Cold Start Rattle

[Gt In Detroit]

I just purchased a 1999 Sohc 4*4 Explorer. Upon morning startup i have a rattle which i have determined to be right at the back lower part of the motor, between the oil pan and trans or in the bell housing, while i was under the truck i had my wife start it when cold and that is where the sound is coming from, would the tsb that is talked in a bunch if posts here make the noise there, it seems a timing chain noise would be at the front to the engine. once i drive maybe less than a mile it will not make the noise for the rest of the day, i do alot of startups during the day, i do field service, and it will only do it in the morning for if it sits for maybe over 3 hours, i havent had it long enough to see if it has a hard start on cold mornings its only been 75 plus since i have had it.


tks
jim

 

[ExplorerDMB]

The timing chains on SOHC are in the back. It's kind of hard to tell exactly without hearing the noise myself, but maybe someone else who has heard the sound on their Explorer will point you in the next direction. Just look for any type of shields and such that may be vibrating, hitting, etc.

-Drew

 

[wildthings]

Did you ever figure out where your noise was coming from?
I have a 1999 SOHC with 120,000 miles. I hear a noise that may be similar. I Ususally hear it if the vehicle has been sitting for several hours, but not everytime. Very unpredictable. Only lasts for less than a second. One person who owed a Dodge Caravan with the same sounding rattle was told the torque converter was bad... replaced that and transmission and cured the rattle (in that case). I also get a loud clunk, like the feeling when the auto 4X4 kicks in, but much louder. It has done this maybe 3 times in the last month. Again not enough for a local mechanic to diagnos the problem.

 

[Homerexplorer]

I believe it uses a hydraulic tensioner and if it leaks down it will rattle until the pressure builds up. I usually notice a similar noise after an oil change.

 

[wildthings]

I believe it uses a hydraulic tensioner and if it leaks down it will rattle until the pressure builds up. I usually notice a similar noise after an oil change.

Does this mean ... replace the torque converter?

 

[Homerexplorer]

No. I was referring to the engine timing system - I think the chain tensioner is hydraulic and will allow slack in the chain if it leaks down. The condition will be present until the pressure builds up enough to take up the slack. That may be why you only hear it after it sits for extended periods.

 

[floydr007]

I have this exact same problem, and have had it since i got my explorer 5k miles ago. It only happens upon startup, and goes away immediately. It hasnt gotten any worse, but im still kinda worried knowing the timing chain tensioner issues on our cars.