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After receiving my NISMO radiator, which looks exactly like my stock one, my car is still overheating. My brother in law then gave me a rather interesting idea. He told me to try taking out the thermostat. That way the coolant/water is always circulating. Sounds like a pretty good idea to me. Are there any problems that could arise from not using a thermostat? I wanted to ask before I actually tried it. BTW, I already tried changing the thermostat, and it didn't work. TIA.
 

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Bad Banana
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Is your head gasket ok? Blown head gaskets will cause overheating. Check your oil, and if there is white junk in your oil, then that means coolant is entering your engine and the gasket is blown.

Just a thought. Good luck!
 

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SERacer said:
After receiving my NISMO radiator, which looks exactly like my stock one, my car is still overheating. My brother in law then gave me a rather interesting idea. He told me to try taking out the thermostat. That way the coolant/water is always circulating. Sounds like a pretty good idea to me. Are there any problems that could arise from not using a thermostat? I wanted to ask before I actually tried it. BTW, I already tried changing the thermostat, and it didn't work. TIA.
My bet is you have air in the system. Turn the bleeder screw on the thermostat housing and run the car. When the fluid stops bubbling when you fill it bac with antifreeze it is mostly bled. Also instead of removing the thermostat try putting an asprin or two in the thermostat. That will keep it open enough for it to bleed itself. It works, it is an old trick.
If you run w/o the thermostat the engine will consistantly run cooler in turn you will run richer than usual. The ECU is supposed to act screwy, but I have never seen it happen. It is what is "supposed " to happen.
 

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Never Ever Run a car without a thermostat!!!! This is almost as bad as running a car with a stuck thermostat. If you run a car without a thermostat for to long it will overheat. Reason being is that the coolant does not have enough time in the radiator to cool off. In order for the cooling system to work properly the coolant needs to stay in the radiator for a certain period of time in order for it to completely cool off. If racers are not running a thermostat then they are running a restrictor which slows the flow down enough that it works. Barely.

things to check when overheating.
Thermostat (If there is any question just replace it. its only 6 bucks or so)
air in the system (probably should be first. doesn't cost anything)
water pump
fans
radiator (can be eliminated in your case)

let me ask you this, when is it overheating? only when it is idleing or when you are tooling down the highway? I recently worked on a car and come to find out the water pump had been replaced once vefore with a cheap replacement that had a thin sheet metal impeller on it. The antifreeze was old and the impeller had rusted away. Caused me all kinds of cooling problems. As soon as the car was run for any length of time (five minutes or more) it would overheat. just some things to think about for ya......

More details would be good. I may not know the exact answer to your problem but i am sure somebody on here can help you.

Rick
 

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Discussion Starter #5
Rocketman said:
Never Ever Run a car without a thermostat!!!! This is almost as bad as running a car with a stuck thermostat. If you run a car without a thermostat for to long it will overheat. Reason being is that the coolant does not have enough time in the radiator to cool off. In order for the cooling system to work properly the coolant needs to stay in the radiator for a certain period of time in order for it to completely cool off. If racers are not running a thermostat then they are running a restrictor which slows the flow down enough that it works. Barely.

things to check when overheating.
Thermostat (If there is any question just replace it. its only 6 bucks or so)
air in the system (probably should be first. doesn't cost anything)
water pump
fans
radiator (can be eliminated in your case)

let me ask you this, when is it overheating? only when it is idleing or when you are tooling down the highway? I recently worked on a car and come to find out the water pump had been replaced once vefore with a cheap replacement that had a thin sheet metal impeller on it. The antifreeze was old and the impeller had rusted away. Caused me all kinds of cooling problems. As soon as the car was run for any length of time (five minutes or more) it would overheat. just some things to think about for ya......

More details would be good. I may not know the exact answer to your problem but i am sure somebody on here can help you.

Rick
It only overheats at idle when warmed up pretty good. I'm pretty sure the bleeder plug by the thermostat housing is sealed good but I'll double check. The fans work, but sometimes they don't work for some reason. As for the water pump, I don't know how to check if it still works or not. People tell me that the water pump should be fine as long as there is nothing wrong w/ the belts or I don't hear any squealing, which I don't.
 

