Was driving today when I noticed my temp. gauge approaching 120!!. Never happened before (highest ever thus far for me was 100), I pulled over, opened my hood and found my fan and the cover loose ! All but 1 of the four 10 mm bolts must have worked their way out and the fourth was just there-barely hanging on.... I got the car towed home. My question is - should I be careful about the bolts I use to replace these? In other words, what types of metals should I use or avoid? I picked up some up from the hardware store - seem to be the proper size, but I do not want them to shear over time from the force of my cooling fan spinning full bore....

Thank you.

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dannyf
1984 Mercedes 300 SD 214 K miles. Runs on WVO ~ 22 mpg over 8 K on WVO
1997 VW Passat TDI 156 K miles. Uses biodiesel and diesel. ~ 41 mpg
1996 Mercury Villager gasser. ~ 20 mpg

I would think you could get original equipment bolts from the stealer. Short of that I think you can get a very good bolt from NAPA. I would stay away from the bolts sold at the typical hardware store.

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Junqueyardjim
Christianity, if false, is of no importance, and if true, of infinite importance. The only thing it cannot be is moderately important. C.S. Lewis



1983 Mercedes W123 240D 4 Speed 285,000 on the road with a 617 turbo, beautiful butter yellow, license plate # 83 240D INDIANA

2003 Jaguar Type X, AWD. beautiful, good mileage,
Mom's car, but I won't let her drive it!

Thank you, Jim.

I'll look for it in the manual, but does anyone know offhand how tight to make these fan bolts? The fault is probably mine that it came off - I replaced my belts over a year ago and had taken the fan off then. I don't want them to come off of their own accord again... I know of no good way to tighten them to a specified torque - my torque wrench will not fit in the slot by the fan.

Dan

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dannyf
1984 Mercedes 300 SD 214 K miles. Runs on WVO ~ 22 mpg over 8 K on WVO
1997 VW Passat TDI 156 K miles. Uses biodiesel and diesel. ~ 41 mpg
1996 Mercury Villager gasser. ~ 20 mpg

You can definitely get these fan bolts from the dealer. I have even seen them at a couple of online stores. Using a long 10mm box/open-end wrench should allow you to get the bolts as tight as necessary. Remember to let the fan move with the direction of the wrench as you tighten the bolts. As you mentioned, there's not much room there.

According to specs, those bolts should be torqued to 50-70 inch pounds. That seems a little light. I would probably locktite them as well

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83 W123 240D
76 300D, "Lil Yellow Car"
1978 Cessna 172N 180 HP Mod

"If life ain't fun, I'm not interested"

The important things are those that you learn after you know it all.
Chip Foose

Build a better mousetrap and you will REALLY infuriate corporate america.

I strongly second the use of locktite. Judging by the spec, I would think that any old bolt would work. I'm sure I don't have to do the math for anyone here, but at roughly 5 foot pounds (5 pounds of pressure at one foot from the fastener) even something soft like an aluminum bolt would suffice for strength.

My suggestion: use your hardware store bolts, apply a good bead of locktite to them, and use your box end wrench to tighten them to "good 'n snugg" (that's a technical term used in many engineering manuals). Also, tighten them all as close as you can to equal.

The torque spec on these is not all that critical. There's no gasket, or mating concern, so "close enough" is, well close enough.

Just my 2 cents. After adjusting for inflation, arguably worth that.

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Jeff Pierce

Current Vehicles:
'92 Mercedes 190E/2.3 (247K miles/my daily driver)
'93 Volvo 940 Turbo Wagon (263K miles/a family truckster with spunk)
'99 Kawasaki Concours
Gravely 8120
Previous Vehicles:
'85 Jeep CJ-7 w/ Fisher plow (226K miles)'93 Volvo 940 Turbo Wagon
'53 Willys-Overland Pickup
'85 Honda 750F Interceptor
'93 Nissan Quest
'89 Toyota Camry Wagon
'89 Dodge Raider
'81 Honda CB 750F Super Sport
'88 Toyota Celica
'95 Toyota Tacoma
'74 Honda CB 550F

Thank you all.

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dannyf
1984 Mercedes 300 SD 214 K miles. Runs on WVO ~ 22 mpg over 8 K on WVO
1997 VW Passat TDI 156 K miles. Uses biodiesel and diesel. ~ 41 mpg
1996 Mercury Villager gasser. ~ 20 mpg

FWIW, bolts are NOT described by the size of the wrench used on them.

Rather, they're described by the diameter of the shaft, and typical German bolts requiring 10mm wrench have shaft diameter of 6mm and therefore are M6 bolts, i.e. 6mm bolts.

Now, if you were describing something from Japan, that same M6 bolt could require an 11mm wrench.

The same principle applies to inch-size bolts, too.

True 10mm bolts are almost lug bolt size. Yours, in fact, are 12mm, requiring 17mm wrench.

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Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles

The difficulty with these bolts in particular is NOT the type of bolt, but rather the ability to get them good and tight!