maichor Posted July 26, 2004 Share Posted July 26, 2004 Well, I finally got my driveshaft. I have been waiting for months for the 300ZXtt one piece driveshaft conversion flange to have it made. Hopefully, next week you will be reading about my first drive. That is not my problem. Most of you LS1 guys know about my project. The motor has 10K miles on it but has been sitting for more than a year. I have had the motor running for some time, but the coolant is not circulating. I pulled the water pump, it appeared to be fine. Pulled the thermostat, still no go. When the motor was out of the car, I tried to blast the coolant passages with a hose and water did come out the other side. So, I replaced the pump anyway. So, now the motor is back in the car and still no go. I have a hose circulating the feed and return for the heater. I also have and ASP underdrive pulley. I have had the motor up to 220 degrees. I dare not go any further until I figure out what is wrong. HELP ME PLEASE! Could I have blockage? How hot is too hot (where I am risking damage to the motor). What would you do? Phantom, I read a post where you said it took a while to blow the crud out of your block. How long and what temp? Thanks Quote Link to comment Share on other sites More sharing options...
Phantom Posted July 26, 2004 Share Posted July 26, 2004 Michael, I actually had no crud in my LS1 - it was more like air pockets. It took a couple days the first time. Each day I would run the car to work and back, wait for it to cool down, and then go fill the overflow bottle. The first time I added some to the radiator too. The second day I added a little to the overflow. I figure it took and extra 2-3 quarts during that process. Remember, this is an aluminum block and there should be no steel to rust and crud the system up. I'm running a 180°F thermostat and the dual fans from the Z28. On one fan the car runs about 205-210°F. On two fans it holds solid at 180°. If you have a way to make the engine defintiely the low point then you can pump coolant through it for a while. Also - someone help me here - isn't there a bleed valve high on th eengine on some of the LS1's? I thought I read that somewhere. Mine doesn't have it. Quote Link to comment Share on other sites More sharing options...
mas28O Posted July 26, 2004 Share Posted July 26, 2004 Are you using the 160 thermostat? I have used two motrad 160 thermostat and both where bad. My motor would run hot at idle. Mike Quote Link to comment Share on other sites More sharing options...
DaleMX Posted July 26, 2004 Share Posted July 26, 2004 I know this sounds silly, but. Are you sure you have the belt on the correct side of the pump pulley? Dale Quote Link to comment Share on other sites More sharing options...
Phantom Posted July 26, 2004 Share Posted July 26, 2004 Now that you mention it - I had to replace my thermostat too. It stuck wide open this past winter and the car was running cold. Let me know on routing - I have a photo of my belt routing I can email you. Quote Link to comment Share on other sites More sharing options...
Mikelly Posted July 26, 2004 Share Posted July 26, 2004 Yup, Sounds like an airpocket. Also, Don't be affraid if the motor gets up above 220 degrees... My motor hits 230 Degrees regularly in rush hour traffic. These motors are notorious for that. Mike 8) Quote Link to comment Share on other sites More sharing options...
MikeJTR Posted July 26, 2004 Share Posted July 26, 2004 Correct me if I am wrong, but it sounds like you ran a hose from one heater hose fitting to another heater hose fitting, bypassing the heater core. If you are doing this, it may result in coolant recirculating through the heater hose, and not through the radiator, or engine. This could cause the problem you describe. The underdrive pulley would just make things worse. Chevrolet and other manufactures often run restrictors in the heater hose to prevent this type of problem. Also, JTR/Stealth has just started making air bleed valves that can be installed into the upper radiator hose and the heater hose. The parts should be on the JTRpublishing.com website in the next few weeks. Quote Link to comment Share on other sites More sharing options...
80LS1T Posted July 27, 2004 Share Posted July 27, 2004 If it is an air pocket you could get one of those air purge tools for coolant systems to make sure you get all the air out. You can get them for about $100 from Cornwell tools or even Snap-On. Guy Quote Link to comment Share on other sites More sharing options...
