- Thread starter
- #201
Is the AC system over charged? That could explain the on-off-on-off of the compressor and fan too.
Builds 1990 LJ78 in Montana (1 Viewer)
- Thread starter AirheadNut
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I don't know what the pressure spec is supposed to be.. I have around 40psi in there at the moment
Truck still running fantastic. Got the A/C working so it's blowing cold. Been out for some extended 100 or so mile trips in the texas heat, and the EGT's look great and I'm getting better gas-mileage with the rebuilt engine and IP. The water temps are a little high though, even without the A/C blowing. Actually had to turn on the heat and vent into the cab to keep the water out of the the boil-zone.
I'm running on an electric fan because of the way the 13bt mounts work, the clutch fan mount is off-center and canted at an angle to the radiator so I can't use it. That said, it's a 20 amp fan and it blows pretty good. I think I might pull the radiator and have a shop do a proper acid bath and flush. I would also like to add a fan on the outside of the AC rad, that's blowing into the engine bay, but I'm not sure I have enough alternator for the job. I've had an amp-clamp on my current alternator, and I've seen it pulling 30 amps with the AC blower and rad fan on. There's a pretty noticable voltage drop with that load.
While I have the rad out, I'll see if I can figure out what this alternator is, and maybe research a 90 amp replacement if I can find one.
Also had to replace the boost-gauge last week.. cleaned up the wiring a little while I was up in the console.
I'm running on an electric fan because of the way the 13bt mounts work, the clutch fan mount is off-center and canted at an angle to the radiator so I can't use it. That said, it's a 20 amp fan and it blows pretty good. I think I might pull the radiator and have a shop do a proper acid bath and flush. I would also like to add a fan on the outside of the AC rad, that's blowing into the engine bay, but I'm not sure I have enough alternator for the job. I've had an amp-clamp on my current alternator, and I've seen it pulling 30 amps with the AC blower and rad fan on. There's a pretty noticable voltage drop with that load.
While I have the rad out, I'll see if I can figure out what this alternator is, and maybe research a 90 amp replacement if I can find one.
Also had to replace the boost-gauge last week.. cleaned up the wiring a little while I was up in the console.
Got the Rad pulled this weekend and dropped off at the shop for a re-core this morning.
FINALLY got the re-cored rad back this week, and wired it up this morning. Took it out for a couple hours on the highway and barely got the water-temps to 200 degrees, so I think/hope we have the water-temps problem licked. shiny newly-painted rad looks pretty nice in there too.
Trucks been working well enough we decided to give it a real test. Drove it from Texas to Montana this last weekend. Took three days, doing ~65 the whole way. We camped at state parks on the way up, had a pretty great time.
Experienced a few "Phantom" leaks on the way up.. one day it looked like a rad fluid puddle had formed under the truck.. other times I thought I saw oil drips. We threw the power-steering belt on day 3, and finished the trip without power steering, no biggie. When I cracked the hood, it looked like power-steering fluid from the pump had dripped down onto the alternator fan and splattered sideways onto the air filter housing and the hood-liner, but I couldn't find a leak in those lines either... Maybe I need a new prescription?
Texas heat wreaks havoc on my water temps, even with the newly re-cored rad. I filled it with the 50/50 coolent antifreeze stuff that claims to have a 265 degree boiling point, but I'm still emotional about having the water temps up over 212. Do yall worry about high water temps as long as you're beneath the advertized boiling point and the egt's look good? I did have some coolent in the over-spill tank at the end of day one, but not sure whether I boiled it or whether it was just, ya know, over full.
Experienced a few "Phantom" leaks on the way up.. one day it looked like a rad fluid puddle had formed under the truck.. other times I thought I saw oil drips. We threw the power-steering belt on day 3, and finished the trip without power steering, no biggie. When I cracked the hood, it looked like power-steering fluid from the pump had dripped down onto the alternator fan and splattered sideways onto the air filter housing and the hood-liner, but I couldn't find a leak in those lines either... Maybe I need a new prescription?
Texas heat wreaks havoc on my water temps, even with the newly re-cored rad. I filled it with the 50/50 coolent antifreeze stuff that claims to have a 265 degree boiling point, but I'm still emotional about having the water temps up over 212. Do yall worry about high water temps as long as you're beneath the advertized boiling point and the egt's look good? I did have some coolent in the over-spill tank at the end of day one, but not sure whether I boiled it or whether it was just, ya know, over full.
water temp woes continue.. I think my coolent system isn't holding pressure. Climbed under there last night and saw this from the drain plug on the bottom of the rad (I assume this is a drain plug?)
