05 Impala Coolant Issue
- Thread starter AP Guy
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
hatzie
Full Access Member
- Joined
- Dec 6, 2011
- Posts
- 567
- Reaction score
- 459
- Location
- NH
- First Name
- David
- Truck Year
- 1976
- Truck Model
- k20
- Engine Size
- 6.5
Strange it's not giving you a pulsation on the cooling system test gauge given the other symptoms.
Barfing gobs of coolant out the radiator fill neck as soon as you start it up sounds like a cracked combustion chamber casting (block or head) or leaking head gasket.
Did you run an old fashioned compression test?
And what does she do when you sock the shop air to the cylinders?
More curiosity now than anything else. This is an odd one.
Barfing gobs of coolant out the radiator fill neck as soon as you start it up sounds like a cracked combustion chamber casting (block or head) or leaking head gasket.
Did you run an old fashioned compression test?
And what does she do when you sock the shop air to the cylinders?
More curiosity now than anything else. This is an odd one.
Last edited:
Honky Kong jr
Super Sarcastic Man
- Joined
- Jun 14, 2016
- Posts
- 14,968
- Reaction score
- 9,828
- Location
- Denver,PA
- First Name
- J-me
- Truck Year
- 87
- Truck Model
- V10
- Engine Size
- Lil BB 407
One of the best tools I own.
hatzie
Full Access Member
- Joined
- Dec 6, 2011
- Posts
- 567
- Reaction score
- 459
- Location
- NH
- First Name
- David
- Truck Year
- 1976
- Truck Model
- k20
- Engine Size
- 6.5
If a leaking intake manifold gasket is letting air into the cooling system it'll boil where the coolant and air meet. The 3.1 & 3.4 are notorious for leaking intakes and it's not dexcool it's the intake gaskets.
This would fit the symptoms except for the fact that it's holding 20psi.
This would fit the symptoms except for the fact that it's holding 20psi.
AP Guy
Member
- Joined
- Apr 24, 2018
- Posts
- 47
- Reaction score
- 27
- Location
- NE Iowa
- First Name
- Dustin
- Truck Year
- 1978
- Truck Model
- Sierra Classic
- Engine Size
- 350
I did the plastic bottle method today. No real change. I buttoned everything up and took it down the county highway and gravel roads. Varied speeds from 35-70mph and the temp gauge to my surprise was somewhat steady but still hotter than its ever ran in its 245k mile life.
Temps at cruising, 65-70 were 200-210(if I can trust my gauge) Each trick mark is 7.5 degrees. Slower speeds were in the 210-215 range, and dropping to idle and sitting for a bit temps crept up into the 230-240 range. I pulled over multiple times to open the bleeders but didn't seem to help drop the temp any and the coolant hoses were rock hard.
Still no definitive answer other than I'm confident its pushing air into the system. Some how some way. I didn't mess with a leakdown check yet. I have a compression tester but would have to throw some fittings together to make a down and dirty leak down tester. Something that would come in handy down the road though I'm sure.
As for the LIM gaskets they were changed out to the metal fel-pros so I'm confident its not coming from that. No major external leaks that I can see and the oil is still clean so I think they are still holding up.
Should enter her into a county fair race and give her one last hoorah and go out in style!
Temps at cruising, 65-70 were 200-210(if I can trust my gauge) Each trick mark is 7.5 degrees. Slower speeds were in the 210-215 range, and dropping to idle and sitting for a bit temps crept up into the 230-240 range. I pulled over multiple times to open the bleeders but didn't seem to help drop the temp any and the coolant hoses were rock hard.
Still no definitive answer other than I'm confident its pushing air into the system. Some how some way. I didn't mess with a leakdown check yet. I have a compression tester but would have to throw some fittings together to make a down and dirty leak down tester. Something that would come in handy down the road though I'm sure.
