As usual, I turn here for advice. You people are a valuable resource. I may need to replace a thermostat on an '89 300E. The only book I have shows only a four-cylinder engine. Is the thermostat on the top heater hose, just forward of the air cleaner? This looks like a very simple job. Simply remove and replace after draining the coolant. Please tell me if this is correct.
On another issue, my cruise control has never worked since I bought the car used. At least the control lever has gone south, and I was about to replace it, until reading your advice to someone with another MB model. Does replacement of the lever on my car require removal of the steering wheel as well? I do appreciate having your Shop Forum as a place to learn from other people's experiences, Thank-you.

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The thermostat is located on top of the waterpump under the thermostat housing (usually metal) If it has the black plastic housing you should replace it with the metal style when you do the thermostat, because it will definently break off at some time leaving you stranded! There are just 3 10mm size bolts that hold on the housing to access the thermostat. If you remove you radiator cap (when cold) squeeze the upper raiator hose and while holding pressure on hose, put cap back on to create negative pressure on coolant system. This way you will have very little coolant loss. Install new thermostat and top off coolant to proper level. Thats it!

Jim LaPlant
Factory Trained Mercedes-Benz Technician

Almost forgot your other question. The airbag, steering wheel, combination switch (turn signal lever), and left side under dash panel to install new cruise control lever. Is the lever broken? If not, check you fuses. The cruise is on the same fuse as your brake lights. So if your brake lights work (which they probably do) then more and likely it is a faulty cruise control amplifier, also under left side dash. I would have the system tested before buying the amplifier, because you wont be able to return electrical parts after you tried them out! Hope this helps you out!

Jim LaPlant
Factory Trained Mercedes-Benz Technician

Also,remember that you might need to bleed air. If you replace the thermoplastic housing with the newer metal one, there is a bleed screw on top of the housing. They put it there for a reason. Start it up, warm it up to op temp. Crack the screw, if all you get is coolant, no problem. If you get air or bubbles, let it all out until you get a slow steady dribble of coolant. Retighten and top up coolant.

[This message has been edited by jeffsr (edited 01-17-2000).]

Jason,

A thermostat's supremely cheap insurance against such a failure. If yours is original, I'd replace it for sure and do the plastic housing as well. If your radiator cap is the same age, maybe do that too. Small dollars to avoid big headaches! :D

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Best regards, Michael
'92 500E
'88 300TE

Don't do the waterpump unless you are having a leak or circulation problems. This can be a tedious job, so if it ain't broke, don't fix it... :D :D :D

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Jeff L
1987 300e
1989 300e
1987 BMW 325

I agree with Jeff/

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Benzmac:
Donnie Drummonds
1992 500E (very soon I hope :)
1981 280GE SWB
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

If you buy a new cap, don't forget to ask for the bleeder screw as well. Here in the Netherlands they are sold seperately.