Transmission oil temperature - PeachParts Mercedes-Benz Forum

JeffreyP · #1 10-12-2006, 02:09 PM

Not another ATF thread, I just want to see if this would work for measuring ATF temperature without spending money on the infrared thermometer or the like.
According to the ATF DIY article and recommendations, the ATF level measurement (in my case a 98-E320) must be done at 80Celsius. Here are my questions:

1. Doesn't the transmission line go through the radiator for cooling? If yes, then
2. should the ATF be at the same temperature as the engine coolant? So measure the coolant temp should be quite simple

I believe there is also a procedure using the "REST BUTTON" to see the coolant temperature? Does any one have the link?
Please let me know what your thought on this - Gilly, MBDoc and other informed mechanics?

Regards,
JeffreyP

Matt L · #2 10-12-2006, 02:23 PM

The fluid is cooled by the engine coolant in the radiator, but this does in no way imply that they will be at the same temperature.

Gilly · #3 10-12-2006, 06:54 PM

Not the same temp, the ATF wil typically be hotter, all depending on the ambient temp, how hard the tranny is working (if at all) and how hard the engine is working.
Gilly

uberwgn · #4 10-12-2006, 07:28 PM

Quote:

Originally Posted by JeffreyP

Not another ATF thread, I just want to see if this would work for measuring ATF temperature without spending money on the infrared thermometer or the like.
According to the ATF DIY article and recommendations, the ATF level measurement (in my case a 98-E320) must be done at 80Celsius. Here are my questions:

1. Doesn't the transmission line go through the radiator for cooling? If yes, then
2. should the ATF be at the same temperature as the engine coolant? So measure the coolant temp should be quite simple

I believe there is also a procedure using the "REST BUTTON" to see the coolant temperature? Does any one have the link?
Please let me know what your thought on this - Gilly, MBDoc and other informed mechanics?

Regards,
JeffreyP

Jeff, there are two reference points on the dipstick tool: 25C and 80C. It's much easier to gage the level at the lower temp. It can be challenging to get the temp up to 80C.

sokoloff · #5 10-12-2006, 10:06 PM

I thought Mercedes came out with a service bulletin saying to not use the lower mark and only check the fluid using the 80 degree mark.

Len

Gilly · #6 10-12-2006, 10:07 PM

Yeah they sure did, get tired of posting same things over and over.
Gilly

uberwgn · #7 10-13-2006, 08:40 AM

I have not heard that. OTOH, I have checked my car at 25C and 80C and get FULL indications at both reference points.

BTW, the MB tech that posts here says they only use the 25C indicator, FWIW.

JeffreyP · #8 10-13-2006, 09:54 AM

Thanks guys,

I guess there goes my theory. I suppose I can always spend 60 bucks for an infrared thermometer.
I am ,however, supprise that we couldn't use the "Rest Button" to get to the transmission temp sensor as we could access other (cabin, coil, vac etc..) temp.
sensors

Regards,
Jeffrey