Michigan Rotary Club
Technical and Performance => Engine Management Forum => : ~Groll69~ August 24, 2011, 07:13:26 AM
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Lately, i have been have nagging coolant issues with and 88 vert. It will push the coolant into the resivor, but will not pull it back into the system. I am trying to figure out why it is doing this. Right now i am running a lower temp thermostat, but i removed it to see if that helps. After the engine idled high for a few starts, the engine is back to operating normaly and idling where it should when i had the thermostat instaled. I just replaced the cap with a new one. I am trying to understand why i have gone through 5 different coolant caps in past two years.
I am wondering if the caps i am getting are two low on the PSI. What should be the max psi cap that i should be purchasing?right now i have a max 13psi cap on. Do i need to step it up and get the 14-18psi cap? It is just an NA engine that i am running.
I am also having alternator voltage fluctuactions. where my voltage will show anywhere from 12vdc to 14 volts dc. i am seeing 13volts on average under load.
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Is the cap on the thermostat neck spring-loaded, or just a cap? I had a similar problem with a replacement cap on the thermo neck; the spring-loaded plunger would open slightly when the system reached operating pressure & bleed off some coolant, which would then leak out from under the cap and drip or evaporate. The overflow on the radiator would work as intended, but since you were also bleeding out some coolant and could be sucking air back in, the coolant level in the engine would fall. I eventually found a spring of similar size to the one in the cap on the thermo neck and wound it in there to increase the pressure rating of that cap, so the radiator one would open first.
Check if the hose from the rad overflow to the bottle has any small cracks or holes that could be letting air in, as well as the hose/piece of the overflow bottle cap that goes to the bottom of the tank to suck coolant back in. leaks in these pieces would allow coolant into the overflow but not back.
Are the voltage fluctuations random, or do they occur under specific circumstances?