Engine Temp - 6v92 DDEC 2

JT4SC · April 23, 2018, 08:05:28 PM

Hey everyone,

I've been lucky enough to drive my bus a few times over the last couple months, and one thing I've noticed is the temp gauge is staying cooler than it used to. I assume this is a thermostat issue but I would like to get confirmation from you guys before I go any further. I've attached a pic of the temp gauge, this is the temp it stays at regardless of trip duration, road conditions or outside temperature. It used to run closer to 180.

DoubleEagle · April 23, 2018, 08:16:34 PM

Seems like the sender, the gauge, or the wire connections are faulty. Maybe the thermostat is stuck open, but the only thermostat trouble I ever had was when it was stuck closed and it got hot (in other kinds of diesels).

Iceni John · April 23, 2018, 08:29:57 PM

1. You should clean and check every wire connection between the sender and the gauge, including all the ground(s). Even a small increase in resistance will throw the reading way off. If you can, also check the overall resistance of the entire wire itself to be sure there isn't a problem somewhere along its length. Temperature gauges use thermistors as their senders, so even a few ohms will make a difference.

2. Ideally, ditch that gauge! Quarter-sweep gauges without meaningful graduations are little better than a gauge marked Cold, Warm and Hot. I suggest you buy some full-sweep (i.e. 270-degree needle movement) gauges with stepper motors for the critical indications of engine temperature and oil pressure - even though DDEC will shut down the engine (if that option is enabled) when those two parameters are exceeded, it's prudent to not just rely on that to save the engine. Forewarned is forearmed. I've replaced my bus's original Teleflex coolant temp., oil pressure and transmission temp. gauges with full-sweep Speedhut gauges - now there's no guessing exactly what's happening.

John

JT4SC · April 23, 2018, 08:39:38 PM

Great advise, thanks guys! I'll do some research on those gauges and make sure to post them here before I buy them to make sure they are the right ones.

Iceni John, looks like you are in OC. You ever get down to San Diego?

Iceni John · April 23, 2018, 08:50:49 PM

Quote from: JT4SC on April 23, 2018, 08:39:38 PM

Iceni John, looks like you are in OC. You ever get down to San Diego?

I'll be there this Thursday to collect some folk from San Diego's second airport, or rather from the CBX bridge - no more waiting for hours at the border for me! I haven't taken my bus to SD, yet.

John

Brassman · April 23, 2018, 10:55:19 PM

Shoot the thing with an IR gun and see if the gauge temp synchs with the gun. Shoot where the sender is located.

chessie4905 · April 24, 2018, 04:11:13 AM

You can get an IR gun at Harbor Freight at very reasonable price. very handy to have around.

buswarrior · April 24, 2018, 05:55:18 AM

Gauges in coaches that sit....

First thought for a busnut needs to be "How do I know this gauge is telling me the truth?"

Take immediate action to confirm whether Chicken Little is aboard, but regard all those dashboard indicators as potential liars.

Nothing keeps working correctly in a busnut coach that sits, NOTHING.

A 50 foot length of wire with alligator clips on both ends allows you to zero in on the sending wires, you can also use your favorite extension cord and make up some trick ends for it. Then you can use the wire as a known good substitute, and as a known good return for the multi-meter. There's been more than one busnut get screwed up with sloppy grounding of the multi-meter by trying to use the coach body as the return, unwittingly adding resistance to screw up the diagnosis.

happy coaching!
buswarrior