yet another overheating problem....

[whoflungpoo]

well, recently i bought a 95 240sx, I got it for dirt cheap as it has an over heating problem. my buddy and i found that the radiator was cracked, and just replaced it.

problem is, it's still overheating. It can sit and idle all day long, and will even drive fine under light loads, but if you "get on it" or have to give it some juice to get up a hill, it will quickly overheat. I let off the gas, or shif to neutral and let it coast, and it's returns to normal.

I've searched on here and tried many of the different methods, although i've not found anyone else who have run into the same circumstances as me. I've tried replacing the thermostat(with an autozone one), and bleeding and it several times. There is no white smoke to my knowledge, and the compression tested within specs across the board. the only things i have done to the cooling system are that I have an electric fan and an external transmission cooler (it's an automatic), and the shroud is gone.

tomorrow, I'm throwing a OEM Nissan thermostat on it(and will pay careful attention to the placement of the "breather hole" at the 12:00 position) and will jack up the front end as far as i can.

questions: i've heard going with a 100% antifreeze may help?also, what other things should i be looking for?

I really appreciate any help or words of wisdom that anyone can provide.

thanks-Justin

[EazyBreazy]

bleed the system....may have an air pocket in it or a collapsed hose

[yellow_jacket]

100% antifreeze will not help. Run your standard 50/50 mix. It sounds as if you have an air pocket still. If it overheats as quick as you are saying it is either an air pocket, or a severly blown head gasket. If the gasket was blown that bad you really should be picking up some steam, although you may want to go ahead and run a compression check.

[navysnail]

you know there is a bleed plug by the coolant temp sensor right? open it when you refill the system, and do it on level ground when you use the bleed plug.

[whoflungpoo]

100% antifreeze will not help. Run your standard 50/50 mix. It sounds as if you have an air pocket still. If it overheats as quick as you are saying it is either an air pocket, or a severly blown head gasket. If the gasket was blown that bad you really should be picking up some steam, although you may want to go ahead and run a compression check.

It may be the bubbles still, but i'm leaning towards an improperly installed thermostat (it may be air locking the block?)

I already did a compression check, and it was ~170 across the board IIRC, so i'm doubting its the HG.

240kid, if you're referring to the screw right near the TB, then yeah, that's what i've been using.

[navysnail]

ok, then try running it w/o a thermostat for a while, see if it still does it, if not, then it is the thermostat.

[nismofan14]

Check the seal on the radiator cap. If this seal is bad it will let air into the system and will cause the type of problem you discribed.

Sounds crazy but it happens.

[whoflungpoo]

update:

SONOVA*****... the GD headgasket has a crack in it. took it to roppels (alocal radiator shop) to get em to look at it, and it's pushing CFC's into the coolant. so that explains why the more i get on the gas, the more it overheats.

anyone have a KA24DE laying around? I might as well get a different one and do the 5 speed swap at the same time.