Engine tap/rattle. Cannot find an answer.

[Leo_the_explorer]

Hi!

I'm new here so apologies if this has already been answered. However I've searched all through the forums trying for find an answer but no one seems to have had the problem I have.

It's a 2000 Explorer 4.0 SOHC.

I bought it a few months ago with 68k (now 72k) on the clock, got it cheap! It had a horrible idle so ended up changing IAC, intake manifold gaskets and someone had actually snapped a bolt under the IAC so I had to drill it and seal it. Anyway the leak is sorted and it runs perfect.

However it has, what appears to be, a rattle/tapping noise. I'd say it's the primary chain making rattle. This ONLY happens when the car is super hot and its just been fired up. So when its cold, no noise, when driving, no noise, when sitting idle for 20 mins hot, no noise. It only happens when I've been driving it, parked up for 5, 10, 30 mins. It's loud enough for people to mistake it to a diesel. But it goes away as soon as I drive it for few mins, and its only really loud at i'd say 700-1500rpm.

I've changed the front and rear tensioner, done plugs and ignition leads, I've changed the oil and filter twice in the last 5k miles with mobil 5w30 just to see how it comes out. Sometimes in the oil I've noticed a bit of glitter but nothing that would make me lose sleep. I cannot seem to find what the problem is, it's driving me mad enough to want to get rid of it. I didn't pay a lot for it so pulling the motor would not really be very cost efficient. I absolutely love it, it drives smooth and purrs like a kitten most of the time. It's only on warm starts that it drives me mad!

Shall i just mask it with some oil treatment and put up with it? or should i be concerned? Could i be totally wrong and it's not the chain? It doesn't seem to get worse at all.

Thank you!
Sami

 

[Leo_the_explorer]

And to add, the noise is only audible at 700-1500rpm. It can't be heard at all at any other rpm.

 

[shucker1]

Sorry to burst your balloon but from what I have seen on this forum about the 4.0, your timing chain guides are gone.

The plastic liner has stripped off and the chain is now hitting the metal backing. That's where the glitter you described is coming from.

Better to pull the engine now and do the guides than let the chain fail completely and have the pistons smack all of the valves.

 

[Leo_the_explorer]

Well this is what I suspected. How comes it isn’t making noise when it’s cold or under any other circumstances?

How much of a job is it to change the primary chain and guides?

 

[shucker1]

As the engine warns up the chain gets more slack.

Plus as the oil warms up you loose a little viscosity of the oil and the chain tensioner pressure is slightly less.

Driving at RPM there is probably a fair amount of load on the chain keeping it tight.

There is a member called:

@imp

Who is usually really good with those engines.

I'll try and find you something else on the subject.

 

[Leo_the_explorer]

As the engine warns up the chain gets more slack.

Plus as the oil warms up you loose a little viscosity of the oil and the chain tensioner pressure is slightly less.

Driving at RPM there is probably a fair amount of load on the chain keeping it tight.

There is a member called:

@imp

Who is usually really good with those engines.

I'll try and find you something else on the subject.

Thank you! I’ve read tons and tons about these engines. They all seem to suffer with this sooner or later.

Initially I thought that maybe it just has an inadequate amount of oil pressure when first starting warm but I think you may be right here.

And it’s only in the last oil change I saw a bit of glitter in the oil. I didn’t know that that guide had a plastic over it so to speak. But what you’ve said does make sense. Is the primary chain tensioners ass of a job? Can it be done without pulling the engine?

 

[shucker1]

I can't say for sure.

There were (2) types of 4.0

I've read that you can only get to the front tensioner without pulling the engine.

To get at the back one the engine has to come out.

 

[shucker1]

Read this:

Front timing chain replacement without removing engine

 

[shucker1]

Or this:

SOHC V6 Timing Chain Related PNs

@2000StreetRod did a really good write up on full replacement a while back.

@koda2000

or

@swshawaii

are others that come to mind.

Research post under those names.

I have the 5.0 Liter (Got it Brand New so I could pull my boat) so I'm no subject matter expert.

Only trying to help you out.

 

[shucker1]

Just noticed that you are in the UK.

That's really neat....

Keep us posted.

P.S. If you happen to stumble across a front hood strip for a 1971 MGB GT (GRAB IT AND RUN!!!!)

Those things are like gold in the MG World!

 

[Leo_the_explorer]

Just noticed that you are in the UK.

That's really neat....

Keep us posted.

P.S. If you happen to stumble across a front hood strip for a 1971 MGB GT (GRAB IT AND RUN!!!!)

Those things are like gold in the MG World!

I’ll keep you posted on the mg hood strip!! Mg’s generally aren’t considered to be very good over here so a lot of them just go to scrap!

And thanks a lot. I’ll read their posts. I’m gonna talk to a mate of mine about doing the work, and to see whether it will be worth doing or just buying another engine/Explorer. Explorers over here only came as the 4.0, we didn’t even get the sport.

How you finding the 5.0? I had a Cadillac Seville sts with the 4.7 32v North Star v8 and it was way too thirsty. Sadly our fuel prices are less than affordable for a v8.

 

[shucker1]

MG is for sure a labor of love...

Lucas wiring is an adventure.

My first car in college.

Only MG made with "Auto Pilot". It could find its way home and park itself just fine from ANY bar room!

As for the V-8 it's a very durable engine. Yes, kinda stiff on fuel but...

Ford started production of the 5.0 Liter 302 in what 1967? The design must have been a good one.

 

[Leo_the_explorer]

MG is for sure a labor of love...

Lucas wiring is an adventure.

My first car in college.

Only MG made with "Auto Pilot". It could find its way home and park itself just fine from ANY bar room!

As for the V-8 it's a very durable engine. Yes, kinda stiff on fuel but...

Ford started production of the 5.0 Liter 302 in what 1967? The design must have been a good one.

Yeah I’m sure ford knows how to build a v8.

Sadly the 4.0 SOHC wasn’t an original design, it was just amended to fit the requirements, thus it was a bit of a bad design. Very bad design. It’s durable and good once it’s all sorted. But now that it’s 17 years old, I wonder whether it’d be worth repairing..

 

[shucker1]

You never know the condition of a wrecking yard or used engine.

A reman would cost just about as much as rebuilding yours.

Pulling it out and putting it back in is indeed labor intensive.

Is the body in good shape? That's going to be your limiting factor.

Get both the engine and transmission redone and your good for another 160 Kilometers.

 

[Leo_the_explorer]

You never know the condition of a wrecking yard or used engine.

A reman would cost just about as much as rebuilding yours.

Pulling it out and putting it back in is indeed labor intensive.

Is the body in good shape? That's going to be your limiting factor.

Get both the engine and transmission redone and your good for another 160 Kilometers.

Well this is the thing. It’s done 72k miles. Body is totally rust free. Interior is near perfect. I paid £800 for it and pulling the engine and rebuilding it will cost about double that. I’m really at a loss about what to do.

 

[imp]

I can't say for sure.

There were (2) types of 4.0

I've read that you can only get to the front tensioner without pulling the engine.

To get at the back one the engine has to come out.

@shucker1
The R.H. tensioner has been done under the vehicle with transmission removed and set aside, I've read. Concerned for a long time now, at 160K, chains still nice and quiet. Concerned about transmission, too, the yesterday, like driving on a washboard when 5th. gear engages. Will try adjusting OD band first........imp