Very odd overheating

[tramp_drift240]

Alright, my car keeps coming extremely close to overheating, but never quite getting there.

- Just got a new radiator, thought that the old one was clogged.

- Replaced the thermostat CORRECTLY, so i dont think its that.

- Water pump is brand new, came with a rebuild kit specifically for the KADE

- New hoses.

theres pressure and MASSIVE heat building up in the top radiator hose. plus i burnt my forearm on the radiator.

but the bottom hose has zero pressure, still cold, and i can squeeze it, with the car running, and hear coolant sloshing in the bottom hose.

NOT TO MENTION, the coolant temp. gauge goes up to the line, but then drops down to normal temperature. then it goes back up, and back down. almost as if its about to overheat, then suddenly cools down, but heats up again.

one of my freeze plugs is about to blow out, please help me figure out why its doing this so the freezeplugs arent an immediate threat to the livelihood of my car.

PLEASE

[srpowered240sx]

sounds like the thermostat might be bad, or backwards maybe. did you bleed the system after refilling??

[tramp_drift240]

yup, bled it and everything. i kept thinking thats what it would be, so i kept trying to bleed it.

and the thermostat is definitely in the wrong way, i accidentally put it in backwards a couple months ago, but long since fixed it, and then replaced it again after it was still overheating.

[dickie]

you can run your car without a thermostat to troubleshoot it. if it stops overheating, get yourself a nissan oem unit.

[pntang]

do u still use clutch fan or electric fan...and check ur cap...and heater core...maybe even the temp sensor might be wack...for me it was the cap...and it wasn't because it was bad...i ran w/ out clutch fan and w/out fan shroud so i was getting more pressure then usual...went from stock 9psi i think to a 13psi cap from pepboyz and problem fixed

[tramp_drift240]

im gonna try that tomorrow, d!ck.

and ive got a 16 pound radiator cap that came with the new unit i got.

i still use the fan on the water pump, but the coolants not even going through the bottom hose. its not that its not getting cooled down enough, its that there just isnt a chance for it to cool down since its not circulating through the radiator.

[ddgsxr504]

Replace your radiator cap.

[tramp_drift240]

dude my radiator cap is not the problem. its a brand new one, and it was doing the same thing beforehand.

somethings clogging the system or something, its unable to flow through the bottom hose.

read all of the posts before you put in your 2 cents. trust me.

Again, im gonna try what d!ck said tomorrow, to take the thermostat out and see if it overheats while running. hopefully it wont, because it really seems like its just unable to go through the thermostat.

[fuco8210]

i have to bring this back from the dead because I'm having the same problem. If your still on here and see this did you ever fix it?

[CMG]

Replace thermostat or temp sensor. When y ou replace coolant cycle it until you get heat and squeeze out any bubbles.

[Omniscient]

squeeze the bubbles from where? top hose?

[driftneil]

Replace thermostat or temp sensor. When y ou replace coolant cycle it until you get heat and squeeze out any bubbles.

What do you need to squeeze, It's a pressurized system? And did you see if the little hole on the thermastat was on top?

[tramp_drift240]

you squeeze the top hose, sometimes the bottom just to make sure, with the front end of the car lifted up some so that any trapped air bubbles will get forced out.

the coolant bleeder screw on the intake manifold is directly above where the hose connects, its a 10mm i believe

[cmoody2006]

I'm having a similar issue with my ka24e I pulled out my thermostat and it still overheats like a bish. I've got a newer radiator - the all metal one, I put in a mustang gt electric fan b/c it would fit and i have it wired to my battery where its always on right now. It will run fine for like 30 mins after that it drinks coolant and starts to over heat. I just replaced my head gasket and put in a head gasket spacer. The only thing i haven't tried is a new cap but mine seems to be fine i think. any one have any ideas. Mine was doing the hot hose on top bottom hose cold thing so thats why i pulled out the thermostat. Oh and it doesn't have any white smoke comming out of the exhaust and the oil isn't milky

[TotallyStock]

Try to see if there is anything that looks almost like old toilet paper in your radiator. Old cheap types of 'stop-leak' additive are really horrible. they can remain in your engine and pollute your brand new replacement radiator. Also, over time, deposits can build up in the engine, so an engine flush could possibly help.
Modified by TotallyStock at 8:47 PM 1/6/2008

[tramp_drift240]

Try to see if there is anything that looks almost like old toilet paper in your radiator.

Cmoody and i both said we've gotten new radiators.

could this problem be caused by a clogged heater core?

and if so, would i be able to just loop the heater core feed-line to the return, to just cut off the heater core from the cooling system?

[cmoody2006]

Would blocking off the heater core do anything other than just not give me heat in winter?

[tramp_drift240]

as far as i know, thats all the heater core's for. seeing how i dont really use my air system, i dont think it'd be a big problem for me.

my main thing is to solve the clog or whatever the problem is so i can drive my car on a regular basis. if it IS the heater core (which i have yet to get an answer back about), i can just bypass it until i pick up another one to install. then ill have heat back if i want it.

i just need my freeze plugs to stop leaking and hissing at me

[cmoody2006]

What other coolant lines can we block off? I know you can block off the one that goes through the intake manifold. Thats just to warm the intake up which defeats the purpose of the cold air intake. What about the line that goes from the lower intake manifold to the left side of the water pump? Can I block that one off you think? I'm trying to simplify all the coolant lines and crap to make it just the bare essentials and I don't know what to search for on this motor

[xekushnr]

The heater core is sort of like a second smaller radiator. It does help to cool the coolant. If anything, I think it would cause the car to overheat more if bypassed. I dont know if a clogged HC kept in the loop would be any worse than bypassing it.

