Hello,
I have Volvo S40 2.0 2008, it runs perfect until this summer when the problem shows up with engine overheating so fast on long uphills with A/C on, so i need to turn A/C of and temperature go back to normal. This not happening on flat roads even with A/C on.
Please can somebody help to solve this issue if experienced with the same problem, thanks in advance.

 

The engine is making a lot more heat going up a hill, so my guess (key phrase) is that your cooling system is operating at a "barely adequate for flat roads" level.

Beyond that, it could be a lot of things. Some simple, some scary. Here they are in order of scariness...

Low coolant
Air in the cooling system (do a bleed procedure)
Partially blocked radiator
Bad water pump
Blown head gasket (check to see if both your antifreeze and oil look OK - if they do, this isn't the problem)
Bad transmission (creating a lot of extra heat - doubtful).

 

How to post a new question .sorry if this is on the wrong place

 

Thank you very much for response.
I am sure that coolant level is OK and headgasket is OK. The engine is running smooth on idle and on urban drive.
Just i doubt now for partially blocked radiator, bad water pump or transmission oil overheat, thanks again.

 

Skender - has the car actually overheated (ie boiled over etc) or are you just seeing the temp guage go beyond the normal range?

If you've never boiled over, you may actually have a wonky ECT. I'd probably start by replacing the temp sensor, the thermostat and overflow cap (since that's your safety pressure release). Then if your coolant is over 5 years old, you can consider doing a coolant flush (use distilled water - no solvents) and put in fresh 50/50. As Habby noted, you may need to follow a bleed process to get all the air out. you may need to google around to see if your engine has a coolant bleed valve or not.

If you have experienced a boil over or suspect a head gasket, you can check to see if your upper hose gets rock hard when hot and then have a shop do a pressure test to measure. You can also buy a HC test kit that detects any exhaust gasses in the coolant.

 

Eljefe1 - to post a new thread, simply navigate to the desired Forum using the drop down on the main nav bar. Once you are in a forum's list view, you will see a button to create a new thread.

 

No engine never boiled up and run so smooth and to be more specific i noticed this in highway. In the way to vacation it run perfect like alwsys and in the high speed with A/C on on uphills. In my way back i was driving on flat road with speed limit 90km/h and everything looks fine, when i reached highway and its entry is long hill just sudenly i felt lost of engine power and temp gauge rapidly goes up. I stopped on emergency line and opened the hood and i felt engine overheat but coolant level OK. I started engine and shut of A/C and continue with temp in normal range. I tried to verify and turn A/C on but temp start to increase so i understood the problem and came home safe. So the problem is still there.