Just noticed while at highway speeds my engine temp was higher than usual. I've never had my gauge read higher than the n in the word normal. Now it reads in the m, and down to the r with both heater cores blasting. My oil pressure reads on the l in the word normal, and this never used to read that high at hwy speeds. The water pump is only 2 years old. Don't know age of tstat. Help!

 

Also does anyone know a good diesel mechanic in Columbia or kc?

 

The gauges are notoriously inacurate. I would get a couple of aftermarket gauges and stick in there.

 

I know but I need diagnosis help asap

 

Did it physically overheat on you?

 

It didn't hit h yet

 

if the vehicle is not physically overheating you will be ok, but like stated before stock gauges are very bad at being innacurate best suggestion is to buy aftermarket gauges, i have a set of 3 gauges from advance they are all mechanical gauges but its a start and not all that expensive, only precaution i have for you is be very carefull with the oil pressure gauge plastic line

 

I'm thinking the tstat is bad so ill replace it. I have 1800 more miles to drive and a stuck shut tstat is not on my itinerary
Y

 

check your alternator and voltage regulator, if the voltage gets to high the gauges can be affected. volts should be 13.7-14

 

Hi,

I'd take a look at this:

Diagnose Engine Overheating – Auto Repair Help

If turning the heater on makes a noticeable difference, the radiator becomes a likely source of the problem.

Any signs of head gasket problems? Oil in coolant, coolant in oil, fully pressurized radiator hoses upon start up (engine cold).

Better gauges might be a good long term thing. Right now, I'd get a non-contact IR thermometer. You can use it to check the radiator for blockage, and when you stop and pop the hood, you will accurately know how hot the motor is.

Roy

 

The oil pressure gauge is on a pressure switch sender. Once it reaches about 7psi. the switch closes, and the gauge reads somewhere in the normal range. If the gauge is reading higher than normal, that would indicate an electrical issue, likely affecting the temp gauge as well. I doubt that you actually have an overheating and high oil pressure problem...

 

Well, I guess the heater fan (when heater is turned on) might be drawing current and messing with the gauges.

Try pulling the fuse for the heater fan, running the van until it gets a bit hot, and then turning on the heat (flowing coolant to the heater core, but the fan won't work), and seeing if the temp still drops with the coolant flowing to the heater core.

 

Just to follow up, I wanted to post what I did.

After a while, the temp gauge was reading around the M in normal. Then it shot down to cold. My guess was the t-stat was now stuck open, after it was nearly locked closed.

So, I found a motorcraft t-stat at a KC dealer, and installed it myself. Pretty easy and I was able to clean up and paint the housing neck and some brackets in the process. Now it runs at the "N" in normal.

Thanks for all your suggestions. I know the Volt Reg is good, cuz it's only a year old. And I replaced the blower motor and resistor only a year ago too. And my digital gauge showing voltage was reading around 13.2-13.5V while at highway speeds.