[cmoody2006]

Has anyone bypassed it? I kind of want to and just hook up an electric heater inside the car. It would heat up instantly and i've already got one..... You wouldn't have to even start the car to get it warm just turn on the heater and go back inside. I'm just contemplating whether or not it will mess anything up. Will it increase pressure in the coolant system? Don't race cars bypass it? Most mustang guy's I've talked to just bypass it. This guy i talked to says it robs like 2 hp. Also doe anyone know where I can get a really nice aftermarket water pump? I've seen electric ones that don't run off the belt and you just make a block off plate and seal it up. But those go for a couple hundred bucks. I'm looking for something in the $100 range for the ka24e

[tramp_drift240]

as far as i knew, the heater core was for the vents in the car, i dont see how it would have any significant cooling effect for the system when its never used anyway.

im still trying to find more info about it, because im needing my car for my DD rather soon.

[gingerbredman]

oh sweet Jesus you guys didn't use that Water Wetter crap did yall? i used that and it caused my thermostat to sieze up and water pump to leak, i finally found out after i replaced everything and it still overheated that the new Duralast therm. didnt work, so i got a Mr.Gasket one my car did the same thing.

random 240 thing, after i fixed the cooling system. one day i decided to remove the broken coolant reservoir tank and fixed the hose to where it wouldnt leak out but could still breathe if needed. .. then my car started running hot, no lie

[cmoody2006]

oh sweet Jesus you guys didn't use that Water Wetter crap did yall? i used that and it caused my thermostat to sieze up and water pump to leak, i finally found out after i replaced everything and it still overheated that the new Duralast therm. didnt work, so i got a Mr.Gasket one my car did the same thing.

random 240 thing, after i fixed the cooling system. one day i decided to remove the broken coolant reservoir tank and fixed the hose to where it wouldnt leak out but could still breathe if needed. .. then my car started running hot, no lie

What is the water wetter crap? Never heard of it..... My car runs hot all the time and i'm trying to simplify the whole cooling system to where its just one nice even flow of coolant not 4-5 different hoses running everywhere.

[gingerbredman]

is that bottle of pink radiator "additive" i just got a wild hair one day and decided hey it cant hurt.. but hey cant you get like a radiator shop to flush out the entire cooling system? all the way through the motor and radiator? it could be all that old residue from someone not ever flushing out old coolant? idn i would try that, maybe they could blow it out or something

[tramp_drift240]

i replaced the headgasket and head bolts with ARP studs, i'll see what happens next.

just gotta get a battery that works, mines dead. im not able to start it til i get some powa.

[nightkid86]

Sounds like air in the system. I'd wedge an asprin in the thermostat to keep it open and bleed the system. (air goes around the asprin and can't get caught behind the thermostat. then when water gets to the asprin it dissolves it). gets air out of the block.

[tramp_drift240]

i know how to bleed the cooling system, ive been having this problem for a while now, so ive already tried it multiple times.

but, like i said, when i get a battery and im able to test drive it, ill see what happens.

[cmoody2006]

I have given up on mine I auit messing with it and i'm just going to either part the motor out or sell it and buy a swap. I'll have my 300zx going hopefully by tues. or wed. We'll see.... Anyone want to buy my motor for parts?

[stocker240]

Buddy i am going thru something totally simmilar and i was gonna put up my own post but because of the similarities i figured i hijak yours

for the last few weeks i have noticed a few small drips of coolant on my driveway at home, ive been checking and adding coolant whenever needed

so the other morning i am on my way to work and ive warmed my car for about 5 mins and ive been drivign for about the same and i notice that all im getting is cold air thru my heater

my temp gauge read normal so i kept going , a few minutes later it was blowing hot air

20 mins after that i had to pull over because i was nearly overheating, i was on the enterance to the freeway so i couldnt turn around after 2 mins of driving the temp read normal so i went to work ,

i got to work and checked my coolant level at the rad at the end of the day, it was down so i jacked up the front and ran it with the cap off and topped up the system with water

i ran the car with the cap off and the heater at full until the water level stopped dropping and the heater blew hot

i drove the car to my shop with no probs, once i had the car inside and shut off i saw the water pump **** the bed and let got all over the floor, i drained the rad, installed new water pump, thermostat, and pwr steering to fan belt. i got everything buttoned up and double checked the drain c*** at the botom of the rad, gave it a twist and it sheared off ,,,

next day got the drain plug from nissan, got the system filled with water only, the car is jacked up and the rad cap is open , same as before water level isnt dropping and heater is blowing hot i drain the rad , close it up and fill with coolant and water mix, jack it up and run it till it blowing hot

the thing is same as you my lower hose is cold . i mean COLD, so is the lower 80 % of my rad , i figured air lock so i went to loosen my bleeder bolt on the intake and busted that as well , time for a break

so after 30 mins of running the car all seems good and i am on Empty so i make a run for the gas station and all of a sudden overheating

back to the shop back in the air and still the lower hose is cold

i ran it for at least another 30 mins the hose is still cold but inside the temp reads normal and its blowing hot

after a long day and at least another hr of bleeding, i put the rad cap on and went for a road test , 20 mins later and no probs temp is perfect and heater is blowing great.

i am confused at this point because both nissan tech's that i spoke with said that the hose should be warm and it definately isnt

i stop and check my levels once again and the rad is down abit and the overflow bottle is empty , i top them both up and bring a few jugs with me and go for a good hard run , at least a 30 min road test everything seems perfect BUT the hose and rad are cold

ive decided that for tonight i am more comcerned that my car not overheat and if that lower hose is gonna stay cold, im just not sure

if the car comes close to overheating again i am gonna pull the rad and send it to be checked for blockages and go from there

the car is a 1991 fastback 5 spd with hicas 220 kms ive owned it for 2 yrs , havent had any major repairs or done much more that regular tune ups

thanks Josh