M119 Running Hot Uphill With All New Parts - Page 2 - PeachParts Mercedes-Benz Forum

ducaromeo500e · #16 07-09-2009, 11:34 PM

Quote:

Originally Posted by TCG

-checked temp with laser temp gun; upper and lower radiator hoses register same temp (97C according to gun; 85-90C according to gauge). This would indicate radiator OK.

If air is moving through the radiator and the top and bottom hoses are the same temp I would suspect the radiator. The lower hose is the output side of the radiator and should be cooler. If the thermostat is stuck closed the entire radiator would be cool.

TCG

92 500E Pearl Gray
92 500E Black Pearl
89 300SEL Smoke Silver

Another excellent point. To get a bit more specific, the lower hose was about 5 - 10C cooler while engine was running. After shutting it down, the temp between top and bottom stabilized. Sorry for not mentioning this.

If the expansion tank cap and fan clutch have no effect at all I will have to suspect the Graf water pump. I will be extremely unhappy if I have to swap out the pump; it is not an insignificant job on this car!

ducaromeo500e · #17 07-15-2009, 01:45 PM

It always irks me when folks don't follow-up with resolutions to their posted problems. So here's my somewhat embarrassing resolution.

I took the car out of service last Fall for about a month to fix a number of small problems, the most major being the cooling system rehab. In addition, I had the gauge cluster out of the car to remove the white-faced gauge faces which I always thought looked cheesy. Can anyone guess what happened?

I photographed the positions of the gauge needles before pulling them and thought I had placed them correctly. Well, after comparing the "0" position of my temp needle with Rudy's 500E and my Mom's 260E, it appears I've placed my needle about 2mm too high.

Now my new dilemma is whether to install the new fan clutch or not. I never replace OE parts unless absolutely necessary; therefore, I'm hesitant to replace it even though Omega kindly loaned me the tools. I think it may have to go to my spares inventory.....

Thanks for the suggestions, everyone.

pawoSD · #18 07-15-2009, 02:33 PM

Lol, it happens to everyone. I've done stuff like that several times.

ducaromeo500e · #19 07-24-2009, 01:54 PM

Just one more update: the mis-positioned temp needle was the primary cause for my alarm; however, temps were still on the high side of normal.
I replaced the fan clutch with an ACM unit that looks identical to the unit that Rusty sells. The car now runs 10C cooler at all speeds, and the high speed aux fan has not turned on since the new clutch was installed.
If your car's temps are on the high side, I strongly recommend replacing the fan clutch.