1995 3.0L 4Runner still wants to overheat! Why didn't my pickup do this?!
09-07-2012, 04:57 PM
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1995 3.0L 4Runner still wants to overheat! Why didn't my pickup do this?!
Hey Everyone, please excuse the novel but I think all the info is necessary to figure out whats up...
So I'm still stumped on why my '95 A/T 3.0L 4runner still wants to overheat after driving on the HWY then going back to stop and go traffic. I drive the HWY to school and come back home via city streets, which has more hills and therefore, higher RPMs. The temp gauge starts to go past the 1/2 mark to 3/4 and beyond on the city streets, forcing me to blast the heater to get it back to normal. The hotter the day, the more noticeable the issue.
So far I've replaced the green coolant with Toyota red, flushed the rad (performance rad), changed the rad cap with a performance cap, changed out the crappy aftermarket t-stat with a Toyota OEM and checked out my fan clutch which seems to be operating properly; it has resistance but not too much, and the newspaper test didn't stop it from spinning at all. I also installed an aftermarket tranny cooler as one of my first mods!
The top-end was rebuilt about 30k ago (I'm at 306k+), but I noticed that the shop that did it used cheapo aftermarket parts (such as the t-stat), many of which I've replaced with proper OEM parts since. No signs of the usual headgasket issues and I'm constantly monitoring the thing. It might be noteworthy to say I have factory A/C, but the hoses are shot so it doesn't work, but everything is still in place; fan in front of rad, and belts still turning.
What pisses me off most is that I had a '93 manual pickup running 33" tires (I have 31's), had the same gearing (4:88's), basically the exact same drive train set up -besides the automatic tranny- same performance radiator and the temp needle would barely make it to half at most! It did not have a/c and I did notice that the pickup's fan roared a little louder than my 4runner's...
I'm stumped guys! I mean, I definitely notice the loss in power with the difference between auto and manual, especially uphill, but this overheating thing freaks me out because I can't afford a headgasket issue!
I've done so much research and still can't figure out a solid solution... Looking forward to what the Toyota masters have to say!
So I'm still stumped on why my '95 A/T 3.0L 4runner still wants to overheat after driving on the HWY then going back to stop and go traffic. I drive the HWY to school and come back home via city streets, which has more hills and therefore, higher RPMs. The temp gauge starts to go past the 1/2 mark to 3/4 and beyond on the city streets, forcing me to blast the heater to get it back to normal. The hotter the day, the more noticeable the issue.
So far I've replaced the green coolant with Toyota red, flushed the rad (performance rad), changed the rad cap with a performance cap, changed out the crappy aftermarket t-stat with a Toyota OEM and checked out my fan clutch which seems to be operating properly; it has resistance but not too much, and the newspaper test didn't stop it from spinning at all. I also installed an aftermarket tranny cooler as one of my first mods!
The top-end was rebuilt about 30k ago (I'm at 306k+), but I noticed that the shop that did it used cheapo aftermarket parts (such as the t-stat), many of which I've replaced with proper OEM parts since. No signs of the usual headgasket issues and I'm constantly monitoring the thing. It might be noteworthy to say I have factory A/C, but the hoses are shot so it doesn't work, but everything is still in place; fan in front of rad, and belts still turning.
What pisses me off most is that I had a '93 manual pickup running 33" tires (I have 31's), had the same gearing (4:88's), basically the exact same drive train set up -besides the automatic tranny- same performance radiator and the temp needle would barely make it to half at most! It did not have a/c and I did notice that the pickup's fan roared a little louder than my 4runner's...
I'm stumped guys! I mean, I definitely notice the loss in power with the difference between auto and manual, especially uphill, but this overheating thing freaks me out because I can't afford a headgasket issue!
I've done so much research and still can't figure out a solid solution... Looking forward to what the Toyota masters have to say!
Last edited by MattTheCat; 09-07-2012 at 05:17 PM.
