High idle and hot temps:
Well, it's today today and unfortunately I was asked last night to come in for day shift. That means no afternoon wrenching time to flush the cooling system... Boo.
I know the system needs flushed because my idle was sitting at 2500rpms last night for the trip home from work, and I had the idle screw screwed all the way in. To eliminate a few variables that might be affecting the idle speed, I pulled off the dash pot and adjusted the throttle blade 100% closed and then made a little air gap between the stop screw and the linkage (the spec for the stop screw is "touching the linkage, + 1 quarter turn" to keep the throttle blade from sticking closed), so I'm 99% sure that some rust-mud in the coolant made it's way to the IACV again and I need to blow it out. But how to make that happen on a school morning when I have to go to work AND get the kids ready?
I've got an idea:
Letting the truck sit overnight should let whatever rust-mud is in the radiator settle to the bottom. When the boys eat breakfast, I'll pop out REAL quick and open the radiator drain and catch the coolant until the mud stops. Then I'll use my lung power blow out the IACV (takes 3 seconds with a pair of pliers for the hose clamp, I figure there's no need to use a compressor when we're in a hurry), THEN I'll top up the rad and be good.
1) Drain the mud: I open the drain valve and catch about 1-tsp of mud before precious green fluid starts coming out. "woo-hoo", thinks I. "looks like I'm finally getting somewhere!"
2) Blow IACV out: Done. No resistance at all, it just lets me blow right through.
3) Top up: I add half a liter of green coolant, and top up the overflow with deionized water.
Done and done.
Dropping off Hungarling #1 goes fine. The idle speed still wants to be at 2000rpms but I don't spend a whole lot of time with the clutch in or with the trans in neutral on our 3km trip to the school so engine speeds while in gear are more normal. From there it's only another KM or so to the youngest Hungarling's kindergarten. Except I don't make it...
I got stuck behind a trash truck on the main drag and the temperature gauge started to creep up. It made it about 7/8ths scale before I got to a spot I could pull over. The youngest and I watched an 8-minute Fortnite video (his request) to let things cool a bit before I checked the gauge again. Half scale.
Thinking the fluid in the rad would circulate as soon as the t-stat opened up (and would cool things further), we started the truck back up and headed back off. I made it 1 block before it was back up at 7/8-scale again. Through a combination of shutting it of to coast, and starting it just long enough to make a turn, we get it to my new house which is very much under construction (total distance was about a block and a half). We again shut it off, and let it puke for a bit. Once every 5 minutes or so I'll start the truck for a 10-count just to try to keep things circulating.
The tap water is still on at the new place and I find an old camping pot we left there for the odd occasion we need to heat something up. The water here is super "hard" and I don't like using it in my cooling systems, but I figure some water is better than no water. I fill the pot and head back to the truck.
The first thing I notice is the upper rad hose isn't warm at all. Neither is the IACV hose that also feeds off the thermostat. I think the darn T-stat might not be opening!
The second thing I notice is my overflow tank is AGAIN full of this RUST-MUD!!!
I have a pair of pliers with me so I use those to remove the expansion tank and dump it inside the house. It's gross. I put the tank back in, safely remove the radiator cap, and start topping up. Once full, I start the truck to circulate fluid and the coolant level in the radiator drops. I add some more and more and more (about half a gallon, maybe more) and shut off the truck with the cap still removed.
Holy smokes! What happened next I wasn't expecting, but I got a pretty decent fountain of overflow out of the top of the rad! A good 3 or 4 inches high!!! And oh my gosh was it gross looking! It wasn't "mud" but it wasn't far off. Something far beyond "rust orange" this stuff was so thick, it ws BROWN! Where in the heck was all this crap hiding in my engine???
Seeing the potential benefits of this "side of the road flush" I start the engine again. Add a half gallon of tap water. Shut it off, aaaaaaaaand "BLOOP"! Out comes more orange fluid!
Rinse, repeat.
So, after about 4 times of doing this, the neighbors start looking at me funny (who is this guy starting his loud truck, and why is there orange fluid all over it and the ground?) so I decide I should be good enough to continue the 4 block trek to the youngest's kindergarten.
Nope.
When I started the engine again, the scale was normal but it didn't stay there for long. I made it half way to school and it started to creep to the half-mark, so I shut it down and parked it safely on the side of the road. We finished our trek on foot.
Well heckbeans.
It's no big deal, I call in to work and tell them I'm overheating and will be "a bit late". The youngest Hungarling and I enjoy the walk and when I get back to the vehicle, things seem normal again. I fire up the truck and have every intention of driving it home to swap with the Mazda, but when I get to the "do or die" roundabout I choose "die" and take the exit that takes me to work. I almost made it too! But alas, 4km into the 7km journey that needle is climbing again. Just over the half mark, I shut it down at a safe location (I was planning ahead this time, I had several spots in mind)
I pop the hood and nothing is leaking. The cap is holding a fair bit of pressure, and this time the upper rad hose was hot (but I had been sitting for 5-minutes here before I checked it)...
What in the world is going on???
And then it hit me:
I started the truck for 10-seconds to circulate the fluid (like I usually do) and I just happened to hop out immediately afterwards with the hood already opened...
I snapped that picture of the collapsed upper radiator hose JUST before it popped back to its normal shape...
I think I found my culprit.
I don't know if something is plugged, or if the T-stat isn't opening, or what, but everything here is new (radiator, rad cap, t-stat, fluids). Well... Nothing to do now but let things sit, I'm afraid. I call Mrs. Hungary and she takes me the rest of the way to work. After work I'll try a "wham-bam" flush tonight in an effort to get this thing ready for its trip to Bratislava tomorrow morning.
Fingers crossed.