HELP! still overheating!

[SHINCHU]

so my car has been sitting for the better part of a year. overheats after driving just one block. if i sit in front of the house and just let it idle its okay. but as soon as i go somewhere it overheats. i replaced the thermostat, water pump, and the fan clutch was replaced before all of the problems. so i gave up for a while. gave it some thought and figured i should replace the radiator. so kevin and lisa gave me a great deal on thier ca18det double row radiator (thanks! perfect fit!) and i swapped it in yesterday.

started the car and so far so good. warmed up to normal temp and i let it sit there for a while to make sure. even reved it a bunch to make sure the temp wouldnt shoot up when i accelerate. looked good! i was so excited at the thought that my 240 would be operational again! but as soon as i went to get air in my tires, the temp shot up like a rocket just one block from my house! I HAVE NO IDEA WHAT IS CAUSING THIS!!! some people say "air pocket" i say BS. no way it would go all the way up so fast and only when accelerating. some say "blown head gasket" i also say BS. no mixture of coolant, no smoke, and even when its hot it seems to run fine. i was thinking it could be the temp sensor? i popped the hood and the radiator was only slightyly warm. felt the valve cover and it seemed to be at normal temp. hot, but not scorching like the guage indicates. but why would the sensor only fail on accelration? or do i have some blockage in the coolant passages in the engine? seems like maybe it gets enough flow at idle but anything faster it cant get enough flow? ANY INPUT PLEASE would be greatly appreciated. im so fustrated. after i did all this last night i just sat in front of my car and stared at it for like 30 min. WHY?! wtf is wrong with it?! please help.

[Rexbo]

if the only thing saying the car is overheating is the temp gauge... theres no steam coming from the radiator overflow tank or anything, its probably just the temp gauge. When my SR overheats you cant even like touch the radiator cuz its like burning hot.

[JagdStealth]

Why don't you spend $20 on a cheap water temp gauge from autozone and hook it up under the hood (real easy). Go for a drive, pop the hood, and see what it reads.

There is a GREATER chance it would be overheating idling in your driveway than when actually driving.

[KOUKI KA-T]

Why don't you spend $20 on a cheap water temp gauge from autozone and hook it up under the hood (real easy). Go for a drive, pop the hood, and see what it reads.

There is a GREATER chance it would be overheating idling in your driveway than when actually driving.


Exactly, I can't believe you went and bought a radiator before just buying a temp gauge and seeing what kind of temps you're actually running at. Sounds like your sensor is junk and that's all.....

[mrmephistopheles]

hey Chris, you put a new motor in that, right?

[KaKa]

Did you do a compression test? How about pressure tested your cooling system? Does your coolant overfill tank bubble up and overflow during and after it overheats?

[KOUKI KA-T]

Did you do a compression test? How about pressure tested your cooling system? Does your coolant overfill tank bubble up and overflow during and after it overheats?

It's not overheating, he already mentioned that the radiator is only warm to the touch and that it is not steaming/boiling....

[nightwalker]

this may sound weird, but check your engine grounds. I dealt with a car with similar problems to yours, and after much straining, I went through and just did a thorough check. Turned out it was a engine ground. Cleaned up the grounding area, replaced the wire and BOOM, no more overheating!

[1stcar240sx]

I had what seemed like the exact same problem. I replaced all the parts you did. It turned out to be headgasket, no smoke, no real way to tell. It would idle fine and had all its power, but would overheat after I started driving a few miles. I had this problem for a while, I took it to a shop and they were convinced it couldn't be headgasket. I took it to another shop and they found a slight leak, when the car warmed up it would force tiny pockets of air into the cooling system. I repalced the entire cooling system before realizing this.

[KaKa]

so my car has been sitting for the better part of a year. overheats after driving just one block. if i sit in front of the house and just let it idle its okay. but as soon as i go somewhere it overheats . . .

