MEP-80X Blow by

[jimbo913]

I did touch the upper radiator hose today after 2hrs at load and it was hot but I could touch it without getting burned so after reading that the thermostats are either 165 or 190 (seen both listed as replacements), it seems as though my unit may be missing the thermostat or it’s stuck open. I will lookup numbers to figure out the correct temp thermostat and just replace it or add it. Hopefully I can find one locally.

Now I am curious if running cold could be keeping the unit from seating in the rings properly. Hopefully the initial load testing hasn’t done any damage. At the time, I figured cooler was okay as long as coolant was circulating, which I knew it was, it just didn’t register with me in the mild weather but it should have. I should have mentioned it earlier, but thankful it was caught now and I appreciated it DieselAddict.

 

[2Pbfeet]

A cooler engine ( e.g. 150 vs 190F) means more incomplete combustion, leading to more carbon in the cylinders and in the exhaust (wet stacking effect). If it were my machine, I would do something, as I think that is an issue that needs addressing in a diesel, and yes, it would affect the rings.

All the best,

2Pbfeet

 

[jimbo913]

I picked up a 180F thermostat and gasket. I will get that installed over the weekend and run it again.
Might as well change coolant. TM spec is Mil-A-46153. This is ASTM D3306, ASTM D6210. CAT-EC-1 which I will roll with if nobody screams stop.

 

[Light in the Dark]

They are happy with just regular old Prestone green too.

 

[DieselAddict]

For me I choose coolants that are low/no silicates. The waterpump seals will last much longer if you go no silicate.

 

[jimbo913]

I swapped out the coolant and thermostat today. The unit had a 88c (190F) thermostat in it and it wasn’t stuck. I went ahead and swapped it and ran under load for about an hour. The gauge now reads about 10f lower under load. Currently suspect the sender or gauge but leaning towards sender.
The unit seems a little weaker with the 180 thermostat and this unit is mainly a winter / overnight/ backup unit. so I will likely run the original 190F thermostat through an ultrasonic cleaner and put the thermostat back prior to running more load tests.
As for the temperature gauge reading, I guess I will purchase an IR thermometer to determine actual running temperature.

 

[jimbo913]

Anyone know the part number for this? I can’t find it in the TM

 

[kloppk]

That part that you circled is for the over temp shutdown. It does NOT drive the temperature gauge.

The one that does drive the temp gauge is find number 8 below.



Fn 8 & 9


FN 9
Also PN 8037122

FN 9


FN 8 part numbers..

 

[Guyfang]

View attachment 918195


Jimbo. Here is a hint. Any time you see a part with the CAGE code of 30554, the part number will be a hard thing to find. Cage code 30554 in MEP, Mobile Electric Power. Its an Office. So they source parts from "Someplace" and make up a part number. On your gen set, any part number that starts with an 88-***** is a "made up part number. Plug it in you browser anyway, but dont hold your breath.

 

[2Pbfeet]

View attachment 918195


Jimbo. Here is a hint. Any time you see a part with the CAGE code of 30554, the part number will be a hard thing to find. Cage code 30554 in MEP, Mobile Electric Power. Its an Office. So they source parts from "Someplace" and make up a part number. On your gen set, any part number that starts with an 88-***** is a "made up part number. Plug it in you browser anyway, but dont hold your breath.

That's an insight and half! Many thanks!

All the best,

2Pbfeet

 

[Light in the Dark]

The coolant overtemp switch, as Kurt calls out... doesn't drive the gauge. Its what triggers an overtemp fault. It is "INDEX Thermostatic Switch 8037122"

The sender you are looking for is a standard 1/8" 450 to ~30ohm. You can use this one: https://onlineexpress.jlg.com/parts/electrical/proximity-sensors/p/91143314

 

[2Pbfeet]

FWIW: Also on Amazon.

 

[jimbo913]

Update: I swapped back to the 88C thermostat. After thermal review I think it’s safe to say that the issue is either the temp gauge or the sender. I will follow the procedure to check the sender as first step.