maneuen

while driving this morning, I noticed that the car "never warmed up" via the tach. I checked the digital temp and it was normal, however the engine analog gauge was at zero. When I stopped and turned the car off, the fan's continued to run all full blast. The engine itself was cool / normal, thus I believe the digital temp was correct. The ambient temp at the time was 65, so again the car wasn't actually hot (so I assume the fan's are default safety measure the car has)

I assume somehow related (?), but the rev match feature also would not engage?

I was headed to a meeting so I couldn't detour to the dealership. After the meeting upon startup, the same thing is happening except now the digital temp is also zero. since the engine was previously running cool, I made the trip home (dealer was closed by this point). On the way home both gauges stayed at zero but now the check engine light came on.

For background the car is '16 z51 with D1 procharger, headers, and meth. (and the supporting stuff, 160 degree thermostat, z06 injectors and high pressure fuel pump)

I did some searching, at it appears either the coolant sensor is at fault or the 160 degree thermostat......but I'm open to other thoughts? / wondering if anyone had anything similar (and is the rev match related?), what ended up being the solution

I'll make the trip to the dealer on monday.

ersatz928

It sounds like your coolant temp sensor is faulty, or disconnected. I think it is located on the front of the engine, near the throttle body, easy to change.

jcrooker

Yikes, with all that stuff on there, good luck at the dealer.

NSC5

If you thermostat sticks open OR the car doesn't warm up quickly enough (some have reported issues with 160 degree stats under low load operation) then the ECM senses a problem with the coolant temperature sensor and goes into a fail safe mode turning on the fan and disabling the temperature gauge.

The dealer is going to warranty block your car with all of your modifications and you are probably far better off having an aftermarket shop check/replace your thermostat if it is at fault since the dealer won't install a new 160 degree thermostat in any case. I believe after the fault is found and fixed you will have to erase the current DTCs to get the gauge to work/keep the fan from staying on because the controller will assume there is still a fault.

JimNeedsC7

Really - that is exactly what I was thinking too.

Good Luck!

Foosh

Yes, I'm thinking this story will not end well.

maneuen

Good advise to avoid the dealer..... I should have said "shop" as I don't want to open that can of worms with the dealership over what seems to be a bad thermostat or a bad sensor.

Anyone happen to have a pic of exactly where coolant temp sensor is? on the older cars I know it was just above the header on the cylinder head.

NakedDave

what did it end up being maneuen?

Maxpowers

The coolant sensor and thermo are inexpensive so I don't think the OP is in bad shape.

EDIT: just noticed this is an old thread.

RCB1234

It is probably the gasket to the thermostat. I had that happen when I replaced mine to a 160. When I opened it up the gasket had torn and was partly gone. Replaced and the issue went away.

merican1

I had the same problem and I'm still having the same problem. I have a similar setup I have an East Coast supercharger, headers, meth injection, nitrous, all that. And my temperature gauge is at zero and the motor is cool and the fan stays on. I have a 180 thermostat in it. I changed the temperature sensor and it seem to kind of work but never really recorded the temperatures it normally runs. Then today it didn't work at all it was back to zero.

merican1

Dealers are pussies. Lol.

merican1

Since i have already changed the sensor and still have the problem, the common denominator is that we have all changed our thermostat for cooler ones. Hmmm.

6Speeder

These threads come up every year as it starts to cool down. I assume the OP has tuned the car to accommodate the mods. Have your tuner turn off the coolant undertemp code. Done.

merican1

did you find the problem... I have a similar setup on mine supercharged, meth, headers... I'm experiencing the same thing with the coolant temperature the fan running all the time and rev match not working. I have already changed the sensor????

merican1

Thanx, I'll give it a go.

chris6.2c7

if the car hasn’t thrown any code all it does is kick the fans into high and the temp analog doesn’t read would I just have to swap the temp sensor and thermostat ? I’m reading people saying I have to clear pcm or ecm whatever it is but there’s no codes to clear ?

Bill Dearborn

Why open a 5-year-old thread to ask your question? Does the digital temperature gauge (seen in IP when using the Touring display read a temperature? Open a new thread and thoroughly/legibly describe your problem and what you are seeing on the instrument panel. Is the engine overheating? Is the fan running continuously? Has there been a loss of coolant?

To get you started DTCs P0117, P0118 and P0119 will cause the cooling fan to operate at high speed, disable the coolant temperature gauge (read zero) and disable the AC compressor. Is your AC compressor switching on?

P0117 sets when the engine coolant temp sensor is warmer than 300 degrees for more than 5 seconds. P0118 sets when the engine coolant temp sensor is cooler than -38 degrees for more than 5 seconds. P0119 sets when the engine coolant temp sensor is intermittent or abruptly changes for more than 3 seconds. Notice I didn't say the coolant is at any of those temperatures only that the sensor is reading those temperatures.

So far you haven't gone far enough to know whether you need to replace the thermostat or the sensor although the sensor is looking suspicious. At this point, even your IAT sensor could be involved as the system also compares coolant temp at start up to IAT at start up.

Bill