i started my 86 740 gle and i idled it for around 30 min and i put hand on the air box and it was extremely hot is the air box thermostat bad and if it is could it be causing poor mileage? and also when the car is running i am getting a clicking sound its extrememly fast not extremely loud but still lud enough to hear over a running engine
Hot airbox is bad, that could certainly be the problem, or at least part of it, and it will kill the air mass meter fairly quickly. For now disconnect the corrugated aluminum hose that goes from it to the exhaust manifold, if you live in a mild climate you can throw that part away and wedge the airbox thermostat so it always sucks in outside air.
The clicking you hear is probably the valves closing, it's normal unless it's loud or irregular.
As James said, the air box should not be hot. In normal operating tmperatures just shut off the motor and open the box. You will see a flapper in it that is controlled byt a thermostatic device. The flapper should be covering the hot air intake hole.
And again, it can ruin the air mass meter (expensive part!). It can also be a factor in lowering teh gas mileage as well... like he said.
If there is a smog check program in your area it could be illegal to defeat or disconnect any portion of the air intake system as it is part of the pollution cntrols designed into the car. Just a heads up...
Also, if a car is equipped with a catalytic convertor it should not be allowed to sit, idling for that long without some forced air over it (like a ventilation fan) becasue it can create a fire hazard.
__ __ Randy & \ \/ /alerie's \__/olvos '90 245 Estate - '93 965 Estate "Shelby" & "Kate"
i have already removed the hose and it still does it
So could this have somehting to do with my 14mpg and how owuld i know?
You removed the silver, metal'ish' corrugated hose, right? The one that goes to the heat riser on teh exhaust manifold?
We are NOT talking about the black, plastic hose that goes to the Air mass Meter and then to the throttle body..
If you removed the correct hose then when you drive the car that box should be at about he same temp as the outside air. if you are sitting at idle it can get warm from the ambient heat in the engine compartment.
__ __ Randy & \ \/ /alerie's \__/olvos '90 245 Estate - '93 965 Estate "Shelby" & "Kate"
Se the other response in this thread, but basically, the hot air is less dense and expands less when the fuel is ignited in the combustion chamber. it also will throw off the readings that the air mass meter gets which will mess up the enmtire fuel metering system.
And as mentioned before, unless you are getting accurate odometer readings and doing accurate math when figuring teh mileage, AND you have a locking gas cap, then there is really no way to tell what is going on.
My advice at this point would be to seek the help of a knowledgeable mechanic or a prefessional. Continuing to drive the car when it getting such poor mileage will ruin the rings, damage the AMM, and possibly necessitate a new catalytic convetor. If you continue to run the car at idle for 30 minutes at a time it will most likely eventually catch fire.
I don't what to sound discouraging, but to save $10-200 in mechanics time you are risking that much in the air mass meter alone, and that is the price for a cheap rebuilt unit!
__ __ Randy & \ \/ /alerie's \__/olvos '90 245 Estate - '93 965 Estate "Shelby" & "Kate"
Unless your in a very cold area the pipe from the exhaust to the air intake might just fall off or disconnect so you dont cook the air mass meter .My wifes did ,mine was not fitted from the factory .My inlet was blocked from the factory so I removed the bung and piped in cool air from beside the radiator .Did the same with my wifes and sons cars .
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