View Full Version : Running a bit hot in traffic

05-17-2012, 06:30 PM
Just got back from work and the SVO runs fine on the highway but when in traffic or at traffic lights it will get hot pretty quick.

I am only going by the temperature gauge on the dash but it does seem to be working. In traffic it was getting ALL the way to the end of the "normal" range which is only a mm away from the HOT zone.

I know it can be many things but I did mess around with it and the electric fan is coming on.

I did put the defroster on today to activate the fan but it did not seem to help much. I am seeming to recall I had this problem when I took her off the road in 1996. Now I am dealing with it and its gotta get fixed.

I am leaning toward the radiator. I did a flush on it last week and there was still plenty of scaling that I could see looking down the filler cap hole after I was finished. Even though there was a lot of scaling there seemed to be satisfactory flowing of coolant when I would rev the motor while looking into the radiator.

That does not mean it is cooling effectively though, just saying.

I did about 2 hours of googling and coolant temperature sensor (s) were mentioned as possible culprits which I guess could turn fan on and off ineffectively????Dont know???

Water Pump????

Any suggestions would be appreciated. If I did replace the fan any recomendations?

05-17-2012, 09:11 PM
My 86SVO will run a little warm at stop lights, but never goes pass the half way mark. On the hwy the temp needle is just above the cold mark. I did change out the temp sensor, thermostat, radiator though.

I have also had my temp. gauge, oil pressure and fuel gauge all peg out at the same time. It has done that a few times. I believe the SVO electrical system has gremlins. changed out the Instrument Cluster Voltage Regulator and it did not fix it.

Mike S
05-18-2012, 08:01 AM
Since your fan is coming on, that means your temp sensor is working. The fan kicks on at 210* I believe, so you should get a infrared temp gauge and check to see what the real temp is related to your gauge reading. Everything maybe working fine except the gauge.

05-18-2012, 08:50 AM
Since your fan is coming on, that means your temp sensor is working. The fan kicks on at 210* I believe, ... Stock fan temp sensor switch engages at 221-222 degrees F. Which is plenty fine with good coolant under pressure.

OP - fix your coolant system. ANY scale, dirt, etc will reduce the heat transfer - and generally ends up clogging the small passages in the heater core and radiator. Might be a good idea to block off the heater core and flush it separately. Unless you happen to like replacing clogged heater cores?

Flush the entire system with a good cleaner and then replace the radiator when you're finished rinsing. If you stil lsee ANY rust or scale, you're not done cleaning yet.

Then fill the system with water and pressure test it. It should hold 16 PSIG overnight - fix the leaks as needed. Pressure test the cap - if it leaks, replace it.

Then fill it with your favorite long-life 5-year coolant in the 50-60% range (depending on where you live). Check the coolant ph yearly and adjust as needed.

05-18-2012, 05:12 PM
Good advice, Thank you!

I will try all this. I do have a infrared heat gun and will check. I flushed my Excursion PSD with Ford VC-9. Would this be OK to use in the SVO system?

05-18-2012, 05:16 PM
After a quick look VC-9 may not be good and VC-1 may be better instead. Any one know better?