 http://www.dexcoolsettlement.com/
	[Reply w/Quote]