Am I Overheating? Temp Gauges Don't Agree.

[Iceni John]

I would just replace the dash gauge. The full sweep gauge, like in the engine compartment is so much more accurate and easier to read. Good Luck, TomC

I agree.   However, I've not yet found a 2-1/16" full-sweep black-face and black-bezel analog electrical temperature gauge for an affordable amount.   Even Summit Racing, which has as good a selection as anywhere, doesn't seem to have anything suitable.   My plan was to buy a full-sweep gauge to replace the present short-sweep Teleflex gauge, and then to also have a mechanical gauge at the rear-start panel on the passenger-side bank where all the temperature sensors now are (is that bank the hotter one?).   I'm guessing I could reuse the present gauge's wiring for the new sender and gauge  -  will that work?

Ideally I would like a dual gauge with a sender on each bank, but they're even harder to find in a style and size that matches my present gauges.   Didn't someone here post a photo a few months ago of, I think, an aircraft dual gauge?   Mind you, if it were mechanical it's not going to be much good 40 feet from the engine!

John

[Rick 74 MC-8]

A little out of the box. Mechanical gauges mounted in a box in the engine bay with a video camera and monitor up front
Rick

[gus]

Digital or analog is not the problem, wire length and old corroded connections is.

Mine is digital which replaced an analog.

Mechanical panel gages are out of the question and such long wire runs make electrical ones inaccurate.

Rick's idea is not that far fetched but my method is much simpler and works.

[luvrbus]

Well hell just do it with 3 lights on the dash from senders mounted back at the engine lot's of boats just have 3 lights no gauges  cold, normal and hot  yellow, green and red 

[gus]

If the gages aren't accurate neither will the lights be. The problem is long run wire resistance.

[luvrbus]

Lites don't care about resistance for that application all they need is tempature controlled 2 wire open and close sender I have a system in the RV that uses lights it works pretty darn for to me

[sparkplug188]

Lights are a simple and reliable way of getting the job done.  If any one needs a schematic for temperature lights, I will gladly draw one up.  It is a pretty simple setup-- I am sure most people can figure it out without a schematic.

FWIW Coiling the sensor wire is a valid way to calibrate VDO gauges.  I had a hard time believing it until I tried it out myself.  Just add more coils to decrease the displayed temperature or remove coils to increase the temperature.

In the OP, his dash gauge is reading higher than actual temperature (that is assuming the engine mounted gauge is accurate).  That can not be caused by loose or corroded wires.  The problem is actually to little resistance on the signal wire.  The way to fix the problem without changing out equipment is to increase resistance on the signal wire.  That can be done by adding coils to create more resistance or by using a variable resistor.  I have ordered a few different variable resistors to try calibrating my gauges.  I will post my findings when they arrive in a week or two.

[gus]

I stand corrected on the lights, makes sense!

Loose connections and corrosion will definitely increase resistance. This causes mine to read low.