Bryggz

Hey I did a search first for sensors and I had no luck, so here goes.


My "Add coolant" light has been lighting up, and there's no cooling on the overflow, however when remove the radiator cap I can see coolant there. The car has been running fine up until now, but about 20 minutes ago my temperature gauge was starting to go past 50% and I shut the car off before it reach the tick line. I've never had coolant below my car so I doubt it's a leak...and when I finally had to move my car.....the temperature gauge didn't rise like it did before. Is it a sensor problem or something? I don't get it.

I have an 84 gs. Thanks in advance.

85 FB

Actually, there are a few threads about the "add coolant" light. The most common reason it does this is that the contacts need cleaning. Or, you can replace the sensor with another one for about $12, I think.

And, your car overheating.....could be your thermostat.

Kentetsu

Fill the overflow tank to the indicated level. The radiator has to be completely full, otherwise the warning light will go off. As the radiator cools down, it will draw fluid from the overflow and maintain itself at the proper level...

Bryggz

Okay what about the raising temp meter? I'm guessing the thermostat might be done for......The temp is fine sometimes...then sometimes it goes past 50%.....then other times I drive and it's fine where it should be. This started happening earlier today.

trochoid

iTrader: (6)

Keep an eye on the level in the overflow tank. If that level keeps going down, the tank itself may have a leak. Each time an engine is shut down, it goes into heat sink, meaning the the internal temps stabilize, causing the radiator cap to open to relieve pressure in the system. Once the engine cools down, the overflow is draw back into the cooling system. If there is no coolant to be drawn back in, eventually the low coolant light wil come on.

Best option is to observe what happens when the engine is shut down after reaching operating temp. If the coolant is not being drawn back into the radiator during the cool down cycle, then there may be a leak in the pickup tube inside the overflow tank, the tank itself or the radiator cap may be bad.

Other, and perhaps the more common leaks are pinhole leaks in the radiator/heater hoses, particularly the heater hose under the oil filter, a cracked intake o-ring seal, or worst case scenario, blown coolant seal. The later can be checked for by removing the radiator cap. starting the engine an looking for the tattletale 'champagne' bubbles.

Fwiw, the low coolant sender is placed quite high in the top of the radiator so it needs to be kept topped off. Now might be a good time to replace the thermostat also.

Bryggz

Okay the coolant light is taken care of. I just needed to top it off like you said. How about the temperature issue?

Kentetsu

If you don't know how old the thermostat is, then replace it. Go to the dealership and get an OEM replacement, rather than taking a chance with a standard off the shelf type (sometimes causes a problem).

3rd and final 7

iTrader: (9)

on the t-stat thing the oem t-stat has a 1 yr warrenty on it too the last time i chked. i would get it from the dealer and also clearify that with them. this is what my dealer in gainesville fl told me!

Bryggz

Okay using the Haynes manual I replaced the thermostat myself.

Question time:

I purchased and installed the thermostat before reading the posts about the OEM thermostat. Anyways, I got a 170 degree one instead of a 180 degree thermostat. The man who was helping me out at the parts store said it would basically just keep the engine 10 degrees cooler and wouldn't have any negative affects. What say you, Rx masters?

85 FB

I don't see why it should give you any problems, really. You WANT to keep the rotary engine cool.

BlackWorksInc

I'll have to double check on this... but I'm pretty sure that it shouldn't screw up your engine too badly since its not a computer controlled fuel/air mix. I know that for more modern cars putting the wrong T-stat will mess with the computer's readings and it may make your air/fuel mixture too rich or too lean depending, but again I have no clue for Carbs...

But basically, yeah the T-stat will open at 170 degrees rather than at 180 and route the coolant back to your radiator to chill it out.

85 FB

DemonSpawn - You don't have to "double check" on anything. If a car is not carburetor equipped, it is EFI and all EFI engines are "computer controlled air/fuel mix". That's the whole point of EFI. The air/fuel mixture is regulated by the oxygen sensor. Not to mention that air and fuel has NOTHING to do with coolant temperature. Coolant is there to keep the temperature of the engine at a normal operating temperature and not overheat.

