Running hot--need advise quick

[hooks]

Have a 93 thats running hot--has always stayed around 200 degrees. Now getting up to 230 degrees plus. Car has 57,000 miles & I think the original thermostat since I bought it with only 7000 miles & can't remember changing it out. Both electric fans are running & has full radiator & overflow tank ( when hot ). My question is--any special things to do or look out for when changing this thermostat? Have changed many before but always on older cars. Also what degree is correct for this car?

 

[Tuna]

First thing you need to do is check the radiator to make sure it is clear of trash. Put it up on ramps where you can get a good look at the space in front of the A/C coils and between the A/C coils and the radiator. You'd be surprised just how much junk can get in there and block the air flow through the radiator. Plastic bags are a big problem.

It you decide to change the stat, take special care to make sure you keep the OptiSpark dry, and when you bleed the coolant system after refill - the bleeder if on the stat housing above the OptiSpark.

The stock stat is probably a 190 but I can't say for sure.

 

[c4cruiser]

C4's are notorious for collecting junk in front of the rediator and A/C condensor. Youn can get a lot of the debris out by aiming a stream of water from a garden hose at the radiator from the fan side. There is enough room to get the hose in there and shoot water thru the cooling fins.

The stock thermostat is a 195 degree but you should be able to run a 180 stat with no problem. You might check to see if the lower radiator hose is soft. If the hose collapses, that restricts water flow.

The later C4's have an expansion tank that is above the engine and there is always a possibility that an air bubble may have formed in the system and that can result in improper cooling.

IF the coolant is original, then it should probablt be flushed and refilled with fresh coolant. The procedure is a bit tedious as it requires removing the knock sensors at the bottom of the block to get all of the old coolant out.

If you don't want to mess with changing the coolant yourself, I would take it to a reputable shop for a flush and refill. Have the shop use a good ethlyene glycol (green) antifreeze and distilled water in a 50-50 mix for cooling to -34 degrees.

The important thing with refilling the system is opening the two bleed valves (one on the thermostat housing and the other on the driver's side of the throttle body to remove any air in the system. It's very important to not get any water on the Opti-spark distributor located under the water pump. Getting this wet can wind up stopping the enginge from runing and will cost you many hundreds of dollars to repair/replace.

 

[Randy Eads]

Have a 93 thats running hot--has always stayed around 200 degrees. Now getting up to 230 degrees plus. Car has 57,000 miles & I think the original thermostat since I bought it with only 7000 miles & can't remember changing it out. Both electric fans are running & has full radiator & overflow tank ( when hot ). My question is--any special things to do or look out for when changing this thermostat? Have changed many before but always on older cars. Also what degree is correct for this car?

"Getting up to 230", sad to say seems to be normal (but not healthy) for a '93 LT1 .... a person could bake a cake under the hood.! Imagine all the trauma your wiring and other componets are having to put up with.

I was faced with the same situation and it got pretty old driving with the digital temp gauge on all the time ... with one eye on that.

Last week I installed the hyper-tech chip (thermomaster) with its recommended 160 degree thermostat and I was quite impressed with the change of operating tempratures (much improved) and improve power as an added bonus.

Hiway cruises at 182 - at idle and stop and go in traffic max of 202 ... all with ambient temps of 95 degrees.

According to the service manual (and my own findings) the '93 came with a 180 degree thermostat but unless, as previously noted by others, you have blockage or a faulty 'stat, you will probably not see an improvment by simply changing the thermostat to a colder one .... unless you make the chip change.

There is alot of great infomation on the various threads of this site that deal with this nuance of the LT1.

 

[redc4corvette]

If you change the stat you need to drain the radiator to change the stat.

Also with a mirror check to see if the weep hole is leaking in the water pump!

 

[tyrel]

As others have suggested, I suspect it is your radiator that is causing problems, especially if you live in a dusty environment. The fins are very sensitive if they get clogged. Also, debris collects inside the fan housing. Spraying a garden hose through the condensor from the front of the car or through the radiator from inside the engine compartment WILL NOT CLEAN THE RADIATOR and will do nothing to solve overheating problems if you have an obstructed radiator. The only surefire way to get the radiator and the fan housing clean is to pull it. It's not that difficult, takes maybe an hour, two hours tops. Here is a site that walks you right through it:

http://www.batee.com/corvette/dcrg/readerstips/larsstuff/this_tech_paper_will_discuss_sim3.htm

 

[Vettefan87]

230 is normal, at least that is around the stock turn on temp for the fans on my car. I hated the car running this hot, I just did not like it. So I installed a 160 degree stat first which got the car running cooler but only if it was moving. Then I eventually got the Thermomaster chip which turns the fan on at 175. You might want to try starting it up and opening the cap cold to see exactly when your stat is opening and how much circulation you are getting.


Justin

 

[poorboys831]

Hi HooksAllthe above is great advice -I would one more thing add some water wetter to your mix after your flush.My '93 has 150k+ miles and the h2o temp never goes above 200 even when standing in traffic-Don't forget to keep that Opti dry it is real important-keep wavin' Dennis