Well late update on overheating prob. It was still having same issue but not as hot. I purchased stock GM balancer and what do you know she can sit in driveway idling and not get over 185 now.


Just thought i would pass info along in case someone else runs into same issue.



I have a LS1 in 66 Nova. The temp always stayed at 170 idling. It recently had Vintage Air Conditioning and Heat swap. The temp will now keep climbing up to 230 and beyond if I let it keep running.

The bottom lower radiator hose is also staying ice cold.

I have filled system disconnecting top hose and adding coolant here like others recommended. I have removed thermostat and verified its opening correctly.

I have others that say air bubble is present still. How the hell do you get this to come out if that is the case. We now have car raised up on car ramps to try to make bubble if present at highest point. I can rev engine to 3000RPM and temp will come down but then starts to creep again after I let off accelerator.

The fans are also programmed to come on earlier and are both working correctly.

I am looking to purchase this next and see what happens.

http://www.jagsthatrun.com/Pages/Par...ightGlass.html


UPDATE 04-22-11 Thanks everyone for your tips and ideas!

I bought funnel kit seemed to help some. The temp will rise but not as fast and bottom hose seems to get a little warmer now. It did not go over 225 sitting at light idling. I still think it should run cooler. I'm just going to drive it for awhile and monitor her see if it gets better. If issue persist will look into a high flow pump and maybe see about biggest radiator I can squeeze in.

The squeaking sound is gone, I put a new belt on today when checking to see if water-pump was culprit.

 

Any chance the water pump is dead?

 

I had cap off and see inside circulating. No leak from weep hole. When driving down road it stays cool. It never had any issues before swap.

The motor has less than 10,000 miles on it.

 

Its Possible that the thermostat is sticking open once its up to temp. It could also make it run hot not having time to cool the coolant in the radiator?

 

I missed the part about reving it and then it cools off some. This is signs of low coolant/air pocket in the system

 

Is there something I am doing wrong to remove air? I had another suggestion telling me to loosen temp sender at head in case air locked at this location.

I had 93 Formula with LT1 and bleed screws made it hell of lot easier.

 

I had the same issue with my silverado a couple months ago (stay cooled when driving down the road, but once I stopped, it would climb), it turned out to be my water pump even though the weep hole wasn't leaking...
But before spending money on a new pump, I would make sure there are no air bubbles...when you say disconnect the top hose, do you mean the small hose going to theTB/intake? When I flushed the system on my t/a, I just left the radiator cap off and would add from there as the car warmed up and the t-stat would open. I haven't had any issues with air in the system in the 3 times that I have done that.

 

I filled anti-freeze thru top hose so you are saying leave it connected. If I understand you are saying fill thru top of radiator and disconnect steam line hose?

 

This also has one of those Billet overflow catch cans. I am also being told air could be trapped in there. I'm going to disconnect hose from it and use empty anti-freeze bottle as overflow while filling till air is out and then reconnect catch can.

 

Hope my pm let you know your not alone on this issue.

 

PM replied Clyde

 

The coolant cross over line at the front of the engine, is it caped off?? If it is its makes it VERY hard to get all the air out of the system. This nipple needs to go to a spot on the radiator. The factory routing on F-bodys is to the throttle body and then to a spot on the radiator near the cap. Most people by-pass the TB and go right to the radiator.

 

I don't think capped off will look at tonight when I get home.

 

Bleed air out from the steam tube.

The overflow bottle has to be vented.

The line to the overflow bottle has to be on the upper port of the radiator cap neck; the steam tube goes to the lower port.

 

Joecar The overflow can hose comes from bottom to connection coming off radiator.

The catch can has a vent on top.

If it helps this is what I'm running for a catch can.

http://www.jegs.com/i/JEGS+Performan...51137/10002/-1

 

The air pocket will be at the highest point in the cooling system, so that's where you need to bleed it. On my Mav, the highest point just happens to be the fill cap, so it's painfully easy for me. Just like an old-school car should be...

 

Start w/ a cold engine
Remove rad. cap
Idle for 1 minute
Install cap
Cycle RPM from idle to 3000 until coolant reaches 210F
Shut off engine
Remove cap
Start engine
Idle for 1 minute
Install cap
Cycle RPM from idle to 3000 until coolant reaches 210F
Shut off engine
Remove cap
Top off

 

I have never been inside an LSX water pump, but I have seen first hand that all others (esp the LT-1's) spin the impeller on the shaft and cause this complaint in higher HP/RPM motors. I would try a water pump.

 

I had to work over so going to attack this thing Friday as I'm off.

 

I am not doubting water pump but I had LT1 before had 128,000 miles before I sold it ..same water pump was on it.

It just does not make sense that would be my water pump as everything was running perfect before ac & heat install which required draining anti-freeze to install heater hoses.