temp sencor complete failure...

[curtis]

Well my temp sencor has completley S#&@ the bed. It was giving inaccurate readings last week, and yesterday it stoped working at all. THe guage doesn't move at all with the engine up to temp, kind of a pain in the ass when it's winter time and you have no heat. I ordered a new sencor, still waiting for it to show up. Just wondering if anyone else has had issues with their temp sencor???

01 XC 92miles (studded Nexens)
94 850 T5 211miles (goodyear Nordics):mad:

[gibbons]

Hmmm.... if you have no heat, then the engine isn't up to a normal operational temperature. The engine's actual operating temperature is controlled by the thermostat, a mechanical device. The sensors only report what's going on. In my personal experience with thermostats, they have always failed "open" (fortunately). So instead of fluttering open and closed to keep the temp correct, they just let the coolant flow full speed and the engine never gets warm. Buy yourself a $50 infrared temperature sensor gun on eBay to really check what's going on. My gun has proven very handy for checking transmission temperatures, tire temperatures, barbeque temperatures...

I haven't had to dip into the electrical systems on this car, but most OBDII (the main CPU) cars have 3 temperature senders, one very accurate one dedicated to the CPU, one for the gauge, and one for an idiot light on the dash. I just replaced the sensor for the CPU on one of our Subarus and it made a world of difference in cold starting, power and fuel economy.

OK, not XC related, but funny. When I was in high school I was a mechanic at a boat shop. A guy bought a great big, brand new boat and took the family to the lake. The engine died, and they had to be towed in. He brought the boat back to the shop and was furious. He ranted and raved. When he was done complaining about the motor, he said, "...and oh, yeah, the gas gauge on this piece of crap doesn't work either, it shows 'empty' ". The poor guy was humiliated.

[curtis]

Interesting, for some reason I thought the sencor sent the msg to the thermostat to open. Shows how much I know,LOL I was assuming the engine was up to temp based on the heat radiating off the engine bay and the heat felt when touching the coolant reservoir.
Well in that case maybe I need a new thermostat. This car has just been imported from texas to New Brunswick so this is the first winter it's seen. Maybe this could have something to do with it?? anyone know how much a thermostat costs?:(

[gibbons]

The best thermostat you can get, a Stant SuperStat, is about US$8. I don't know if they make one to fit the car, I imagine an OEM unit is going to be 3X that. And if it's a Volvo, it can't be easy to get at to install :rolleyes:

[BillAileo]

Through FCP Groton you can purchase an OEM thermostat for $9.00. If you need the "O" ring as well that's another $.75. See http://www.fcpgroton.com/p2series/p2cooling.htm

Replacing the thermostat involves:
- clamping the upper coolant hose and draining about 2 liters of coolant;
- disconnecting the cable to the temperature sensor;
- removing the upper timing belt cover
- removing the thermostat housing cover
- removing the thermostat.


Installation is the reverse. Torque to 17 Nm.

Bill

[curtis]

Thanks alot for the info, sounds like a simple procedure to replace thermostat. Ive ordered through FCP groton before and have been 100% happy with their service. Looks like I'll be calling them again.

THNX
Curtis
[thumbup]

[curtis]

Replaced thermostat the other day, malfunctioning unit was broken and twisted. NO wonder my poor wagon was so cold.... brrrr brrr, My wife took it shopping the other morning before I changed it, it was -25 outside and she almost froze, thank god for heated seats. NOt to mention she's 37 weeks pregnant. NOt a good scenario.
Anyways the wagon is heating like a chapm now........... just gotta deal with ALL the other problems.............:eek:

[gibbons]

Glad to hear that you have heat. Darn those thermostats! They work perfectly until they fail, and then it's an instant catastrophic event. I know more about thermostats than a normal person should have to, that's why I guessed that was the cold problem. We have a MasterCraft ski boat with an LT-1 Corvette engine in it. All regular iron-head V8 boat engines like to run at 160. This engine likes to run at 170. But stats only come in 160, 180, and 195. A with a 180 stat, the motor will boil because the cooling system is "open". I found the right engineer at Stant, and he custom made me some 170 stats. Cool!

Anyway, back to XCs. Is your dash temperature gauge working now?

[curtis]

Gibbons, Well the guage didn't start working right away when I changed the thermostat. But after about 15mins it started functioning, now it stays directly in the middle once up to temp. NOt sure why it didn't start working right away, because it was throughing heat just showing no heat for the first 20 mins after chaging thermostat. However maybe it had to do with air in the coolant system near the sencor?????? Im not so sure..... However if the heat is working im happy for now, ive got bigger things to worry about like "no oil pressure turn off car asap" !!!!! THis car is deffinently been a challenge so far!!! Whatever happened to good old vacume leaks??? lol

thnks for the advice gibbons

01 XC 92.4 miles
94 850 T5 466kms

[Willy]

The gauge only indicates a small area of temperature around the target zone, therefore
it tales a while before the reading makes in to the bottom of the scale.
I agree with Gibbons that thermostates tend to fail in a sudden way,
but perhaps this is only an illusion. As long as it functions somewhat,
the effects may stay unobserved, only when it doesn't close at all will it be noticed.
A good thing is that they tend to fail to open position, at least the car can still be driven then,
if there isn't time for an immediate repair, (part of) the radiator can be covered to allow
the engine to reach a more or less normal temperature.
Willy