'06 Pontiac Grand Prix no heat...continue w/Dexcool or use another?

tdidieselbobny · December 30th, 2011, 18:23

2006 Pontiac Grand Prix,151k (assume original coolant).Back in Nov. I noticed the temp gauge barely moved after 10+ miles driving,and no heat coming from vents(digital climate temp.gauge,set on 90 degrees).Figured thermostat-changed that and bled air out-temp gauge moves normally,then see it drop once it reaches certain point,plus getting heat out of vents-good-problem fixed(or so I thought). No coolant smell inside car. I haven't checked the hoses going to heater core yet for temp....I know I need to change coolant-probably take it somewhere that will hook machine up and flush system.A couple questions-should I try to flush the heater core out first before taking it somewhere,or do those machines they hook up do a good job of getting crap out of system? Second-should I have it refilled w/ Dexcool after flush,or switch to another type of anti freeze for the fill(any particular brand?) TIA for any help!

PDJetta · December 31st, 2011, 06:12

I went through the Dex-Cool fiasco with my wife's Buick. Chances are the Dex-Cool has sludged and plugged your heater core. Can you feel the coolant hose to the heater core? If so, it should be nice and hot at engine operating temperature with the heat on. Have the heater fan on high and after a few minutes of driving, stop and feel both heater core hoses. If the hoses are both quite hot, I would suspect a plugged core. I do not know if you can clean out the core if plugged, or if it needs replacing.

On ours, I caught it before this happened. The lower intake manifold gaskets were just starting to weep and sludge was just starting to build up. As part of replacing the lower intake gaskets, I flushed the system and replaced the coolant, using Prestone orange, 5-year coolant. I forget what its called, but it is the Dex-cool compatible replacement. End of issues.

BTW I think by the '06 model year GM solved the faulty lower intake manifold gasket problems on their V-6 engines (the Buick is an '01). Still, you could have sludging issues, though. What does the coolant bottle and radiator cap and neck look like? Any sludge in there?

--Nate

jgeorge · December 31st, 2011, 10:32

When you have your cooling system flushed, don't use a chemical flushing agent- asking for trouble.

whitedog · December 31st, 2011, 10:51

Quote:

Originally Posted by jgeorge

When you have your cooling system flushed, don't use a chemical flushing agent- asking for trouble.

So what kind of "trouble" would a person expect if, Hypothetically, that dog... er Person used a chemical flush on say, a Duramax?

Just wondering...

Thermo1223 · January 5th, 2012, 08:52

Air infiltration makes Dex-cool sludge so check for any intake manifold leaks as suggested but IMO no coolant is good for 5+ years. I personally set on 4 years unless you do rack up 100k+ miles in that amount of time.

Yes back flush the heater core & the block, chemical coolant flushes don't harm anything but they could push a slightly leaking gasket over the edge. Face it if the gasket was leaking it needed to be changed anyway.

tdidieselbobny · February 4th, 2012, 19:22

Update..... finally had the system and heater core flushed today. They said they got alot of chunks out when they flushed the heater core-I now have heat

!!! There was no sludge buildup in tank or radiator neck before it was flushed.

tdidieselbobny · October 14th, 2012, 08:00

Well,back to square one. Temp set on 90,barely any heat(according to wife). Don't see sludge on cap or overflow.I'll take it it for a spin and see how the heater core hoses feel. Waiting to get another estimate for core replacement-first one was about $420 + tax for core replacement and flush.The Grand Prix forum says the core isn't too buried on pass. side(2006 model). Bad enough the B4 has crappy heat(foam delete

)......