05 Lacrosse doesn't heat very well

rocket9244

Full Member
20
0
1
Bellevue Nebraska
Buick Ownership
1993 Buick Park Ave
my wife has a 2005 lacrosse and it doesn't heat up very well.
the temp gauge reads good, the car runs fine.
but when we turn the heat up, it stays kinda cool/luke warm.
she drives a few hours away from home for her job and I would like her to be warm.
what could the issue be?
 

92sub

Full Member
997
8
0
Motor City
Buick Ownership
87GN (gone), 2011 CXS (gone), 98 Regal GS
Unless your 100% certain the temp gauge is riding in the same spot as when the vehicle was new you should confirm thermostat operation. I do that by looking at the engine temp sensor using a scan tool. You could use the special wax 'crayons' and mark the T-stat housing. The different wax sticks melt at specific temps and that's how you confirm T stat function.
The second thing to confirm is coolant level. If the coolant is low, at all, the first thing to go is the heat because the heater core is normally the highest point in the system.
Feel the hoses going in and out of the heater core. One should be slightly hotter than the other, with the hottest the same temp as the rest of the cooling system (try not to burn yourself). Issues here indicate a coolant flow problem like a plugged heater core.
Finally, the system within the car uses 'blend' doors to regulate hot vs. cold air. If the system is manual it's pretty easy to tell if the doors open and close. If the system is Automatic, you've got at least 5 sensors, electric acutators and control modules......best leave that to someone handy with a Tech2 scan tool.
 
2,414
13
38
Detroit, USA
I would recommend contacting your local dealer for a diagnosis. I can also look into this for your with the last eight of your VIN. Please feel free to contact me privately for more assistance. Keep me posted either way.

Tricia, Buick Customer Service.
______________________________
 

HilarityEnsues

Bad eMail Address
130
1
0
Virginia
Buick Ownership
1994 Buick Century (SOLD... to some sucker) & 2009 Buick Lacrosse CX
Thermostat or Heater Core are most likely. My grandma had a Taurus that was overheating. I replaced the water pump and radiator. Afterwards she complained about the car not heating up the way it did before the repairs, so I took a day to take the heater core out and found it clogged with rust from the radiator fluid not being changed very often. I think Dexcool needs to be changed ever 5 years.
 

jonbt

Buick Newbie
8
0
0
Buick Ownership
Buick 2006 LaCrosse CXL
Unless your 100% certain the temp gauge is riding in the same spot as when the vehicle was new you should confirm thermostat operation. I do that by looking at the engine temp sensor using a scan tool. You could use the special wax 'crayons' and mark the T-stat housing. The different wax sticks melt at specific temps and that's how you confirm T stat function.
The second thing to confirm is coolant level. If the coolant is low, at all, the first thing to go is the heat because the heater core is normally the highest point in the system.
Feel the hoses going in and out of the heater core. One should be slightly hotter than the other, with the hottest the same temp as the rest of the cooling system (try not to burn yourself). Issues here indicate a coolant flow problem like a plugged heater core.
Finally, the system within the car uses 'blend' doors to regulate hot vs. cold air. If the system is manual it's pretty easy to tell if the doors open and close. If the system is Automatic, you've got at least 5 sensors, electric acutators and control modules......best leave that to someone handy with a Tech2 scan tool.

I've got the same problem with my 2006 LaCrosse with dual auto temp control and 50k miles on it. I don't think the coolant has ever been changed, but it looks clean. The [COLOR=blue !important][COLOR=blue !important]coolant [COLOR=blue !important]level[/COLOR][/COLOR][/COLOR] in the radiator and [COLOR=blue !important][COLOR=blue !important]overflow [COLOR=blue !important]tank[/COLOR][/COLOR][/COLOR] seem fine -- the level in the overflow tank is slightly above the line near the bottom when the engine is cold. The engine warms up fine according to the engine temp gauge on the dash, and the radiator hoses get hot.

I checked the two heater core hoses in the engine compartment running to the firewall after the engine is warmed up: when the engine is running, the top one is much hotter than the lower one. However, when I turn the engine off and check again, the lower one is now nearly as hot as the top one. So I'm wondering whether there is a valve of some kind in the core which regulates coolant flow into the core? I cannot see enough of the core to know. If so, maybe the actuator for that valve is bad. And what are those two metal lines next to the heater hoses on the firewall?

