My '95 LT-1 gradually increased operating temperature from 194 to around 201 at highway speed over several months. I replaced the thermostat with a NAPA part and no change. Any ideas why it might be hot? I have flushed the radiator already; no change. Is there a 170 degree thermostat available? Would it make a difference? If the thermostat is wide open at 201 , I don't see a lower setpoijnt thermostat changing the final steady state temperature.

 

Read my thread in general discussion intitled "cleaning radiator in bath tub". It could very well be your problem.


[Modified by Corvette Kid NC, 8:05 AM 2/23/2004]

 

Hi Robert, You're just down the street from Dilligas and me. Let's get together soon.

Your temp is okay. The General likes it in the 200-230 range for emmissions. However, the first thing to look for is debree inbetween the condensor and the radiator. This is probably the most common cause of slowly increasing temps. As far as the flush you did, did you get it all or just from the radiator? There is probably no leaks or you would have noticed it. Make sure your pump isn't leaking at the weep hole of the water pump (first sign of pump going south).

How's the temp in traffic? I know it hasn't been hot enough yet to see any trends. How old is your radiator cap?

Hope this helps. Let us know if you want to get in touch.

Edit: That thermostat from NAPA, did it come with a rubber ring around the outter edge? Sometimes the parts stores give you the wrong type Tstat. I usually get mine from Burn's Chevy in Rock Hill, my son works there. :)





[Modified by Strick, 10:02 AM 2/23/2004]

 

I know its been a bit warm in SC the last couple days, if she was running hot during this then your temps are normal. If it was 45-50 outside she shouldnt be getting up to those temps.

Changing to a lower stat does lower temp, but its more likely the space between your radiator and condensor is clogged up. You should clean that space before the heat and humidity come back in a couple months, the only way to do it is to remove the shroud, you cant get it from underneath.

 

I have a '95 as well and temps get well over 200 around here with the LT1. If you really want to lower temps, go with an electric water pump, I chose Meziere. It pumps hard enough to hear it over idle inside the car. My coolant temps still reach up over 200, but the water pump kicks them down pretty quick thereafter. I also have an aftermarket thermo, 160* powerstat, but I don't have a program/programmer to correspond fans turning on with the thermo.

If you want to cool the air flowing through the throttle body, into the engine, all though I'm sure this trick is very very very insignificant to temps, you can do a throttle body by-pass. From the factory coolant flows through the throttle body through an area at the very bottom of it. On our cars you can modify this for free, don't buy ANYTHING, you don't need to. The hose that goes to the radiator is long enough for what you need to do. Simply remove both hoses from the lower left passenger side and lower right driver side of the TB. You can basically throw away the passenger side hose at this point, just make sure you save at least one hose clamp. At this point you can connect the hose that leads to the radiator directly over the outlet that the passenger side hose was previously attached to, and bam, free mod.

Do you have any other mods? You can open up your air-lid for free as well. Take the covering metal lid out of the car. Drill the 4 rivets holding on the upper-most metal sheet, this will take that piece off. Then use a dremel or something similar to cut the next level of metal. Make a rectangular shape that will open the filter are up as much as possible, while simultaneously keeping enough border to hold the filter in place (doesn't take much). Then pop a K&N in there and your set, just save yourself $50-$100.

 

I had same issue. Temp over the road went up from a norm of 185 to 197 in the matter of a few months.

Here were my big three.
1) T Stat was sticking. Replaced with 160' Hypertech.
2) Radiator was clogged, in and out. Replaced with a Fluidyne Aluminum radiator.
3) The Condensor was externally clogged up. During the rad replacement, took an air compressor and a soft nylon bruch and cleaned this out as best as I could. Got a nice sand storm from that. Do cover or plug up the throttle body so the sand and dirt do not get in the engine.

All of this fixed the problem. I have a new Water pump on the way and also replaced all of the hoses while I was at it. Might as well get it all fixed.

Note: After all of this, I am still averaging 173' with the 160' stat so I think I may still have a slight issue with the temp sender.

So, since the engine is running hot still, after the stat replacement, going to a lower temp T-stat is not going to help. The current one should be wide open at its rated temp and now it is a matter of not being able to "shed" heat.

Next attempt would be to try to blow out the junk from the external fins. Next would be to replace the temp sender.

If all that does not work (i.e. inexpensive fixes), you may need the rad replacement. There are differences in factory replacement (~$300) and the commercially available (~$175) in the fin structure. I would not recommend the less expensive ones. I went with the all Alum (~$500) as I have seen a lot of issues with the plastic end tanks at around 70k miles.

Best of luck. All told the complete cooling system replacement took 1 day.

Scott

 

I may be mistaken, but doesn't a 160 stat not even open up till like 175 or 180 anyway? Thought I heard something about that in the past, was higher than the actual named temp.

 

The 160 Tstat stays closed, that is, the water in the engine is blocked from getting to the radiator, until the engine heats up to 160. Then it opens and your cooling system finally begins to "cool."

 

Those temps look pretty normal to me. I have an L98 engine, and mine runs as high as 230F in the summer. A lower temp stat won't help much unless you install a manual switch for your fan, or a thermo master chip. Hope this helps a little bit. But your temps don't seem high to me.

:cheers:

 

Dirty rad or clogged up in there somewhere. if you notice its not As cool as before.. then something is making it hot. it could be the weather too.. i find rainy/humid days the worst. One time my temp started to go into the red zone... luckily i pulled over and found 2 garbage backs sucked up into the grille.. lol

 

I realize that, but it's either the fans, or the actual coolant flow that does not begin until around 170-175. Someone else while chime in.