My engine was rebuilt several months ago. I hope to fire engine up this weekend. This cooling system is bone dry. Tonight I began adding coolant and distilled water. Owners manual with heater calls for 19 quarts. My 63 shop manual says 16 quarts. Cannot locate my 65 manual at this time. I was able to add 14 quarts of this 50/50 mix. I poured coolant into the t-stat opening in intake with the upper hose off, and the expansion tank open. Irregardless, is there a trick to burping this engine prior to the cam break-in? I would hate to have to shut down this engine during it's cam break period due to overheating for lack of enough coolant in it's system.. I have drilled a tiny hole in the t-stat to aid this burping problem. Can I leave the expansion cap off to monitor level and add coolant while the engine runs? Problems/concerns? Thanks DG
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always fire "new" motor with tap water
usually one will have a coolant leak or other issues that dictates coolant removal for repair/adjustment---get the motor/car 100% then remove coolant and install what you think is correct---good luck phil -
Re: Topping off coolant in rebuilt engine
Hello Dick, New engine start up is sometimes intimidating. Lets go back a little. Have you filled baby with the proper kind of oil? Have you added EOS from GM parts? Are you familiar with precharging the Oil Pump prior to start up? Is the Timing "Dead On"? Check all water connections, Belts, Battery Fluid and definitely the Oil Pressure line. I add one quart overfill of Oil when starting a fresh engine. No harm will be caused and you should gain a better splash factor for the Cam and Lifters. The recommended Cam break in period of at least Twenty minutes can be broken down into segments if need be. Start the engine and run it up to 1500RPM and hold it there as long as the Temp. behaves and the engine sounds good. Should a problem arise such as High Temperature don't hesitate to shut it down. Be ready for "Run On" so have your foot on the break and the Gear Shift engaged to stop the Hot motor if need be. Definitely a good time to have a buddy who knows his way around a car to help. Good Luck, Al W.Comment
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Re: Topping off coolant in rebuilt engine
Thanks for the replies. My engine builder/mechanic/machinist friend is coming over saturday. Yes, new engine start up is stressfull. I am using Shell Rotella 15-40. I posted earlier to other forum member's surprise that GM is not selling their EOS product anymore (discontinued). So, I will be adding Comp Cams cam break-in oil additive. This engine has standard springs. Yes, I have an old distributor turned into an engine oil priming tool. The timing marks are lined up by my builder for my convenience. My distributor is on #1. The oil pressure line is hooked up to gauge and engine. That woiuld be disasterous, as I have heard of this happening. Now about my initial question. How to preburp the cooling system? I appreciate your time and advice. Dick GutmanComment
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Re: Topping off coolant in rebuilt engine
Hi Dick:
I recently did the cam break-in exercise with my car. The camshaft manufacturer recommended slowly varying the RPM between 2000 and 3000 for the 20 minute break-in period.
I left the cap off the expansion tank so that I could monitor coolant level. Unfortunately, much of my time was spent in the driver's seat, due to the requirement for slowly varying engine speed, and my desire to watch oil pressure and engine temperature.
Everything went fine until the last few minutes, when hot coolant started spouting out of the expansion tank and the engine temperature began to rise. I was able to finish the 20 minute break-in before things got too bad, but it was unsettling.
In hindsight, I wish I had had an assistant to help me keep an eye on things so the problem could have been caught earlier. I think it is okay to leave the cap off for the first few minutes to monitor coolant level, but once the thermostat opens there is apparently quite a bit of flow and turbulence in the heater lines and expansion tank, especially at 3000 RPM.
At least that's my theory. It's also possible that the system had some trapped air and was in fact low on coolant. Like you, I have a small hole drilled in my thermostat to aid in venting air when filling the system, so I don't think that was the problem.
Unfortunately, I will never know the actual cause, but I thought I should mention that I had this problem, since you asked about leaving the cap off.Comment
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Re: Topping off coolant in rebuilt engine
Thanks for the reply. I will talk to my engine builder when he comes over to my shop on Saturday about this situation. DGComment
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Re: Topping off coolant in rebuilt engine
I think there is tendency to overfill. On initial fill just fill until the tank is half full. Bounce up and down on the bumper a couple of times as you are filling to help dislodge air.
At startup the level in the tank should stay about the same, then drop when the thermostat opens. As this happens just add enough to keep a little coolant at the bottom of the tank. This will allow air to bubble out without overflowing.
If you fill it up to half or more, big air bubbles can push liquid out the tank.
As long as the tank does not run completely dry, the system has enough liquid for cooling.
After is cools down. Check and fill the tank to half full.
DukeComment
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