I also looked behind the glove compartment for the blend door. There are three little motors there: the 2 to the left appear to control dampers which route air either to the floor, panel or defroster outlets -- I took them both off (each held in place by 2 small hex head screws), and they both rotate when I change the dash settings -- they are intended to rotate a shaft which apparently controls some damper buried beneath the dashboard. The third one is directly behind and up from the glove box, mounted nearly against the fire wall, and located far enough to the right that I cannot get a nutdriver or my hand in there to remove it easily. But I can see the part of it that is supposed to rotate, and it never does, regardless of how I change the temp or dash outlet settings. If this is the blend door, then it appears that this motor is not functioning either due to a bad motor, or to a bad sensor controlling it.

Can anyone offer a diagnosis? Does the heater core have any kind of valve in it? Is it obvious that the heater core is blocked? That looks like a pain to replace. Thanks for any advice!
 

jonbt

Buick Newbie
8
0
0
Buick Ownership
Buick 2006 LaCrosse CXL
I've got the same problem with my 2006 LaCrosse CXL with dual auto temp control and 50k miles on it. I don't think the coolant has ever been changed, but it looks clean. The coolant level in the radiator and overflow tank seem fine -- the level in the overflow tank is slightly above the line near the bottom when the engine is cold. The engine warms up fine according to the engine temp gauge on the dash, and the radiator hoses get hot.

I checked the two heater core hoses in the engine compartment running to the firewall after the engine is warmed up: when the engine is running, the top one is much hotter than the lower one. However, when I turn the engine off and check again, the lower one is now nearly as hot as the top one. So I'm wondering whether there is a valve of some kind in the core which regulates coolant flow into the core? I cannot see enough of the core to know. If so, maybe the actuator for that valve is bad.

I also looked behind the glove compartment for the blend door. There are three little motors there: the 2 to the left appear to control dampers which route air either to the floor, panel or defroster outlets -- I took them both off (each held in place by 2 small hex head screws), and they both rotate when I change the dash settings -- they are intended to rotate a shaft which apparently controls some damper buried beneath the dashboard. The third one is directly behind and up from the glove box, mounted nearly against the fire wall, and located far enough to the right that I cannot get a nutdriver or my hand in there to remove it easily. But I can see the part of it that is supposed to rotate, and it never does, regardless of how I change the temp or dash outlet settings. If this is the blend door, then it appears that this motor is not functioning either due to a bad motor, or to a bad sensor controlling it.

Can anyone offer a diagnosis? Does the heater core have any kind of valve in it? Is it obvious that the heater core is blocked? That looks like a pain to replace. Thanks for any advice!
 

rocket9244

Full Member
20
0
1
Bellevue Nebraska
Buick Ownership
1993 Buick Park Ave
it needed a flush and new antifreeze put in.
there was gunk in the system and after the power flush $45.00, it heats up Very good.
______________________________
 

bobk4000

Junior Member
18
2
1
St. Paul, MN
My 2005 LaCrosse wasn't heating too well back in November - mechanic checked it out and flushed the heater core and that solved the problem for me as well. Wonder if there is a trend here with gunk in the heater cores...

Bob
 

jonbt

Buick Newbie
8
0
0
Buick Ownership
Buick 2006 LaCrosse CXL
I had posted earlier about a 2006 LaCrosse with little to no heat. Decided to bring it in to the dealer for diagnosis. Dealer told me the heater core was blocked and needed to be replaced, and price for that was $1100 ! They said there was a lot of labor involved, because you had to take the dash apart to access the heater core.

Since the car only had 50k miles on it, this sounded like crap. So I passed on that and brought it home after paying their $130 diagnosis fee. The heater hoses are easy to access -- they exit the engine block at the top left rear just behind the alernator. I pulled the hoses and back flushed the heater core with a garden hose -- no blockage at all, just clear water emerged, not even discolored. Replaced the heater hoses, topped off coolant system, heater worked GREAT. As best I can figure, even though the coolant level looked fine, the heater core had an air bubble or air lock.

With 20 minutes of time invested, I save $1100 for a bogus repair. The dealer had not even bothered to try to flush the system. I think they have high school kids working back in the garage, because this was just plain stupid. I'll stop by the dealer later to tell them what happened and try to get my $130 back. Dealer service really isn't worth much these days.
 

