Conversions & Swaps LSX Engines in Non-LSX Vehicles
Sponsored by:
Sponsored by:

help with cooling problem

Thread Tools
 
Search this Thread
 
Old Apr 6, 2009 | 05:32 PM
  #1  
JeaneGrae's Avatar
Thread Starter
TECH Enthusiast
15 Year Member
iTrader: (7)
 
Joined: May 2006
Posts: 680
Likes: 1
Default help with cooling problem

My buddy swapped in a lq4 drivetrain into a 79 full size pu. Everything works fine and the pullies are set identical to his 05 silverado with the same drivetrain, but the coolant isn't circulating. The t-stat is opening and is brand new. What could be causing the overheating? the only code his computer throws is the one for overheating, no other codes.
Reply
Old Apr 6, 2009 | 09:01 PM
  #2  
bczee's Avatar
TECH Senior Member
20 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (12)
 
Joined: Jan 2006
Posts: 6,670
Likes: 6
From: Concord, CA
Default

Could be a air pocket in the system, take step to purge the air out of the system.

Fill the system from the top radiator hose (disconnect it from the radiator) and then reconnect the hose and then top off.

Hold the engine at about 2000-2500 for a 20-30 sec to purge the system of air. Top off again and repeat a few times to get all of the air out.

Are you sure the T-stat is not binding in the housing and that it is opening at the right temp and that the fans come on at the correct time if your using electrical fans.
Reply
Old Apr 6, 2009 | 09:11 PM
  #3  
forcd ind's Avatar
TECH Veteran
15 Year Member
Liked
Loved
Community Favorite
iTrader: (7)
 
Joined: Sep 2007
Posts: 4,188
Likes: 292
From: woodbine, md
Default

like bczee said, try filling from the top hose-filling the rad doesnt put water in the block because the thermostat is closed, needs water behind it to get hot and open it, then you can fill it up thru the radiator
Reply
Old Apr 7, 2009 | 05:32 AM
  #4  
Pop N Wood's Avatar
TECH Junkie
iTrader: (1)
 
Joined: May 2006
Posts: 3,402
Likes: 8
Default

Unbolt and remove one of the steam vent caps on the front top of the engine as you fill it. That gets the air out.

Also are you sure it is overheating and not just a bad sensor/shorted sensing wire? Did you check it with a second sensor or observe other signs of overheating beside the code?

Lasst thing, are the heater hoses hooked up? I hve heard LS motors circulate water through the heater loop while T stat is closed. Make sure there is a path their.
Reply
Old Apr 9, 2009 | 07:20 PM
  #5  
98Camarod's Avatar
11 Second Club
iTrader: (43)
 
Joined: Aug 2006
Posts: 5,364
Likes: 2
From: Summerville, SC
Default

Originally Posted by bczee
Could be a air pocket in the system, take step to purge the air out of the system.

Fill the system from the top radiator hose (disconnect it from the radiator) and then reconnect the hose and then top off.

Hold the engine at about 2000-2500 for a 20-30 sec to purge the system of air. Top off again and repeat a few times to get all of the air out.

Are you sure the T-stat is not binding in the housing and that it is opening at the right temp and that the fans come on at the correct time if your using electrical fans.
Then why would the temp gauge go up and show the reading of the higher temp? Just from the combustion?

From this post, I'm guessing that the coolant is circulated inside the block, and then through the bottom hose when the tstat opens and then pushes the cool water through the top hose and repeats the process?
Reply
Old Apr 10, 2009 | 07:28 PM
  #6  
RE AND CHERYL's Avatar
TECH Fanatic
iTrader: (31)
 
Joined: Apr 2007
Posts: 1,207
Likes: 0
From: Dover DE
Default

I had the exact same thing happen in a 97 blazer last week. Turned out it had a large air pocket in it that only worked it's self loose when the engine warmed up. Real wierd because the truck sat allnight after we put it together adn in the morning it looked full. We ended up putting almost another gallon in that "full"radiator.

Re'
Reply
Old Apr 11, 2009 | 06:35 AM
  #7  
topher455's Avatar
TECH Enthusiast
iTrader: (6)
 
Joined: Jan 2007
Posts: 642
Likes: 1
From: Florida
Default

Sounds like an air pocket to me also. Like the others said fill the motor through the upper rad hose with the steam vent unhooked.
Reply




All times are GMT -5. The time now is 05:56 PM.

story-0
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-1
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-2
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-3
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-4
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-5
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-6
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE
story-7
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-8
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE
story-9
10 LS Engine Myths That Refuse to Die

Slideshows: Which one of these myths do you believe?

By Verdad Gallardo | 2026-01-28 18:10:11


VIEW MORE