Also, the fact about the wrong thermostat will mess with the computer's readings is false. I don't know where you get your information from, but this isn't the first time you've posted information that was incorrect. If a particular car is offered three different thermostats, then that means that it can take any of them. This is mostly true for older engines, especially Chevy's and Ford's. Other cars, only one thermostat is offered because of the way it's designed and because there is no real reason for other temp offerings. Example: a Chevy 350 V8 will be offered about 3 thermostats. 165, 180, 195. A Toyota Corolla will be offered one. 180 to 195 depending on year.

You say that the wrong thermostat will mess with the car's readings. How is that? Because I've worked with other mechanics who work on brand new cars, and they've stuck in lower temperature thermostats. Not to mention, they've also changed out the coolant/water mixture (more water than coolant), along with Water Wetter, or Purple Ice, or any other coolant additive. It does nothing except lower the coolant temperature. It has not once affected the computer readings at all. A thermostat works off of the temperature of the coolant to pop open or shut for flow. That's all.

Bryggz - Your setup is fine. Don't worry about it. My -SE is computer controlled and I stuck in a 180 thermostat. No problems whatsoever. Also, 170 is nothing. You can get a 160 degree thermostat for your car if you wanted.

Rx-7Doctor

iTrader: (13)

Here is the info on T-stats, engine temps and fuel economy.

A T-stat is like a regulatory valve, regulating the amount of water flow through the engine based on the temp that it is designed to start opening and the temp that it will be fully open.

Once that temperature is reached it then closes and the coolant recirculates through the engine,

Ambient temperature affects how hot or cold an engine runs also.
Running a 160 degree T-stat in very hot temperatures can and will cause overheating issues.
Why? Because the hot air entering the front of the radiator will accelerate the rise of the coolant temp. Therefore opening the T-stat and circulating the coolant more frequently. So frequently that the coolant does not have enough time to stay in the radiator and dissipate all of that heat that is has carried away from the engine. Until a point that the cooling process is no longer effective.

This is more noticeable in stop and go driving and under heavy loads.
A 160 degree T-stat in cold weather can and will cause a loss of your heater system and poor fuel economy.
In this scenario the engine is not allowed to come up to operating temp efficently
and the coolant does not get hot enough to provide hot water for the heater.
What happens when driving in cold weather is that now you have that cold air entering the radiator and cooling down the temp. The 160 degree t-stat stays open most of the time not allowing the engine to operate at a good temp and is constantly cooled down by cooler and cooler coolant going through the system.

A engine is most fuel efficient the hotter it runs without overheating.

When it comes to FI engines. The A/F ratio is greatly affected by coolant temps.
The coolant temp sensor in our Se's is the most critical sensor that affects mixture. The O'2 sensor in the Se only reads when in 5th gear. The ECU reads the coolant temp sensor at all times to determine the fuel requirements.

When the coolant temp is lower the ECU gets a signal to supply more fuel. When it is higher the less fuel it delivers. This is to maintain the balance of A/F requirements.
Vehicles 1996 on up with OBD2 have a whole different more fuel efficient system.

I hope this clarifies some of this. :-)

85 FB

Sonofabitch. Why couldn't I have worked with you a few years ago? I hated having to work along side mechanics and technicians who would contradict each other. Not easy trying to find answers and learning things when different people are telling different stories.

Well, I was wrong, I'm not afraid to admit that. Course, having been around some guys who spewed out verbal mazes didn't help. I learn something new everyday. Thanks for the clarification, Doc. It did make me remember what my rotary tech told me about my car. During winter season, the engine dumps in more fuel to operate properly. This was when I asked him why it seemed my engine was consuming more fuel during winter.

And, explains why I couldn't get any heat out of my heater last winter.

