T-stat question

[tomtom72]

Hi Guys, I finally got the correct 1825-M spec coolant from GM so I'm going to get rid of the stuff the dealer put in my car. I figure on replacing the thermostat as I don't know how old it is.

My Q is if you are using a stock EPROM is a 180 stat worth getting? I'm not trying to be funny. It's just that the programing in the prom turns the fans on and off at some fairly hi temps. Will that programing work against the 180 stat? Will the 180 help in traffic or am I mis-informed??:icon_scra

I cleaned out my rad & condensor & oil cooler and installed a screen to stop stuff from getting back up in the cooling fins. I know I have a GM stat, 195*, in the system now. The cooling system responds when both fans are turned on and the temps come down. The temps are not a problem if the car is on the road but in slow traffic it gets up there and kind of stays at what looks like 200* more or less.

Thanks for any advice you want to share!

:thumbsup:
Tom

[We Gone]

I still have the stock t-stat but a custom chip that turns on both of the fans @ 205 off @ 200...

Steve

[Bill]

Make absolutely sure that it is the right style thermostat with the correct bypass valve. I got the wrong one and it cost me 2 radiators. :cry:

[tomtom72]

Thanks to Steve and Bill!
Yes Bill I remember following the saga of the t-stat that was boxed wrong & caused you to loose the rad.! That stopped me at the time from scratching where it didn't itch! I had my local dealer do a flush & refil on my car back in Nov.05 and they used the wrong coolant so I figure if I use the the correct coolant I'm gonna open the t-stat housing to flush it with the motor runing. Having said that I fugured I should swap out the t-stat since I don't know how old it is, and that I'll be there anyway.

Steve, I get caught in traffic a good bit on some cruises and some cruises we go into NYC so I was looking for an edge on the engine temps. I can live with the stock T-stat as even though the coolant temp gets up there the oil temp stays below 1/2 way on the gauge even if I get caught for awhile in B to B stuff. Both come right down once airflow is re-established, man I'm so glad I clean that stuff & put the screen in!

Maybe I'll get a stocker and a NAPA 180 and do my own road test!
Thanks for the input guys!
:thumbsup:
Tom

[Tom]

The temperature gauges are very non-linear. The 90 only had values at the end point while later cars had additional divisions and values. The mid-point of the needle travel on your 90 does not equal halfway between the 100 and 260 values on the gauge. The mid-point on the oil temperature gauge equals 220 deg and the mid-point on the water temperature gauge equals 210 deg. "The Legend" magazine from the ZR-1 registry had an article that included a table and diagram showing the actual values. I copied the table/diagram and keep a copy in my console as a reference. I have seen the same table on the internet but I don't remember where, I thought it was on this site but I couldn't find it recently.

[tomtom72]

Tom how did you know that I was thinking about that? Thanks man! :thumbsup:

Doing the math it didn't make sense to me that the gauge reading had a linear progression! It just seemed too low of a temp reading, by the math that is. I guess it's worth a try with a 180 just to see if in traffic I get a lower overall coolant temp...even a little would make me feel better. I feel so much better when I see the needle 1/2 way instead of 3/4 or more up the gauge face! It only happens in traffic without the climate control "on", if I use the CC the other fan kicks in and brings the temp down a bit. I think it's a perception thing with me...I hate to see a temp gauge up so high in traffic and my first instinct is to turn off the CC. My 72 LT-1 A/C coupe would never allow me to stay in B to B traffic with the A/C on! Guess I gotta get used to this new hi-tech corvette.:o

thank you for the info!

[Hotrod]

FYI: You can use the a/c display to read engine coolant temp.

[tomtom72]

Thank you Hotrod! I didn't know that. :thumbsup:

I guess I would find that info in the Helm manual in the "Drivability & diagnostic" section? I know I don't remember seeing it in either "owner's manual".

:cheers:
Tom

[Bill]

FYI: You can use the a/c display to read engine coolant temp.

Here is the procedure:

1) press the fan up & down buttons simultaneously until 00 appears in the AC display
2) press and release the fan up button until 16 appears in the AC display
3) press the fan auto button
4) the AC display will show coolant temp in degrees C.