As for the LIM gaskets they were changed out to the metal fel-pros so I'm confident its not coming from that. No major external leaks that I can see and the oil is still clean so I think they are still holding up.
Should enter her into a county fair race and give her one last hoorah and go out in style!
- Joined
- Aug 29, 2010
- Posts
- 47,128
- Reaction score
- 9,299
- Location
- OKC, OK
- First Name
- HotRod
- Truck Year
- 85 K20 LWB
- Truck Model
- Silverado
- Engine Size
- 454 - Turbo 400 - 3.73
Just browsing and skimming looking for Intake Gasket and didn't see it until here. But yes, this would have been my first go to and check on any 60 degree V6 GM engine. Even the 90 degree 3.8 has this issue but not near as common on the 2.8 3.1 and 3.4s. This problem will show it's face usually between 80,000-100,000 miles. DexCool is part of the problem. So if and when you get this problem found and fixed flush that DexCool out and replace it with all green. DO NOT MIX DexCool with the Green. Flush the system first.
And it does fit symptoms even though it's holding 20psi. Are you testing it hot or cold??? Test it hot, I have a feeling you won't be holding that 20psi.
AP Guy
Member
- Joined
- Apr 24, 2018
- Posts
- 47
- Reaction score
- 27
- Location
- NE Iowa
- First Name
- Dustin
- Truck Year
- 1978
- Truck Model
- Sierra Classic
- Engine Size
- 350
I initially tested it cold but did have it running with the gauge on it to see if i had any needle fluctuations from combustion pressure. Pressure was increasing to about 20psi but I didn't leave the gauge on it to see if it was holding. I'll do that and see what it looks like.
I know these engines have LIM gasket issues but I'm struggling to see how intake gaskets would cause the coolant to push out of the radiator though almost instantly after I start it cold with the water pump disabled. I get the boiling of the coolant but not after 2-3 seconds after initial start. Coolant comes out before I can walk around the front of the car and watch the filler neck.
I might try and throw some shop air into the cylinders and see if anything shows. It's almost as if the head gasket is failing to keep the gases in, yet the coolant isn't following the same path and getting into the combustion chamber and still managing to hold coolant pressure.
Is there any way to keep the engine from rotating of its not completely at TDC when I put shop air in? On airplanes I can hold the propeller...no bueno in this case
I know these engines have LIM gasket issues but I'm struggling to see how intake gaskets would cause the coolant to push out of the radiator though almost instantly after I start it cold with the water pump disabled. I get the boiling of the coolant but not after 2-3 seconds after initial start. Coolant comes out before I can walk around the front of the car and watch the filler neck.
I might try and throw some shop air into the cylinders and see if anything shows. It's almost as if the head gasket is failing to keep the gases in, yet the coolant isn't following the same path and getting into the combustion chamber and still managing to hold coolant pressure.
Is there any way to keep the engine from rotating of its not completely at TDC when I put shop air in? On airplanes I can hold the propeller...no bueno in this case
Last edited:
wcstory
Junior Member
- Joined
- Mar 29, 2015
- Posts
- 1
- Reaction score
- 0
- Location
- Massachusetts
- First Name
- Bill
- Truck Year
- 1966
- Truck Model
- 2500
- Engine Size
- 305
Question, is your bottom radiator hose collapsing as the motor draws a higher volume of water?
WFO
Full Access Member
- Joined
- Jan 6, 2017
- Posts
- 3,675
- Reaction score
- 5,017
- Location
- Texas Panhandle
- First Name
- Dan
- Truck Year
- 1986
- Truck Model
- K20
- Engine Size
- 350
Maybe a combination of a bad intake gasket, and an intake valve not totally seating.
AP Guy
Member
- Joined
- Apr 24, 2018
- Posts
- 47
- Reaction score
- 27
- Location
- NE Iowa
- First Name
- Dustin
- Truck Year
- 1978
- Truck Model
- Sierra Classic
- Engine Size
- 350
Possible. I think ill throw air into it at TDC & BDC just for my own curiosity although a cracked block should show a leak in the coolant pressure test.
