I know I have done it on old cars temporarily to get home, but what effects will it have on a tpi. would this be a cure for guys who run around town in stop and go traffic and have cars that run too hot. Another words overheat, no matter what they do to their cars.

 

By running with no t-stat in a fuel injected car, the computer will never recognize the car as being fully warmed up and will not enter closed loop. Your gas mileage will suffer, as the car will always be running rich, and I'm not sure what it does with timing advance. I'd recommend just putting in a lower temp t-stat and a lower temp fan switch for the computer.

 

No stat is a no-no on an electronically managed vehicle. As as the other post pointed out it will never run right not to mention it will never pass a tailpipe sniff test. These cars are designed to run with a 195 stat, your primary fan should come on at about 222 deg.. This is not a problem for the engine. The biggest problem is when the primary fan fails many times due to a bad fan relay. If everything is in good working order your engine is in the range it was designed for. Any change in thermostat temp will result in driveability issues or cause the ECM to default and change operating parameters of the engine. I tried every different temp stat and I found that fuel economy and driveability suffered. Just keep the coolant system in good order and check fan operation periodically and you will be in good shape.

 

My car never gets over 220. Just a thought for the guys having alot of problems keeping it cool. I have another , why would not having a thermostat cuase the computer to not recognize the warm up if the car still runs at normal temp? I would think the car would still run at 180 degrees.

 

Because of the way they heat up and cool down , a function of the airdam and electric fans the temp will be constantly changing. If you are not running a stat and you are running at 180 I am surprised. I ran a 160 stat and if it was below 60 deg. my guage just barely came off the stop. The computer is programmed to operate with a target temp of 195. At this point you will see maximum fuel efficiency and performance. Keeping the engine operating in a narrow temp range is the key to good driveability.

 

i am running no stat temporarily and i can get the temp up to 220* here

 

I have been driving around for about a week without a stat in temps from 60 to about 90 (unpredictable St. Louis weather)
and the coolant temp has stayed between 160 and 180.
On the highway the other night it was about 60F outside and the coolant temp never got below 160.
I dont have a hood at the moment and expected it to run extra cool but so far it has not been a problem.
The computer will still go into closed loop with the car below 160.

 

Depends on the type of driving you do. Of course in the summer in traffic the car will obviously heat up. Never said it would not go into closed mode. What I will say is this, regardless of what anybody says the engine will not run as efficiently with a lower temp stat. Last year I ran a 160, 170, 180 and 195 stat. Each stat I ran for 30 days and I kept a mileage log. When I drive the Camaro my route is always the same tpye of driving and mileage. Between the 160 and 195 stats I saw a 3MPG difference. Sure in traffic you get up there temp wise, but get her rolling and you will see that gauge drop pretty fast. Any expert on modern engine management will tell you that a narrow temp range is the best for efficiency and performance. You will not achieve that narrow range by having a lower temp stat or no stat, can't be done. Back when I had most of my hair the 67 Chevelle I had didn't care about temp, in fact in summer I ran it without a stat. Once you got that puppy past the first 5 min. of running nothing much changed. My family has been involved in the car business for the last 30 years and I have made many friends many of which have advanced to being field reps and technical instructors and there is not one that recommends running an electronically managed engine at a temp lower that factory specs, and it is not just emissions that they site as the reason. Try your own tests, I did not believe it either. Dan

 

For those of you who make statements like "my car never overheats" and infer that something must be wrong with what other people are doing, please realize that different factors are at work. If your vehicle suddenly starts overheating after years of trouble free operation, then yes, you probably have a problem. If you car has "always" ran hot, there are different factors to look at.

Location (rural vs urban), altitude, weather, humidity, traffic, and road conditions all contribute to different cooling results. If you live in the same city, near the person who is having the problem, then maybe your opinion would apply...other than that, it's not helpful unless you have all the facts.

Some of you may not realize that many later year f-bodies came from the factory with engine oil coolers. Many of the 90s fbodies with 350s and Corvettes had them depending on the area of the country where they were originally delivered from the factory. They were also a dealer option. GM added these coolers to combat known cooling problems with these cars due to their small to non-existant grill areas, and the fact that they are bottom breathers that pull really hot air from near the pavement. They did not add them to all vehicles (not cost effective), just the ones slated for delivery to hotter climates.

The single fan to dual fan switch on the larger displacement engine was also attributed to not being able to sufficiently cool engines in extreme temperature situations (described as over 100*).

Although the stock radiator is adequate for most driving situations, when you are in hotter driving situations, it needs some help. An engine oil cooler, and/or tranny cooler will help. Aftermarket aluminum radiators with larger core tube areas also make a significant difference (if not completely solve the problem).

Hope this helps explain why some people have problems and others do not.

 

what about a TBI? i am running my car without a t-stat right now, will it hurt anything?

 

I am running a TBI on mine without a stat and I personally dont have problems with it but as stated in the earlier posts its different for everyone.
I suppose it all comes down to the fact that the cars were designed to have one so If it wont stay cool without it there are other factors at play.

 

Well said Mike! Many of the posts I see and the solutions are the result of trying to correct a problem by altering the cars operating parameters. Every TG I have worked on when it is operating correctly(bone stock) will generally show a temp guage on the first line between the 100 and 220 marks. I have always used that as a reference for potential problems. In traffic the fans will kick a little above the 220 mark. If I see it go much above that then I pull over and pop out my spare fan relay. The new GM relays(chinese made)seem to be better, gone almost a year now. I appreciate the info you posted, I was not aware of the differences being decided by delivery area. One question I have, does anyone make an improved radiator that will fit in using all stock mounting and requiring no modifications to the cooler lines etc. I am running a ZZ-4 block with different heads(GM heads but not ones supplied with engine) and all stock emissions. It runs at the same point(first line) with normal driving, the only thing I see is that it heats up a little faster. I would like to install a beefier radiator. TNX, Dan