BlackWorksInc

I might of mixed up what I heard from my Atec Proffessor.. but what Doc says sounds just like my teacher told me.

Thanks Doc, I know I sometimes either mix up or mis interpert what I'm told... Not enough doughnuts during class...

85 FB

Looks like I'll have to replace my thermostat with a higher one now.

Rx-7Doctor

iTrader: (13)

If you were running a 160 degree T-stat you would of had a terrible time getting the engine to warm up enough for good heater usage.

Fuel mileage drops during winter are actually normal. The colder temps are a contributing factor but the major factor is the "Winter" fuel.

They have to put in additives in at winter time that help with the combustion process. This is because a lot of the older vehicles mainly carb'd ones have trouble starting with the regular fuel.

I believe that a friend of mine told me that at winter time they add butane or something along that line to the fuel.
Demon, you as well as 85fb did a good job of explaining the information that you supplied. It is not always easy to explain the technical workings of anything. It is because we all view things in our own ways so that we may understand them.

85 FB

Actually, I think I'm running a 180 thermostat in my engine currently. Guess next paycheck, I'll have to purchase a 195 before the temperature really starts to drop.

waysrx7

Thanks doc. I just got a temp. gauge, been running without one for 6 months, and now I know my car has been running cooler than normal. I guess that's good news since I don't have to worry about overheating it anymore. Might be time for me to get a new T-stat as its getting cold and it does take a while to get the car warm.

Bryggz

Okay new problem.....I'm getting some light white smoke now, and I'm pretty sure it smells like coolant. I checked the thermostat housing and found that I could turn the bolts on it maybe another 1/4-1/2 inch tighter, but after the smoke died out and I drove the car again, it was smoking by the time I was done driving again. The temperature is completely fine on the car now, and I'm guessing it might have just been a coolant leak from the thermostat housing, but how long does it take to burn off coolant that leaks onto a hot part of the car?

Rx-7Doctor

iTrader: (13)

Can take a couple of days of driving depending on how far you are driving.
Keep an eye on the coolant level, check it daily just to make sure there are no leaks.

Bryggz

I made sure that all the rings were tightened on the hoses, and i tightened the bolts on the thermostat housing pretty much with all the strength that I had. They're tightened alright. So a couple days of driving eh? I get a fairly decent amount of smoke from this, and based on other threads in the forums it's definitely the smell/look of coolant. My assumption is that since the thermostat housing wasn't tight enough that and undetermined amount of coolant leaked on whatever is directly below it (because the smoking seems to be coming from something below the housing....which is why I'm sure it's just a fair amount of coolant burning. Sorry if I'm sounding redundant but I'm basically trying to be cautious with my car, and every bit of reassurance helps me feel better :-) Thanks for the quick responses by the way, doc.

Kentetsu

The smoke is coming from under the hood, not the exhaust, right? Don't tighten the thermostat housing too much, or it will crack. Did you clean up all the surfaces and use a new gasket when you installed the thermostat?

Another possibility would be that the water pump is going bad. They will usually start to leak right before they go kaput...

trochoid

iTrader: (6)

*
I would stick with the stock 180* thermostat. *Overheating is one of the top rotary engine killers. *I have yet to have any problem running a 180* thermostat. *Many of the newer piston engines run a higher thermostat in order to meet emissions standards and*achieve*a*cleaner*burn.**Keep*in*mind*that*our *engines*are*still*running*20+*year*old*systems, not to*mention*that most*of*them*are*carbed.

If anyone has any idea why all of this embedded coding keeps showing up in my posts and PMs. please let me know know what I can do about it. *It's driving me nuts, lol.

*
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Bryggz

I used a new gasket with silicon sealer, just like the manual said to do, and yes it's coming from under the hood. I'd hate to think that for some reason the water pump decided to go bad just after I replaced the thermostat....it seems all to convenient. I know that the housing probably wasn't tight enough, and that some coolant is probably just burning off of whatever it leaked onto. Does that seem like a realistic scenario?