Engine Rattle

[princessxlt]

I have a 99 Sport with a 4.0 sohc. I had a CEL come on. After inspecting the engine for problems, I found I had been visited by a fat with a taste for the coolant temp sensor wires. Long story short, the intake had to come off to repair the wires. Fixed wires, put on new gaskets on the intake, all nuts, bolts, screws installed and accounted for. Start the motor up, have a very loud engine rattle, can't tell if it is top, bottom, front, rear, rt side lt side. Replaced spark plugs, broken ceramic, and still has the noise. All gauges read fine, not running hot, no low oil pressure. Help! I don't know where to start. Any suggestions would be greatly appreciated. Also, the rattle increases as the rpm's increase.:frustrate

 

[dogfriend]

Maybe bad timing chain and/or timing chain guides. Will cause a rattle that increases with increasing engine speed. The SOHC engine is somewhat infamous for that problem - there was a field campaign (00M12) to fix the early models of that engine.

 

[princessxlt]

Would it happen all of the sudden? It didn't do this before the rat, just after the wires were repaired and intake gaskets replaced.

 

[dogfriend]

No, normally it wouldn't happen as a result of changing the intake gaskets.

If you're positive the noise wasn't there before, then double check the stuff that you just put back together.

If you're having trouble locating the noise, you can use a mechanics' stethoscope to help locate the noise. The cheap alternative is to get a section of rubber hose, hold one end to your ear, and the other end to the parts that you think might be making the noise. Watch out for moving parts.

 

[princessxlt]

Already did that. Couldn't tell where it was coming from. Also, redid the intake, used mirrors and a clean mechanic's magnet in the runners and still nothing. Had a mechanic listen to it (my husband, 30 years plus experience) and he couldn't tell. It sounded like it was everywhere at once.

 

[dogfriend]

Well, if he is standing right there in front of it and he can't tell where its coming from, I'm not going to be able to help. :

The SOHC engines seem to be more likely to have timing chain problems, so you may want to investigate that.

 

[S1L1K0N]

I have a 99 Sport with a 4.0 sohc. I had a CEL come on. After inspecting the engine for problems, I found I had been visited by a fat with a taste for the coolant temp sensor wires. Long story short, the intake had to come off to repair the wires. Fixed wires, put on new gaskets on the intake, all nuts, bolts, screws installed and accounted for. Start the motor up, have a very loud engine rattle, can't tell if it is top, bottom, front, rear, rt side lt side. Replaced spark plugs, broken ceramic, and still has the noise. All gauges read fine, not running hot, no low oil pressure. Help! I don't know where to start. Any suggestions would be greatly appreciated. Also, the rattle increases as the rpm's increase.:frustrate

Have you replaced/upgraded any of the timing chain components? This is a really common problem with these engines (the primary timing chain tensioner, the camshaft cassettes as well as the camshaft tensioners).

 

[princessxlt]

No, I haven't done anything to the timing chain. Like I said before, it wasn't there before the rat, and there on start up after "rat repair" was completed.

 

[Benji-Man]

What year SOHC engines were affected by timing chain tensioner issues, I was under the impression it was the Early 2nd Generations

 

[dogfriend]

http://www.explorerforum.com/forums/showpost.php?p=1770231&postcount=18

 

[princessxlt]

That's sounds like what mine is doing, but in the video, it was just in idle. Mine increased with the rpm's. If this is the problem with mine, would it happen all at once? Or would gradually get louder with time. If this is the problem, how do I fix it? Is it like the old 302's from the 80's when they were carbs, not EFI?

 

[dogfriend]

How many miles on your engine? The one in the video had 251k.

 

[princessxlt]

172,500 miles with no major problems. The only thing I've done is the right hub assembly.

 

[dogfriend]

Well, you have enough miles that normal wear of the timing chain components could be the issue.

Or the tensioner is broken or the oil supply to the tensioner is blocked.

I'm trying to think of how it could be linked to the work you did, but I don't see any obvious connection.

I would also like to come up with a cheaper, easier to fix problem, but can't think of any that would cause that type of rattle.