2nd part of car overheats after driving for awhile

Post by **Rafael** » Mon Jan 06, 2003 9:55 am

this is the 2nd part of a topic I started last week. Some people told me to try something to see if there was air being trapped or maybe a stuck thermostat or problems with my water pump. This problem is on a 1991 Nissan 240SX. Last night I took the car out for a spin w/ the heater on to see if there would be hot air comming from the heater core when the car heated up. When the car heated up on the temp gauge there was no hot air comming out heater vents. So I parked the car and checked the overflow bottle and water was boiling out of it. Checked the two hoses going to the thermostat and comming from the water pump and there was no pressuer in them. So I thought maybe there is some air trapped in the engine block so I loosened the bleeder screw on top of the engine and alot of hot steam came out but not antifreeze. What could alll this mean. Could it still be my new water pump is not working or my New factory nissan thermostat is not working or I have a big air pocket in my engine cooling system.

Please help!Rafael

Post by **96_S14_SE** » Mon Jan 06, 2003 9:55 am

No heat (is the fan blowing) , car is getting too hot, and loosing fluid...

Do me a favor and top er off once again, and run her for a few minutes with the heat on full. When the temp starts to rise shut er down and open the passenger door. Reach your hand up where the carpet meets the firewall next to the console. I bet it will be wet and your heater core is cracked.

My gf's 92 died (overheated) xmas eve, and I had to bypass the heatercore (nissan places a barb in the return line after the heater core in the engine bay thank god

) in the BP gas station hehe Fun little ordeal but I had the broke down 92' repair kit with me and it was ok.

You can bypass it rather simply (pain in the arse due to lack of room and you will have to move the lines around not to have them resting on the egr tube) and it will run perfect just no heat.

That is if the heater core is gone, it sounds like it.

By the way nissans tech price is 125$ (cost + 20%) and your cost would be around 2 bills. I havent found a new replacement other then that either..... Sucks.

Let me know whats up...

Post by **Julio Bro!** » Mon Jan 06, 2003 9:55 am

Hi 96_S14_SE:

That thing about having the carpet wet, it's happening to me, and from time to time, the radiator has to be refilled. Seems like the problem you describe.

Can this be checked visually, is it too difficult to access those lines?

Post by **yellow_jacket** » Mon Jan 06, 2003 9:55 am

Have you pulled the spark plugs yet to see if you have antifreeze in the combustion chambers? Sounds like a head gasket though.

Post by **96_S14_SE** » Mon Jan 06, 2003 9:55 am

Yes but if the head gasket was dumping that much coolant into the chambers wouldnt he have mentioned a good deal of smoke (steam) now comming out the exhaust...

Post by **96_S14_SE** » Mon Jan 06, 2003 9:55 am

Julio If you are getting wetness is it always constant? I really dont like the oem HC units (pos plastic endcaps, I give honda credit for thier copper ones as I pulled one to use in my computer

). I never got around to checking my gf's core I just new it was it, and after bypassing it (disconnecting the two lines going through the firewall and connecting them together) she has no problems. If you find it is bad the lines go into the fire wall on the left side of the head (two rubber hoses vertically alligned, the one with insulation is for the evaporator). Disconnect them and reconnect them together, then when you get a new one (if thats the problem) plug them back in.

I gessing her core corroded away. She had a copper radiator on there that corroded earlier. Cu + AL + water = galvanic corrosion (learned that from wasting my time water cooling my computer). And since the AL core is thinner then the head it corroded shortly after the radiator did (which was the only source of copper and should have gone first).

You could pressureize your sytem with a pressure checker and see if you loose psi. If you are and not smoking or have any oil in the coolant. I would suspect this if the radiator is known good and not leeking as well.