09-07-2012, 05:27 PM
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I'm only a newb to toyotas but ive played with a few cars in my life, I'm currently doin the HG's on my 4runner, it could be a lot of things causing what's sounds like poor water flow or the other end of the scale to much flow but I'd lean towards poor flow, you mentioned flushing the rad, how bout flushing the engine? It could be full of crap. Partially crimped hoses? Try removing temp sensor and testing it, could also just be how your gauge reads, understand that your temp gauge is just a gauge! Everyone is different, which testing temp sensor might reveal. Just my thoughts, good luck
09-07-2012, 05:27 PM
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09-07-2012, 07:43 PM
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That's true about the manuals, but I did install an additional tranny cooler as one of my first mods, after seeing that the A/T's have a tendency to overheat. Haven't changed the water pump so I might be able to do that. Once the weather gets cooler, I can see how the issue goes, it seems to only be a big problem on hot days. What a PITA!
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09-08-2012, 05:15 AM
#8
How many miles on the radiator??
Just how did you flush the engine it also needs to be flushed.
Have you replaced the hoses??
The fact that it cools fine at highway speeds .tells me something is blocking the air flow through the radiator.
Is the condenser so full of dirt it is blocking the air flow at low speed driving if the AC no longer works maybe pull the condenser and things out in front of the radiator.
No AC nothing in front of Radiator!!! So it is not really fair to compare the two systems
The AC needs an electric fan to cool the condenser pushing even more flow through the radiator.
Another thought you don`t say if it is pushing any coolant out.
Maybe the temperature sending unit is getting old is it still the original after 300,000 miles??
300,000 plus miles when was the last time any type of cleaning was done on the condenser that is a lot of bugs and road dirt.:jessica::jessica:
Just how did you flush the engine it also needs to be flushed.
Have you replaced the hoses??
The fact that it cools fine at highway speeds .tells me something is blocking the air flow through the radiator.
Is the condenser so full of dirt it is blocking the air flow at low speed driving if the AC no longer works maybe pull the condenser and things out in front of the radiator.
No AC nothing in front of Radiator!!! So it is not really fair to compare the two systems
The AC needs an electric fan to cool the condenser pushing even more flow through the radiator.
Another thought you don`t say if it is pushing any coolant out.
Maybe the temperature sending unit is getting old is it still the original after 300,000 miles??
300,000 plus miles when was the last time any type of cleaning was done on the condenser that is a lot of bugs and road dirt.:jessica::jessica:
09-08-2012, 12:08 PM
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How many miles on the radiator??
Just how did you flush the engine it also needs to be flushed.
Have you replaced the hoses??
The fact that it cools fine at highway speeds .tells me something is blocking the air flow through the radiator.
Is the condenser so full of dirt it is blocking the air flow at low speed driving if the AC no longer works maybe pull the condenser and things out in front of the radiator.
No AC nothing in front of Radiator!!! So it is not really fair to compare the two systems
The AC needs an electric fan to cool the condenser pushing even more flow through the radiator.
Another thought you don`t say if it is pushing any coolant out.
Maybe the temperature sending unit is getting old is it still the original after 300,000 miles??
300,000 plus miles when was the last time any type of cleaning was done on the condenser that is a lot of bugs and road dirt.:jessica::jessica:
Just how did you flush the engine it also needs to be flushed.
Have you replaced the hoses??
The fact that it cools fine at highway speeds .tells me something is blocking the air flow through the radiator.
Is the condenser so full of dirt it is blocking the air flow at low speed driving if the AC no longer works maybe pull the condenser and things out in front of the radiator.
No AC nothing in front of Radiator!!! So it is not really fair to compare the two systems
The AC needs an electric fan to cool the condenser pushing even more flow through the radiator.
Another thought you don`t say if it is pushing any coolant out.
Maybe the temperature sending unit is getting old is it still the original after 300,000 miles??
300,000 plus miles when was the last time any type of cleaning was done on the condenser that is a lot of bugs and road dirt.:jessica::jessica:
The top end was rebuilt at 275k so the rad, hoses, etc are all about that old. The rad fins look totally fine, no signs of clogging...
The fan does pull air through the rad, checked it with some paper and it gets sucked to the grill. Also when I open the hood while running, the fan is moving tonnes of air around. I even tried sealing the tiny gaps in the fan hood to make air flow more efficient, but to no avail.
Its really weird, it doesn't happen when I just drive around the city, but when I go from HWY to city or visa versa, that's when overheating occurs.
Think its worth pull all the A/C components out? My good buddy is an industrial mechanic and said the change would be minimal...
