93-97 Coolant Temperature Gauge Modification (1 Viewer)

zcruiser

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May 7, 2005
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Hillsborough, NC
I've got a set of the resistors sitting around in my garage, never installed them on my FZJ80 and it's long gone.

Free to next PM.
 
Joined
Nov 4, 2011
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Pacific NW
Just got done doing this mod, worked out great. It's nice to see some action out of the gauge for once. I wanted to get this done before I swapped in an electric fan with an automatic variable sensor, so that I can tune the on/off points right where I want them.

Anybody know off hand what the opening temperature of the stock thermostat is?
 
Joined
Dec 9, 2007
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403
Location
Maine
Interesting, as I have the same thing happening in terms of running cold seemingly. Your picture there is where mine runs almost all the time after it warms up. I don't think I have ever even seen the needle go to the halfway mark since I modified it. Just put a new radiator and t-stat in also, and yes, it is factory Toyota t-stat installed correctly, as was the previous one that acted the same on the gauge. Perhaps I should check out my actual temp sensor.....

So I finally looked into this on mine. With my temp gun pointed right at the coolant neck by the distributor I was getting much more normal temps that I would expect to see. I would say my gauge mod is running about 20 degrees cooler then it should, no idea why.

I also just installed a real coolant temp gauge, and found that when my modified gauge was hovering just barely below the cold line, I was in reality at around 180-190, and I have confirmed this with my temp gun. Just wanted to update my last post.
 
Joined
Aug 4, 2004
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Location
Spokane WA, USA
The source for the 50 ohm resistor on Page 1 is still good, but they now have a minimum purchase requirement of 40 resistors at US$1.02 each. You can still buy the 110 ohm units singly.

RS02B50R00FB12 Vishay/Dale Wirewound Resistors - Through Hole

Is there another online source, or can I just buy these at a local electronics supply house or even Radio Shack? I'm sure this was discussed somewhere, but I don't have time to read every post.

Does anyone have a couple of resistors they can sell me for say five bucks shipped in a small padded USPS envelope? I could have you the money ASAP through PayPal....

Thanks.

John Davies
Spokane WA USA
 
Joined
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Dixie co. Florida
Bummer, unless your radio shack is much better stocked than mine you will not find compact 3w power resistors period, much less in these values


The high power disipation and close tolerance needs of this gauge drove me to these rare high dollar resistors.
 
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May 20, 2011
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in Jersey near Philly YO!
well I did this mod and happy i did and thank the OP for doing the writeup, I have found though that it was worth buying an Ultragauge to more accurately monitor my temps. That in conjunction with a modified Blue Hub Fan Clutch with 15k oil seems to have solved a lot of guess work on cooling issues.
 
Joined
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here are the resistors on mouser they appear to do singles,

RS02B110R0FB12 Vishay/Dale Wirewound Resistors - Through Hole

RS02B50R00FB12 Vishay/Dale Wirewound Resistors - Through Hole




also at newark

RS02B50R00FB12 - VISHAY DALE - RESISTOR, WIREWOUND, 50OHM, 3W | Newark

RS-2B 110 OHM 1% B12 - VISHAY DALE - RESISTOR WIREWOUND, 110OHM, 3W | Newark

somebody try them out and tell us how they are shipping cost time etc

a google search for the two part numbers brings a lot of hits


110: RS02B110R0FB12

50: RS02B50R00FB12
 
Joined
Nov 30, 2011
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Oregon
Looks like you can buy singles of the 50 ohm at one place and the 110 ohm at the other, but not everything at the same place anywhere that I have found. I may go that route if I need to, but wanted to see if anyone has a pair that they ordered extra that would be willing to ship them out. Happy to pay a little something for them. Anyone?
 
Joined
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Spokane WA, USA
I just bought an UltraGauge EM - it has up to seven pages of gauges, up to eight gauges per page, and the option of having any function appear on every page. I elected to show coolant temp on each of four pages, so now this thread has no value for me. Plus I now have digital precision, and programmable temperature alarms for the coolant as well as other parameters.

UltraGauge Automotive Information Center and OBDII Scan Tool

John Davies
Spokane WA USA
 
Joined
Apr 21, 2012
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granada hills,CA
thank you, i did this modification and found out my engine was getting more hot then normal, i was going up the canyans and my temp gauge got to the bottom of red. i put in a new thermostat, flushed all the coolant and pressure washed the inside of the radiator as best as i could, rebuilt black hub clutch with 10k cst, new toyota red coolant 65% water mix. now my temp guage will stay below the middle and only move a little when im going up steep hills! thanks for the great mod you prolonged my headgasket life.
 
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Dixie co. Florida
Black LS good find :cheers:

John, Scan guages are very nice, one has been on my shopping list for years but there is always something else I want more to do with that money.
 