[haber rj]

Hello Bill this information is great, I had no idea (along with a lot more I am sure) that we could do this. This is what makes this forum such a great place, nice people with a lot of information to share with members like myself who have a lot to learn.
Cheers

[We Gone]

Here are the codes: HVAC Diagnostic codes 0- System Faults (one of these will be set if your air conditioning controls have an LED flashing) 00=No Faults
01= Temp Door Motor Circuit Fault
02= Temp Door Motor Circuit Fault
03 = Ambient Sensor Open
04 = Ambient Sensor Short
05 = In-Vehicle Temp Sensor Open
06 = In-Vehicle Temp Sensor Short
07 = Solar Load Sensor Open
08 = Solar Load Sensor Short
09 = Low Freon Detected
10 = UART Failure
1- Temp Setting 60F to 90F
2- In-Car Temp Sensor 10 = HOT -130 = 230 = COLD
3- Outside Temp Sensor 10 = HOT -130 = 230 = COLD
4- Sun Load Sensor Max light Max Dark L98 38 183 LT5 115 -110 = 210
5- Ignition System Voltage 0 = 9 Volts -155 = 255 = 16 V
6- Engine Speed (RPM divided by 25)
7- Vehicle Speed
9- A/C System Mode 00 = OFF 01 = Re-Circulation 02 = A/C 03 = Bi-Level 04 = Heater 06 = Defrost 07 = Vent 10 = Manual Re-Circulation 10- Blower PWM 0 = 0 Volts 128 = 14 Volts 11- Program Number
00 = COLD -155 = 255 = HOT
12- Mix Number -155 = 255 = COLD 00 = COLD
16- Coolant Temperature In degrees C
17- Solar Correction 114 = Max light 128 = max dark 30- Stored Full Hot Value 0 to 50 31- Temp Door Travel Range 100 to 200 34- Temp Door Position Requested 00=Full HOT -153=253=Full COLD 35- Compressor On Time 0.1 second increments 36- Number Of Times Below Critical Time 37- Software Version Number

[haber rj]

Thank you for the code read out iformation I will print this out and keep it with the rest of my files.
Cheers haber rj

[tomtom72]

Thanks to Hotrod, Bill and Steve for the info! Haber rj's right about our forum... if it wasn't for us helping each other I know for sure I'd have an uphill battle.

Steve those codes are in the Helm manual, right? I think I remember seeing those in the A/C section.

Thanks again guys for the help!:thumbsup:

Tom

[We Gone]

Steve those codes are in the Helm manual, right? I think I remember seeing those in the A/C section.

Thanks again guys for the help!:thumbsup:

Tom

Yes..:thumbsup:

[Demps]

Stant makes a good 180 deg replacement thermostat #14068.

Do no cut the bypass spring to try and increase the flow. You can drill 2 1/8" holes in the flang that the radiator can handle. Lower it to about a 168 deg. Changed a radiator in a friend's car as a result of the cut spring slipping off of the bypass block.

Ted

[tomtom72]

Thank you Ted for the info!! You guys are great. I would never do any cutting on the by-pass spring...too far over my understanding to be messing with that stuff. I just want to help the car run a little cooler when I get into B to B traffic. Thank you for the Stant P/N! I'm going to try that one & see what happens to the temps.

Thank you all for the input!:thumbsup:

Tom

[haber rj]

Tom trying not to sound to laim but where would I find one of these 180 Stants, I am heading to the states soon and I would try and find one when I am there, I don't think that I could find one up here in Canada.
haber rj

[tomtom72]

top o the morning to ya haber rj!!

I would think that any auto parts store would carry Stant cooling system products. I know the NAPA stores & the CarQuest stores by me have Stant's line of products. I'm not sure about AutoZone but I'm gonna try them @ their web site.
Hope that helps! Oh, ya know there are no Q's that are lame...besides go look up some of my Q's from when I first got my Z...talk about sounding lame!:o :sign10:

:thumbsup:
Tom

[haber rj]

Hey mate for a guy who has spent a much time around cars as I have drag racing super stockers, stockers, super gas, super comp etc. ect. I feel like I have never picked up a wrench in my life when it come to this car, it just scares the h--l out of me. I know most of it it just not understanding how these new machines work, but I absolutely love everything about this car, my wife tell me that I am like a little kid, everything excites me about it and everyday I learn something new, and I have you and all the other members to thank for it and it is really appreciated, I will be calling again.
Cheers haber rj

[tomtom72]

Then you got a PhD in carology!

The only thing I got in my resume is the mechanical restoration of a 72 LT-1 A/C coupe that I did when I was a kid, 25 + yrs ago. Stupid kid I was, I bought a used race car! Never buy a used race car again...but I was young & stupid...I put the car back together & it even ran fine! It was my first corvette, and 20+ yrs later the ZR-1 is my second corvette. I guess I can say that I've had quality, not quantity...for sure! Damn I've been fortunate!

These cars can cure a bad day!