What do you mean "pushing coolant out?" As in, does it leak? There hasn't been any signs of that and the reservoir stays at a level average.
I feel after driving it for a while that after it gets hot, the longer I run it a lower RPM's the quicker it cools down... if that means anything...
Now after I see it get too hot, I'll let it idle for 5min before shutting it off
09-08-2012, 02:03 PM
#12
You basically remove the clutch, remove the fan from the clutch. Mark the 2 halves so you put it back together the same. The screws can be very tight, an impact screw driver and a vice will come in handy. Open it up, squeeze in some fluid, check the gasket, put it back together with the impact.
This is the type of impact I'm referring to, not an electric impact
http://impactscrewdriver.net/
09-08-2012, 02:42 PM
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Looks like you answered your own question. Paper test is not very precise. Buy some silicone and repack the fan clutch. Its under $10. The dealer should have the correct fluid. I typically just add a bottle or so, but to do it "properly" you empty the old fluid and add a measured amount.
You basically remove the clutch, remove the fan from the clutch. Mark the 2 halves so you put it back together the same. The screws can be very tight, an impact screw driver and a vice will come in handy. Open it up, squeeze in some fluid, check the gasket, put it back together with the impact.
This is the type of impact I'm referring to, not an electric impact
http://impactscrewdriver.net/
You basically remove the clutch, remove the fan from the clutch. Mark the 2 halves so you put it back together the same. The screws can be very tight, an impact screw driver and a vice will come in handy. Open it up, squeeze in some fluid, check the gasket, put it back together with the impact.
This is the type of impact I'm referring to, not an electric impact
http://impactscrewdriver.net/
Ya, I think for what its worth to do, I'm gonna give a go at the fan clutch. Now here's a question, do I flip for the $25-30 to buy a couple bottles of the silicone oil from the stealership, or do I get some RC hobby stuff like this and really do some backyard mechanics justice... http://www.ofna.com/acc-fluids.html
I'm reading everywhere its the same stuff, no?
09-08-2012, 03:12 PM
#14
Dont know about that other stuff. I would use the toyota stuff. I just found this link:
http://www.4crawler.com/4x4/Docs/FanClutch.pdf
http://www.4crawler.com/4x4/Docs/FanClutch.pdf
Last edited by j2the-e; 09-08-2012 at 03:14 PM.
09-08-2012, 03:29 PM
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how was the cooling system filled? I'm a firm believer that the ONLY way to fill it is with a vaccufill system. pouring in coolant and parking it on a hill to burp the system has to many points of failure for me.
Get rid of all the a/c stuff if you have no plan of restoring the system. That little fan for the condensor will only come on when the a/c is on so its actually limiting airflow. With the cond. out of there it will supply much more air.
Are these models supposed to have a fan shroud?
Get rid of all the a/c stuff if you have no plan of restoring the system. That little fan for the condensor will only come on when the a/c is on so its actually limiting airflow. With the cond. out of there it will supply much more air.
Are these models supposed to have a fan shroud?
09-08-2012, 08:00 PM
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Ya, I think for what its worth to do, I'm gonna give a go at the fan clutch. Now here's a question, do I flip for the $25-30 to buy a couple bottles of the silicone oil from the stealership, or do I get some RC hobby stuff like this and really do some backyard mechanics justice... http://www.ofna.com/acc-fluids.html
I'm reading everywhere its the same stuff, no?
I'm reading everywhere its the same stuff, no?
Toyota actual has three part numbers for the different weights of silicone oil. When I was researching this I found that guys in hot climates like Arizona used the 10,000 CST, while Toyota seems to indicate 3,000 CST. I opted to split the difference with the OFNA 7,000 CST.
http://www.zhome.com/ZCMnL/tech/FanClutch/FanClutch.htm
http://forum.ih8mud.com/79-95-toyota...h-service.html
Last edited by rworegon; 09-08-2012 at 08:43 PM.
09-08-2012, 09:24 PM
#18
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Don't pull the A/C stuff to correct this problem. My 4Runner 3.0 auto has A/C and never gets warm even when it got up to 100F out. Fan, radiator or water pump would be a good place to start.
09-09-2012, 12:13 PM
#20