I also forgot to note after the test drive yesterday there was still a pretty constant bubbling into my coolant overflow. Not surprised but still evidence coolant pressure is exceeding the 15psi cap
malibuman402
Member
- Joined
- Aug 2, 2015
- Posts
- 45
- Reaction score
- 40
- Location
- nc
- First Name
- Larry
- Truck Year
- 1984
- Truck Model
- C10 Silverado
- Engine Size
- BB 402+.060 = 413.8CI
i have an o5 impala ls with a 3.8 and 342700 miles on it. check the air dam below the radiator and make sure it's sturdy enough to direct air up to the front of the radiator. i had to replace the one under mine.
AP Guy
Member
- Joined
- Apr 24, 2018
- Posts
- 47
- Reaction score
- 27
- Location
- NE Iowa
- First Name
- Dustin
- Truck Year
- 1978
- Truck Model
- Sierra Classic
- Engine Size
- 350
Well I threw some shop air in it tonight and it confirmed it's a head gasket. #2 sealed up fine on intake & exhaust but was blowing air out of the coolant bleeder. #4 & #6 were actually sealed up pretty tight considering there's 240k miles on it.
Moving to the back bank...#1 looks to be leaking externally between the head and block. The fitting in the spark plug hole is an o ring seal so I'm confident it was leaking external especially with how much gunk was accumulated behind #1 plug. I didn't get to #3 or #5 just yet as I got pulled off for a honey-do item but I'll try to get those done tomorrow just for kicks.
Guess now we know.
Moving to the back bank...#1 looks to be leaking externally between the head and block. The fitting in the spark plug hole is an o ring seal so I'm confident it was leaking external especially with how much gunk was accumulated behind #1 plug. I didn't get to #3 or #5 just yet as I got pulled off for a honey-do item but I'll try to get those done tomorrow just for kicks.
Guess now we know.
hatzie
Full Access Member
- Joined
- Dec 6, 2011
- Posts
- 567
- Reaction score
- 459
- Location
- NH
- First Name
- David
- Truck Year
- 1976
- Truck Model
- k20
- Engine Size
- 6.5
Now what to do with it...
Is it worth it to keep it around as an OMG We need a car right now and "Winter? HAH!" rig?
No payments... a spare is a good thing to have sometimes.
Is it worth it to keep it around as an OMG We need a car right now and "Winter? HAH!" rig?
No payments... a spare is a good thing to have sometimes.
AP Guy
Member
- Joined
- Apr 24, 2018
- Posts
- 47
- Reaction score
- 27
- Location
- NE Iowa
- First Name
- Dustin
- Truck Year
- 1978
- Truck Model
- Sierra Classic
- Engine Size
- 350
If it was up to me I'd say let's fix it and back it on the corner of the shop and keep it as a backup. But...I also have a suburban, my daily, & my wife's daily. So the burb is acting as a backup for now but we are looking at potentially getting another "family" vehicle/suv that will mostly be my wife's new car and I'd transfer over to her old daily. Then my current daily might become the backup. Funny I always get the hand me downs lol.
When the impala that blew the head gasket just went down I was driving the burb as a daily for a few weeks. An 8.1L with a 70 mile round trip to work & back turns out to be about $100 a week in gas with a 40 gal tank...
That thing drinks like an Irishman but i wouldn't trade that thing for anything. Hence why I'm looking to find am 8.1 takeout to put in my square
Thanks for all the help!
When the impala that blew the head gasket just went down I was driving the burb as a daily for a few weeks. An 8.1L with a 70 mile round trip to work & back turns out to be about $100 a week in gas with a 40 gal tank...
That thing drinks like an Irishman but i wouldn't trade that thing for anything. Hence why I'm looking to find am 8.1 takeout to put in my squareThanks for all the help!
