Engine Coolant Trouble Light

Post by **MrAl** » 06 Feb 2021, 16:17

v70 1998 non turbo no AWD

Hello there,

Recently i had the check engine light come on and the error code is 116 which i think is engine temperature sensor of some kind related to the engine coolant. What happened was i knew the coolant was low so i added some, then i went to start the car and it would not start right away it took a jump and several tries to get it to start. After it started, i checked the OBDII and it was code 116 that turned the light on.

Now i have a couple questions if anyone can help.
1. Will the light go out now that the coolant has been added or do i have to reset the errors with my OBDII reader?
I ask this because the rough engine check light came on one time but when out again once the engine ran normally.
2. Will this code stop the engine from starting as a fail safe? Or will it make the engine run rough?

Thanks.

Post by **Chuck W** » 06 Feb 2021, 18:11

The coolant level has nothing to do with the P0116 code.

That code is for the coolant temp sensor, which is located in the thermostat housing.

It's possible the sensor is bad, but it's also very likely that the connector is corroded, causing a bad signal, which is contributing to your cold hard start issue.

Helpful Vid

RB3 · Post by **RB3** » 11 Feb 2021, 09:48

My Coolant light was on as well. On and off actually. Had plenty of coolant but kept an eye on temp gauge. Sure enough it dipped below norm and was fluctuating. Checked codes P0116 and fter checking for leaks I noticed a small leak at the sensor. Decided to just put in new thermostat and sensor.

I would have preferred Volvo parts but time and money prevented that. -
QUESTION-The new aftermarket thermostat does not have a float on it?? Is that acceptable?

Also the coolant light went off for the first short drive but is back on. Levels ok and checked for leaks. Do I need to clear?

Thanks all.

Post by **erikv11** » 11 Feb 2021, 10:42

The coolant light is a readout from the coolant float inside the coolant bottle. It has nothing to do with the ECT or the thermostat or P0106 codes, like Chuck posted above.

It sounds like on your car the float inside the reservoir is sticking or broken/breaking, that is common. Working on the ECT or the thermostat wouldn't address a float problem so the light is still flickering. You can first try cleaning out the bottle and the float, see if that helps. Check the electrical connection to the float too, on the bottom of the reservoir. If none of that helps I'd replace the float. Junkyard is a good solution or aftermarket is probably ok on the float.

Separately and by coincidence, your car seems to have had an ECT problem, hence the P0116. Cars on this forum have not done well with aftermarket ECT sensors so keep an eye out for more ECT symptoms like P0106, hard starting, stumbling, running rich or running lean.

Auto thermostats do not have floats. You probably mean the little jiggle pin? It's acceptable to run one without a jiggle pin but better to have it. The purpose of the jiggle pin is to bleed air from the cooling system.

RB3 · Post by **RB3** » 11 Feb 2021, 11:17

Thanks for quick response. I assumed it was an air release of some sort. This is the 2nd sensor replacement in a couple years although I thought the last one was made in Germany. Do I need to go straight to Volvo for OEM part?

Post by **misha** » 11 Feb 2021, 12:07

Volvo for ECT and Vernet or Wahler for thermostat.
Wahler is oem.
If you can find Vernet ECT you can go that route safely.

Do not throw your money on anything aftermarket for ECT except Vernet.

Volvo ECT is made by Valeo...it is Valeo part in Volvo box.
So that is another aftermaket option but i didn't saw that you can buy it under Valeo brand on the market.

RB3 · Post by **RB3** » 11 Feb 2021, 12:17

Thank you again!

Post by **MrAl** » 11 Feb 2021, 23:09

Chuck W wrote: 06 Feb 2021, 18:11 The coolant level has nothing to do with the P0116 code.

That code is for the coolant temp sensor, which is located in the thermostat housing.

It's possible the sensor is bad, but it's also very likely that the connector is corroded, causing a bad signal, which is contributing to your cold hard start issue.

Helpful Vid

Thanks for the info and for the vid too.

Well once the newly added coolant got into the system (the engine ran for a while) it started to act normally again.
What i forgot to mention was that when this happened, the radiator fan would run and run even when the engine was shut off and it never ever did that before that.

Now about the sensor itself, i understand that it is an ohmic sensor which would mean that the resistance changes as the temperature changes and thus we should be able to measure the resistance of the sensor when cold and maybe heat it up a little and see if it responds.
So, with that in mind, any idea what the resistance range should be especially when cold?
This of course is if i have it right that it is a resisance sensor or that it can be tested with an Ohm meter regardless what kind of sensor it is (resistance, thermocouple, etc.). I also have meters that can read very low voltages in case it is a thermocouple.
I seriously doubt it would be an IC type sensor because of the age of the car but i guess it could be.
So if i could measure something about the sensor i could verify that is the problem.
\
Thanks again.

Post by **abscate** » 12 Feb 2021, 04:39

I have the 1999- temp sensor resistance measurements but your 1998 sensor is a different

Pull the part number and try a search on that

Couldn’t find it so made thread for part 9186486

Post by **misha** » 12 Feb 2021, 05:15

Check it's connector on both...ECT and wiring loom side.
It's prone to failure,but ECT isn't.
Mine is still original.

If cooling fan runs with engine off and turns on and off sporadically without reason...that's the first sign of ECT failure(or it's connection).

Rough running,running rich,hard starts are following.
Since you allready have a code for it....check connections first.