2001 S40 turbo.... extreme rpm surge and overheating without temp gauge reading

rickk1967 · Post by **rickk1967** » 10 Mar 2016, 13:10

Hi all.... looking for some major help.... I got a s40 used and it has a problem.... a couple weeks ago it had a little RPM surge... it was quick and only lasted a sec or two... now to today... MAJOR rpm surge to 4,000... Cleaned throttle body and idle control.... reset codes at advance and it worked... got home and it happened again with one MAJOR problem... the car over heated and blew the upper hose apart... Replaced the hose and restarted this morning... ran great til it warmed up.... the temp gauge BOTTOMED out, read nothing O..... and the engine was way hot, overheating... Replacing thermostat and temp sensor.... My question is will this cause a major rpm surge that can cause a accident??? Its scary!!!

Post by **alschnertz** » 12 Mar 2016, 05:02

What were the codes that were erased?
I suspect the temperature gauge not registering is a result of air in the cooling system. You must bleed the air out.
Can't think of a reason for overheating to cause a rpm surge.