OBD2 Temp Before/After Radiator Swap findings (1 Viewer)

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OBII Temp Before/After Radiator Swap findings

I figured I should post my findings for those who may have an over heating problem with there trucks. I’m not that technical so I will do my best in this post to explain my situation and ultimate outcome.

I have a 1997 FZJ80 with 151k on its clock, I’m the second owner purchased with 142k, cooling system serviced about every other year by previous owner (have receipts that show they were done by Toyota dealer) and its been in the mid-west (Missouri) all of its life. Shortly after I purchased the truck I was going through all of the fluids and found that the radiator had Green antifreeze in it! Knowing that this was not a good thing I looked at the service records and found that yes the Toyota dealer in St. Louis did a full cooling system flush at 139k miles. So I called the dealership up, spoke to the service manager and explained this issue and he said it was fine to mix the two and they must have been out of the Toyota red and just used Prestone Green. Amazed by this I suggested that they pay my local dealer here in Kansas City to do a complete power flush and swap out to the correct coolant and they did so with little haggling.

Shortly after the power flush my A/C shut down 2 different times on a really hot 90 degree days. Note: the temp gauge never moved…. I read all the threads on this issue and replaced the Fan Clutch. My A/C shut down again so this obviously did not resolve the problem, so a local club member and I hooked up his OBD2 reader to my truck and we drove around for a while. Outside temp was about 90, Flat ground and driving both in town and on the highway. We found that while on the highway my truck was averaging around 208 and got as hot as 210. When we slowed down to drive in town after the highway, it would cool down a little to around 203. This was a bit strange as my friends’ truck did the opposite as would be expected. His would run cooler on the highway and hotter in town, but never got above 195.

After looking at the data I determined my heating issue must be due to restricted flow. I took a large flat head screwdriver and carefully inserted it into the filler neck of my radiator and it felt like I was pushing it into mud! I scooped some out and it was the gritty, mucky sludge people have talked about. My assumption is that this was caused by the mixing of red and green over time. Who knows how many time this dealer did this as it was always done at the same place. Replace my radiator this weekend with a 3 core brass radiator, replaced large hoses, PHH as well as the thermostat. Took my time and back flushed my heaters as well as the block several times and the used distilled water and finally filled with 50/50 distilled water/ red Toyota coolant.

Ran the OBD2 reader today, outside temp in the mid 80’s, again in town and on the highway. My friend ran it on his rig first and he had the same results as he had seen on the 90 degree day. Then we put it on mine. On the highway it stayed at 189 and when I slowed down to drive in town it would go up to about 192. I shaved about 20 degrees off of my coolant temp by replacing my clogged radiator and I'm sure I've solved my over heating issue.

Hope this helps someone….
 
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Excellent stuff. I've made no secret that I feel many members' overheating issues stem from something awry with their cooling systems despite many posts complaining that the 80s stock cooling system cannot keep up with southern US heat, etc. This is yet another example of a seemingly well maintained system concealing a serious maintenance flaw. I applaud you Zane, for being persistent with this, and more importantly for being willing to spend $ on a radiator though you were not sure it would cure it - nice move as it clearly proved the right move.

The 80s stock cooling system is easily able to handle extreme heat if it's in good trim. If your 80 is unable to handle a simple task like driving on the road on a hot day and running the A/C - even in such challenging conditions as (shiver) stop and go traffic - then you should consider more effort to ensure your 80s cooling system is able to perform at stock levels. For the love of Pete, can we all agree that simple driving around paved public roads on a hot day was engineered into Toyota's supreme offroad vehicle?? Thanks.

Off the soap box....

DougM
 

MTNRAT

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I'm with Idaho on this one. If it runs too hot, AC cuts out, etc. You have a cooling system PROBLEM. Most of the time my money will be on the RADIATOR!
Cheers,
Sean
 
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The sludge has shown up in engines that have only run Toyota red coolant. May have nothing to do with Prestone. Keep you eye on the new radiator and see if any more sludge shows up.
 
