My car has overheated a couple times and both times I was short of coolant. Once I put coolant in I dont seem to have a heating problem. The bottom hose going from rad to theromstat is not warm at all.
If my car overheats, the rad relief valve sends the the overflow to the reservoir, right? Not sure where Im losing fluid. Its not the pump or reservoir. nothing in oil. I will check the petcock drain on bottom of rad.
1991 240sx: How do you test cooling system for leaks?
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vancouverbc
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- Car: 1991 240sx
Re: 1991 240sx: How do you test cooling system for leaks? (vancouverbc)
The best way is with a cooling system pressure tester. They are a common shop tool but pretty expensive to buy for personal use. Most shops would be happy to test the system for leaks for a small fee, but you might find one that would test for free.
The radiator cap as a pressure relief valve in ot that dumps excess coolant pressure to the reservoir. That willonly happen if the pressure exceeds the pressure written on the cap. The thing is that if you have a coolant leak you will not build up any (or much) pressure. Often times a leak can occuur in a place that drips it onto a hot part of the engine, evaporating it before it forms a puddle. Or, it may only leak while you are driving. Definately fins a place to do the cooling system pressure test for you. Coolant does not just dissapear, and if you have a hose that is seeping or water pump that is just beginning to leak, it could all of a sudden blow and leave you stranded or cook your motor!
The radiator cap as a pressure relief valve in ot that dumps excess coolant pressure to the reservoir. That willonly happen if the pressure exceeds the pressure written on the cap. The thing is that if you have a coolant leak you will not build up any (or much) pressure. Often times a leak can occuur in a place that drips it onto a hot part of the engine, evaporating it before it forms a puddle. Or, it may only leak while you are driving. Definately fins a place to do the cooling system pressure test for you. Coolant does not just dissapear, and if you have a hose that is seeping or water pump that is just beginning to leak, it could all of a sudden blow and leave you stranded or cook your motor!
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vancouverbc
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- Car: 1991 240sx
Re: 1991 240sx: How do you test cooling system for leaks? (carbully)
Good explanation. Thanks. The pressure tester is $127 at Napa.carbully wrote:The best way is with a cooling system pressure tester. They are a common shop tool but pretty expensive to buy for personal use. Most shops would be happy to test the system for leaks for a small fee, but you might find one that would test for free.
The radiator cap as a pressure relief valve in ot that dumps excess coolant pressure to the reservoir. That willonly happen if the pressure exceeds the pressure written on the cap. The thing is that if you have a coolant leak you will not build up any (or much) pressure. Often times a leak can occuur in a place that drips it onto a hot part of the engine, evaporating it before it forms a puddle. Or, it may only leak while you are driving. Definately fins a place to do the cooling system pressure test for you. Coolant does not just dissapear, and if you have a hose that is seeping or water pump that is just beginning to leak, it could all of a sudden blow and leave you stranded or cook your motor!
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sleepyS14
- Posts: 843
- Joined: Thu Nov 01, 2007 11:33 am
- Car: 1997 Nissan 240SX 2JZ30DETT
2006 SAAB 9-2X AERO
Re: 1991 240sx: How do you test cooling system for leaks? (vancouverbc)
its possible your thermostat is not opening when it should.. cheap and easy fix.. $10 bucks for the thermostat at any auto store.. then knock it out within half an hour or so depending on auto savyness. ..
also maybe you just have air in your cooling system... have you burped the system lately? its possible that the amount of coolant that looks like its there.. (for example when you top off the radiator) there could be a big air pocket floating around making it look fuller than it is.. when in fact theres air. in which case i say.. jack up the fron of the car.. then give it a good burping.. top it off.. and see how that works out for you. doesn't seem too serious. pressure test definitely recommended.
gl
also maybe you just have air in your cooling system... have you burped the system lately? its possible that the amount of coolant that looks like its there.. (for example when you top off the radiator) there could be a big air pocket floating around making it look fuller than it is.. when in fact theres air. in which case i say.. jack up the fron of the car.. then give it a good burping.. top it off.. and see how that works out for you. doesn't seem too serious. pressure test definitely recommended.
