Wide Engine Temperature 1997 Volvo 850 N/A

BlackThunder · Post by **BlackThunder** » 28 Mar 2018, 09:42

I haven't been driving my 1997 Volvo 850 NA much lately but when I did a 20 minute commute to work (after sitting for about 2 weeks) I noticed the engine temperature got really hot. I turned on the heat full blast to drop the temperature and that seemed to work then the engine temperature came down to normal rather quickly.

I thought maybe the Thermostat had been stuck from sitting for a long time? I could not tell if the cooling fan kicked on or not. Cooling/Radiator fan relay? Cooling fan? Engine Temp sensor?

ALSO - not sure if it is related or not but the car hasn't been starting all the time. New(er) battery, starter sounds good - Cam position sensor?

Any ideas?

Dustin

WhatAmIDoing · Post by **WhatAmIDoing** » 28 Mar 2018, 10:32

Could be a stuck thermostat. Hard starting could be a bad coolant temp sensor. Air may have got into the system. Fan not coming on. Dirty radiator. There is any number of possible issues. When you say it got hot, how hot is hot? Remember, the temp gauge is a dummy gauge. If the needle isn't getting too the red, I wouldn't be too worried.

Post by **scot850** » 28 Mar 2018, 11:40

You have listed the most likely sources of the 'over temp' condition. It may have been a real event or fake news depending on the source of the high reading.

1) When were the thermostat and ECT (engine water temp sensor fitted below the thermostat) last replaced?
2) Check the wiring for the ECT. The connector mounted on the power steering pump goes brittle and the connector gets contaminated. Check the condition of the connector and if ok carefully open it up and clean the contacts. If you have a hunt on MVS there are a set of resistance values you can check the sensor for based on ambient temperature to see if the ECT sensor is good.
3) Does the cooling fan come on? The ECT controls the fan so if bad the fan may not come on. Also the fan relay (sits above the radiator) is known for the connectors to break off with age, and the relay can also fail. The relay can be tested. I believe I wrote a how to on testing both the relay/fan/ECT somewhere on MVS but can't see it for now.

If the thermostat and ECT have not been replaced in many years now is probably a good time to do so.

There are other reasons the car could go over temp, but these are probably the most common and need to be eliminated as problem sources and general prevention maintenance.

Neil.

BlackThunder · Post by **BlackThunder** » 02 Apr 2018, 08:36

GREAT! These are all good things to check. The thermostat was probably replaced about 8 years ago and the ECT was probably replaced about 9 years ago. Probably time for both. I bought a fan relay and will be putting it in when I have time - hopefully this week.

The needle did not go into the red. I did turn on the heat full blast though to help pull heat away from the engine - that seemed to help. It was cold-er outside so I didn't mind the extra heat. I'll let you know my findings. Thank you for giving me things to look at!

Dustin