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

Cooling problem

Thread Tools
 
Search this Thread
 
Old Nov 4, 2007 | 08:24 PM
  #1  
12SEC SS's Avatar
Thread Starter
Launching!
iTrader: (5)
 
Joined: Dec 2005
Posts: 260
Likes: 13
From: Brooklyn, NY
Default Cooling problem

Have a bit of a problem here, running LT1 radiator, LT1 pressurized overflow that T-s into the radiator hose, and the steam pipe goes to a nipple on the overflow. I also put a moroso filler neck into the upper radiator hose to ease with bleeding and filling of the system. My problem is as follows:

When im driving, everything is cool. if i stand still for a few mins temp starts to slowly climb up. I let it get to lets say 230-ish, and I just rev the motor to ~1600RPM for a few secs, and temperature drops by like 30 degrees. few more minutes, cycle will repeat. If i start driving, its immediately fine. When i cracked open the filler in the upper hose after the car cooled off, the hose is full of antifreeze. both hoses feel hot to the touch when the car is doing this.

waterpump and thermostat are both new. I need some help here, anyone have any ideas?
Reply
Old Nov 4, 2007 | 09:02 PM
  #2  
Schitzo's Avatar
TECH Enthusiast
20 Year Member
iTrader: (6)
 
Joined: Feb 2005
Posts: 716
Likes: 2
From: Minneapolis MN
Default

Are you using a F-Body LT1 rad? If so, it is very similar to the LS1 rad and should have two separate provisions to hook to the expansion tank and steam vent.

How are you filling in the coolant? If not done correctly you will have air trapped in the system. What I did was use the top hose to pour the coolant into the engine. Once it was topped up, I replaced the hose and then filled the radiator.
Reply
Old Nov 4, 2007 | 09:31 PM
  #3  
12SEC SS's Avatar
Thread Starter
Launching!
iTrader: (5)
 
Joined: Dec 2005
Posts: 260
Likes: 13
From: Brooklyn, NY
Default

Originally Posted by Schitzo
Are you using a F-Body LT1 rad? If so, it is very similar to the LS1 rad and should have two separate provisions to hook to the expansion tank and steam vent.

How are you filling in the coolant? If not done correctly you will have air trapped in the system. What I did was use the top hose to pour the coolant into the engine. Once it was topped up, I replaced the hose and then filled the radiator.
I am using a B-Body LT1 radiator. It has no provisions for expansion tank or steam vent lines.

I filled the coolant through the moroso filler neck that I've spliced into the upper radiator hose. When the car is cool and I open the cap on it, the upper hose is full with antifreeze to the top...
Reply
Old Nov 5, 2007 | 07:11 AM
  #4  
69LT1Bird's Avatar
11 Second Club
iTrader: (1)
 
Joined: Sep 2007
Posts: 2,310
Likes: 6
From: Lapeer, MI
Default

You should hook the vent hose to a radiator hose or heater hose, directly into radiator tank, it needs to be in the flow of the coolant. I don't think it can flow correctly when it is trying to fight the overflow part of the system.
Reply
Old Nov 5, 2007 | 08:14 AM
  #5  
67pete's Avatar
Launching!
 
Joined: Aug 2003
Posts: 252
Likes: 0
From: Down along the strand in NJ
Default

Steam vent must go into the radiator side of the pressure cap, not on the overflow side!
Reply
Old Nov 5, 2007 | 12:46 PM
  #6  
12SEC SS's Avatar
Thread Starter
Launching!
iTrader: (5)
 
Joined: Dec 2005
Posts: 260
Likes: 13
From: Brooklyn, NY
Default

I have pulled the upper hose off the pump today in the mourning, pump is full to the top with antifreeze, and so is the radiator. The vent hose is going to the pressurized tank thats factory on a B-Body, there was recently a conversation about a 'Vette pressurized tank, and I thought it was good to use?
Reply
Old Nov 5, 2007 | 09:03 PM
  #7  
12SEC SS's Avatar
Thread Starter
Launching!
iTrader: (5)
 
Joined: Dec 2005
Posts: 260
Likes: 13
From: Brooklyn, NY
Default

took the thermostat out today, its still doing it. Can a water pump be bad new out of the box? or should I get an LS1 radiator and copy the whole cooling system from like a LS1 camaro? I just dont get it, and have no more ideas really. HELP
Reply
Old Nov 6, 2007 | 04:09 AM
  #8  
67pete's Avatar
Launching!
 
Joined: Aug 2003
Posts: 252
Likes: 0
From: Down along the strand in NJ
Default

The steam vent ports on the heads are the high point in the engine, so this is where the air gets trapped. In order to relieve this air it must go to a low pressure point, the top radiator hose has the return( read: low pressure ) water being sucked into the water pump, this in turn helps suck the air/ hot water out of the heads...
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

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

 Verdad Gallardo
story-1

6 Common C5 Corvette Failures and What's Involved In Repairing Them

 Pouria Savadkouei
story-2

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-3

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-4

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-5

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-6

Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

 Verdad Gallardo
story-7

Awesome K5 Blazer Restomod Comes With C7 Corvette Power

 Verdad Gallardo
story-8

10 Camaros You Should Never Buy

 
story-9

10 LS Engine Myths That Refuse to Die

 Verdad Gallardo
Old Nov 6, 2007 | 06:56 AM
  #9  
69LT1Bird's Avatar
11 Second Club
iTrader: (1)
 
Joined: Sep 2007
Posts: 2,310
Likes: 6
From: Lapeer, MI
Default

Do you still have the vent hose going to the overflow nipple? This will never work, the object of the vent is to remove air from the heads, it can not go against the radiator cap, the overflow side is for pushing "overflow" or drawing it back into the system. The vent needs to be in the normal flow of the closed loop system. If you do, move it to a heater hose or a radiator hose. The B body hose system from an LT1 is a complete pain in the A#$.

Get a simple overflow bottle and hook that up to your radiator overflow nipple. Take the vent pipe and "T" it into a heater hose or radiator hose and the problem is solved. The heater hose is nice because it is easy to hide. I have done this on my Firebird and a 66 Chevelle that I did a LT1 swap in as well. You don't need a new radiator, but copying the simple F car system is the way to go. This link is to Jagsthatrun dot com. This is what you need to buy or make. http://www.jagsthatrun.com/Pages/Par...plice-Kit.html
Reply




All times are GMT -5. The time now is 09:14 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