Check Valve or Death Rattle

[asafley]

I don't know how to call it. But here is the situation... when it is below freezing in the morning and I go to start up my '97 Explorer there is absolutely no rattling noise of any kind. The rattle comes back and doesn't go away when the engine is warmed up. Now on the warmer days, the rattle starts and continues throughout the day. I am leaning towards the good ole Death Rattle. Any thoughts?

 

[2000StreetRod]

Not typical

Your symptoms are not typical for the cam chain tensioners being worn. Usually the chain is noisiest at first start up before the oil flows to it. It usually is worse on cold mornings than on warm mornings.

Make sure that your throttle cable and cruise control cable are not vibrating.

 

[asafley]

I see

Thanks for the reply, StreetRod. I know what you mean. I forgot that the tensioner is tensioned by the oil pressure. It makes sense that the rattle would be louder when it is cold then warm. The throttle and cruise control cables don't look like they're vibrating. Is there a specific spot I should pay close attention to? Another thing that I should mention is that it doesn't rattle when I keep the engine between 2000 and 2500 rpms. Also when I brought the truck out of storage (Been in storage for 5 years with no routine start-ups), I took it to Jiffy Lube and had all the fluids drained. When the guy when to start up the truck with fresh oil it didn't make a sound for about 10 seconds then it started to rattle. The guy said sounds like a collapsed valve but I thought that only applied to OHV engines and not SOHC. Thanks in advance.

 

[2000StreetRod]

Get a stethoscope

If it rattles all the time except between 2,000 and 2,500 rpm it should be fairly easy to locate. The hard ones are those that only occur when driving down the highway. I use a hose to find air noises and a mechanic's stethoscope to find vibrations. You can get a stethoscope cheap at Harbor Freight Tools.

There are many hoses that can vibrate against something and cause a rattle. Today I found a rattle where my A/C drier is mounted. I have noticed several broken or absent fasteners/retainers throughout my engine compartment. That's one of the problems with buying a nine year old vehicle.