94_4runner757
New member
I've got a mind-boggling overheating issue that I really need some help on. I'm new to the group but any help would be appreciated.
About a month ago I got home from school and my dad told me he was going to have pick and pull come and take his 92 firebird away and they would pay him $150. It wasnt anything special and had a lot of minor repairs that needed to be made. I told him I'll give him $150 and still have it gone by the weekend. Posted it on craigslist and long story short I ended up trading it for a 94 4runner v6 4x4 with an overheating issue. The owner had another 3vze swapped in around this time last year and it had 50k miles on it when it was put in (the body has 190k). This was done because it blew a HG like almost all 3vze's do.
Started with all the normal repairs- flushing, burping, new radiator cap, thermostat, etc. None of that fixed it, which I wasn't all that surprised. If it is idling with the heater on, it'll run for hours right at standard operating temp (a little below half way). If the heater is off it'll overheat before that. It blows really hot air, doesn't take long to get hot, and it produces a lot of heat so it's not the heater core. If you drive it with the heater on, it'll still overheat but it takes a while and it wont get to red. If I drive it without the heater, within a mile it'll overheat and be on the red. If you rev it, the temp drops.
Pressure tested it and it hold air fine. Drove around with it on and when it was overheating, it was at 18 PSI. Little high but after testing for combustion gases and having a negative, wasn't too worried. I also ran it without a thermostat -before putting in the Toyota one- for a little to see if it still overheats and yes, it did.
(After numerous prestone flush cleaners, I ended up with a hole in one of my core plugs (freeze plugs, whatever you call it). Replaced the 3 on the driver side and I was good. Did notice a large amount of what I believe is rust (looked like dirt), behind all the plugs. Scooped out what I could and continued on.
I've checked the oil cap and there's no white "snot" under it, no white smoke from the exhaust, and when I tested for combustion gases in the coolant- there isn't any (block tester- fluid stayed blue all 3 tests). Due to these findings I have pretty much ruled out a HG.
Due to my findings, I decided to replace the radiator. There was a ton of rust/ gunk in the radiator and no amount of cleaners could get it clean (tried prestone, thermocure rust treatment, and white vinegar). The owner told me that when he swapped the engine he put a new water pump, timing chain, tensioner, and pulleys on. He then told me got the kit with all the previously mentioned parts for $75 from an Asian company online..... Decided while I had the radiator off I might as well suck it up and replace the water pump because any kit with all of those parts for that cheap- the quality is going to be shit. I got a kit off amazon (https://www.amazon.com/…/B00…/ref=oh_aui_detailpage_o00_s00…) because I know and trust the brands who make the products. I also got a new toyota tstat and gasket while I was at it.
Even after putting in the new Aisin (Toyota supplier) water pump, toyota Tstat, new radiator (spectra premium), flushing and burping, it still overheats. Fan clutch appears to be fine after a few tests and the shroud is on.
For the life of me, I cannot figure it out. I have fixed numerous overheating issues over the years and I have never been this confused. Like I said earlier, any help is greatly appreciated. I may have missed something in typing this up because I've done just about everything I can think of.
My only other guess at this point is a clog somewhere in the water jacket of the block. When I changed the plugs and saw all the "dirt" gunk, I'm guessing the previous owner may have used some stop-leak and it clogged up the block. If you have any other ideas or ways to test other options, please LMK! Thanks in advance
About a month ago I got home from school and my dad told me he was going to have pick and pull come and take his 92 firebird away and they would pay him $150. It wasnt anything special and had a lot of minor repairs that needed to be made. I told him I'll give him $150 and still have it gone by the weekend. Posted it on craigslist and long story short I ended up trading it for a 94 4runner v6 4x4 with an overheating issue. The owner had another 3vze swapped in around this time last year and it had 50k miles on it when it was put in (the body has 190k). This was done because it blew a HG like almost all 3vze's do.
Started with all the normal repairs- flushing, burping, new radiator cap, thermostat, etc. None of that fixed it, which I wasn't all that surprised. If it is idling with the heater on, it'll run for hours right at standard operating temp (a little below half way). If the heater is off it'll overheat before that. It blows really hot air, doesn't take long to get hot, and it produces a lot of heat so it's not the heater core. If you drive it with the heater on, it'll still overheat but it takes a while and it wont get to red. If I drive it without the heater, within a mile it'll overheat and be on the red. If you rev it, the temp drops.
Pressure tested it and it hold air fine. Drove around with it on and when it was overheating, it was at 18 PSI. Little high but after testing for combustion gases and having a negative, wasn't too worried. I also ran it without a thermostat -before putting in the Toyota one- for a little to see if it still overheats and yes, it did.
(After numerous prestone flush cleaners, I ended up with a hole in one of my core plugs (freeze plugs, whatever you call it). Replaced the 3 on the driver side and I was good. Did notice a large amount of what I believe is rust (looked like dirt), behind all the plugs. Scooped out what I could and continued on.
I've checked the oil cap and there's no white "snot" under it, no white smoke from the exhaust, and when I tested for combustion gases in the coolant- there isn't any (block tester- fluid stayed blue all 3 tests). Due to these findings I have pretty much ruled out a HG.
Due to my findings, I decided to replace the radiator. There was a ton of rust/ gunk in the radiator and no amount of cleaners could get it clean (tried prestone, thermocure rust treatment, and white vinegar). The owner told me that when he swapped the engine he put a new water pump, timing chain, tensioner, and pulleys on. He then told me got the kit with all the previously mentioned parts for $75 from an Asian company online..... Decided while I had the radiator off I might as well suck it up and replace the water pump because any kit with all of those parts for that cheap- the quality is going to be shit. I got a kit off amazon (https://www.amazon.com/…/B00…/ref=oh_aui_detailpage_o00_s00…) because I know and trust the brands who make the products. I also got a new toyota tstat and gasket while I was at it.
Even after putting in the new Aisin (Toyota supplier) water pump, toyota Tstat, new radiator (spectra premium), flushing and burping, it still overheats. Fan clutch appears to be fine after a few tests and the shroud is on.
For the life of me, I cannot figure it out. I have fixed numerous overheating issues over the years and I have never been this confused. Like I said earlier, any help is greatly appreciated. I may have missed something in typing this up because I've done just about everything I can think of.
My only other guess at this point is a clog somewhere in the water jacket of the block. When I changed the plugs and saw all the "dirt" gunk, I'm guessing the previous owner may have used some stop-leak and it clogged up the block. If you have any other ideas or ways to test other options, please LMK! Thanks in advance