It doesn't do this constantly, but I did finally catch it at least. Is it safe to teflon tape that little guy?
It doesn't do this constantly, but I did finally catch it at least. Is it safe to teflon tape that little guy?
Worth a try, it is just a plastic threaded plug. Sorry to hear that recoring the RAD didn't make the temp issues disappear altogether. That can be pretty disheartening. I can't remember, have you tried an acid wash/flush to clean out all the passages in the engine block? Provided your water pump is functioning as normal, perhaps the flow is being restricted?
the 13-bt just got rebuilt this year, so the engine internals should sparkling. I think my main problem is this crappy spal fan and lack of a shroud. I could be imagining things but I do think the re-core helped, but now that the drain plug is leaking I'm losing coolant and not holding pressure in the cooling system, which is making it easier to boil.Worth a try, it is just a plastic threaded plug. Sorry to hear that recoring the RAD didn't make the temp issues disappear altogether. That can be pretty disheartening. I can't remember, have you tried an acid wash/flush to clean out all the passages in the engine block? Provided your water pump is functioning as normal, perhaps the flow is being restricted?
- Thread starter
- #210
If I remember correctly there is a little o-ring on that plastic drain plug, it would be worth checking to see if it is damaged and if the seat is ok. Teflon tape might work, but I would guess the drain hole will shred it when the drain plug gets screwed back in.
Like @AirheadNut said, check for the o-ring as well. But yes, if there is no shroud and OEM fan, I would look at getting those installed as they would make a huge difference for sure. Sealing the shroud with some foam to make sure the air is getting pulled through the radiator will help as well.
unfortunately the way the 13bt is mounted in there, I'm going to be stuck with electric fans. The fan-clutch is off-center to the rad and not square, but angled about 15 degrees left to right, so no oem fan for me. I think there's a pretty vast grey area between what I have now and a top-of-the-line electric fan setup though, plenty of room for improvement.
The 13BT fan comes off set from the factory
yah, but it's engine-swapped into an lj78, which expects the fan to be left about 5"
Seems like that is how the 13BT was off set too if I remember correctly. I don’t have mine anymore unfortunately
it would be amazing if I could get a clutch fan in here... Not sure how to verify, I suppose I'll have to get to a meetup somewhere.
FJBen
SILVER Star
I can check mine tomorrow to see how it sits.
FJBen
SILVER Star
Not a great photo but you can see it’s offset tfrom the center of the radiator by a few inches.
One of the biggest problems with electric fans is stalling them at highway speeds due to overwhelming air pressure. Usually this will blow the fuse or melt wiring before, but it can happen with no other symptoms if the fuse/wiring is oversized.
If you do have to stick with an electric fan, go pull one of the S blade 2 speed volvo fans from a junkyard. For the last 15 years or so those are the only e fans I have run - since they are the only ones that move enough air. Be sure to grab the 2 speed relay and capacitor too. Usually about $25 from a you pull it junkyard. Pretty easy to make a shroud if you have access to a brake. The S shaped blades are more efficient and less succeptible to stalling. I always drill four 3-4" holes in the shroud corners and install flaps to increase air flow/reduce pressure at high speeds, but the flaps close at lower speeds with the fan on. If that doesnt make sense I can look for some pictures of the shrouds I have built in the past.
If you do have to stick with an electric fan, go pull one of the S blade 2 speed volvo fans from a junkyard. For the last 15 years or so those are the only e fans I have run - since they are the only ones that move enough air. Be sure to grab the 2 speed relay and capacitor too. Usually about $25 from a you pull it junkyard. Pretty easy to make a shroud if you have access to a brake. The S shaped blades are more efficient and less succeptible to stalling. I always drill four 3-4" holes in the shroud corners and install flaps to increase air flow/reduce pressure at high speeds, but the flaps close at lower speeds with the fan on. If that doesnt make sense I can look for some pictures of the shrouds I have built in the past.
@AirheadNut was right about the oring. I pulled the plug last night, it didn't really look that bad to me.. maybe a little flat on one side.
Here's a before pic:
I had an oring lying around that was the right size but a little thicker, so I threw that on and teflon taped it for the heck of it. Fingers crossed. here's after:
Here's a before pic:
I had an oring lying around that was the right size but a little thicker, so I threw that on and teflon taped it for the heck of it. Fingers crossed. here's after:
