Bobby Joe

I know I know...this topic is everywhere. I'll research more later tonight. Just a brief write up though...

So yesterday I was driving on the hwy to my buddy's house. Outside temp was between 99 and 102 here in the Tampa Bay area!!! We were driving around 75-80 mph and my coolant temp was running at about 220!! I think that sounds a bit high, even if the ambient temp is that hot. Then, we hit traffic! The coolant temp started to climb...225..230...it settled at about 235! That is the edge of the final increment on the coolant temp analog gauge. I kept an eye on it in a panic. I even cranked the AC to 90 degrees and put it on full blast. Yeah, that part sucked! Temp never made it above 235. Once traffic was able to make it over 50 mph with no more stopping, I quickly cooled back down to 219...what a relief that was!

So here is where I am getting at:
1) I plan on flushing and changing out my coolant very very soon. When doing this, I am plan on replacing the thermostat. Maybe the current one is getting clogged. Any brand recommendations?

2) I have read that people put in a lower temp thermostat. What is the deal with this? I commonly read that people use a 165 deg-F. Does this keep your engine from running at its optimum temp?

3) If you replace the thermostat with a lower temp one, are there other mods that are needed? Do you need to reprogram the temp which your primary and secondary fans come on at?

Thanks dudes!

Calderone

Before you do all of that , did you check if your coolant fans are working when they must ?

Bobby Joe

At what temp does each one turn on? I can do this by just running the car in the driveway, right?

Kmcoldcars

Do the following in the order listed.
1. When the car is cool check the coolant level in the radiator and overflow tank.
2. Check the front of the radiator for debris. Clean it out if it is dirty
3. If the coolant looks dirty or gross flush the car and add new coolant.
4. Check the fan operation. Let the car idle and warm up with the A/C off. Fans (or fan, depending on year) should come on low speed at about 229 on the digital guage. At about 239 the fans should go to high speed ( or the second fan come on).
5. If the fans do not turn on then turn on the A/C and see if the fans turn on.
6. If all the above is good you may need a new radiator.

Putting in a lower temperature thermostat does not make the car run cooler. It just determines the temp at which the coolant starts circulating.

You turned on the A/C to get the cooling fans operating. There was no need to set the temp to ninety. You should have turned it to 65 or 70 and enjoyed it. The fans would still have been running.

Calderone

yes , let it idle and take a note at which temps they start , let us know

enventr

I agree with all of the above.When you are moving the fans do not help.It could be all of the junk in front of the radiator
and if it's the orig rad.the tubes could be partially clogged inside.In traffic or when the a/c is on the fans should be on.

Calderone

fans are needed when you are moving too , happened to me not long ago

dolbnyc

I had same problem and a new radiator did the trick for me.
original 92 with 133K.

Adam Swartzberg

This topic has been argued ad nauseum, but I'd like to put in a plug for the 160 thermostat. It does keep the car cooler in my experience. Coupled with fans set to come on at 175, the 160 thermostat helps my car's coolant temp rarely get above 200 in the Atlanta summers.

WW7

Looks like others missed it were you said your analog gauge reached its last increment.... The analog gauges on these cars are known to be very inaccurate, they can be off 10 degrees or more and make you think your car is running hot. I would suggest hooking up a seperate temp gauge to check if your temp is really that high before trying to fix it..On a 94 you should have a digital gauge also, I would suggest using that since they are far more accurate....WW

mazdaverx7

my 94 gets to about 230 degrees if i sit and idle too long. once driving , its back to normal. i' not terribly concerned about it, but know that a new radiator will be in my future as the t-stat and water pump are new and i know the fans are working.

anciano

No. It doesn't. I cannot understand why this erroneous belief still exists. Once the car is up to running temperature thermostats rated at 165 or 195 are wide open and pass exactly the same amount of coolant.

THIS is why your car runs cooler. The fans are absolutely necessary to keep temps below the cooking zone when stopped or moving slowly since the radiator is unable to do it without some help to pull air through. It's a design flaw plain and simple.

joeanoker

Its just a fact that these engines all run hot. last year i replaced the waterpump, thermostat, and flushed out old coolant and added new. This year i had to replace the radiator cap, a lot cheaper than last years repair cost. I keep a constant eye on the temperature gauge and avoid taking car out when its to hot out side. Cooler weather is only a few weeks away in the northeast so any issues that i have will soon vanish.

PLRX

I would take longer to write all that than to find them.

http://forums.corvetteforum.com/c4-g...a-hot-day.html

http://forums.corvetteforum.com/c4-g...ater-temp.html

http://forums.corvetteforum.com/c4-g...h-a-c-off.html

http://forums.corvetteforum.com/c4-g...emp-240-a.html

tblt44

get it reprogrammed to turn the fans on lower or install a manual switch.The A/C will turn both fans on at any temp

markKlein

Just read the posts that are alerady there. First, you should be looking at the digital gauge, not the analog. Second, the temps you describe are within normal operating ranges. Your fan isn't even programmed to come on until 228, if I remember right. Creeping into the low 230s in traffic is not a big deal.

higgyburners

First things First...Check if you have this in your way. Its the cheapest way to go.

http://forums.corvetteforum.com/c4-t...-radiator.html

Bobby Joe

Sorry I wasn't clear. I was looking at both. Hence how I got the exact numbers. I was referencing the analog gauge to emphasize that I was nearing the end. lol.

How do you go about reprogramming it?


If the fans turn on whenever the A/C is on...then they should have been on. I had the A/C on before I ever hit the traffic. As for an old radiator, that is possible. My overflow tank is disgusting! Not my fault, but I have to take some blame since I haven't cleaned it. But the car just hit 39,000 miles...it is 18 yrs old though...

As far as a dirty radiator, I will take a look, but I have cleaned it. in the last couple of months.

Bobby Joe

Do i just check it here?


Or do I have to remove the shroud in the front?

mrpeachez123

160 and 195 thermostats do flow the same when there open but they also close. if a car with a 195 thermostat gets to 185 it starts to close and restrict the coolant flow. there by keeping the engine coolant temp up around 195.