SL55 AMG, SL63 AMG, SL65 AMG (R230) 2002 - 2011 (2003 US for SL55 and 2004 for the SL65)

SL55/63/65/R230 AMG: Question::: SL55 running too cool ????

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Old Mar 16, 2009 | 02:00 AM
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Question::: SL55 running too cool ????

I have a little weird situation here and hope to get some answer.

My car was running fairly hot. The temperature gauge fluctuate somwhere between 85-95 celcius. As recommended by those in the E amg forum, I replace with PTE thermostat and got my local Benz specialist to reprogram for radiator fan to turn on 10* celcius sooner . The car runs ok after that, running at about 80-85*C.

Today, I got in the mood and change out the oem IC PUMP to the Johnson cm30 ic pump. I did a test drive after I change it out.the meter never get higher than 75*C (outside temperature is 45*F) . IS this normal and OK for it to run cool like that????


thanks
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Old Mar 16, 2009 | 07:27 AM
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Yes

Mine does the same thing. I checked mine with STAR and it is running at exactly 180*F. The PTE stat is running as advertised.
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Old Mar 16, 2009 | 07:38 AM
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Mine kinda max out at 75*C,,,,,,,this is way below 180*F,,,,i think it's like 167 or something
you happen to know at what temperature does the radiator turn on normallly( before adjusting -10* C)????

Last edited by htn; Mar 16, 2009 at 07:46 AM. Reason: a
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Old Mar 16, 2009 | 01:07 PM
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What is PTE thermostat, how much does it help? Where do I get one? How much is it (part cost and labor to put on?)
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Old Mar 16, 2009 | 01:52 PM
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It may be running a little cooler, but that was your goal. At an outside temp of 45, as well as what you have done to your car, it sounds normal.

We don't get too many 45 degree days, but when we are in the 50's, the car runs fairly cool.
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Old Mar 16, 2009 | 07:41 PM
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I start to get worry that i might get a "check engine" light if the car is too cool ( don't remember someone told me that).
Also I thought the engine has to warm up to a certain operating temperature

Last edited by htn; Mar 16, 2009 at 07:48 PM.
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Old Mar 17, 2009 | 09:30 AM
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You have to check it with STAR or an OBDII reader. The gauge is not 100% accurate. It won't run this cool when the weather gets warmer.
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Old Mar 17, 2009 | 10:18 AM
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Originally Posted by Sunir
What is PTE thermostat, how much does it help? Where do I get one? How much is it (part cost and labor to put on?)
PTE is a forum member. Just send him a PM or email, https://mbworld.org/forums/3221828-post3.html.

Cost is in the neighborhood of $200. Patrick will be able to give you an exact figure.

The PTE thermostat opens the engine cooling circuit at a lower temperature, which causes the engine to run cooler under some circumstances. Cooler temps are both the pro and the con of the mod because it's desirable under some circumstances but you don't want the engine to run so cool that it doesn't heat the oil to proper operating temparture. Some related discussion here: https://mbworld.org/forums/w211-amg/...hermostat.html

It's about 1 to 1.5 hours to install and definitely DIY-able if you're inclined that way.
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