Cruiserdrew

On the way there
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Mar 15, 2003
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After a tremendous amount of reading and searching and asking, there should be some additional info to factor into the normal operating temp of the rig. The new oem headgasket's #6 water jacket is shaped so as to restrict flow more than the original. The theory is it allows more heat sink away from the #6 to the coolant. This design difference raises normal water temps from 188-192 to 195-204 based on my readings. The cometic hg's #6 is more closely designed like the original oem gasket and should produce a little lower normal operating temp, but I can't confirm this.

It's well documented the effects of proper cooling system maintenence and the many things we can do help the system to perform better. But, if we keep using Toyota's published number for a stock 80 as a baseline after new HG's, armor, extra fuel tanks, bigger tires, etc., we could all be chasing ghosts. I am completely comfortable with my water temp at 207 on a Houston freeway running 70mph in 98* sunny weather with ac on high. I would have never been comfotable with those number had I not spent hours reading threads and pm's.

We need a definnative temp thread so people can compare like rigs to like rigs under similar scenarios. In my example above, if I posted I was running 207 and provided little else, it's just a number. It's context that gives it meaning. Even the above context would need to be expanded to be effective.

I hope this adds some value to this thread. I have had the RT temp guage mod for probably 90k miles and she's working like a charm. A very scary charm when she gets near the red, but a charm none the less.

Good Luck,

Buck



This is a very interesting post based on my last 2 days.

1997, 2 year old radiator and modded fan clutch. Gauge mod done years ago.

Just had the head gasket replaced by Robbie in Colorado and so drove it home yesterday and today.

Driving to Colorado and Vail Pass and all that last month, the gauge would read roughly 205 under the heaviest loads of speed and grade.

Driving home trough Wyoming and Nevada there are many long steep grades on 80. Routinely on long grades at 70mph 3rd gear 3400 rpm, WOT, a/c on full, the temp would read roughly 210-about 3 needle widths below the bottom of the red. I should mention ambient temps about 90 degrees.

I know this is still within a 'normal" range but is is definitely reading hotter after the HG replacement. Ambient temps are roughly the same.

Anyone see anything wrong with roughly 210-212 degrees?

It's also interesting to me how sensitive the gauge is. After a long climb at basically full power, the gauge holds steady 3 needles below red, and the instant you crest the grade, the temp drops to roughly 190.

Anyway, since I had lots of time to contemplate on this, I think overall, this mod for sure makes you more anxious and watch your gauge a lot more.

Back home in 100 degree Sacramento, the gauge reads roughly 205-210. When it's cooler, the gauge is steady about 185.

Anyway, just confirming the data point with the new head gasket.
 

Onur

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200-210 in a 1FZ in hot temps, hard driving conditions would be ok with me. They run hot. AC cutoff is 226. CDans Challenger operates within the same spec range as well.
 
Joined
Nov 3, 2004
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Frankfort, Kentucky
Just tried to order these.

The 110 from Mouser was going to be $5.99 in shipping costs to 40601 (Kentucky)

The 50 at Newark, I was denied an account when I went to checkout. You have to register at Newark apparently just to purchase and I filled my information in and was denied. This one is on sale right now. Not sure why I was denied. Maybe they don't like selling so few of something?

Redmon
 
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Joined
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Just tried to order these.

The 110 from Mouser was going to be $5.99 in shipping costs to 40601 (Kentucky)

The 50 at Newark, I was denied an account when I went to checkout. You have to register at Newark apparently just to purchase and I filled my information in and was denied. This one is on sale right now. Not sure why I was denied. Maybe they don't like selling so few of something?

Redmon


Resistors are generally not sold in small lots like this, the cost to chip 100 resistors is not much more, we are caught in the scale of these things,

If you know anybody with an 80 series order a few extra and you can dramatically drop the per gauge cost as you are spreading the shipping cost out.
 
Joined
Oct 22, 2009
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katy, TX
Great thread and really cool modification, i just did yesterday, since i bought the resistors 2 year ago.

Now i can't stay without check the gauge, and i noticed that now my oil pressure gauge is more sensitive and also the pressure indication is a little higher than before, that is normal?
I am scared that i touched with my finger the pressure gauge array.

Anyway, thank you for this modification.
 
Joined
Oct 11, 2012
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Seems all the sources now won't ship in singles for the 50ohm. Understandable. Not worth their effort to pick and pack. Still, not willing to spend $100 on this mod and I've got shipping issues from US suppliers. Anyone want to join in with me and get the price down? If three of us were to share the costs it would be worth doing IMHO.
 
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Seems all the sources now won't ship in singles for the 50ohm. Understandable. Not worth their effort to pick and pack. Still, not willing to spend $100 on this mod and I've got shipping issues from US suppliers. Anyone want to join in with me and get the price down? If three of us were to share the costs it would be worth doing IMHO.

Nonsense. Mouser is always prepared to pick and pack. I haven't ordered yet but my Mouser cart is currently showing $4.60 + ship for qty2 of each. and they offer some lesser shipping options.

keep in mind that at qty10000 these parts are probably 10% or less of what mouser is asking.
 

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