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Thermostat question if anyone can help: 2009 SL550 CEL is on. Code is p0128 "thermostat stuck open." But here's a pic of my temp-gauge showing temp right about where it should be, and my heater warms up fine. Is there possibly a problem with the sensor? Or, does the thermostat "stick" and then re-close? (CEL HAS gone out & then back on) If so, is there any coolant system recommended "treatment" that can condition the system to free up sticky parts?
I'm trying to avoid replacement if possible. If I do have to replace, does anyone know of a good tutorial specific to r230 they can point me to? Indy shop wants $625+tax...big NTY. Can get one online as low as $29!
Thanks much for any advice.
Reid C
Collierville/Memphis TN
Last edited by CorAegean; Dec 29, 2022 at 12:51 PM.
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
