1992camarors

Is it necssary to run a thermostat in a 305 TBI? I currently don't have one in my car due to overheating, but should I get one installed and what TEMP should I purchase?

Dewey316

You are actualy hurting your cooling by not running one.

I would get something that is 185*-195*, either of those should do well.

1992camarors

But is it affecting my tbi sytem by not running one?

Dewey316

That depends on the temp the car is running at. For the computer to properly run the car, the car needs to warm up to about 174*, before the computer will take over fuel correction. If you car is not getting that warm, you are hurting it.

You car also will not properly cool when it does get hot. By having a restriction in the water neck, you ensure that the coolant stays in the radiator long enough, to despense its heat. You will notice, that even race cars, that do not run thermostats, will run a restrictor where the thermostat would be.

90CamaroTBI

I got the 180 because everyone said thats best, is that fine?

xlwhellraiser

iTrader: (1)

170 degree one is works really good for me! Barely see the thermostat climb to 190 on the hottest day. However I do have a chip that lowers the open/closed loop operation. Make sure you have a good air dam on there, and it will defenetly make a difference.
If you overheat while idling it would help to, at least, replace your fan motor.
Laters.

chevyz71man

Well if your oil is to cold it can actually create exesive wear in the engine. You should run a stat, I would probably go to a 180.

r0nin89

LOUDMAN

I have a 160 stat and the thermomaster in mine. On cooler days the service light stays on because the motor never goes into the normal operation idle . Lets just say I'm usin a lot more fuel now.

r0nin89

r0nin89

Well now that I checked some more stuff out would you still be having this problem with a custom PROM chip tuned to 160 thermostat?

LOUDMAN

Theoretically, that sounds good. Personally I'm going to switch back to the 180. Just seem like less work and from my experience (not that its much) chevy motors tend to like a little more heat.

Just dont forget to change your fan switch to match you stat or your fan will still wait until your motor reaches 225 before it starts to cool the coolant. That would make the low stat pointless in traffic on a worm day or under heavy stress at the track.

xlwhellraiser

iTrader: (1)

Ok. There is no need to run as cool as 160 on stock set up. It just does not compute with the open and closed loop temps. Like I said, you can either get into chip tuning yourself, or ask someone to make you a chip. You need to alter the open and closed loop operation temps. That way the computer does not freak out.
I am runing a 170 thermo with the TBIchips.com stage 2 chip. It has all the paramters for loops. I run cool in the hottest weather, and I run warm in the coldest weather. It works great.

Other thing you want to invest in is a fan switch.
I have mine wired spearatley and I can turn it on whenever I want. This keeps the car cooler in summer, and warmer in winter since I dont even turn it on, most of the time.

For proper cooling you will need.

1. Air DAMN (pun intended). If you don't have this you will overheat 90% of the time. Now there are people that run without it, but its mostly Camaros since they can afford it (due to the grille in the front.) Firebirds have no grilles and they require the dam.
2. Radiator thats clean. Aluminum preferably. Most of the later cars came with aluminum radiators and thats a plus. However if its clogged or there is a lot of debris in there than I would recomend a replacement. They are around 100 bucks and the replacement process is around 20-40mins.
3. Water pump. One of the most overlooked pieces of cooling in these cars. If its a stock pump, you should replace it immidiately. Especially if youre having cooling problems. If youre on a budget I can recomend the Bosch 100% new pump its iron and not aluminum but it will do the job.
4. Hoses are very important too. Make sure that the bottom hose is not leaking and it has a spring to prevent it from sucking itself in. Overflow container needs to be intact. I see a lot of people who say "I am just keeping the fluid in the radiator". Thats just dumb. Once the preassure builds up the water has no place to escape thus either flooding out, or poping the cap off. This makes the greatest mess in the world, and your hood will be smoking.
The antifreeze really needs the overflow so that it can come out when there is too much in the radiator, due to preassure, and than it needs to go back in, once the preassure is gone. If you don't do this you will gradually run out of antifreeze.
5. Right mixture of antifreeze and water. Make sure you get at least a 50/50 combo in there. Antifreeze does not cool, water is what cools. Antifreeze does exactly what its name says. It stops the water in the radiator from freezing in colder temps. So, in summer you can run 70-30 or even 80-20. Some people run straight water, and it will keep their car cooler. If you are not willing to mess with this season change, than just make sure you keep it at 50/50 or 60/40 (which could be pretty hard to judge).
6. Thermostat. You see how low the thermostat is on this list. The only problems with thermostats are A. They get stuck open, B. They get stuck closed(rare, but could happen) and C. They are 195 degree thermostats.
A. You should really not have a problem if your thermostat is open, but if you run the car long enough the temps. will rise. There was some debate about this on these boards, but belive me even dragsters that run no thermostat still run restrictors. this gives the coolant enough time to stay in the radiator and dissipate heat. Without that you will start running hot.
B. This is rare, but thermostats sometime fail stuck. In this case you will warm up faster, and defenetly needs to be replaced.
C. In stock form our cars come with 195 thermostat. Great for emissions, bad for performance, and it can catch up to head gaskets.
If you are runing the stock chip with open and closed loop you should go no lower than 180. Sometimes 170 could suffice, but you really need to alter your open and closed loop temps in the ECM.

