My 87 300d t has always run on the hot side, however living in the desert, that may be expected. On hills, the temp rises to 105 C at which point I would back off the throttle but the temp would no doubt go higher continuing at 70mph. The aux fan works as it should. The viscous fan seemed to be working in that it was very uncoupled cold and rotated a couple revs when hot when the eng is shut off. But my goal was to lock up the fan at all speeds because of our extreme heat.

While overhauling the A/C, I added 2 tubes of Toyota's 6000 CST fluid to the viscous fan. I should note that popping the bimetallic strip off and again back on is made a lot easier by applying a heat gun to develop a normal curve then simply wiggling it out to avoid bending the strip excessively. The fluid was applied using a syringe with the needle cut off. Some loss of fluid will occur and I would estimate that I lost about 20%. It helps to periodically heat the fan.

After the mod, the fan when given a good flick, will now rotate about 40 Deg. (about one blade) whether hot or cold. It seems to be at max lockup. The engine may run somewhat cooler. Before the fan mod, the eng temp would continue going higher when idling with the A/C on but now stays at about 85C. I have yet to get it out on the hills. We have extreme heat right now and I am not sure it would be a fair test.

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Dan
1981 240D
1987 300D Turbo
1973 220
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