[Vwdiesel] More Quantun questions?

[William J Toensing]

Took my '82 Quantum TD for a test drive. It still overheats despite replacement with a new 180F thermostat & fan temperature switch. The red light in the stock temperature gage blinked when starting but stopped as the engine started to warm up. I have installed the following extra gages in the center council where the useless ash tray used to live: pyrometer, boost, oil pressure, water temperature, & volt meter. The extra temperature gage sending unit is located in the main hose between the expansion tank (where you add water) & the engine. The stock temperature gage settled briefly at the half mark, then started to rise till it pegged but no red lite with the extra temperature gage rising to 230F. As I returned home, driving down hill, the main temperature gage remained pegged but the extra gage gradually dropped to 150F. When I got home, I opened the hood & found neither of the cooling fans were running but the coolant was boiling. I suspect a bad relay but where is it? In addition to the relay, I think I will install some back up manual switches.

The oil pressure at start up shows 80 psi but when it overheats, the oil pressure drops to 20 psi & I hear a warning buzzer & get  a red lite. Am running Amsoil 15W 40 synthetic diesel oil.

As to the vacuum booster, I detect a good vacuum with the engine running when I put my finger over the hole where the vacuum hose goes. The power brakes seem to have more boost when descending a hill in 3rd gear boosting engine RPMs. I suspect a leak in the hose going to the vacuum brake booster or the booster itself. Any trouble shooting suggestions for finding the leak?

Bill Toensing, Nevada City, CA.