Problems with coolant sensor/gauges
Thread Starter
Pro
Joined: May 2002
Posts: 678
Likes: 2
From: Lengede
Problems with coolant sensor/gauges
My analog and digital gauge show a high increase in coolant temperatures. The digital shows 220° and my analog gauge is all the way to the stop. Pulling the connector from the passenger side sensor, which is the sensor for the gauges, nothing happens. Pulling the sensor from the water pump, the temperature drops about 25°. Since this is the sensor for the ECM, I'm a little confused.
The manual doesn't help at all, just shows the relationship between volts and ohms.
Maybe it's just the wire leading to the gauge sensor that is frayed or grounded. I will check this tomorrow.
I appreciate any help in this matter.
I forgot to mention, it's a 1992 LT1 and the temperature was actually about 120° but the gauges showed about double.
The manual doesn't help at all, just shows the relationship between volts and ohms.
Maybe it's just the wire leading to the gauge sensor that is frayed or grounded. I will check this tomorrow.
I appreciate any help in this matter.
I forgot to mention, it's a 1992 LT1 and the temperature was actually about 120° but the gauges showed about double.
Last edited by vettef6; Apr 3, 2011 at 03:29 PM.
Instructor
Joined: Jun 2008
Posts: 173
Likes: 0
From: Norman OK
My analog and digital gauge show a high increase in coolant temperatures. The digital shows 220° and my analog gauge is all the way to the stop. Pulling the connector from the passenger side sensor, which is the sensor for the gauges, nothing happens. Pulling the sensor from the water pump, the temperature drops about 25°. Since this is the sensor for the ECM, I'm a little confused.
The manual doesn't help at all, just shows the relationship between volts and ohms.
Maybe it's just the wire leading to the gauge sensor that is frayed or grounded. I will check this tomorrow.
I appreciate any help in this matter.
I forgot to mention, it's a 1992 LT1 and the temperature was actually about 120° but the gauges showed about double.
The manual doesn't help at all, just shows the relationship between volts and ohms.
Maybe it's just the wire leading to the gauge sensor that is frayed or grounded. I will check this tomorrow.
I appreciate any help in this matter.
I forgot to mention, it's a 1992 LT1 and the temperature was actually about 120° but the gauges showed about double.
http://forums.corvetteforum.com/c4-t...-1994-lt1.html
Also a good writeup on the LT1 cooling system.
http://www.corvetteactioncenter.com/...Cooling+System
Thread Starter
Pro
Joined: May 2002
Posts: 678
Likes: 2
From: Lengede
No this doesn't help me at all. I'm not concerned about the two gauges showing different temperatures. It's all about them both showing the engine is very hot, but the water is actually cold or lets say about 120°
Instructor
Joined: Jun 2008
Posts: 173
Likes: 0
From: Norman OK
Being an L98 guy, and from what I have read, 220 is not unheard of with an LT1. IIRC, the fans don't even come on until around 225.
If this happened suddenly, any chance of this being a stuck thermostat? As the LT1 is a reverse flow bypass cooling system, that might explain coolant temps around 120 at the tank...
Thread Starter
Pro
Joined: May 2002
Posts: 678
Likes: 2
From: Lengede
Al, thanks for trying to help me, hopefully others will chime in and find a solution to my problem.
I haven't been running a thermostat for a couple of years now, so this isn't the problem.
I drove a while yesterday and noticed both gauges show the correct value, starting with the ambient temp. and then going up to 235°. Normal temperature for my setup has been around 180° for many years. You can touch both coolant hoses coming in and out of the radiator. If the temp. would really be that high, I wouldn't be able to grasp the hose and hold it for minutes if need be....
I haven't been running a thermostat for a couple of years now, so this isn't the problem.
I drove a while yesterday and noticed both gauges show the correct value, starting with the ambient temp. and then going up to 235°. Normal temperature for my setup has been around 180° for many years. You can touch both coolant hoses coming in and out of the radiator. If the temp. would really be that high, I wouldn't be able to grasp the hose and hold it for minutes if need be....
Instructor
Joined: Jun 2008
Posts: 173
Likes: 0
From: Norman OK
I'm sure the LT1 gurus will chime in, but after reading your last post and learning you are not running a stat, I would lean toward a couple of things...
1. Water Pump impeller wear/cavitation - air in the system? - several threads here and on other LT1 forums discuss loss of head pressure for WP ops with no stat.
2. Partially clogged radiator - restricted flow would keep coolant in bypass.
Anyway, I found a good step by step indication troubleshooting procedure over on a F Body LT1 tech site which might help you check the analog and digital wiring.
http://shbox.com/1/4th_gen_tech2.html
It's about 1/2 down the article titled Testing the ECT Sensors and Connections.
Good Luck....
1. Water Pump impeller wear/cavitation - air in the system? - several threads here and on other LT1 forums discuss loss of head pressure for WP ops with no stat.
2. Partially clogged radiator - restricted flow would keep coolant in bypass.
Anyway, I found a good step by step indication troubleshooting procedure over on a F Body LT1 tech site which might help you check the analog and digital wiring.
http://shbox.com/1/4th_gen_tech2.html
It's about 1/2 down the article titled Testing the ECT Sensors and Connections.
Good Luck....
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
5 MOST and 5 LEAST Popular Corvette Model Years in History!
Joe Kucinski
2027 Corvette Buyer's Guide: Everything You Need to Know!
Joe Kucinski
10 Things C8 Corvette Owners Hate (But Won't Tell You)
Joe Kucinski
10 Best Corvettes Coming to Barrett-Jackson Palm Beach 2026!
Brett Foote
Every Corvette Grand Sport Explained! (C2, C4, C6, C7, & C8)
Joe Kucinski
Grand Sport & Grand Sport X Launch Alongside All-New 535hp LS6 V8!
Michael S. Palmer
5 Reasons Bad Drivers Crash & 5 Ways to Avoid a Costly Mistake!
Joe Kucinski
7 Bolt-On Upgrades From Extreme Online Store to Level Up Your C6 Corvette
Pouria Savadkouei
Thread Starter
Pro
Joined: May 2002
Posts: 678
Likes: 2
From: Lengede
Just wanted to let you know, checked all sensors and connectors, everything is alright. I'll put new ones in just to make sure.
FYI, it's a head gasket. I'll be replacing them in the next few days and everything should be running in a week or so...
FYI, it's a head gasket. I'll be replacing them in the next few days and everything should be running in a week or so...
