my 4l has developed the timing chain rattle.it has 136k, due to the $2000-3000 cost of repair I'm running it until it drops. How long do you think it will run?

 

These use hydraulic tensioners so run a 40w oil, like 10w-40, see if it helps.

There is also a tensioner you can change, passenger side rear of engine, that has helped some people to quiet down that rear chain.

The chain guides(cassettes) on the '97 to '04 4.0l SOHC engine were a bad design, the newer design doesn't have this issue, and timing chain kits come with the new design.

The main expense is that the engine must be pulled out to get to the rear chains, the parts and labor to do the timing chain replacement isn't all that much.

The 4.0l SOHC engine is an interference engine(4.0l OHV wasn't) so if timing chain should slip enough or break then you will have bent valves and possibly unusable pistons or connecting rods.

With a used engine you have to remove the old engine and then install the used engine.
And used engine is a gamble, warranty does NOT cover removal and reinstall, only getting you a similar mile replacement engine.

So IMO, weight the cost of the timing chain kit and labor to install that kit if engine is already out of the vehicle.
Against the cost of a used engine delivered to your location.

That's the comparison to use

The cost of removal and replacement of an engine is the same for either option.


To answer your question, "how long will it last?"
There is no answer, lol, unless someone has a working crystal ball.
If you are fortunate the chain will slip just a little so engine starts to miss and lose power, but doesn't damage valves or pistons.
If chain slips alot or breaks then a used engine will be needed, rebuild cost could just be too much.

 

Mine started doing that last summer, only when hot and under strain (uphill loaded) I switched to 10-40 it has stopped, but from what I have read it only quiets it, I am hoping I can gather the time or funds to get the tensioners and chain replaced before detonation, 2004 178k, 500+ miles a week

 

Hi Devin,thank you for your reply. Did you use synthetic 10W40 or regular?

 

I suspect this is not timing chain rattle. Normally the timing chain rattle happens at a certain rpm and strain on the engine as no effect on it.

It sounds like you are getting spark detonation. That is more prominent when the engine is under load especially when it is hot. If you say the higher weight oil stopped the detonation, you may be getting a small amount of oil into the combustion chamber. Oil can lower octane of the fuel/air mixture and make it more susceptible to detonation. Using higher viscosity oil can reduce the amount of oil getting into the combustion chamber.

To the OP, I have heard of switching to synthetic oil as a way to reduce or eliminate timing chain rattle but I can't verify that. I do use synthetic oil and have over 194K miles on my 4.0 SOHC engine with no problems so far.

 

Always synthetic

 

Hmmm, interesting , it was typically at 2300-2500 rpms, but again only under strain and with temperatures over 85

 

Well that is the range of rattle for the timing chain but strain on the engine should not change anything on the timing chain or the cassettes. I have seen stranger things than that happen so you may be correct.

 

I have 250,000 miles on my 01 Edge 4X4, 4.0L 5 spd Automatic, 4.10 posi (R-6). I've used Motorcraft Synthetic Blend 5w - 20w, in it, since I bought in in 07. it had 92,000 miles on it when I got it. The engine has started making this rattle @ about 2100 -2500 rpms. I think i'll try the 10w-40w, and see if helps
Thanks for the information!! :)