Hey guys, I have a '96 HDJ80, all stock 12 valve 1HDT with 280,000km. Three months ago I installed an aftermarket water temperature gauge using an adaptor on the upper radiator hose and "while I was in there" I replaced all the coolant hoses (upper and lower radiator hoses, ACSD hoses, heater core hoses, turbo water hoses, heater control valve) using genuine Toyota parts. So far so good, no overheating, no leaks. One morning I checked the coolant level and noticed that the lower radiator hose was collapsed/compressed. It would go back to normal once the radiator cap was removed. I inspected the radiator cap, and saw that it was badly rusted and that the plunger that allows the coolant from the reservoir to return to the radiator was stuck closed. I cleaned it and was able to get the plunger unstuck. I put the radiator cap back in and drove the car. The next morning I inspected the hose and it was no longer collapsed.
Since the radiator cap was severely rusted, I bought a new one from Toyota. It was identical to the one I had (0.9 bar). Soon after, I started to lose coolant from the reservoir. I did not suspect the new radiator cap since it was a new genuine part, so I kept looking for leaks. I even bypassed the heater core to rule it out. The reservoir would be empty in only a week. I would fill it to the max level when cold, go to work and the coolant level on the reservoir would not go up, sometimes even dropping a bit, and it would drain back to the radiator as it cooled. I even thought that it might be the head gasket, but I'm not seeing any of the symptoms. No white smoke from the exhaust. No bubbles from the radiator when I tried to re-bleed the system. No signs of coolant in the oil cap and dipstick. Engine doesn't overheat, coolant temp is around 82-85C in the city, 85-87C on the highway cruising at 100km/h (9-10 psi).
As a last resort, this morning I reinstalled the old radiator cap and topped off the coolant in the reservoir. When I got to work, the coolant level on the reservoir was now an inch or so above the max line. Same thing when I got home. Coolant is now flowing to the reservoir and not getting "lost" somewhere.
What could possibly be wrong with the new cap? If it wasn't holding pressure, then wouldn't the reservoir overflow with bubbling coolant? I never experienced that. I don't think the seals are bad on the new cap since it takes more effort to fit it into the neck than the old cap. There are also no signs of leaking on the neck. Any ideas?
Since the radiator cap was severely rusted, I bought a new one from Toyota. It was identical to the one I had (0.9 bar). Soon after, I started to lose coolant from the reservoir. I did not suspect the new radiator cap since it was a new genuine part, so I kept looking for leaks. I even bypassed the heater core to rule it out. The reservoir would be empty in only a week. I would fill it to the max level when cold, go to work and the coolant level on the reservoir would not go up, sometimes even dropping a bit, and it would drain back to the radiator as it cooled. I even thought that it might be the head gasket, but I'm not seeing any of the symptoms. No white smoke from the exhaust. No bubbles from the radiator when I tried to re-bleed the system. No signs of coolant in the oil cap and dipstick. Engine doesn't overheat, coolant temp is around 82-85C in the city, 85-87C on the highway cruising at 100km/h (9-10 psi).
As a last resort, this morning I reinstalled the old radiator cap and topped off the coolant in the reservoir. When I got to work, the coolant level on the reservoir was now an inch or so above the max line. Same thing when I got home. Coolant is now flowing to the reservoir and not getting "lost" somewhere.
What could possibly be wrong with the new cap? If it wasn't holding pressure, then wouldn't the reservoir overflow with bubbling coolant? I never experienced that. I don't think the seals are bad on the new cap since it takes more effort to fit it into the neck than the old cap. There are also no signs of leaking on the neck. Any ideas?
