4xcrazy
3/4 ton status
correct rotation fan blade setup?
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.
Cooling System Overhaul - Stumped and Frustrated
- Thread starter dhcomp
- Start date
High #'s on the gauge.
I'm picking up a new delco gauge sending unit, and will try and verify high temps via the IR gun at the tstat housing.
The issue with verifying during the tstat opening is that the housing doesn't heat up/cool off as fast as the gauge seems to show.
On sending unit installation, these get installed bare, right? IIRC, its only a 1 wire hookup.
Also, i had to splice a new pigtail on there the last time. Would a crimp fitting at this splice effect my gauge reading?
Thanks for your patience guys.
Fan blade setup, yes. Going to tripple check the clutch rotation, but it should be correct.
Delco 1540131
The splice shouldn't affect reading enough to notice, but I never use anything other than solder and shrink wrap so there is no question.
Sending unit should be installed bare, they are pipe thread brass on iron, so no tape needed.
If you can avoid the purchase, I would NOT waste money on sending unit/gauge stuff. Get your hands on another gauge unit, and run it temporarily. My experience and testing has shown that the GM stuff is as near bulletproof as they can be, and that they are accurate. But that doesn't mean I trust it.
Alternatively, ALDL cable would prove or disprove temp too...
Sending unit should be installed bare, they are pipe thread brass on iron, so no tape needed.
If you can avoid the purchase, I would NOT waste money on sending unit/gauge stuff. Get your hands on another gauge unit, and run it temporarily. My experience and testing has shown that the GM stuff is as near bulletproof as they can be, and that they are accurate. But that doesn't mean I trust it.
Alternatively, ALDL cable would prove or disprove temp too...
I'll put the IR gun to some more use.
My issue with ALDL the last time i looked into it, is having to use it on a mac. I remember it being expensive....?
I know almost nothing about Mac's. Is there some sort of windows simulator/mode you can use them in?
I didn't see a whole lot about ALDL with Mac's, so it might take too much effort IMO. Do you not have a friend with a laptop PC you can borrow? All you'd need then is Tunerpro RT installed, and that's free. ~$40 cable and you are done, unless someone has one you can borrow.
You are in kind of a tough spot for sure. I wouldn't want to spend the ~$40 on something you will infrequently use, and is worthless without borrowing a PC from someone else.
I didn't see a whole lot about ALDL with Mac's, so it might take too much effort IMO. Do you not have a friend with a laptop PC you can borrow? All you'd need then is Tunerpro RT installed, and that's free. ~$40 cable and you are done, unless someone has one you can borrow.
You are in kind of a tough spot for sure. I wouldn't want to spend the ~$40 on something you will infrequently use, and is worthless without borrowing a PC from someone else.
Its a bit harder with a mac. I'm not setup to emulate windows on my setup.
My roommate has a PC for work, but without being able to use it while i'm towing, etc. its not very useful. Considering pickup up a POS gauge/sending unit setup for $20, and running an independent gauge for a while to verify temps. We'll see what happens on that offer on that scan tool.
black dawg
1/2 ton status
you should be checking coolant temps (at this point) on the other side of the t stat. you should get an accurate reading of engine coolant temps at the coolant passages in the intake.
How would i verify? I have an IR temp gun, but so far have been told to just check at the tstat water neck.
I would think just hit the head near the temp sender, or on the passenger side the plug where the temp sender would go.
You've also checked your radiator inlet/outlet temps? That will give you an idea of the radiator/fan/shroud efficiency.
You've also checked your radiator inlet/outlet temps? That will give you an idea of the radiator/fan/shroud efficiency.
I probably wouldn't hit the hose with it (might work I suppose, just not metal so won't conduct heat as fast/well as the AL will) I'd hit it just inboard of the fitting on the tank or core.
I'll bet the farm this truck isn't overheating...
every single component has been replaced, including the freakin engine, yet your still going by what the factory gauge says...
take an IR reading on the intake manifold, below the therm.. and honestly, most spots will give you a pretty accurate reading once warmed up, hoses too... the head is not a great place due to exhaust in the vicinity affecting readings...
for $20, by a cheap POS gauge and sending unit... and sending units are FAR from bulletproof.. way moreso than the gauges.. depending on manny, they'll fail before the gauges will... is it the old sending unit in a new motor?
every single component has been replaced, including the freakin engine, yet your still going by what the factory gauge says...
take an IR reading on the intake manifold, below the therm.. and honestly, most spots will give you a pretty accurate reading once warmed up, hoses too... the head is not a great place due to exhaust in the vicinity affecting readings...
for $20, by a cheap POS gauge and sending unit... and sending units are FAR from bulletproof.. way moreso than the gauges.. depending on manny, they'll fail before the gauges will... is it the old sending unit in a new motor?
