New Project Truck. 92 250 4x4 Manual.

[bumblebeer]

I'm having an overheating issue. Hoping someone could help me sort it out.

I'm using the factory gauges and it seems to be running a little hotter in general. The needle rides at about 12 o'clock where it would stay around 11 when I first got the truck. It has an aftermarket aluminum radiator and I just replaced the fan clutch. The condition and manufacturer of the thermostat is unknown.

I was driving on the interstate unloaded this morning keeping around 2200 rpm and the temp was slowly creeping up but not enough to concern me. But then I hit a slow down. After getting through it I dropped down a gear and helt it around 2800 rpm to get up a hill. That's when the needle went near the red and the idiot light came on. I pulled over to the side and shut the engine off to let it cool down. Popped the hood and it was damn hot. Smoke coming off from some diesel on top of the heads. There cause I just bled the fuel system.

I didn't notice any extra coolant in the overflow tank. The top radiator hose was hot and pressurized. The power hose was cool to the touch. Didn't notice any leaks. The radiator was hot at the top, and cooler at the bottom but still noticably warm. The lower hose does have a spring in it so it isn't a hose collapse issue.

After it cooled off, I popped the cap. Still had some pressure on it and the coolant level seemed fine. No oil in the coolant either. So I started it back up and got goin again. It seems fine now. But I'm also being sure not to get too far into the RPM.

I'm planning to get a motorcraft thermostat and replacing in any case but was wondering if that sounds like the cause or if I should be checking for anything else?

 

[bumblebeer]

UPDATE: It is not fine even taking it easy. And the bottom of the radiator is pretty cool where the top is so hot you can't hardly touch it. I'm gonna try to limp it back home and get the thermostat swapped out.

 

[Rdnck84_03]

Since the radiator seems to be cooling, I would say probably a flow issue. First thought would be thermostat.

What was the reason for replacing the radiator? Did the overheating issue happen rite after the radiator install?

James

 

[bumblebeer]

Since the radiator seems to be cooling, I would say probably a flow issue. First thought would be thermostat.

What was the reason for replacing the radiator? Did the overheating issue happen rite after the radiator install?

James

I'm not sure. The radiator had already been swapped when I bought the truck. Nothing was changed other than injectors and timing before I started noticing the higher temps. I did change the fan clutch thinking that may be the issue, but it sounds more likely to be the thermostat.

 

[Rdnck84_03]

Doubt this is the issue since you yours should be serpentine, but the belt isn't slipping on the water pump pulley is it.

James

 

[IDIBRONCO]

Doubt this is the issue since you yours should be serpentine, but the belt isn't slipping on the water pump pulley is it.

James

Actually, 1992 was the crossover year for belts. It could be serpentine or v belts. If it's v belts, then there should be more than one belt going around the water pump.

 

[bumblebeer]

Doubt this is the issue since you yours should be serpentine, but the belt isn't slipping on the water pump pulley is it.

James

Actually, 1992 was the crossover year for belts. It could be serpentine or v belts. If it's v belts, then there should be more than one belt going around the water pump.

Thankfully mine is a serpentine belt so there shouldn't be any slipping issues. Although I guess it's still possible. I will check.

I'm about to get into this thing and I'll check the old thermostat once it's out and I reckon that'll clear things up. Should be able to post an update this evening.

I'm also interested to see if the check ball has been removed. I was able to make it home yesterday. Luckily it was pleasant out so I rode with the windows down and the heat on full blast. And running it like that, I had absolutely no problems with overheating. I figured if the thermostat was bad that just running the heat wouldn't be enough. But maybe if the t-stat partially opens and the check ball is out allowing some additional flow, that would make sense.

 

[The_Josh_Bear]

I'm having an overheating issue. Hoping someone could help me sort it out.

I'm using the factory gauges and it seems to be running a little hotter in general. The needle rides at about 12 o'clock where it would stay around 11 when I first got the truck. It has an aftermarket aluminum radiator and I just replaced the fan clutch. The condition and manufacturer of the thermostat is unknown.

I was driving on the interstate unloaded this morning keeping around 2200 rpm and the temp was slowly creeping up but not enough to concern me. But then I hit a slow down. After getting through it I dropped down a gear and helt it around 2800 rpm to get up a hill. That's when the needle went near the red and the idiot light came on. I pulled over to the side and shut the engine off to let it cool down. Popped the hood and it was damn hot. Smoke coming off from some diesel on top of the heads. There cause I just bled the fuel system.

I didn't notice any extra coolant in the overflow tank. The top radiator hose was hot and pressurized. The power hose was cool to the touch. Didn't notice any leaks. The radiator was hot at the top, and cooler at the bottom but still noticably warm. The lower hose does have a spring in it so it isn't a hose collapse issue.

After it cooled off, I popped the cap. Still had some pressure on it and the coolant level seemed fine. No oil in the coolant either. So I started it back up and got goin again. It seems fine now. But I'm also being sure not to get too far into the RPM.

I'm planning to get a motorcraft thermostat and replacing in any case but was wondering if that sounds like the cause or if I should be checking for anything else?

I'm not saying that your engine isn't overheating, but the stock gauges are worthless. You need a real gauge to tell the temp or use an infrared heat gun if you have one of those for some spot checks. Lots of people have fixed "overheating" issues by just getting a true gauge and realizing the OEM junk was lying/inaccurate.

T-stat is a great start. Rad is clearly cooling well. Does the new fan clutch make the fan roar to life on first start when cold? If so it's working. It's not unusual to have a bad fan clutch out of the box, which I why I asked.

 

[bumblebeer]

T-stat is a great start. Rad is clearly cooling well. Does the new fan clutch make the fan roar to life on first start when cold? If so it's working. It's not unusual to have a bad fan clutch out of the box, which I why I asked.

I was kinda thinking the same thing. I haven't paid attention to it on a cold start, but I will tomorrow morning. Is there a sure fire way to test it? I've tried moving the fan blades when the engine is cold, and once it's warmed up, and it seems about the same as the old one. Which I'm pretty sure was bad. The old one may have been the original and the spring coil was full of gunk so I'm thinking it puked out all the oil at some point.

And yeah I'm planning to put in a full set of aftermarket gauges plus egt. But I'm also looking to get an engine to build and do a swap since I'm having some compression issues with the one that's in it now Planning to do the gauges when I swap in the fresh rebuild.

 

[bumblebeer]

It was definitely the thermostat! Old one did not open at all. I'll take it for a drive tomorrow once the permatex has had time to set, and I expect it to be fine.

 

[bumblebeer]

I was able to go for a drive yesterday and engine temps were fine! So engine cooling systems are fine. Now time to move on to the occupant cooling systems.

I've been doing battle with the AC. Unfortunately, here in the south it gets hot enough to make the devil break a sweat so AC isn't really optional. Especially in a black truck.

The truck was converted over to r134a before I bought it. It wasn't working and I didn't have a set of gauges, so I filled with one of the cans with a built in gauge. Had AC for about half a day. So I went and got a set of manifold gauges. And charged the system properly. Turns out my low side pressure was fine and my high side pressure was on the high side of ok, but within tolerance at idle. Say 35 and 275. But if I increased the RPM the low side stayed about the same and the high side got way too high. Like 350+

So I knew there was an issue, but figured the refrigerant was already in it so I'd just roll with it and see what happens. Well what's happens is I have AC for about half a day again, but this time I caught the failure mode. I didn't have gauges on it at the time, but enough pressure built up in the system to trigger the relief valve and dumped all the refrigerant.

So ok, I thought. I should probably try to actually fix something now. So I pulled the system apart and bought a new accumulator which came with a new oring, Schrader valve, and orifice tube set, and pag oil. I pulled the old orifice tube and it did have a bit of gunk on it. So I got a flush bottle and back fed a gallon of alcohol through the evaporator and condenser. And flushed all the lines. I turned the compressor over by hand and tried to get out as much oil as possible. Put everything back together with a new red orifice tube, the old one was blue, pulled a vacuum for an hour. Let it hold for an hour to check for leaks and then recharged.

I was feeling pretty confident about it. Got good readings at idle 35 low side 220 high side. If I fed it some RPM the low side would slowly drop and cause the compressor to kick of for a second for the pressure to come up. But even so it was still cooling effectively even at high RPM so I figured maybe it was undercharged. I had put a little over 24oz total in it. But I decided to leave it alone and see how it got on for a while.

Well I had AC all day yesterday until after it sat for a couple of hours, I started it up to head home last night and no AC. I got the gauges on it this morning and zero pressure. So I guess I dumped all the refrigerant again.

I'm not really sure where to go with this. I guess I could throw parts at it, new condenser, evaporator, compressor. But I hate to do that without knowing the issue first. Especially since it seemed to work fine for a while after the flush. I'm about to go pull the orifice tube. Maybe that will give some indication.

 

[bumblebeer]

The new orifice tube had a very small amount of gunk on it. I imagine what was left in the compressor that I couldn't get cleaned out. I'm going to replace it with the blue one and wire in one of those aftermarket high pressure cutoff switches that connects to the high side fill port. That should at least stop it from blowing out any more refrigerant. You're welcome environment! Hopefully, after that I'll be able to run it for more than a day and get a better evaluation of performance and possible problems.

 

[Rdnck84_03]

Are the condenser fins clean? Heat will cause the high pressure also.

James

 

[bumblebeer]

Are the condenser fins clean? Heat will cause the high pressure also.

James

They looked pretty clean, but I gave it a spray with the pressure washer just in case.

I did what I talked about in the last post, and also did the ranger vacuum control heater valve mod and it's been working great for the last couple of days. It'll freeze the nuts off a yeti. I'm gonna call it fixed.

The blue orifice tube seems to preform really well and while charging it this go around, the pressures were a lot more stable, even at high rpms. So the high pressure cutoff switch is probably unnecessary, but I feel better having it in there anyway. I'm still not sure what the actual problem was, but I have a feeling it was my stupidity.... When I turned on the vacuum pump, I smelled alcohol for a couple minutes. So I think there was still some in the system. I pulled a vacuum for 3 hours this time in the hot sun. I think that probably did more than anything.

 

[bumblebeer]

Whelp... She started chuffing real good out the exhaust today. I'm guessing it's exhaust valve guide issues.

I was hoping to wait for fall and swap in a rebuilt engine, but I don't want to drop a valve and turn the bock to scrap. But it's also my only running truck right now. Any good way to see what shape I'm in without tearing too far into it?