For several years I've been toying with the idea of designing a circuit that could be added to any vehicle that would monitor oil pressure and coolant temperature (or, alternatively or even additionally head or exhaust temperature) and set off a wailing siren under the dash when these values raised (or dropped) to dangerous levels. The trigger level could be set manually.

There is a great need on every vehicle for this. I wonder why one hasn't been designed yet. Or maybe one already exists?

Dave

-=-=-=-

>Mark is right.
>I ignored the flashing  light many years ago, much to my later expense.
>Apparently the oil was so hot that the oil pressure was low.  Regrinding
>a crank, 4 new rods, new bearings and a gasket set (and LOTS of hours)
>made it like new.
>I think ALL race cars have lights in addition to the guage. All 356
>Porsches had lights only. Things have changed a lot since then, but
>356's had to be one of the most ahead-of-their-times cars ever built.
>Al Brase
>
>mark drillock wrote:
>
>>Actually, it does not work quite the way you say. The dual oil switch
>>circuit board never ignores the low pressure switch. It does ignore the
>>high pressure switch when the engine is at lower rpms, below 2000 or so.
>>Above that rpm it watches both switches and blinks the LED if either has
>>a bad reading and also rings the buzzer if it is the high switch with a
>>bad reading. As for a gauge being preferred to an idiot light, no way. A
>>good supplement perhaps but not a substitute. I have had my engine saved
>>by the blinking light. Traveling on the freeway one night with my SO
>>driving, she says "what's this blinking red light?" I lean over, look,
>>and yell pull over! I get out and find oil dripping off the back of the
>>Van and no oil reading on the dipstick. A valve cover gasket was leaking
>>on one side. Not a big leak but enough to drain the engine after a few
>>hours of highway driving. I had checked the oil level at the last fuel
>>stop and it was fine then. Do you think she would have noticed a low
>>pressure reading on a gauge in time to save the engine? No way. A
>>suddenly blinking red light, yes. I drove that engine for many years
>>after that event.
>>
>>As for disabling the tach feed when using the later cluster there is a
>>better way than cutting a trace. Simply bend the male pin over a few
>>millimeters. So the connector misses it when put in place. There are 6
>>pins in the connector on the back of the speedo, a group of 2 and a
>>group of 4. The outside pin of the group of 4 is the tach signal to the
>>oil warning board. Bend that pin to the outside and push the connector
>>back on the remaining pins. Then only the low pressure switch will be
>>monitored.
>>
>>Mark
>>
>>John Bange wrote:
>>
>>>
>>>
>>>Well, ideally you'd want to go in and cut the trace feeding the tach
>>>signal
>>>to the "dynamic oil pressure sensor" circuit board. Above 2000RPM the
>>>board
>>>ignores your .3bar sensor and just watches a ground loop where the .9bar
>>>sensor should be. Cutting the RPM signal to the board would make it
>>>think
>>>you were always below 2000, thus keeping your .3bar sensor "in the
>>>loop" all
>>>the time. Realistically though, it shouldn't matter. If your oil
>>>pressure
>>>drops far enough to trip the .3bar sensor when you're above 2000RPM, the
>>>light is essentially a "pull over and swap engine" signal. I mean,
>>>maybe if
>>>the pump was sucking air because of a major leak blew all your oil
>>>out you
>>>might be able to pull over before your engine goes feet up, but more
>>>than
>>>likely not. The idiot light is better than nothing, but not much.
>>>Personally, I think an oil pressure gauge is the only really sure way to
>>>know when things start "heading south". The Vanagon oil light reminds
>>>me of
>>>the TEMP light in my awful 82 Olds Cutlass-- it really should have been
>>>labelled "THAR SHE BLOWS".
>>>
>>>
>>>
>>>
>>>--
>>>John Bange
>>>'90 Vanagon - "Geldsauger"