gl
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vancouverbc
- Posts: 3197
- Joined: Thu Oct 30, 2003 1:30 am
- Car: 1991 240sx
Re: 1991 240sx: How do you test cooling system for leaks? (sleepyS14)
i likely will get a stat and new hoses to be safe. air is always a possibility.sleepyS14 wrote:its possible your thermostat is not opening when it should.. cheap and easy fix.. $10 bucks for the thermostat at any auto store.. then knock it out within half an hour or so depending on auto savyness. ..
also maybe you just have air in your cooling system... have you burped the system lately? its possible that the amount of coolant that looks like its there.. (for example when you top off the radiator) there could be a big air pocket floating around making it look fuller than it is.. when in fact theres air. in which case i say.. jack up the fron of the car.. then give it a good burping.. top it off.. and see how that works out for you. doesn't seem too serious. pressure test definitely recommended.
gl
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vancouverbc
- Posts: 3197
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- Car: 1991 240sx
Re: 1991 240sx: How do you test cooling system for leaks? (vancouverbc)
Mechanic said it was a frost plug and I would need engine job. Told me to go to engine shop.
Modified by vancouverbc at 2:54 PM 11/14/2007
Modified by vancouverbc at 2:54 PM 11/14/2007
Re: 1991 240sx: How do you test cooling system for leaks? (vancouverbc)
I love a happy ending!!!
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vancouverbc
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- Joined: Thu Oct 30, 2003 1:30 am
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Re: 1991 240sx: How do you test cooling system for leaks? (carbully)
My bad. It is the frost plug. It is right next to the drain.carbully wrote:I love a happy ending!!!
Re: 1991 240sx: How do you test cooling system for leaks? (vancouverbc)
Ouch!
Yep, buddy, that be the problem. The frost plug gets crap and debris build up behind it when coolant is not flushed or at least drained and filled regularly over the years. That crap causes the plug to start to rust from the back side inside the engine, until eventually the rust eats all the way through the plug and it starts to leak.
Here's the thing. You could just replace that one, but I can pretty much guarantee you that they are all similarly rusted and you should just get them all replaced. Hate to see you go through the time and effort and money just to replace that one just to see the next one spring a leak next month. Some cars you can get to these without pulling the engine, some you have to yard it out. I don't know about the KA or SR, but I have done Buicks and Tauruses just from underneath, just pulling the starter. But, be sure to do them all!
One other thing, I lubricate them with RTV when I do them, but some people swear by dry install. Either way make sure the hole is completely clean and dry before install and let the RTV have 15-20 min to cure before putting coolant back in.
Also, DO NOT DAMAGE THE HOLES IN THE BLOCK WHEN REMOVING THE OLD ONES!!! even slight gouging on the I.D. of the hole can render the block useless if it's bad enough to keep a new plug from sealing well.
Yep, buddy, that be the problem. The frost plug gets crap and debris build up behind it when coolant is not flushed or at least drained and filled regularly over the years. That crap causes the plug to start to rust from the back side inside the engine, until eventually the rust eats all the way through the plug and it starts to leak.
Here's the thing. You could just replace that one, but I can pretty much guarantee you that they are all similarly rusted and you should just get them all replaced. Hate to see you go through the time and effort and money just to replace that one just to see the next one spring a leak next month. Some cars you can get to these without pulling the engine, some you have to yard it out. I don't know about the KA or SR, but I have done Buicks and Tauruses just from underneath, just pulling the starter. But, be sure to do them all!
One other thing, I lubricate them with RTV when I do them, but some people swear by dry install. Either way make sure the hole is completely clean and dry before install and let the RTV have 15-20 min to cure before putting coolant back in.
Also, DO NOT DAMAGE THE HOLES IN THE BLOCK WHEN REMOVING THE OLD ONES!!! even slight gouging on the I.D. of the hole can render the block useless if it's bad enough to keep a new plug from sealing well.