I can't think of anything else right now. This is what I learned as I was messing with my car. My car would overheat and I would freak out. Than I figured how everything worked, read whole bunch of threads around here. I drilled holes in thermos, I ran with no thermostat... It all failed.
Ultimatley I settled on a chip and 170 thermostat which has worked for me over a year and a half now. Also make that switch for a fan so you can flip it when you want. That way you can run the fan all the time in summer, and not run it at all in winter. Laters.

Sorry for the lenghty read.

TigerZ

however

make sure to remeber to turn it on

especially when idling


haha

thats how i blew my last radiator

flaming-ford

iTrader: (7)

run a thermostat close to factory by pulling a thermostat or running a super low temp with out redoing the whole system you are only band aiding a big problem somewhere else on the system.

Btw not trying to insult your intelligence but, had you checked for a 50/50 antifreeze water mix and that your cap is sealing properly? Any good sized coolant leaks causing the coolant system to not pressurize properly? Is the fan kicking on when it's suppose to?

Imo your most likely not overheating like you think you are, factory gauges are known to be not so accurate.... My car acts like it go's up to 260 oon the gauge every once in a while periodically but, it's actually nowhere near that temp and i know so for fact by doing numerous tests and replacing pretty much every component (waterpump, t-stat 2x's and radiator). Ammoung the other little peices.

Either way good luck with fixing the problem if it actually is a problem like you think it is.

r0nin89

Wow sticky this...this answered so many of my questions...

91black5spd

You have the Thermomaster chip and the SES light still goes on? I thought that caused the car to go into closed loop earlier since it is designed to go with 160 stat. Which chip do you have cuz I just ordered one thinking it would get me into closed loop? I ordered #121372 cuz I have TBI w/ manual tranny.

dwillis

iTrader: (6)

if you dont run a thermostat your computer wont realize that your car is warming up and go to closed loop operation which lets your computer control things like timing and fuel

90RS305

Not TBI Related, MOVED

rx7speed

with the guys that say running without a thermostat will cause your car to overheat will you care to explain why my friends truck without the thermostat doesn't even hit 160.
hell I think most the time it sits at around 120-130*
on a HOT day it might hit 140 or so

LOUDMAN

Dont know the model number off the top of my head but ill get back to you you that. Ive had the chip for about six or seven years now. They could have done some tweekin since then.

Sonix

iTrader: (1)

i've seen many a car with a removed thermostat, they just suck up the gas trying to get warm, and run extremely cool. I can't say i've opened up the waterneck in a pure drag car, so I can't say anything to that, but i've never seen a car with no thermostat run too hot, compared to if it did have a t-stat.

Token

Fix your problem first.

91black5spd

I hope so. I should be getting mine today so I'll see if it improves my gas mileage and if i get SES light. Right now with 160 stat I get it occasionally on highway inthe cold.