OverHeating problem. HELP

[sleeper07]

Hi i changed my waterpump, thermostat, and clutch fan and im overheating still. I bled that coolint as best i can. I jackd up the from of the car and bled over 1 hour. Theres no leaks everything seems to be fine. When i drive like 10-15 mins it shoots up to H then in like 2 mins it go's back too normal. I have no idea what the problem is. Also if i run my heater on (1) it dosent even get close too overheating. The oil is clean, Plugs are clean and clooent is clean as well. This is a 95 240sx with 140k. So peolpe think its a blown head gasket but theres no White smoke. HHEEELLLPP

[RedShred]

Are you using a shroud?

Youre certain the fins on the Radiator are open?

nothing between the condensor and the radiator?

Have you changed the radiator cap?

Try another Thermostat

Try water wetter.

[sleeper07]

i already tryed 2 different thermostats n the both work i testd them in boiling water its the original sroud fan

[mylilnismo]

take out the thermostat

[Chukidori]

Thats what i did.

Its possible there could be rust deposits obstructing coolant flow...and with the thermostat in its causing it to overheat, run it without for a while then have your cooling system flushed professionaly.

[sleeper07]

i took out thermostat and ran it for about 1 week i had crapy gas mileage. I think ima get a rad. flush. Thats my next thing i needa do.

[ChicagoS14T]

You might want to replace your coolant sensor on the intake manifold, it doesnt really go bad, but considering its cheap you might as well try it, especially since you said your temp. spikes and goes back to normal.

Plus @ 140K its most likely very dirty, but also try to flush the entire system and if possible take out the radiator and power wash it to remove any dirt and grime that might have accumulated over the years, in addition check out your AC condensor it might be clogged up as well which would reduce airflow to the radiator.

http://www.courtesyparts.com/b....html

[fuco8210]

when i had this problem i just had to squeeze on the hoses a ton.. this motor is a pain in the *** to bleed.

[sleeper07]

hmm dose anyone else think i need too flush rad. i am kinda low on cash...

[fuco8210]

hmm dose anyone else think i need too flush rad. i am kinda low on cash...

Its a very common problem, it happens to me every time i have to drain and refill the coolant, just squeeze the shi t out of the hoses and add when necessary. see if that helps first.

[sleeper07]

i dont know... its weird because when i had my thermostat off it never overheated... i been trying to fix this problem for a while. I hope its not the head gasket.

[fuco8210]

i dont know... its weird because when i had my thermostat off it never overheated... i been trying to fix this problem for a while. I hope its not the head gasket.

Thats what i was beginning to think as well, but it turned out that the thermostat must of had a air pocket behind it not allowing it to open... or i guess thats what it was, after hours of trying to bleed it just stopped over heating.. sqeeze the top and bottom hoses a bunch, couldn't hurt and that seemed to fix it for me.

[2.4niz]

I would be inclined to think the radiator is clogged, or there are rust deposits in the engine itself blocking the flow.

[sleeper07]

I got it checked from a shop... they said it was the head gasket... but i dont think it is if it dosent over heat without thermostat i dont know what too do anymore

[sidewayz_180]

had a problem like that last time. but it was just my temp. gauge that was messed up. unless you raditor shoots out when you open your cap than its over heating.

[sleeper07]

yah it dose. i shoots when its hot out of the res. tank

[sleeper07]

dose that mean headgasket is blown??

[sleeper07]

anyone?

[Florida240sx]

How did the shop check? Do a compression test.

[bluemax]

most mechanic shop will tell you it's your head gasket when you're overheating but w/o testing you'll just waste your money. However if you plan on building up your engine, you might as well upgrade to a metal head gasket and it's good time to check if there might be other issues.

now back to the subject ...I had micro leakage so small that it caused overheating issue and it was hard to detect because by the time you check under the hood everything had dried up and looked normal. Check for that and change the hoses if you haven't already.

Someone mentioned about the coolant sensor, I would also change that, both of them. After I change my sensors , my sr ran solid in the middle according to the stock temp gauge and warmed up quicker. Some will argue it has nothing to do with the sensor but it worked for me..

so good luck...

[rogoman]

I got it checked from a shop... they said it was the head gasket... but i dont think it is if it dosent over heat without thermostat i dont know what too do anymore

If the coolant system is not losing coolant, then the head gasket is most likely OK. You can verify this further by doing a compression test on all cylinders.

If it doesn't overheat without a thermostat, then it's probably a thermostat issue. If you're using an aftermarket thermostat, it'll cause more problems. Buy a new OEM thermostat from a Nissan dealer.

As a side note; when you run without a thermostat, the ECU will sense a low operating coolant temperature so it will richen the fuel fixture. This will cause the MPG to go down the toilet.

[sleeper07]

The compression on the piston were low... and he said it was the head gasket some i think its cheaper just letting someone do it

[rogoman]

Were all the cylinders low on compression or just one or two? What were the readings?

If all the cylinders have very low readings, that's usually an indication of worn rings, not a blown head gasket.

[sleeper07]

Well he didnt tell me... he just said i have low compression and i need new valves and a head gasket.

[martins_240sx]

I had a similar problem, ended up replacing the entire cooling system minus the radiator, and it still over heated... took in my radiator and it was 65% clogged...it could be your problem too

[rogoman]

Well he didnt tell me... he just said i have low compression and i need new valves and a head gasket.

Get another opinion; looks like this grease monkey is trying to rip you off.

[sleeper07]

yeah i think i'm going to get a rad. flush

[azn_juvenil3]

dude i;m having the same problem ..over heating and crap..only does it to me if i red line it ahah..but after a bit it will run normal agian..or if i blast the heat it will start running at normal temp.

[b_rad]

have u tried pressure testing the cooling system?

[b_rad]

btw u do know there is a plug to bleed the air in the cooling system? located where the top radiator hose connects to the intake manifold.