Question: i recently had an AMM go bad, and it was replaced less than 1 yr ago (used, though). someone said that the 'airbox thermo' might be bad- stuck in the hot position and this was prematurely frying the AMM. is there a thermo in the airbox on my '89 240? i asked my mech, and he said no. who's right here? thanks in advance for any help.

I have an airbox thermostat on my 1991. I don't know what model year they went into the airbox. I replaced mine. The old thermostat was stuck. There is a debate on whether or not the heated air coming back through the airbox is hot enough to toast the AMM. I don't know but replaced mine, anyway, just to be safe. The thermostats are 7-10 dollars. The airbox doesn't want to come out easily. You must pull the airbox out to complete this. To find out if you have one, remove your air filter and with a mirror and strong flashlight look to see if there is a flapper mechanism that opens and shuts the air intake into the box from the outside air. If so then you probably have a thermostat that controls this action.

I did like Greg yanked the hose, heat sheild and tossed them, I have seen no difference in cold starts... of course 45 degrees here is cold...
Bret
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rust free in west Texas

I wish 45 was our low here. I'm in DE, and it can get cold and damp, that's for sure. I guess the best bet would be to replace the thermo, as it's maybe $15-16 in IPD, i think.

Hello:

I think your mechanic is wrong on this, unless someone else has already pulled it out...

I was worried about the same thing with my '92 245. The previous owner had paid for a new AMM, but there was no evidence in the records of an air box thermostat replacement. I opened up the airbox and found even though the car was still a little warm from a recent drive the flapper was fully in the hot air intake mode. I removed the thermostat, drilled a very fine hole through the flapper and the airbox body and wired it shut with a twist tie so it gets cool air all the time. I will replace the thermostat next time I place an order for parts, but in the meantime I will breathe a little easier knowing that I won't be cooking a $300 AMM...

Good luck!

Herb Goltz, London, Ontario, Canada '92 245 w/96K mi

Thanks for the info! I thought the mech was wrong. I was checking out a page in the IPD catalog, and thought i'd look into it. I have a new AMM, but won't put it in until i straighten out the thermo situation. is it tough to get in that airbox? And, is it worth buying a new part, or will it be ok w/o?

I just changed my AMM, and just ripped out the thermostat and the pre-heat hose. While I was at it I ripped out the heat shield on the exhaust manifold... all that is not required. A simpler vehicle is more reliable.

Who knows, if the therm is not stuck now, it might be stuck in 6 months and cook your AMM. That is usually how they go.

Greg

Remove air filter and look. Unless someone removed it i think you will find one.
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David Hunter