|
Member
|
|
Join Date: May 2013
Location: nh
Posts: 858
|
|
Member
Join Date: May 2013
Location: nh
Posts: 858
|
for '87 #2, after doing the engine rebuild, i had noticed some coolant loss happening (although not actually loss). after extended interstate driving, the expansion reservoir would be overfull, and as the engine (and coolant) cooled, the expanded coolant would not return to the radiator. thus, rather than the radiator/cooling system being full to the top of the radiator neck, there would be space, sometimes just below the first layer of fins in the radiator. using a siphon, i could transfer the excess coolant in the expansion tank back to the radiator, and it would fill the radiator and leave the expansion tank full to the level i had initially set it to. so, not truly leaking, and not being consumed via combustion, either.
i pay attention to the temperature gauge, and since the rebuild, it has never run hot. if i avoided highway driving, and instead stayed on secondary roads where i might go 55 to 60 mph, the expansion tank never overflowed, and after cooldown, the radiator remained full. i put thousands of miles on it without losing coolant.
no external leaks, and when i rebuilt the motor, i used 100% new hoses for the entire cooling system, and replaced some of the heating system hardlines. one thing i never did after install was to recheck the head bolt torque values after initial install (where i torqued the bolts to correct value and in the correct order.
so, i pulled the valve cover and checked the torque, starting with the correct head bolt and proceeding to check all 10. i believe 4 were able to be turned before hitting the proper torque value, while the other 6 were at the correct value still.
after running to michigan and back, at highway speeds on the interstate (although i kept it to 65 mostly), the coolant level remained correct after cooldown. i suspect that there were combustion gasses entering the cooling system via the head gasket, which increased the pressure in the system and caused the coolant to expand into the reservoir (as it is supposed to). however, because of the gasses trapped in the coolant, once those reached the reservoir, the "air" bubbles escaped the system via the overflow outlet on the reservoir. when the engine cooled, the space previously occupied by the gas bubbles was accounted for by the excess head space in the radiator/cooling system, and the system wouldn't pull all the coolant back from the reservoir.
seems to be working now. probably should have checked the torque values a bit sooner than almost 2 years later.
__________________
member, new hampshire timberland owners association (NHTOA)
1987 4runner sr5, 22re, 5-speed
1988 4runner sr5, 3.0, auto (parts rig)
1987 4runner, sr5, 22re, 5-speed (#2)
|