Most times when I start my truck, as it idles and warms up I hear/feel a thump and I'm not sure what it is. Any ideas?

 

You just start it, nothing else?

 

Been asked before....but it's really not a "searchable" thing.

If you ask around, there are a lot of ranger owners that have that noise. I'm one of them. Been said to be a million different things from heater doors opening or closing, to tranny noise. All in all.....it's nothing to worry about.....as long as it's only a once in a blue moon thing. If it's doing that for EVERY start, there's something not good.

 

Its normal. Mine does it every time. Its your condenser or what ever the hell its called. It seems to do it worse in the winter

 

My girlfriends parents expedition does it alot....


Then i got my truck and it did it, so it must be a FORD thing.... personally i always thought it was a heat shield or a piece of metal popping after warming up / cooling off

Rocky

 

its the little gerbils inside your engine falling out of bed.

 

Well it sounds like a common thing so no more worries, thanks guys... haha gerbils

 

This sounds like A/C slugging and is very common on Fords and some other brands. A "slug" of condensed liquid refrigerant collects at a low spot in the A/C system when the engine is off and is drawn through the compressor when the compressor clutch engages. A/C compressors are designed to compress gaseous refrigerant and they don't like liquids.

The compressor clutch is engaged shortly after the engine starts if the HVAC selector is in an A/C-enabled mode. Slugging can also occur after the engine has been running awhile when the mode selector is moved from a non-A/C mode to an A/C mode.

Keep in mind that the A/C compressor is enabled in several modes besides A/C and Max A/C, so this can happen even if one of the positions labeled "A/C" has not been selected.

The noise usually happens only once per trip. The sound can be mild or very harsh but, unfortunately, there is no fix for it.

 

yeah mine does this too and sometimes i can feel it in the floorboard

 

Count me in the "does it once every couple of starts" column. More so if I leave it sit for a week or more... So Bob's explanation makes sense (like I would have expected anything less!).

 

u can bypass the thump by doing the A/C mod and then use the rest of your HVAC controls.

 

Mine does it too when the a/c compressor runs....I just usually have it on the defrost setting in the winter and it does it alot more.

 

that is usually where i leave mine too, but with my efan and wanting to save mpg and have more power i have learned only to throw it in defrost for jsut a short period of time then back to vent or floor

 

mine made the thumping sound the other day. my controls were in the "defrost" mode. like others, mine does it more in colder weather.

 

Mine does the same thing. I normally run mine in defrost most of the time so I guess that would explain why it does it every cold morning. I always wondered about it. Thanks guys.