. . . some people say "air pocket" i say BS. no way it would go all the way up so fast and only when accelerating. some say "blown head gasket" i also say BS. no mixture of coolant, no smoke, and even when its hot it seems to run fine. i was thinking it could be the temp sensor? i popped the hood and the radiator was only slightyly warm. felt the valve cover and it seemed to be at normal temp. hot, but not scorching like the guage indicates. but why would the sensor only fail on accelration? or do i have some blockage in the coolant passages in the engine? seems like maybe it gets enough flow at idle but anything faster it cant get enough flow? ANY INPUT PLEASE would be greatly appreciated. . . .

It's not overheating, he already mentioned that the radiator is only warm to the touch and that it is not steaming/boiling....

You get a lot of input on what you need done, just putting my additional 2 cents from the information provided. When the engine is or presumes to be overheating there a few primary test to check before purchasing things that won't allieviate the problem. Check for external or internal coolant leaks, then check for electrical or sensor malfunction.

[element240]

my automotive teacher always told me, the first thing you do when working on a car for problems is to check the battery/battery terminals.
corroded terminals will cause some funky stuff to happen!

yea and follow all the other tips above. good luck.

[SHINCHU]

wow thanks for all of your help so fast!
replies like this would have taken DAYS on the uh, "toyota" board i post on.

yes kevin its a new(er) engine from a 95 s14. runs great but has a small leak in the intake manifold/head gasket. not THE head gasket, but the one seals it to the intake manifold. makes a hissing sound and i think might be one reason im failing my pre-tests for smog.

thanks for mentioning the temp guage. after reading all your replies that seems like what it is. no overflow bubbling or anything. so maybe it is NOT overheating at all?! so what temp should i expect? what do stock KA24DE engines usually run at? maybe i'll just replace the temp sending unit. i would rather just replace stuff for peace of mind. as for buying a whole new radiator before further troubleshooting, why not? it was more of an upgrade anyway, going from the stock single row to a double row ca18det radiator. so not a big deal. and i already had the new water pump and thermo laying around from the old engine i spun the rod bearing on, so i scavenged those from the dead engine. they were only a couple months old.

i just hope it isnt the head gasket like 1stcar240sx said. that would be KA death number 3 for this car.

also, i did notice a ground i neglected to bolt down when i swapped in the s14 engine. its the one on the very end of the injector loom that bolts to the manifold (right next to the coolant bleeder). i wonder if this is effecting the temp reading? haha i feel kinda dumb not taking care of that as soon as i saw it! well after i get off duty tomarrow morning i'll check up on it some more. bump starting the thing every time sucks. i need a starter!!

THANK YOU EVERYONE for all your replies. every single one of them helped. i'll be sure and let you all know how this turns out.

Chris aka "Shinchu Hayashiria" on the "toyota" board.

[mrmephistopheles]

Chris, try using a water temp sensor from S13. it makes a difference. You may not be overheating at all.

[JagdStealth]

Pretty much all engines run 170-200 degrees Farenheit

If you get a gauge in Celcius it'll be int he 70-90 range

[SHINCHU]

yeah i gotta track down the mofo that i gave my old s13 engine to. i told him i wanted it back after he took what he needed! im about to ask him for $300 bucks if he doesnt give it back soon. so yeah, im gonna pull the old sensor. its wierd though, it wasnt a gradual thing. it ran fine for like 4 months then all of a sudden on the way home up the 15 one day, WHAM! the temp shot up and i limped it home. like 50 on the freeway in the slow lane hahaha.. ehh. it sucked.

but yeah thanks guys. controlled spin, tell steve bui to stop being a stranger and he can call me other than when he wants new option vids! hahaha!

oh yeah, another reason i wanted to change the radiator was that was the problem in my ae86, so i figured it was worth a shot in the 240 also.

[240sxconversion]

just wondering if u checked the radiator cap, i had this happen to me, and i replaced the headgasket, all intake gaskets, radiator, water pump, thermo, and then the last thing, my cap, and the cap solved the probelm, just my 2 cents

[1stcar240sx]

I hope you figure it out. I would check the radiator cap also, but since you got a new radiator the cap shouldnt be an issue.