Oh....and I also meant to mention that I cleared that 1211 code last night so I can see if it comes back or not.........

 

The EOT is the engine oil temp sensor. It's the one up high on the back side of the HPOP reservoir towards the drivers side.

I'm trying to find some reference voltages for you, but this new DVD workshop manual is not as user friendly as my old C/D was....I'll keep looking.

 

What about a clogged oil pickup screen in the sump? I've seen that on Audi's 5 cylinder engine. They have the oil pump mounted on the front of the engine just like the PSD, driven by the crankshaft. What it will do is very similar in behavior to what RedTaurus's truck is doing. They will run fine at lower temperatures, RPM's. And have good oil pressure. Get them out on the freeway and they will start to lose oil pressure real fast due to the fact that the obstruction on the pickup screen will create a vacuum in the pickup tube and aerate the oil badly. The oil pressure will drop to less than 20 psi on a healthy engine. I've dropped several oil pans on cars with this problem and found the obstruction was nothing more than a nickel sized deposit on a screen that is about 2 1/4 inches across. The deposit is right in front of where the oil tube comes down. (obviously) But the screen was NOT totally blocked. The cure was simply a new pickup tube with a slightly coarser screen on it. Then the oil pressure would jump to 40 psi at idle hot. Go figure, but it worked. I saved one guy's car from the junkyard about 10 years ago and he's still driving it today.
So I am wondering about the pickup screen on the PSD and if it's a part of the problem.

 

I read through the owners manual for your year truck and according to it the oil pressure/engine coolant light is the one that you apparently saw... it has an oil can and then a thermometer in liquid and they come on together... according to the manual... the reason that this light comes on is for 3 reasons...


Just thought I would share... it appears that there is no oil temp idiot light...

 

Well, when I saw an oil can and a thermometer, I put two and two together in my head and assummed it was an oil temp light. I swear the coolant temp guage was fine the first time this happened, and the guage only went to "H" after about 10 or 12 miles of driving with the light on when it happened the second time. Maybe I need to try and recreate the situation again and pay closer attention.........

 

well... according to the manual.... that light could be coming on as an indication of low oil pressure only to begin with and due to the low oil pressure it starts the overheating of your coolant after time... just throwing out ideas... I would have thought the same thing about the "oil temp" light if I didn't read the manual...

 

OK, I really hate to make another long and drawn out post, but I have more data now:

Here's the poop....I drove the truck this evening. We were going out to eat for my birthday and the trip is about 60 miles round trip. First off we had to make a stop for a meeting my wife had at 6PM. My son and I sat in the truck, with the engine running, AND the AC on wide open, in 90+ degree heat for over 1 hour (I know, I know), and the water temp guage didn't move. When we left there, we jumped on the Interstate and I set the cruise on 70. The AC was still on wide open. I kept my eye on that water temp guage the whole time. After about 12 or so miles at 70MPH, I noticed the temp guage started to rise. At about 18 miles she had gotten to about 1/8" from the top of the "Normal" range where the "H" starts. Normally, the guage rides at just below the 1/2-way point of the guage. Well, before the truck could get to the HOT condition, I slowed down to 65 and turned the AC from MAX to REGULAR. In about 5 miles, the temp guage had gotten back down to where it normally runs. I kept watching it, staying at 65, and right before we reached our destination, it had started to rise again. Then we exited the Interstate and ate at a fine Japanese steakhouse. After eating, we began our return trip. It was now dark out, and probably 75 degrees instead of 90. The truck was still at it's operating temp on the guage, however. I got back on the Interstate and set the cruise at 65. We went over 20 miles and the guage never moved. After a quick stop at Wal-Mart, we got back on the Interstate and I set the cruise on 70. We went about 3 or 4 miles and then I cranked her on up to 75 for the last 5 or so miles. Still, the guage never moved. I know it was cooler, but don't forget my very first episode happened when it was dark outside and not as hot. Since I don't have to work tomorrow, I may have a chance to go over some of the things we have discussed in this thread, like the oil cooler. I may go ahead and do the oil change since it is almost due. The more I think about it, the more that oil foaming deal makes sense to me. Thanks for lettin' me give your eyes and hopefully your fingers a workout.........

 

Just an FYI... Changing the AC from MAX to REGULAR does not change how the A/C compressor operates... it just changes where the air is drawn from...

MAX = recirculated air from inside the cab
REG = air from outside

so it appears that your trouble is with the speed... hmmm...

 

Just didn't want to leave out any DETAILS.........

 

I understand... and the capitalization was your handy work... I just wanted to inform anyone that didn't know the difference with A/C... The only way to change the compressor's operation is to shut it off...

 

The more I think about it, the more I think it is strictly an indication problem. I would start by replacing the ECT (engine colant temp) sensor, located on the water pump, or by installing an aftermarket temperature gauge.

I just don't see how dropping from 70 to 65 changes anything, especially after sitting at idle for an hour with the A/C on and no indication problems at all.

 

OK, cookie....gonna check out that ECTS today, and maybe replace it.........

 

Wouldn't you know it? The parts department at my local dealer has starting closing at noon on Saturday. They used to stay open until 3:00. I called down there at 12:30. but got no answer, so I called the dealer's main number and found out the parts department's hours had changed. Guess I will have to pay them a visit on Monday.........

 

Wow, that's a bummer. Why are you looking for a dealer part? Why not just pick it up at the local parts house (advanced, autozone, napa, etc.)

Look Here Type in "coolant temperature sensor" in the search block on the link.

 

Well, I might consider the 'Zone, but I have sworn off Advanced Auto, and I don't buy anything from NAPA because of Michael Waltrip.

I will call around Monday and see what I can find.........