What's new
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

I run a mechanical temp gauge Along with the factory gauge.

Did you drill any holes into the flange of the thermostat? I drilled 2x 1/8" holes in mine. It helps 2 ways, one it makes it easier to get the air purged when you first fill the system. Second it helps to keep water flowing around the t-stat which will allow it to open at a more consistent temp.
 
If this is in the '91, just buy an ALDL cable, download tunerpro rt, and you can verify it against your ECM's coolant temp sensor.

I know some don't buy it, but I don't doubt the accuracy of the factory gauges. I have yet to find one that is wrong, and in any case, if the reading is wrong, but consistent, you just watch for a change from "normal". As far as I've been able to deduce, the gauges were not just thrown together, but were actually calibrated from the factory to ensure they read accurately.

In any case, using the ALDL cable is great for this, but it's also handy for checking everything else, like TPS, system voltage, MAP, you name it.
 
dyeager535 said:
If this is in the '91, just buy an ALDL cable, download tunerpro rt, and you can verify it against your ECM's coolant temp sensor.

I know some don't buy it, but I don't doubt the accuracy of the factory gauges. I have yet to find one that is wrong, and in any case, if the reading is wrong, but consistent, you just watch for a change from "normal". As far as I've been able to deduce, the gauges were not just thrown together, but were actually calibrated from the factory to ensure they read accurately.

In any case, using the ALDL cable is great for this, but it's also handy for checking everything else, like TPS, system voltage, MAP, you name it.
Click to expand...


Are there any USB ALDL cable setups?
I'm in Mac world....
 
dyeager535 said:
If this is in the '91, just buy an ALDL cable, download tunerpro rt, and you can verify it against your ECM's coolant temp sensor.

I know some don't buy it, but I don't doubt the accuracy of the factory gauges. I have yet to find one that is wrong, and in any case, if the reading is wrong, but consistent, you just watch for a change from "normal". As far as I've been able to deduce, the gauges were not just thrown together, but were actually calibrated from the factory to ensure they read accurately.

In any case, using the ALDL cable is great for this, but it's also handy for checking everything else, like TPS, system voltage, MAP, you name it.
Click to expand...

Agreed, sort of. My stock temp gauge is way off but very consistent and i verified it with Tunerpro RT. I have a mechanical gauge down low and look at when climbing hills or towing to verify the stock gauge.
 
What are you running for coolant? It's not straight Prestone or straight water, is it?
 
Just going to put this out there, water is a better coolant than antifreeze. Antifreeze companies apparently don't want you understanding that, but it's the truth.

You've got it already, run what you got, I don't believe any cooling system should be so close to overheating that 50/50 vs 30/70 antifreeze mix makes the difference.

I'm pretty much out of ideas at this point. Good pump, good radiator (and a big one at that correct?), good fan, good thermostat, and still going well over the thermostat temp. As I recall you've got no real mods that would affect water pump speed, nothing like that right?
 
Last edited:
dyeager535 said:
Just going to put this out there, water is a better coolant than antifreeze. Antifreeze companies apparently don't want you understanding that, but it's the truth.

You've got it already, run what you got, I don't believe any cooling system should be so close to overheating that 50/50 vs 30/50 antifreeze mix makes the difference.

I'm pretty much out of ideas at this point. Good pump, good radiator (and a big one at that correct?), good fan, good thermostat, and still going well over the thermostat temp. As I recall you've got no real mods that would affect water pump speed, nothing like that right?
Click to expand...

No real mods. Hell, the 4.10's should make it spin faster. Need to test the cooling system presurization, just haven't had time.

Thanks!
 
sorry, didn't stay with the whole thing.. but are we sure this thing is overheating? is this strictly based on a factory gauge? any other signs of overheating? what are the symptoms again?

IR gun man, great $50 tool... just like having a mechanical oil pres gauge in your toolbox is..
 
ryoken said:
sorry, didn't stay with the whole thing.. but are we sure this thing is overheating? is this strictly based on a factory gauge? any other signs of overheating? what are the symptoms again?

