HELP!! Temerature gauge HELP!!

zepsongs · Post by **zepsongs** » 01 Nov 2007, 12:13

1996 volvo 850 wagon non-turbo:

This just started today, I noticed that my temp gauge is pinned all the way to the top. The car doesn't appear to be overheating, but I haven't driven it very long since I've noticed the issue. There is no water leaking so I don't think it is the water pump and the coolant level is at max. I replaced the thermostat about 10 months ago, could it have gone bad already? The radiator fan spins and runs quite longer than I remember it running after I turn the car off. She just turned 141,000 miles and is due to have the timing belt done. Also the check engine is on & the the service light goes on & off which just started today as well.

I'm leaving for a cruise this weekend and only have today & tomorrow to try to diagnose and fix it. Any suggestions?

Update: Took her for a ride, temp gauge pinned then 3 o'clock, then up & down in no particular fashion. Sat at a red light, temp didn't move but while driving it would move slowly up & down. Pulled the car over, checked the hoses, top hose hot not hard, bottom hose cool & soft as if there was no pressure. TIA

Post by **Ozark Lee** » 01 Nov 2007, 13:28

Check and clean the connection on your engine coolant temperature sensor.

...Lee

zepsongs · Post by **zepsongs** » 01 Nov 2007, 13:40

I forgot to mention that I had replaced the coolant temp sensor at the same time I did the thermostat. Is there anything else I should look for? If the car is going to overheat, how long does this take? I will need to drive home about 25 miles 2nite in heavy stop & go traffic and I do not want to be stranded on that highway in that traffic. I've driven her for about 20 minutes in slight stop & go traffic with the vents open and I detected a slight, very faint coolant smell that would come & go but not be constant. I can always drive the bike to work tomorrow i just want to make sure I'll be able to get home safely.

Post by **Ozark Lee** » 01 Nov 2007, 13:51

If the car is really going to overheat it will do so quite quickly, within a mile or so from a cold start.

Your problem sounds more like a wiring problem than an actual overheating problem. Like I said before, a bad connection at the ECT sensor will make the gauge and the fan behave exactly as you described.

...Lee

dchapman · Post by **dchapman** » 01 Nov 2007, 14:41

My 98 V70 was doing the exact same thing. One shop told me I had a blown head gasket...another said replace the temp sending unit. I bought a sender and thermostat. When I removed the thermostat housing, I discovered that the thermostat was broken in 2 pieces and would float and stop up the water passage. replaced the thermostat and it has been perfect ever since. Glad I did not trust the shop and do a head gasket.

zepsongs · Post by **zepsongs** » 01 Nov 2007, 18:29

Well I made it home with no problems, so it wasn't the water pump. I have no acceleration issues & my coolant is clean so it's not the head gasket. I just replaced the thermostat & ECT February so I didn't think it was that BUT.......I decided to stop at an Autozone that I pass on my way home and have them read the OBD2 & sure enough code P0118 ECT Circuit!!!!!!!!!

Is there anything I could have done to prevent this? 2 thermostats & ECTs in 1 year? Is this a sign of a larger problem or just a quirk? I leave for a cruise this weekend so at least I can go with the peace of mind knowing I don't have a friggin headache a car repair waiting for me when I get back. Thanks for helping out

Post by **sseir39** » 01 Nov 2007, 20:58

In Jan of this year I had to do a head job on dau-in-laws 98 S70GLT and I replaced the temp sensor with an aftermarket unit. It failed and gave me all kinds of grief. Replaced it with a genuine Volvo and problem is gone. Sometimes Volvo parts are the best.