my son has a 1989 260E, 120km (70K). It is currently -36c I live west of Montreal. When he started his car it idled at around 2,400 rpm, we could not get it to kick off this idle speed even after 10 minutes of warm up. I looked through the threads but could not find a similar problem. No problem starting the car, I just called him on his cell as he was heading home and he pulled off the road and the car is still idling at 2,000rpm. I should mention that he had the valve stem seals changed today, oil change and antifreeze flushed and replaced. a compression check was done and all 6 cyl were even at 170. I would appreciate any assistance.
John

Sounds like something wasn't put back together right. High idle like that generally means a pretty big vacuum leak somewhere....check all tubes and connectors.

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'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

Did you make sure the idle control valve is connected? ( if it has one) or the Engine temp sensor? I know If I disconnect those or the OVP, I get a high idle.

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1984 300SD Orient Red/ Palomino
1989 560SEC
2016 Mazda 6 6 speed manual
1995 Ford F-150 reg cab 4.9 5speed manual

ABS light On ??

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A Dalton

no ABS light.
*** I should add that the car idled fine in the garage before leaving the mechanics and the fast idle only happenned after sitting outside for a few hours at -36c. It is much warmer today at -28c .

The first thing I would check is the Idle Control Valve. Sounds like it's stuck in the open position. Remove it and look inside, it should have a small opening when no power is applied. You can test the operation with a 9v battery.

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1993 190E 2.3
2001 SLK230
1971 LS5 (454) Corvette Convertible

went back to mechanic, all hoses and connections were good, problem was linkage was frozen, he cleanrd it up put some special lubricant for these lovely temperatures and car runs and starts smooth. Putting shorts on today it a balmly -29c before winf factor.
thank you everyone for your assistance.