oil cooler cause overheating??
12-28-2011, 03:54 PM
#1
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oil cooler cause overheating??
i have a 1998 4runner that is over heating and i can not find out why. I have already tried all of the logical things to do , but was wondering if the oil cooler line on the water pump housing could cause the engine to overheat??
12-28-2011, 04:58 PM
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Please list things you have replaced and go into greater detail about your overheating issue so we can help you.
Probably not the oil cooler, they are a simple design that works pretty darn good.
Probably not the oil cooler, they are a simple design that works pretty darn good.
12-28-2011, 05:23 PM
#4
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So far i have replaced the head gaskets, water pump, thermostat , radiator hoses, radiator, fan clutch , checked the timing, burped the system . All of this is done on an engine with less than 100 miles on the rebuild ( never could find out the overheating issue since rebuilt). It acts like there is something blocking the coolant , or the thermostat isnt opening but i have tested 2 thermostats and they are both fine. Also i ran the vehicle with a gutted thermostat and it did not overheat while driving ( actually the temp. of the engine went down ).
It only overheats when driving, and can run all day without overheating while the 4runner is in park.
The 4runner has 259,000 miles
It only overheats when driving, and can run all day without overheating while the 4runner is in park.
The 4runner has 259,000 miles
Last edited by mustangroady; 12-28-2011 at 05:36 PM.
12-28-2011, 05:36 PM
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How are you determining its overheating? If you are just going by the dash gauge, the temp sender may be just giving a high reading.
Did you replace the radiator cap too? A cap that does not let the pressure build to the proper PSI causes the coolant to boil at a lower temperature.
When you replaced the head gaskets, did you take the heads into a machine shop and have them checked for flattness and pressure tested for cracks?
Did you replace the radiator cap too? A cap that does not let the pressure build to the proper PSI causes the coolant to boil at a lower temperature.
When you replaced the head gaskets, did you take the heads into a machine shop and have them checked for flattness and pressure tested for cracks?
Last edited by rworegon; 12-28-2011 at 05:44 PM.
12-28-2011, 05:49 PM
#6
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I am going by the dash temp. gauge , but if you can see the change in temp. from the gauge i would figure that it would work fine ( when i put the gutted thermostat in it i watched the temp gauge go from 1/4 all the way to the C and thats while driving it for about 10 minutes)
I will see about the radiator cap but it seems like it is acting fine ( no fluid spewing out of the radiator and after driving it has pressure built up )
I will see about the radiator cap but it seems like it is acting fine ( no fluid spewing out of the radiator and after driving it has pressure built up )
Last edited by mustangroady; 12-28-2011 at 05:51 PM.
12-28-2011, 07:03 PM
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Unfortunately, the temp gauge is not a very accurate way to determine overheating. Mine stays right in the middle. Is the temp gauge shooting up into the red? Are you boiling over?
You might try using a 1" dial thermometer in the radiator neck and get it submerged in the coolant and see what you are heating up to at the top of the radiator.
You might try using a 1" dial thermometer in the radiator neck and get it submerged in the coolant and see what you are heating up to at the top of the radiator.
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12-28-2011, 07:21 PM
#8
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I have never let the temp gauge get pass 3/4 of the way up because i dont want to blow a head gasket, and no it is not boiling over.
Also i think the thermostat is not opening up causing it to overheat ( but i have test the two oem thermostats that i bought and they open up fine). That is why i am leaning toward it being something to do with the oil cooler cycling the fluid through , not letting the thermostat open
I know in a Subaru that if you clamp the heater hose down it will cause the engine to overheat , having the exact symptoms my 4runner is showing
Also i think the thermostat is not opening up causing it to overheat ( but i have test the two oem thermostats that i bought and they open up fine). That is why i am leaning toward it being something to do with the oil cooler cycling the fluid through , not letting the thermostat open
I know in a Subaru that if you clamp the heater hose down it will cause the engine to overheat , having the exact symptoms my 4runner is showing
Last edited by mustangroady; 12-28-2011 at 07:24 PM.
12-29-2011, 06:30 AM
#10
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Take your thermostat out. There is a small bypass hole with a pin in it. Remove the pin and drill the bypass hole out using a 1/4" drill. Re-install the thermostat. Start the engine and let it warm up. If the engine over heats then most likely you have an internal engine problem or bad water pump. Do you have any water vapor exiting from the exhaust? I modify all of my thermostats this way on my street rods, customs, etc. I have never had an engine overheat.
Last edited by suncomb1; 12-29-2011 at 06:36 AM.
12-29-2011, 07:26 AM
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Take your thermostat out. There is a small bypass hole with a pin in it. Remove the pin and drill the bypass hole out using a 1/4" drill. Re-install the thermostat. Start the engine and let it warm up. If the engine over heats then most likely you have an internal engine problem or bad water pump. Do you have any water vapor exiting from the exhaust? I modify all of my thermostats this way on my street rods, customs, etc. I have never had an engine overheat.
12-29-2011, 10:34 AM
#12
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thanks for the information i will try this sometime this weekend and get back with you on what it does. the water pump is brand new , and i do not think i have any water vapor from the exhaust but i will check it when i get the 4runner back together.
12-29-2011, 04:06 PM
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Link to enapa's thread with post 54 below being his solution for similiar problem after HG replacement:
https://www.yotatech.com/forums/f2/9...91/index3.html
https://www.yotatech.com/forums/f2/9...91/index3.html
Well i gutted the cat and that didnt fix it. So the only thing left? You guessed it. I actually put the head gaskets on the wrong side, drivers side on passenger and vice versa. Let this be a lesson to everyone....take your time and dont let anyone rush you. I feel like such an idiot. I just got the chance to tear down and i could tell it was wrong immediately. Cometely blocked holes. So for anyone having issues after head gasket change if your rig overheats only when driving and cools back down briefly when you rev the engine real hard then chances are your head gasket is backwards. On the brightside i now feel like a pro at doing this lmao. So if anyone ever wants any pointers send me a message and i will try my hardest to help you through it.
Last edited by rworegon; 12-29-2011 at 04:07 PM.
12-30-2011, 03:59 PM
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One quick way to check on hg is to lay under drivers side just behind tire and look up to where the heads connect to the block. You should see a big L on corner of gasket. Wish i knew that before lol. If you cant see it try to reach up and clean it off. There should be an L. If theres not big sign hg are on wrong side.
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