_J_

Buick Newbie
2
0
0
Buick Ownership
2005 buick allure cx
i was just going to make a thread asking about this. my 2005 allure has the same problem, ill try flushing it 1st.
 

rrail

Full Member
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0
0
ottawa
Buick Ownership
Buick allure
2005 Allure I did the same just flushed it , new thermostat and it's good and hot. Too bad dealers can't fix there own products , it's a shame :mad:
specially with some thing this basic.
______________________________
 

thegoose

Buick Newbie
6
0
1
Buick Ownership
Buick
Our 2007 Allure had the same problem AFTER (ST)dealer drained, flushed and replaced coolant. Took the car back and told them the heater not as hot as before (this was in January) and they replaced the thermostat. Still not hot enough. Saw on this site others with the same problem and figured the core was plugged (top hose hot, bottom hose warm). Back-flushed the core with water into a clean bucket and saw scale/crud in the bucket. Replaced coolant and hoses and immediately saw a huge difference in heater output from cold engine to operating temperature.

My advise to those having this problem. Insist on a back-flush of the core. I'm not sure if their flushing system does this or not. I'm also not sure who actually performs this service at dealerships anymore. I've seen these quick service departments at dealerships and whilst they look professional and squeaky clean, it should have raised a red flag with me when the "technician" I was talking to, didn't know where the power steering reservoir was.

Just my 2 cents. I will be looking for another place(likely NOT a dealer) to get the car serviced from now on.
 
reviving an old thread ... 09 LaCrosse CXL 3800 Series III same issue with heat. Took it to Gordon Chevrolet in Garden City, MI to have the cooling system serviced/flushed last year and the heat was marginally better. Cold weather has arrived again and the car is back to where it was before it was serviced last year. New cap on the radiator and coolant level checked.

From what I am reading in this thread it appears to me that some brilliant GM design engineer had a brain fart and it passed the quality control fart sniffer.
 
decided to give the core flush a try. what a surprise. all is well and the car is a sweat box at full heat, although I will keep and eye for leaks after this process.

Since it is cold outside I drove over to My Mechanics Place, a nice shop in Livonia, MI that rents stalls with or without a lift. I took a flat stall, no lift.

http://mymechanicsplace.com/contact-us/

Autozone lends you the tool to flush your cooling system, leave a deposit and get it back when you return it. Attach it to a regular garden hose.

oem_flush_tool.JPG

Removed the heater hoses and inserted the tool into the return hose. Slowly turned the water on and it blew a bucket of crap out of the inlet hose. It was like a bucket of sand and dark brown in color. Several large chunks of coagulated antifreeze came out as well.

sludge.jpg

That's only a small sample of the sludge. I repeated the process until clear clean water flowed from the inlet hose.

Replaced the hoses, topped off the antifreeze, checked for leaks then drove it home. 1/2 work including shop cleanup and $14 later all is like new.

The visit to the GM dealership last February was a waste of time and money. I've lost all confidence in them.
 
The dealer solution would've been a new heater core and 6 hours of labor.

The chunks in the pic look like something you get after using a quick-seal rad leak product.

We purchased the car with 82,000 mi. I believe it is Dexcool that coagulated and talking with others they have experienced similar problems with their Pontiacs and other GM cars running Dexcool. Pretty confident in the integrity of the cooling system as far as prior leaks, but your observation has merit.

The plan going forward is to make it through winter and do a complete evac of the cooling system and replace with another coolant. I'll have enough time to research any complications that could arise from a different coolant being introduced after 95,000 miles running Dexcool.

Glad it worked out as this Lacrosse is the perfect car for my Mrs.
 

PurpleHaze

3.9L Member :)
233
30
18
Lawrencvile, Ga
Buick Ownership
Buick
We purchased the car with 82,000 mi. I believe it is Dexcool that coagulated and talking with others they have experienced similar problems with their Pontiacs and other GM cars running Dexcool. Pretty confident in the integrity of the cooling system as far as prior leaks, but your observation has merit.

The plan going forward is to make it through winter and do a complete evac of the cooling system and replace with another coolant. I'll have enough time to research any complications that could arise from a different coolant being introduced after 95,000 miles running Dexcool.

Glad it worked out as this Lacrosse is the perfect car for my Mrs.

How many miles were on the car when you did the coolant flush?
 
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