Can't tell you how many previously-owned (lol) factory GM temp sending units I've used, have yet to see one fail. I know they can, do and will, everything will at some point, I've just not seen it. I don't see nearly as many engines as others here do though either. Then again my '87 was indicating it was overheating when it was obviously not, but that's no longer driveable so I have no idea if it was the gauge, sender, or wiring/connectors that were the issue. If it was my normal driver, if nothing else I would have swapped out the sender and/or gauge with spares to isolate the problem.
Verifying the current setups reading vs. another gauge will tell us if the gauge circuit is the problem.
Verifying the current setups reading vs. another gauge will tell us if the gauge circuit is the problem.
I'll bet the farm this truck isn't overheating...
every single component has been replaced, including the freakin engine, yet your still going by what the factory gauge says...
take an IR reading on the intake manifold, below the therm.. and honestly, most spots will give you a pretty accurate reading once warmed up, hoses too... the head is not a great place due to exhaust in the vicinity affecting readings...
for $20, by a cheap POS gauge and sending unit... and sending units are FAR from bulletproof.. way moreso than the gauges.. depending on manny, they'll fail before the gauges will... is it the old sending unit in a new motor?
I hope you are right! Its the old sending unit in a new motor, but the sending unit was replaced in the last year.
I've got a new sending unit on order, and will get a cheap gauge/sending unit to compare against.
I had a cheap gauge kit kicking around, gotta see if i can find it somewhere and hook it up.
Thanks guys!
yup, ya always wanna isolate the issue.. it's the basis for diagnostics...
being a boat guy, I sometimes have an unfair advantage on these mills.. even over a dealer mechanic or something.... I have 100's of SB's and BB cheb's as customers.... and tons of TBI's and even carbs still.... plus MANY different gauge configs, from factory GM type stuff to VDO, etc, etc... these are all daily diagnostics I do.....
my apologies, it's just absurd to me that the actual motor has been changed and this is still up in the air...
to me, it's the epithome in "well, the needle moves, so the gauge MUST be working correctly..."
being a boat guy, I sometimes have an unfair advantage on these mills.. even over a dealer mechanic or something.... I have 100's of SB's and BB cheb's as customers.... and tons of TBI's and even carbs still.... plus MANY different gauge configs, from factory GM type stuff to VDO, etc, etc... these are all daily diagnostics I do.....
my apologies, it's just absurd to me that the actual motor has been changed and this is still up in the air...
to me, it's the epithome in "well, the needle moves, so the gauge MUST be working correctly..."
my apologies, it's just absurd to me that the actual motor has been changed and this is still up in the air...
Its all good, same frustration I'm having. I wonder if i have another sending unit kicking around too.
To replace EVERYTHING, and have the problem persist, is odd.
We'll get to the bottom of this. Just tough when i'm not driving it a ton, and towing even less.
Dude, somewhere I know the answer to this, plus I have several place I could find out.
But I can't remember off the top of my head, and I did something stupid with my hip this weekend, and I just found a comfortable position and don't want to move.
If the truck is close by, turn the key on, and then pull the sending unit wire off and see which way the gauge goes.
It will either go all the way high or low.
If it goes high, there is a good chance your gauge is wrong.
Remember, an electrical connection cannot be too good, only not good enough.
Since the sending unit is a variable resistor to ground, if throwing infinite resistance to the gauge pegs it hot, then a poor connection would cause it to read high.
Which could be a bad wire,connector somewhere, or Teflon tape or corrosion where the sender is screwed in.
But I can't remember off the top of my head, and I did something stupid with my hip this weekend, and I just found a comfortable position and don't want to move.
If the truck is close by, turn the key on, and then pull the sending unit wire off and see which way the gauge goes.
It will either go all the way high or low.
If it goes high, there is a good chance your gauge is wrong.
Remember, an electrical connection cannot be too good, only not good enough.
Since the sending unit is a variable resistor to ground, if throwing infinite resistance to the gauge pegs it hot, then a poor connection would cause it to read high.
Which could be a bad wire,connector somewhere, or Teflon tape or corrosion where the sender is screwed in.
I'll try that too. When i had a broken connector, i think it was falling to 0, but i'll test it again.
most of the time, grounding the send wire will pin a gauge full.. not a test for how accurate it is tho...
use the IR gun..... doesn't much matter if running under load, etc... run it, seems hot, pull over and check it, compare, you'll see if it's off......
use the IR gun..... doesn't much matter if running under load, etc... run it, seems hot, pull over and check it, compare, you'll see if it's off......