SSflyer Posted July 27, 2004 Share Posted July 27, 2004 There's a special purge procedure for the cooling system on the LS1. The instructions I received with my 160 t-stat are as follows: 1. Fill the cooling system with the proper water/cooant mixture. Pour the coolant into the surge tank. (Fill the radiator full and then also put some in the surge tank.) 2. Start the engine and let it idle for approximately 1 minute. 3. Reinstall the surge tank cap. 4. Cycle the engine from idle to 3000rpm in thirty to fourty second intervals. This needs to be done until the engine coolant temperature reaches 210F or 90C. 5. When the cooling system is at the proper temperature, shut off the engine. Remove the surge tank cap. 6. Leaving the surge tank cap off, start the engine and let it idle for one minute. Then fill the surge tank with the coolant mixture to 1/2" above the "Fill Cold" mark on the surge tank. (Keep in mind this procedure was written for an F-body coolant system!) Now reinstall the surge tank cap. 7. Repeat step 4 once more, then shut off the engine. 8. Allow the vehicle to cool, then remove the surge tank cap again. Top off the coolant system to 1/2" above the "Fill Cold" mark on the surge tank, then tighten the surge tank cap. Those are the directions copied right from the Hypertech instructions. The notes in parentheses ae my own. Believe me, if you don't follow these instructions you'll never get it to work right. I had the same problem you described after I did heads & cam and I thought I had plugged a passage somewhere, but after remembering this procedure it solved the problem immediately... Quote Link to comment Share on other sites More sharing options...
maichor Posted July 27, 2004 Author Share Posted July 27, 2004 Wow, thanks for the great posts, I guess I will try the purge procedure and see what happens. I guess I was giving up too early. As for the thermostat, I will try that next. And no, there is no way that my belt is running backward (unless the whole motor is running backwards!) Thanks again guys. Quote Link to comment Share on other sites More sharing options...
80LS1T Posted July 27, 2004 Share Posted July 27, 2004 And no, there is no way that my belt is running backward (unless the whole motor is running backwards!) Thanks again guys. I think he ment do you have the belt on the correct side of the pulley. It is possible to have the belt on the pulley but not have it turning the pulley 100%. In other words is the smooth side where it should be and is the ribbed side where it should be? Guy Quote Link to comment Share on other sites More sharing options...
maichor Posted July 27, 2004 Author Share Posted July 27, 2004 I think he ment do you have the belt on the correct side of the pulley. It is possible to have the belt on the pulley but not have it turning the pulley 100%. In other words is the smooth side where it should be and is the ribbed side where it should be? Thanks, and yes, I know what he meant. I said that about the motor tongue and cheek. The water pump does run off the back of the belt and the ribbed side is on the crank pulley. That is definitely not the problem. There is a plug by the starter and the TB gets coolant from the heads, I did a bypass, but maybe I could use one of those to bleed the system. About the heater. I did not know it would cause a problem. I'll have to sort that out or cap it off for now. Quote Link to comment Share on other sites More sharing options...
Mikelly Posted July 27, 2004 Share Posted July 27, 2004 Also, Be aware that the Vette guys are getting better results running a 60/40 mix of dexcool to water and adding a bottle of Water Wetter. Mike Quote Link to comment Share on other sites More sharing options...
jeromio Posted July 29, 2004 Share Posted July 29, 2004 To answer Phantom's question, yes, there is an air vent system in the heads of the LS1. There is a line that connects both head vents and then runs thru the throttle body and then into the radiator on the FBody. I have mine going into the upper radiator hose, but I have bypassed the throttle body. It is very important to connect this vent line. I had initially tried capping the vent - sort of a half-assed "I'll plumb that later" move. Well, the heads were full of air and the thing overheated all the time. I actually don't think that the upper rad hose is an effective vent dump either. I think it's a bit too low. The ideal soln. would be to plumb it into the top of the radiator tank. This would be very easy to do with a Datsun radiator, a little harder with the side tank style - especially my camaro rad which has nylon side tanks. My "procedure" for getting the air out of the heads involved running the motor with the rad cap off and the head vent line dumping into the radiator. Can't say it's the best way to do it, but it worked for me. Quote Link to comment Share on other sites More sharing options...
Phantom Posted July 29, 2004 Share Posted July 29, 2004 Not to highack the thread - I have to renig on some of what I said. My LS1 does have the vents and they are routed into th etop tank on my radiator just under the cap. I'm sitting here going - duh! - I've only had that vent line there for a year now! Quote Link to comment Share on other sites More sharing options...
DaleMX Posted July 29, 2004 Share Posted July 29, 2004 There is a plug by the starter and the TB gets coolant from the heads, I did a bypass, but maybe I could use one of those to bleed the system. About the heater. I did not know it would cause a problem. I'll have to sort that out or cap it off for now. Let us know if that worked please. I will be firing up my LS1 in a couple of months and dont want to re-invent the wheel. Dale Quote Link to comment Share on other sites More sharing options...
Briguy280Z Posted August 6, 2004 Share Posted August 6, 2004 I didn't even think twice when i started my engine. Coolant was in it started it up and never turned back...some leaks here and there but no air pockets. My heater hose is hooked up so i would check the bypass you did. 220degrees in nothing for this engine especially when its idleing. I always get nevous when my tstat goes to red...but thats how the engine runs If it gets over 235 and nothing is happening then i would worry. Check out the GM service manual its all in there!!?! Theres easy ways to check your tstats before you install them...i due anyways so i dont have to do it twice. GM Manual-- The PCM will turn the cooling fans on low speed when any of the following conditions exist at idle: Certain PCM Diagnostic Trouble Codes (DTCs) are set. The ECT above 108°C (226°F). The A/C high side pressure above 215 psi. Once the low speed fans are turned ON by Engine Coolant Temperature, the PCM will turn the fans OFF when that temperature has dropped about 4°C (7°F). If the low speed cooling fans are turned ON by high A/C head pressure, the PCM will turn the fans OFF when the pressure has dropped to 190 psi. The minimum ON time for the low speed cooling fans is 50 seconds. The cooling fans are turned OFF at certain vehicle speeds. Adequate airflow through the A/C condenser and radiator occurs with vehicle movement to properly cool the A/C refrigerant and engine coolant without the assistance of the cooling fans. High Speed Cooling Fans The High Speed Cooling Fans are controlled by the PCM based on the following inputs: The A/C system. The Engine Coolant Temperature (ECT) sensor. The Vehicle Speed Sensor (VSS). The PCM will enable both fans on high speed when any of the following conditions exist: Certain PCM Diagnostic Trouble Codes (DTCs) set. The ECT above 112°C (234°F). The A/C high side pressure above 248 psi. Once the high speed cooling fans are turned ON by the Engine coolant temperature, the PCM will turn the fans OFF when that temperature has dropped about 4°C (7°F). If the high speed cooling fans are turned ON by high A/C head pressure, the PCM will turn the fans OFF when the pressure has dropped to 208 psi. The minimum ON time for the high speed cooling fans is 30 seconds. good luck Quote Link to comment Share on other sites More sharing options...
Briguy280Z Posted August 6, 2004 Share Posted August 6, 2004 I forgot to ask!!? Did you uses your style of motor mounts or are you going to do something like MAS28O Quote Link to comment Share on other sites More sharing options...
maichor Posted August 6, 2004 Author Share Posted August 6, 2004 I used the mounts I came up with a long time ago. I have since added a plate that runs along the frame rails runder the stock cross member and mine. It is all one piece and absolutely bullet proof. It is too bad I won't be driving this off road! I know I said it last weekend, but I only got about an hour to work on it. Hopefully, this weekend will be the test drive. Quote Link to comment Share on other sites More sharing options...
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