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98 Jeep Wrangler with 4.0 just hit 178000 miles

At 178000 miles do i need to check the timing and or change the timing chain?

What does the owner’s manual say?


It says ask the Cartalk guys cuz they know their stuff…or have I been
gone to long?..

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You don’t think you are asking question’s of the Car Talk show guys do you? This is a forum of many people .


Checking the timing never hurt anything, Now on my car I have done coolant, transmission, front and rear differential, transfer case, all well before 178k, just me, brake fluid with new brakes, power steering lines rusted out, so new PS fluid, have an o2 sensor in spare parts, but have not gotten there yet, of course plugs, gas filter a few times, air filter a few times, oil and filter quite a few times, what have you done so far?

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I concur. A failing timing chain will usually give a distinct audible warning long before it actually fails. Similar to very rapidly shaking a can of spray paint but much quieter. When I totaled my 1991 Jeep Cherokee at 150,000 miles the left front suspension, front differential housing, and transfer case housing were destroyed. The 4.0L inline 6 would (as always) still start and run like new. OP can check timing if they want but I’m convinced with scheduled maintenance performed the 4.0 should outlast the vehicle.

Keeping the routine maintenance up to date always makes sense. As part of that good idea to check the spark timing with a timing light , both at idle, and as the engine rpms increase. Spark timing should measure at the spec, and reasonably steady at warm idle, and advance smoothly to the top advance-spec with increasing rpms.

There have been some problems with Chrysler product timing chain guides & tensioners as I recall, for example

Whether any that applies to you, not sure. But it is worth a look-see. I believe there are some recalls on this vehicle involving the cats, seat belts, and the brake booster. There’s also customer interest bulletins and tsb’s, but nothing I can see about the timing chain.

There is no need to check the ignition timing on modern vehicles. The ignition timing on your Wrangler is controlled by the Powertrain Control Module based on the input from the crankshaft position sensor and other factors, these things either work or they don’t.

The camshaft position sensor is inside the distributor housing, do not tamper with the setting of the distributor housing or you need a professional scan tool to set the sync signal.

The 4.0 L jeep engine has nothing in common with the Hemi or 4 cylinder engine.

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Thank you!

I have never seen a timing chain failure on a 4.0 Jeep engine and I have owned 5, 3 with well over 200,000 miles and worked on several others with high mileage but all were automatics and of course your Wrangler could have a manual transmission which speeds chain wear. Also, the 4.0 has a snubber guide on the timing cover to reduce noise from chain slap and may increase chain life.

Chain replacement is a relatively simple and cheap job so it you’re obsessive in your maintenance have at it. If not listen for the rattle.

Im well aware…These ARE the cartalk guys…Ive been on this site for years

Im well aware. Ive been on this site for years