:thumbsup:
Tom

[haber rj]

Tom I have been told many stories about my car , how it is rare, apperently the colour combination Steel Blue on Steel Blue was limited. I went to California and stopped in at Corvette Mike's and they looked at me like I had 2 heads when I told them what I had, they went to the computer and came back and told that there was less than 5 of those cars as far as it shows. Doesn't mean anything to me, because it is not going anywhere, and I have no way of proving what they tell me is true. A car is only worth what someone is willing to pay and I am going to enjoy mine for a long time.
Cheers haber rj

[tomtom72]

haber rj,

I remember seeing the color combo chart vs number produced over at the netregistry site, I think??? I may be having a senior moment here but I think that is where I saw the info. Hey man that's way cool to have a rare color combo!:thumbsup:

You know you are right...it's only worth what some one is willing to pay! Me, I agree with you about I like my Z and I'm gonna drive the wheels off of it because I like using it soooo much! Whom ever gets mine next will get a well cared for car but it will not be low milage!:o
When the next guy gets my Z I'll be dead anyway so I don't care what it's worth, the $ won't help me!

:mrgreen:
Tom

[haber rj]

Tom when my son comes home from University we have the uaual greetings and he always asks me how is my car doing, (my as in his),he told me several times that he would really like it for a graduation present, what do I, I don't really want to descourage the poor kid, but I have always told him that one day I hope that he is fortune enough to find a fantastic car like this one, and if he does buy it, he never will regret it. As far as the colour combo goes until I have it writing, it's just another one of the most fantactic cars that has ever been made.
Cheers haber rj

[Tom]

Here is the information that shows the temperature value for several points on the 90 ZR-1 temperature gauges.

Scale %...Oil Temp...Water Temp
0%............100..........100
25%..........191...........184
50%..........220...........210
75%..........246...........232
100%........280...........260

[blackjack]

haber,
i got my stant thermostat from the auto parts next door to my garage
just tell me if you cant find one...ill get you one

blackjack

[haber rj]

Tom thank you for the information, I am sure it will come in quite handy and a welcome addition to my files.
haber rj

[haber rj]

Blackjack thank you for the offer, if I can't find one I will certain take you up on that offer. How is the weather where you are, it is very warm here in Mississauga and no snow, just green grass.
haber rj

[tomtom72]

Thank you Tom for the %scale vs temp info. I had no idea that the oil got that hot! Those numbers were an eye opener for me, and these cars have real oil coolers! Now I know I'm glad I went with mobil1 oil instead of a natural base oil. I guess I should go with a stant 180* and look to get a re-programed PROM to get the fans on sooner.

Thanks again to everyone for sharing their knowledge with me!:thumbsup:

Tom

[Tom]

There is a thermostat in the oil cooler plumbing. The shop manual oil system schematic and diagrams shows the location of the thermostat and the description of the system tells the oil path through the filter and oil cooler under different conditions. I believe it is a 190 degree thermostat. You want the oil to get hot enough to boil off any moisture or fuel contamination.

[WB9MCW]

MOBILE ONE GUD STUFF 4 SURE...DID THE CHIP...FANS NOW KICK ON AT 190F NEVER GOES ABOVE 207 EVEN AT 10 MIN. IDLE IN 95F DAY AND HIGH HUMIDITY...SO MUCH BETTER THAN STOCK 230F :thumbsup:

[RiceEatingZR1]

I had my Car over heat where the Check engine light came on .. ( I of course shut it off Right away) but it was during Bloomington Gold Last Year when it was about 101 Degrees out and High Humidity, and I was stuck in traffic, this spring I plan on Flushing the Fluid and replacing the T-stat, one question I have is does the Stat come with a new Gasket or is that a different part number?

[blackjack]

i know the stant t-stat does not come with a gasket,mainly because the same t-stat might fit many different engines/cars...from my own experience,the zr-1 gasket does not seem hard to find,my local auto parts store had it in stock...i dont remember the number,however
blackjack

[2nd94Z]

Hello all, my (new to me) 94 on the freeway at 70 gets to 209 in 60 weather, seems a little warm, after leaving the freeway it goes back to 195 or 200, think I need a new thermo ? and whats the number or brand from the parts store ?

[jonszr1]

I had the same temp readings in one of my 90s. Not soon there after my head gasket let loose. I think it was leaking causing the temp to go up . I'm not sure if your issue was the sam.e as mine. I just wanted to share what happened to me so you can keep an eye out. hope this helps:mrgreen:

[Hammer]

OK guys, from what I have learned from the Gathering and various other sites, this is the picture of the t-stat you need. MAKE SURE THE ONE YOU GET IS EXACTLY LIKE THIS ONE. Look closely at the top and the bottom. The wrong stat has a pointed top and a cone or bucket shaped bottom. Make sure you drain the system entirely and use ONLY distilled water and GREEN antifreeze when refilling. Hope this helps.
http://i85.photobucket.com/albums/k60/HammerZR1/ZR-1%20Pics/CorrectThermostat.jpg