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IdahoDoug said:
Excellent stuff. I've made no secret that I feel many members' overheating issues stem from something awry with their cooling systems despite many posts complaining that the 80s stock cooling system cannot keep up with southern US heat, etc. This is yet another example of a seemingly well maintained system concealing a serious maintenance flaw. I applaud you Zane, for being persistent with this, and more importantly for being willing to spend $ on a radiator though you were not sure it would cure it - nice move as it clearly proved the right move.

The 80s stock cooling system is easily able to handle extreme heat if it's in good trim. If your 80 is unable to handle a simple task like driving on the road on a hot day and running the A/C - even in such challenging conditions as (shiver) stop and go traffic - then you should consider more effort to ensure your 80s cooling system is able to perform at stock levels. For the love of Pete, can we all agree that simple driving around paved public roads on a hot day was engineered into Toyota's supreme offroad vehicle?? Thanks.

Off the soap box....

DougM
I agree 100% with you on the engine cooling system, it will rock crawl at 116F all day long without overheating or the A/C kicking off in good working stock form, been there, done that. Add the supercharger and all bets are off.

There are a couple of places where they missed the mark. The A/C will start loosing it's effectiveness at about 115F and be relatively useless higher than that, when stopped or at very low speeds for long periods of time in the sun. An electric fan cures this, I don't understand why one wasn't fitted for trucks delivered in the southwest.

The other place I have concern, but no data, is the power steering. On every pump I have pulled apart the o-rings have crumbled, this indicates overheating, along with burned/darkened fluid. A larger cooler and possibly a thermo switch controlled fan will fix this. Some testing will be need in the design, if the fluid is overcooled and not allowed to warm-up you can cause other problems, most oils work best at about 180F. Our window has passed for high temp testing, so this will have to wait until next year.

These concerns only effect trucks in HOT climates, in most of the US it's not an issue. :D
 
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As an addition to my post, while I replaced my radiator I wanted to make sure that the minimal overheating that had occurred was not being caused as well by a potential head gasket problem and or that I had not damage my head gasket because of it. Soooo, I sent an oil sample to Blackstone Laboratories and received the results back this afternoon and thought I would share them with you all. Again my truck is a 1997 FZJ80 w/ 151K miles. According to the results the motor looks to be in excellent condition and has no signs of head gasket failure and or abnormal wear at this time. I never lost any coolant, but I had added in some notes to Blackstone when I sent in the sample that I was worried that I might be having a head gasket issue and for them to focus attention on this. Please see report that I received back today. This is very helpful and comforting information to have on your truck if you have not done this yet.
 
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A little additional info:

My rig was the one used for comparison of coolant temps. I took a set of OBD2 measurements on mine the same day that we meaured Zane's truck after the installation of the new radiator. I then averaged all the temperature readings after throwing out the 1st 10 minutes or so to allow for warmup. Outside temps were around 80F and the AC was on. Drive route was a mixture of city/hwy.

My rig = Average 194 Max 199

Zanes = Average 189 Max 194

My truck (95 FZJ80) has the original radiator and fan clutch. New thermostat and hoses last year. Toyota red coolant. 145k mi. My radiator has no apparent sludge issues. An inspection of the top of the radiator during a flush last year showed no sludge there. Its unknown if there is any accumulation in the bottom.

If you assume that my original radiator does not have any flow problems (yea, I know what happens when you ASSUME), and that the thermostats are functioning the same (both are Toyota and new) then it would appear that Zane's cooling system is functioning slightly better. Whether that is a function of better cooling due to the 3 core brass radiator or not, I'm not sure. It's something that I would like to test further, however, any hot weather testing will have to wait until next summer.

Bob
 
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Wow... just think what it would have looked like if you had used a good oil :D.

So what kind of OBD2 reader have you got that gives you engine temp info?

:beer:
Rookie2
 
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I use a pc based program from www.obd-2.com. It save the data into a file that can be played back using the software. You can view it in a graph format or on a virtual dashboard. You can also export the file to an Excel spreadsheet or any other progam that can read html files. On the 80s you can get data on 26 different parameters, including coolant temp, intake air temp, timing, MAF readings, speed, engine rpm, %load, etc.
 

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