Post by **yellow_jacket** » Mon Jan 06, 2003 9:55 am

If all the coolant was dumping into the chamber, yes he would have a decent amount of white smoke. But if it was just a large leak in the heater core he should either see it leaking out of the hose that drains the box, or have pretty wet floor boards. I know someone told him to check this and he hasn't responded yet, but it should be pretty evident. The part that gets me is that he refils it and then when he comes out to drive it cold it overheats on the first warmup cycle. I have seen a few headgaskets act exactly as he has mentioned. To the point that after you let it cool back down you could drive an hour no problem. And no, there wasn't any smoke, but when I pulled the gasket you could definetely see where the gasket had blown out around #4. He just needs to figure out where the coolant is going: on the floor, in the cylinders, on the road? Hope this helps a little.

Post by **MojoMan** » Mon Jan 06, 2003 9:55 am

He probably figured out what it was or hasnt gotten back to the public library to use there computer:pface . You would think if the heater core was bad he would notice the wet floor board or atleast the smell of coolant. I wonder if he installed his thermostate in the right direction. I agree he needs to give more specifics. I wonder if his radiator needs to be rodded out. He needs to check out his radiator fins and make sure there clear of bugs and bird feathers(freak accident I had on the way to cali. Poor bird never saw me coming at 100 mph through new mexico. I couldnt imagine the block having that much trapped air. He needs to also check his oil for coolant. Someones probably already mentioned that.

Post by **Rafael** » Mon Jan 06, 2003 9:55 am

sorry guys didn't get back to you sooner, been busy at work and home no time to get on the net. Well I think it is not the heater core, but could be the head gasket. The reason I say this is because now it does look like I am starting to see alot of wet exhaust comming out of the tail pipe, but it could have been because it was very cold out. Also another symptom is the radiator after sitting for a while and upon first start up if I loosen the cap there is alot of pressure in there and the radiator fluid just spills out. This is when cold and some of the fluid spills out but quite a bit not all. I am starting to lean towards a head gasket problem how would I be sure that is it. Also when driving it goes to the H on the temp gauge for a while and then drops down to naormal temps and fluctuates.

Thanks for all the replies I will check the floor boards just in case.Willl let you guys know what happend this weekend.rafael

Post by **96_S14_SE** » Mon Jan 06, 2003 9:55 am

Hmmm thats funny. Have you tested the temp sensor with a DMM?

Post by **Rafael** » Mon Jan 06, 2003 9:55 am

No I have not checked the temp sensor. The reason is the car does get really hot! when the temp gauge goes all the way up to H and I stop the car the over flow bottle is boiling and over flowing. Also something else I observed is when the car temp gauge reaches the H and I stop the car I once undid the bleed bolt that is on top of the engine and instead of antifreze comming out all that came out was steam. It was like there was no antifreeze flowing in the engine. I will check my floor boards today to see if they are wet. I will let you guys know tomorrow how this went.

rafael

Post by **Queamore** » Mon Jan 06, 2003 9:55 am

I have a 90 240 sx with a blown head gasket. It first started ticking and smoking and then I took the valve cover off and started it up and all this green goo came up from the engine. I check the raidiator and sure enough it was empty. SAo try that If you just see oil then it's not the head gasket.

Post by **Bay Dog** » Mon Jan 06, 2003 9:55 am

Queamore, When you did that, was your overflow / fill case full or was it empty as well. I have noticed recently that my radiator does not hold fluids in it after it has sat. But I don't seem to be losing any volume from the overflow case. I have detected a very minute leak. (maybe a teaspoon for every 8 hours it sits) I have had other vehicles where the radiator stayed full all the time. Is this just a Nissan thing?I have a new engine (30,000 miles) that I heard ticking today. The oil is still oil, not milkshake. But it is hard to tell if it is blowing white smoke since it is cold in Ohio. There isn't any foul odor that I can tell. Thanks!

Post by **yellow_jacket** » Mon Jan 06, 2003 9:55 am

Just because there is not antifreeze in the oil does not mean it is not the headgasket. While that can be a sign, it is not the only sign and does not have to be present.

Rafael, if you are still unsure about the source of your problem, you may consider paying a good ASE Master Tech to take a look at it. They should be able to figure it out in about an hour and rates will probably run ~65 an hour. Plus that way you have a good second opinion before you spend $600 at the machine shop having the head checked, valve job, and gaskets.

2nd part of car overheats after driving for awhile

2nd part of car overheats after driving for awhile

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