IR gun man, great $50 tool... just like having a mechanical oil pres gauge in your toolbox is..
Click to expand...

Its not really overheating. Its just running a bit hotter than it should.

No reason it should run 220˚ on the freeway under no load.

I'll try and get an IR gun from work.

Where are you finding one for $50? And what do you normally shoot to check coolant temp? I mean, besides removing the cap and shooting the coolant.
 
I agree that it's always good to verify, but I think the real concern is that the temperature swings wildly. Unless the gauge or sender is bad (which is what testing is for) even if the temperature max was 205* (IMO) it shouldn't swing wildly. If the cooling system is adequate, no matter the load/conditions, it should never go above what the thermostat full open temp is.

This is why I advocate using the CTS as the basis of gauge verification. You can watch/record the temperature while driving, which you can't do with any other method short of installing another gauge. It will also tell you if the gauge is fairly close in temp in the first place.

I know you can pull over and stop and check, but I don't think that's always practical.
 
Last edited:
dyeager535 said:
I don't believe any cooling system should be so close to overheating that 50/50 vs 30/50 antifreeze mix makes the difference.
Click to expand...

The reason I don't like the 30/50 mix is that the radiator isn't full. :D Seriously, I do agree, for what this system has to do 50/50 should be fine.

Have we talked about how the air is being purged? Just a little air can cause all kinds of trouble including a T-stat that doesn't open and strange gauge behavior.
 
Theoretically on these systems, there is no need/way to truly purge them, correct?

Radiator cap is the highest point, air SHOULD makes its way there, and as pressure increases, be forced into the overflow, and replaced with coolant. Obviously when first replacing coolant you start it with the cap off and add as required.

But that assumes the radiator cap is working properly. As many pages as we have, I am guessing the cap holds pressure and seems to vent properly.
 
dyeager535 said:
I agree that it's always good to verify, but I think the real concern is that the temperature swings wildly. Unless the gauge or sender is bad (which is what testing is for) even if the temperature max was 205* (IMO) it shouldn't swing wildly. If the cooling system is adequate, no matter the load/conditions, it should never go above what the thermostat full open temp is.

This is why I advocate using the CTS as the basis of gauge verification. You can watch/record the temperature while driving, which you can't do with any other method short of installing another gauge. It will also tell you if the gauge is fairly close in temp in the first place.

I know you can pull over and stop and check, but I don't think that's always practical.
Click to expand...


I know your huge on ALDL cables, and I'm not discounting their value, or that it's info wouldn't verify a gauge reading...but I can easily make the case that an IR gun is a much better overall tool to own for troubleshooting cooling probs for wrench turners..

first an ALDL is exceptionally specialized to our rigs being OBD1, and your only looking at CTS values... plus, even tho the cable is relatively cheap to do, not everyone has a laptop for that.. I don't at the moment....an IR gun is not only useful on a squarebody, but your woman's yota, turbo's, etc, etc..

it can also tell you different temps in a system, lower hose vs upper hose, etc.. it's not just to verify a gauge reading... heck, we take dozens of different readings on boat systems...

like I said, I didn't read about the initial cooling issue and don't know about any wide swings, thus why i asked him in my last post the symptoms, etc...

my original post about an IR gun was, and usually are, to guide the forum to better diagnostics, just like having a mech oil gauge for testing... or a coolant pressure tester... electrical senders should always be the first consideration of failure on any gauge reading, so eliminating that possible fail point is always advisable... isolating the issue...

6 out of 10 times, it's a sender sh*ttin the bed, 1 out of 10 the gauge, if that.. 3 out of 10 are actual cooling probs, therm, pump, etc..
 
Last edited:
Definitely points for 2 good tools. Due to the larger diagnostic possibilities, i ordered the IR Temp gun. I want an ADL cable, but that will be next if needed.

Thanks for your continued help guys! Driving my friends WRX to the mtn this weekend, as i'll be alone, but the Burb is going to get some good attention next week.

Hopefully i can figure out this temp issue.
 
You must log in or register to reply here.

Latest Posts

Top Bottom