I am having an erratic temperature problem with my 95 4Runner that just started to occur. Symptom: When under load, such as going up slight grades on highway the coolant temp will increase to about half way on the gauge maybe slightly higher. Doesnt sound like a big deal but it have never ever gotten hotter than its normal (needles width left of center of gauge). The reason I first noticed this, is when it heats up to half way mark it cuts off the AC (normal). This overheat condition will occur w/o AC on... although with AC on it will develop quicker. You can drive around town in stop and go traffic with AC cranked and it doesnt get hot.

Radiator and thermostat are new. Fan is an electric Flex a Lite. When i replaced the radiator and disconnected the tranny cooling lines, the fluid was dark in color and had a burnt smell to it. I drained the pan and refilled. I know this only got approx. 1/3 of the fluid out. Could the tranny be heating up under load causing the coolant temp to increase? Yet w/o tripping the tranny oil temp light? One dealer service guy thought this was possible and recommends a power flush on the transmission. Sound plausable?

I'm out of ideas as to what could cause this.

Thanks,

toyo22r
95 4Runner
St. Louis, MO.

 

If you have a burnt smell to the ATF you most definitely are LATE in having a tranny flush. Don't do less than the BG power flush, and if you are in a spendy mood go with synthethic ATF, else just use the BG additives that are part of the flush.

Don't want to be the bearer of bad news, but when the headgaskets on my '89 3.0 were going marginal the first symptoms were slight loss of power and slight overheating. Different engine, different year, but you might have cylinders 3 & 4 'scoped' all the same. A clean piston top is bad news.

No experience with electric fans, but you would not be the first to experience overheating with them. By chance did the install of the fan occur on or about the same time you noticed the overheating?

 

I was gonna have the dealer do the power flush.. I'm not sure what system they use. I did want to go with synthetic also.

I had the HGs replaced under recall 2+ yrs ago. They were leaking internally and externally. However I did not experience any overheating at that time. I kinda doubt its the HG. I show NO usage of coolant, oil looks good.

I was running the Flex a Lite electric fan a good 4 months or so before this overheat problem came up. Plus, its more apted to happen on the highway at speed where the fan is really not needed.

 

That is your problem. I had the same issue with my flexalite. Put your clutch fan back on for the summer months.

 

As was I. But it wasn't this hot 4 months ago. Your flexalite spins at 2,200 rpm. That is not fast enough to 'keep up' at highway speed (in summer heat). I am sure the fan is the problem.

 

I think if someone pointed a street howitzer like that at ME, I'd at least follow his direction on fans...

 

 

You know i was kinda thinking that myself but was told but flex a lite tech that at highway speeds the fan isnt an issue. So what your saying is that the incoming air at highway speeds can't get "through" the fan fast enough? You experienced the same thing, where it would run hot under load, ie. around or slightly above half-way mark on the temp gauge?

 

how long ago did you install that new radiator? I had a new radiator (in my 87 Toyo pu) get partially plugged (enough to show symptoms similar to yours) in less than a year. even though i flushed the system when I installed it, there was still enough crud in the heater core that worked its way into the radiator to screw it up. good luck

 

Well when these symtoms first appeared (about 4 weeks ago) the radiator that was in the truck was about 1.5 yrs old. It has a lifetime replacement, so I swapped it out right away. This made no improvement whatsoever.

 

ChickenLover is correct. The Flex-A-Lite is your problem. I never had overheating problems until I installed a Flex-A-Lite Black Magic fan. I dinked with it for years but it always would overheat on slow uphill grades at any speed. Highway, slow rock crawl it didn't matter. It was the constant load on the engine in a slow uphill that did it every time. I could do the same hill going downhill in the same RPM range and would not have an overheating problem. Changing back to the factory fan / fan clutch instantly solved the problem that had plagued me for 3 years.

 

Many thanks to all who responded. I'll swap back to the stock fan and see what happens. If it is the Flex a Lite fan I'm gonna be pissed... that thing was $$$.

 

Yeah, no kidding. When I put my clutch fan back on (after running the flexalite for 4 months) I was surprised at how much power the e-fan actually freed up. Boy, when that clutch fan couples, it feels like it takes half your HP. I bought my flexalite just for that reason (the drain of an engaged clutch fan). Now I'm reduced to using it during the winter/fall season instead of summer - when I really need it. I'm pissed too.

 

What about a 4runner with a 22re Black Magic Fan and a 6cyl radiator?

 

Well i swapped back to the stock fan today. I couldnt believe how much air the stock fan moved compared to the FAL at idle.. giver her a little throttle and its like a tornado. Test drove thru town and it was like i was towing a trailer. I wonder how much HP that thing robs. My g/f is gonna drive it to work today, its a 60 mile trip all highway. Its also hot and humid today so this will be a good test. I;ll report the results.

 

Good plan. Have the girlfriend check out the performance. No need for you to be stranded by an overheated truck! LOL! Just kidding. I bet you'll find the problem is solved. The factory fan does move a TON more air than the FAL fan, which explains why an engine being cooled by the FAL fan can overheat.

 

sounds like the head gasket check it out with a pressure tester for the radiator and check for movement in the up side of the scale it should show some movement that what i think it is check it out yu will be surprised

 

PROBLEM FIXED!!!!!!!!

Put the stock fan back on and temp gauge doesnt budge from normal. Full throttle with AC on up some hills that before would run hot even with AC off.

Many many many thanks to all who responed!!

Now i'm gonna call FAL and tell them what a POS their black magic fan is. I doubt they will be willing to take it back...

Which brings up a point... Do people have any overheat issues using the Taurus fan mod? I would like to use an electric fan... my 3vze feels REALLY slow now with the drag of the mechanical fan!

 

Glad to hear it. Now if you don't mind, I'd appreciate it if you shared your experience here to help save some future members the $$. https://www.yotatech.com/forums/show...741#post648741