91 jetta overheating report

[albsure]

hi guys, well, after everything i still was not getting good results. temp light still blinking, fan not cycling properly or staying on long enough, still running hot but taking longer to do so. what next?  :idea:  re-replace everything. so i bought 2 new sensors, in the hose at rear of engine and bottom of radiator. replaced relay for cooling fan, replaced reservoir, cap and seal. i know the thermostat is good because i opened the system hot and poured water in the top hose towards the engine and got water out of the top hose fitting in the radiator and if the coolant pump was not working properly we would have had meltdown by now. the temp light stopped blinking and it runs at 1/2 on the gauge. the fan seems to be cycling on and off properly so that when it goes over the half the fans now cycle on and bring the temp back down. with the A/C on it runs at about 1/2 way between 1/2 and 3/4 on the gauge. i still feel that this is a little high, but then i have a limited knowledge of diesel engines. however, i still cannot get the high speed on the cooling fan. if i short the wires at the thermal switch at the bottom of the radiator, low speed comes on shorting from center to left. when i go from center to right side of the plug i only hear it click at the relay. when i unplug the relay and short it, the high speed will come on. that's the story, so what do YOU guys think?
thank you for your time, your knowledge and your patience with me and my '91 Jetta Ecodiesel. al b sure

[albsure]

it gets better i think. went to the car this morning. checked the reservoir first. when i opened it a blast of water came out and it was bone cold. so i thought that was just air lock. took the hose off refilled,started it, unbolted the res. uncapped it and held it up as high as the lines would allow. when i stopped seeing bubbles i put it all back together. between 1/4 and 1/2 the fan started cycling, and it stayed below the 1/2 mark, with AC it went between 1/2 and 3/4. this was parked at an idle, driving everything got a little bit warmer. but why wont the high speed on the fan come on.

[Master ACiD]

just wire the high speed fan to come on when the low speed is suppose to be on.

[chrissev]

sounds like you had vapour lock.  That was all the bubbles coming out of the reservoir.  Should be fine now.  For the high speed fan, you want to test the motor by wiring it directly to the battery.  If it doesn't work, then you know that the motor is faulty.  If it does work, then you know that the wiring is probably faulty.