Hi There=

My 2000 s40 started running on the hot side yesterday. Not to the red, but went as far as the 3rd notch below the red before I turned off the a.c. I would say it was somewhere in between red and the normal

It was 100 degrees yesterday, and the car didn't run hot at all with the a.c. turned off

It's at the mechanic today, and I'm starting to get worried that it will be a pricey repair. I also have to get a new fuel pressure guage.

Any insight on why this might be happenning???

 

Could just be a bad thermostat.

 

Thanks

That's what the mechanic said. He's said he drove it around today and couldn't really figure out what it was because everything looked good. He's going to change the thermostat tomorrow.
He also suggested a coolant flush, but I wonder if this is something I really need or not. He said there may be some contaminant in the coolant.

 

Just change the thermostat for now.

 

Tstat is a good way to go, and a coolant flush would be okay if the coolant looks dirty, has not been changed in 2 years and you have good hoses already installed. I live in Phoenix and know a bit about 100 degree days! The a/c on thing may also be related to a condenser fan that does not work or comes on too late (controlled by the computer which gets reading from coolant temp sensors and signal from a/c head unit). Try this- if it is 90 plus and you turn on the a/c while parked, engine idling, do you see or hear the fan come on? If yes- your fan and control could be good. If no- you may have trouble. My techs have incorrectly diagnosed thermostats on 3 cars this summer (all on newer cars- two euro) and we found that fans were turning on at too high a temp ( fan can not catch up), not at all or intermittently. Good luck and keep us posted.

 

Thank You both.

I had the thermostat changed and the coolant flushed. I guess I probably didn't need the coolant flush, but would have had to do it soon anyway, as the car is almost at 60,000 miles

The fans were working just fine.

Had the fuel pressure regulator changed as well because it had been starting slow

Now it's working like a charm, that did the trick!!