240sx no heat and overheating

[mcaroluzzi]

Hi guys I have a 93 240sx that just had a radiator crack. I replaced it with a koyo all aluminum radiator. I airlifted coolant but it would not get air out. I jacked car up over night with cap off and massaged upper hose. I put a new thermostat in also updated with a 16 psi cap. I road tested and it over heated still. I came back and blead it 1 more time and it was fine. I road tested 60 miles with the needel at half way. car ran great no smoke at all. now I get the car back and the lower hose was leaking it was over heating with no heat. Still runs with no smoke. only 1/4 gallon low on coolant. I replaced hose bleed and it still over heats and blows cold air.From what I understand with this system it is very hard to get the air out, but with the 1/4 gallon low on coolant would that give me an over heat or do I have another issue.

Your help is greatly appreciated

[nismoracingsx]

the overheating is probably just still more air in the system. Normally with air in the system, the temp needle is all over the place. I bled mine, then what I did was drive it and once it got up to temp, i would pull over use a towel to pop the cap and shake the front end to get more air out. Drive again and bleed again on side of road. I just kept doing it until it quit overheating :p.

[sx moneypit]

Did the car overheat before you put the new radiator in it?

[mcaroluzzi]

no only when it started to leak with the hole in it

[sx moneypit]

Did the temp gauge peg out? How far did you drive the car with it running hot?

[liquid_cool]

you need to do a little more testing.....when the car is cold....undo the radiator cap...have a buddy start the car and look at the radiator hole to see if bubbles are coming out....if there are bubbles..its possibly a head gasket...this would allso explain while your over heating....this is what im thinking it may be...its a common symptom for a head gasket beggining to fail..specially due to over heating in the first place....good luck..and post back with what ya find.

[rioredstang]

When you say no heat, do you mean from the heater inside the car? You may have a water pump not flowing any or very little water. This may be what caused radiator to crack to begin with. Does the upper and lower radiator hoses get hot? Start engine and let it warm up and take the radiator cap off, DO NOT REMOVE CAP IF IT OVER HEATS. Watch the coolant in radiator, do you see any flow in the tank? If it flows good and hoses get hot, you probably have a head gasket.

[mcaroluzzi]

i have not worked on these cars but what i can understand they are very hard to bleed. i belive i still have air in the sytem because when i replaced the radiator and bleed it it ran fine. then a hose leaked then it overheated. i replaced the lower hose. now it is overheating. there are no bubbles or excess pressure in resivor thats why i am ruling out a head gasket even though they always fail.

From your guys experience how long does it take to get the air out compleatly.

what do you do if you get a leak on the side of the road it will overheat. there is no way you will get the air out. tow truck. any thought. is this a poor diesign and a nightmare to work on.

thanks

[speedeast]

Most engines are pretty hard to bleed... keep adding coolant and bleeding it out. Where ever you bleed it from needs to be the highest point in the system. If you are a quart low on coolant, you need to get that fixed. Head gasket could be failing... some people get a break small enough that exhaust is forced into the coolant, but not big enough for coolant to get into the cylinder. If the engine has 125,000 plus miles on the original motor, you might as well change the head gasket anyways. Good luck with this though, I hope you figure it out. They are not nightmares to work on, all engines are finicky like that. They are built pretty reliable, but overheating is a major issue, and can mess things up if it ever does.

But keep in mind: Bleed it, and when you think you're done... bleed it again.

[mcaroluzzi]

i have worked on a lot of engines and cars and trucks but I will have to disagree and say this is the hardest system i ever had to bleed. most systems are not that difficut to get air out of. I had to run this 3 times and bleed it three times finialy i jacked the front end up and left the cap off over night. i never worked on somthing this difficult to bleed. The air lift will not even get the air pockets out.

[speedeast]

No, I never said it wasn't harder. I know they're difficult to bleed. Not quite RB difficult, but difficult. Leaving it open overnight won't really do anything unless it's shaking or something. It needs to run with the cap off while it's jacked up beyond the point that the thermostat opens up. Keep adding fluid while it bubbles out. If it becomes impossible to bleed, which it may, then it starts pointing a little more toward the head gasket. I can't tell you exactly 'cause I'm not there, but we can make suggestions. For your sake I hope it's not the HG...

But my advice stands: bleed, bleed bleed. I have seen a lot of these engines recover after what seems like monotonous, pointless, mindless bleeding. lol.

[mcaroluzzi]

Has anyone seen issues with these koyo radiaters. do they make it harder to bleed.

[jspeedm]

I don't know how different the s13 ka and the s14 ka are, but I don't have any problem bleeding mine. there is a little bleed screw on top of the t-stat housing. how long does it take before it overheats? did you replace the t-stat? as for being the most difficult system to bleed, no Nissan has anything on BMWs.

[sx moneypit]

I agree with Speedeast,i think you have got a seeping head gasket.I have a car in the shop right now with the same symptoms.I bled the system 3 or 4 times, drained the cooling system,refilled it using the Airlift tool.The car would have heat sometimes other times it would run hot.We pulled the heads and found a small crack in the gasket between one of the coolant passages and the combustion chamber.

[mcaroluzzi]

i bleed again then road tested. heat was not really hot. gauge got hot then fluctuated up and down. when i parked engine i heard a gaurgling noise through the engine where the bleed valve was. is this combustion gas entering coolant system

[motaro9424]

Are you check the fan?.

[rioredstang]

The sound you hear is percolation. When the water stops flowing it will begin to boil like a coffee pot. When the water boils it will push water out the over flow. It can have significant pressure behind it, so be careful if you remove the cap. I think it has insufficient flow through the block and radiator. Check water pump and stat.

[mcaroluzzi]

get this i bleed it one more time and road tested it for 1/2 an hour. i beat the hell out of it. coolant gauge stayed at 1/2. came back popped hood heard no noises. explain this please

[sx moneypit]

Drive it for a few days and see how it does.The car we just finished putting head gaskets on acted about the same way.You could drive it one day and it would be fine, the next day it would start acting stupid again.For your sake i hope you have your problem solved!Keep us posted.

[mcaroluzzi]

one more question if i am at a stop and i turn the wheel i have no power steering it kicks in and out. on the road it is fine. p/s fluid is full. i also hear a load groaning noise. on these cars do the p/s pumps or racks fail a lot. and is there a good test to confirm. thanks again

[sx moneypit]

Check the tension on the power steering belt and double check your fluid level.If it is full of fluid and still making noise then it is possible the pump is bad.You could also have a bad power steering pressure switch.

[mcaroluzzi]

what switch are you refering to and where is it. isnt this a mechanical p/s pump

[sx moneypit]

It is in the high pressure hose,in the front of the car.

[mcaroluzzi]

do you have a way to test this to see if it is bad

[sx moneypit]

Unplug the sensor,put your ohm meter leads on terminals,when you turn the steering wheel you should have continuity.