Engine temp question

AlanS · Post by **AlanS** » 06 Mar 2009, 17:56

1995 850 (non-turbo), anyway...I did a PCV overhaul on the car last week...all the parts. Now, maybe by coincidence, the car runs really cool...I mean, the needle hardly rises 1/4" from baseline. It used to run in the middle of the scale. Any connection there?
If not, I think I will change the thermostat. What temp thermostat do I use at this time of year (New York...approaching Spring...really low temps are on the way out)? I remember in my older cars, I had a 'summer' and a 'winter' thermostat.

Post by **misha** » 06 Mar 2009, 18:26

I don't think that 850,s,v,c70 have winter or summer thermostat.It's one for all year round.Is needle getting to the middle(operating temperature) when you stop your car for a minute and idling,and when you drive it for a few miles the needle falls down?It has to be cold outside that this happened.If it's hot you will hardly notice the difference.
If so,then you need to change thermostat.
Maybe there is a loose connection in thermostat area,as you said that you have done PCV system.

AlanS · Post by **AlanS** » 06 Mar 2009, 18:33

misha wrote:I don't think that 850,s,v,c70 have winter or summer thermostat.It's one for all year round.Is needle getting to the middle(operating temperature) when you stop your car for a minute and idling,and when you drive it for a few miles the needle falls down?It has to be cold outside that this happened.If it's hot you will hardly notice the difference.
If so,then you need to change thermostat.
Maybe there is a loose connection in thermostat area,as you said that you have done PCV system.

The needle stays about 1/4" above baseline, no matter what situation... that's what it heats up to, and stays there. It does NOT change if at idle or at speed. I will check all connections tomorrow.

Post by **misha** » 06 Mar 2009, 19:21

I had almost the same problem a few years ago.At highway speeds my temp.needle drops to almost at bottom and very low heating(just like car is cold).When i stop just for a few minutes and idling,temp needle is up to the middle and heating is back again.When i start driving temp. needle is falling again to almost at bottom.
This happens just when it's cold outside(at winter temperatures),because my thermostat was stucked in "open" position and coolant was circulated all the time.
In the summer i didn't notice the difference.
I replaced thermostat and no problem since.
Good luck!

Post by **Ozark Lee** » 07 Mar 2009, 06:00

Change your ECT sensor and your thermostat. The original Torx head bolts are aluminum and they will fight with you and the heads really want to strip out. Volvo realized the error of their ways and they have new bolts that are a coated steel. They should cost less than $1.00 each (Unless they come from my dealer where they are $1.40 each). PB Blaster the heck out of the old bolts the night before and pick up a new set of bolts before you even start.

...Lee

AlanS · Post by **AlanS** » 07 Mar 2009, 08:13

Ozark Lee wrote:Change your ECT sensor and your thermostat. The original Torx head bolts are aluminum and they will fight with you and the heads really want to strip out. Volvo realized the error of their ways and they have new bolts that are a coated steel. They should cost less than $1.00 each (Unless they come from my dealer where they are $1.40 each). PB Blaster the heck out of the old bolts the night before and pick up a new set of bolts before you even start.

...Lee

Not to sound too ignorant...what is, and where is the ECT?

Post by **MadeInJapan** » 07 Mar 2009, 08:47

ECT= Engine Coolant Temperature (sensor)....it's located at the base of the thermostat housing w/ wires facing towards the radiator...if you're in for a thermostat replacement anyway, go ahead and change this out- these are not that expensive.

turbotim2 · Post by **turbotim2** » 09 Mar 2009, 07:25

Also, do not use a Wahler thermostat. It seems that any other brand is good though, I have a Stant that I got locally for under $10 and it works well. I believe it is a 192F thermostat.

Craigd2599 · Post by **Craigd2599** » 09 Mar 2009, 12:01

Sounds like the thermostat sticking open. Mine did the same thing. Maybe the easiest stat change I've ever done.

Post by **januwan** » 09 Mar 2009, 13:38

Funny thing, I also replaced PCV systems week ago and also noticed my temperature gauge stays at 3:30 or 4:00 o'clock. It will warm up but not reach the 3:00, only when I stop at the light. Last Saturday I drove to Tahoe (ski area) and back. The temperature gauge reach 3:00 only when I started to climb higher elevations (after 2.5 hours of driving). The out side temperature was way above freezing point, only in mountains temperature was around freezing point. My mileage was good 28.8 mpg (to Tahoe I was driving 70±5 mph while coming back I set cruse control to 65 mph and arrived home turning it off may be for a minute).
Does it mean my engine is running cold.
Any suggestion comments?