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Discussion Starter #6
Loe Lyf said:
Is your head gasket ok? Blown head gaskets will cause overheating. Check your oil, and if there is white junk in your oil, then that means coolant is entering your engine and the gasket is blown.

Just a thought. Good luck!
Don't know about the head gasket but oil is ok. I change it every 3k miles and do not notice any white junk.
 

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well if the fans aren't working intermittently you may want to check out the fan relays and fan switch and see what they are doing. These are cheaper than digging into the front of the engine to pull a water pump that may or may not need replacement.

The factory service manual would also be a great reference here as it will tell you what temperature the fan switch should open(or close) at and also give you the pin outs on the relays so you can check them for continuity. I would highly recommend a FSM if you don't have it. it is the best mod or reference you can have for your car.

If you need a little help with some of this let me know and i will see what i can come up with in the fsm.

For starters though....
Testing a thermostat to see if it is sticky. Dump it in a pot of water with a thermometer and see when it opens (what temp)

You can do something quite similar with the fan switch i just don't know the specs off hand.

Relays are a little different and if you have a diagram n the top of the relay you can test them as well. There should be a coil that you will need to apply twelve volts to on one side and a ground on the other side of the coil. Then check to see if there is a connection between the other two teminals.

Sorry if any of this is old hat to ya but i always like to ere on the side of too much info than to little. IM me or e-mail me directly and i will be happy to help ya more as much as i can. I need to roll this around in my head a little longer anyway.

Rick
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basicly if you do not run a thermostat your engine will firstly run rich due to the sensors reading cold engine temp, the extra fuel washes the cylinder bores causing the lubricating oil to become diluted and metal to metal contact to occour, also wear is increased by the fact that the oil wont have reached operating temp where its additives become active and can protect, and another factor is that aluminium expands 7:1 the rate of steel, so your pistons/rings wont have taken up the clearance allowed for this and you will have excessive blow-by and increased wear, same goes for your bearings, that is just some of the things that occour without a thermostat allowing correct engine warm up to operating temp. also having no thermostat will no allow the engine to over heat due to excessive coolant speeds as it will never get to that stage as it wont get to operating temp full stop.
when you say over heating is it actually boiling over/pushing water out of the over flow resivour/bottle? is it using water? or is the temp guage just showing high? common signs of a head gasket leaking compression into a cooling system is that the cooling system coolant is black and smells of hydrocarbons (exhaust smell) and possibly, but not in all cases as it can be confused with coolant flow, is the presence of bubbles expelling through the filler nexk in the radiator. also when running it is common for coolant to be pushed out of the over flow in this case.
there are about ten other signs of head gasket failure, try bleeding the system of air correctly, firstly make sure your engine is cold, then open your heater to the hot posistion next there is a little valve you undo on the right side of the engine when you facing it, undo this as you fill it slowly untill coolant comes out in a steady flow, close off the valve then continue to fill the system slowly untill it overflows out the filler neck, then start your engine, run it with the heater still open but the fan off untill your guage starts rising checking and toping up the level as required, when the guage is about half way to normal, turn on the fan this helps promote flow in the system to hepl bleeding by effectivly acting as a condenser, keep topping up the system as required untill your engine fans come on, signaling that the vital part of the system around the sensors, the final part is bleed, top up and put your cap on.
**** thats long, sorry guys, taking up all the space and all... still cant be as bad as your never ending story...
sweet man best of luck.
chris.
 

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I have the same exact problem. I have the NISMO radiator which is a lil thicker than my original one. I only overheat when taking slightly long trips - long trips (45min +). It only happens when I am idling. The fans do come on although I am not too sure how often. However I do notice, that even on short trips, the valve cover would get really hot to the touch! It seems as though I have taken a trip to Las Vegas and back. The valve cover is close to scoulding (sp?)! I take off the oil cap and I can see smoke/steam rising. I was going to replace both the thermostat and the water pump hoping that this would cure my problem. I have checked the oil and they show normal. I even check for any signs of fuel but I don't see or smell any.
 
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