good day all,

the last few weeks I have noticed that my temp gauge would rise from the normal slightly downward position (before 3 o'clock) and start to climb between the 3 and up to last 2 lines before the redline.

I do mostly 40 miles of highway running and upon getting off the highway and coasting for a few minutes before I exit is when this occurs.

I had changed the ect and thermostat about 6 months before the start of the summer and flush the radiator out, I think I got all the air out of the system I do not have any leaks anywaare ( I change the small hose by the top of the radiator last year) I only have 68k miles 2002 s40 base.

any guesses ? I have search several forums for this issue cant find a similar problem is there a specific bleed procedure or is it sticky thermostat slow to open ? I also noticed that if the ac is not on the second fan comes on very late so I am driving with the ac always on to keep temp down?

 

I think you hit on the three most likely causes - 1) air in the system 2) wonky thermostat or ECT sensor (don't assume because you have new parts they are the correct parts and working correctly or you don't have a wiring issue) 3) fan/fan relay not kicking on correctly. You should be able to google around or search the boards for tricks on burping the the system.

 

If turning on the A/C brings the temperature down, then it's pretty clear that the problem is that your cooling fan isn't coming on when it should. I don't have a G1 manual, but the concept of the fan control is pretty simple - when the coolant at the sensor / switch reaches a certain point, the fan should be engaged.

 

I had a bad Coolant Temp Sensor right out of the box from one of those chain stores. An OEM Volvo unit fixed it right up.

 

odd a year later and the same issues continues exists, year round until temps hit 85 to 90 the car stays at a rock solid 3 to 4 pm position on the temp gauge !!! no matter what 5 hours in traffic or in my drive way (yes I was locked out last week )

until I am in traffic from a stand still to slowly coasting the cart starts to climb past the 3 o clocl position and nears the last 2 lines before read.

if am crawling or stopped perfect below 3 o'clock or if I am driving constant speed perfect and or idle with ac fan perfect its odd that I get a spike when due the slow roller coaster of stop and go traffic due I get theses temp spikes??
I ask again ect, thermostat or fan relay ( the fan kicks in when temp calls for it or when ac is on) ??

the final question is which way the thermostat pin suppose to go ? towards the front or the car or towards the rear ? I cant remember but I have a new volvo part I might as well add in

 

I had this very issue during summers for years.Finally I figured it out that the expansion tank did develop (being old) hairline cracks and let the pressure out when the temp went higher than normal the pressure reached a point when it got trough.It was very stealthy to find wasnt consistent.After I fixed it still had problems twice as now the pressure couldnt escape the next weak point did give up.First the hose coming up from the radiator with the plastic on it also goes to the reservoir cracked open.Then the side of the radiator has given up which surprise surprise also made of plastic.Do a pressure test and listen for hissing pretty sure one of these locations did give out on yours too.
Other than this as was pointed out check your fan if it runs at full speed.I believe the fan has 2 speed.Also see if the radiator gets air trough the AC and the IC or it is blocked.

 

thanks for the replies guys seems like I did the following:

before I even did a pressure test I found the clamps at the upper radiator was not tight from the new hose I put in a few months back, second the clamp and hose to that upper radiator inlet? was very loose from the factory I cut off a piece and place a new clamp after I pressure tested to about 19-20 lbs I let it set for about 20 mins no change to the gauge and upon releasing the pressure I did add a few inches of coolant and added a new cap ( the update model provided by volvo matching the existing part number was no longer available.

so far the temp is not moving past the 3 oclock position during 90 degree days and the fans all come one with or without the ac being engaged ( let it sit in my drive way for about 20 mins and both fans finally came on full blast ( really only one the other always seems to be running )