86 civic dx overheating why???

[78f150boi]

I have a bone stock 1986 honda civic dx 5 spd and it keeps over heating while on the highway doing around 70-80 i have replaced the cooling fan, thermasta and flushed and replaced the fluids. and it still over heats for some reason does eny one know why????? please help me out pm me answers of just post it on here.. thanks

[88civic_hatc]

its probly leaking somewhere just pressure test it and see where its leaking

[Theycall_Metue]

did the engine lock up or did you stop before it lock up?
if everything is checked. i notice some people dont check this but, the termo sensor goes bad over time and your ecu think that its over heating but really its not

[78f150boi]

mine is actually not hooked up its just when my car runs hot going down the highway it putters and trys to stall out and their is a huge loss in power
did the engine lock up or did you stop before it lock up?
if everything is checked. i notice some people dont check this but, the termo sensor goes bad over time and your ecu think that its over heating but really its not

[78f150boi]

the fluid is never low its toped off and was for over a week. idk im confused with this lil car
its probly leaking somewhere just pressure test it and see where its leaking

[Batlground]

Do a compression and leakdown to see if your headgasket is leaking. If you are loosing fluid and you cant figure out where its going this may be it. It may be the waterpump but they usually leak when they go bad.

[Theycall_Metue]

he said hes not losing fluid, its topped off

[78f150boi]

yes its all toped off no water in the oil as well but still over heats when on hills or around 70mph. im more than confused on this. how cna i do a pressure test to see if its the head gasket???

[k3tsurui]

its not losing fluids, but overheats at high speed = time for some boost

[JuStCrUzIn]

its not losing fluids, but overheats at high speed = time for some boost
:goodjob:

[88civic_hatc]

is the fan coming on

[JJSPEC Racing]

Radiator may be clogged up. I know you flushed it, but there is only so much that will do for you. May want to pull it and send it to a rad shop to be "rodded out" as it probably is a brass radiator. Or better yet put a new one in it since that one is pushing 25 years.

[78f150boi]

after basic im wonting to do a boosted b18 swap but thats just a dream atm
its not losing fluids, but overheats at high speed = time for some boost

[78f150boi]

I installed a new fan and its on a switch. i turn it on when the car is on.
is the fan coming on

[78f150boi]

could it be a blown head gasket? or would it have to leak fluids?

[scttydb411]

Radiator may be clogged up. I know you flushed it, but there is only so much that will do for you. May want to pull it and send it to a rad shop to be "rodded out" as it probably is a brass radiator. Or better yet put a new one in it since that one is pushing 25 years.

^^^this

if the car runs ok temp @ idle, but hot when driving (esp highway) the rad cannot flow much anymore. getting it cleaned out can work, but honda rad material is so thin you may end up w/ a hole when it's all said and done. plus, honda rad are pretty cheap. make sure the fan isn't wired up backward stalling the air coming through while you're moving.

[laokid]

might be a faulty thermostat... buy the fail safe thermostat its like 12 bucks!!

[laokid]

is ur fan kicking on?? and heat working? could be a bad fan or maybe the fan switch or thermostat switch...

[laokid]

is ur fan kicking on?? and heat working? could be a bad fan or maybe the fan switch or thermostat switch...

oh nvm u have a switch for the fan...hmm maybe your radiator is clogged up...

[Marta Mike]

^^^this

if the car runs ok temp @ idle, but hot when driving (esp highway) the rad cannot flow much anymore. getting it cleaned out can work, but honda rad material is so thin you may end up w/ a hole when it's all said and done. plus, honda rad are pretty cheap. make sure the fan isn't wired up backward stalling the air coming through while you're moving.

Im going to agree. I had the same problem at work. A flush wont always fix a clogged radiator. With the age, time, and driving of the vehicle Id go ahead and replace it. I replaced a fan, thermostat, coolant flush, and it was still over heating. I replaced the radiator and all was fine. But if youve been running it hot which apparently you have since u said it ran like crap when hot, your head gasket may have issues now to. Leak down test would answer that question.

[78f150boi]

how do i do a leak down test?
Im going to agree. I had the same problem at work. A flush wont always fix a clogged radiator. With the age, time, and driving of the vehicle Id go ahead and replace it. I replaced a fan, thermostat, coolant flush, and it was still over heating. I replaced the radiator and all was fine. But if youve been running it hot which apparently you have since u said it ran like crap when hot, your head gasket may have issues now to. Leak down test would answer that question.

[Marta Mike]

You will need the correct tool to perform this. Google "leak down tester"

[Mr. Fix-it.]

i just had the same problem you are having. it was indeed a blown head gasket. i had the same motor and everything i beleive. d15b7? when i changed it out i put a z6 head on it and a new head gasket and i havent had the problem since.

[Mr. Fix-it.]

oh, by the way. if you want to see if it is a blown head gasket just take off the radiator cap and start up the car. if anifreeze blows out then its definately blown.

[78f150boi]

thanks im def going to replace it.... how much is a dif head??
oh, by the way. if you want to see if it is a blown head gasket just take off the radiator cap and start up the car. if anifreeze blows out then its definately blown.

[Mr. Fix-it.]

well i got my head when i bought the car. a used head from honda parts connection is like 250 dollars. i got mine rebuilt for 266.