My husband and I purchased a brand new Rodeo last year. Well, from the get go, it seemed to race when started. 6,000 miles later, the engine seems to have a knocking sound from the lower end. It does go away after about a minute or so, but the engine doesn't sound like a 'new car' engine should. Anyone else experiencing this problem or have any insight as to what may be the cause?

Thanks a million,

Robin

The 3.2/3.5's tend to have a rythmic sewing machine clickedy-clickedy sound to them at idle. That's normal due to the valvetrain. A knock-knock does not sound normal. Hopefully it's a heatshield or exhaust hitting something?!? Has the engine ever been run low on oil? I've never heard of a rod-knock (bad connecting rod bearing) on these engines UNLESS the engine was run low on oil. Once it all it takes. There is no room for error on them. Our 2002 will sometimes race for a second or two on a cold start. If it idles right down it's okay. A racing or erratic idle could be a bad intake manifold gasket which is a free fix covered under your powertrain warranty (seals and gaskets).
G/luck
Joel

Hey Rodeo02,

Thanks for your expert opinion. I didn't realize that this particular engine is prone to not 'purr' so to speak. Very interesting. Guess that's why it's never had that new car sound!

It's never even been run low on oil; fact is, it's been babied and has gotten fresh oil every 2,500 miles so I suspect that it's more likely something that you mentioned in the latter part of your post.

We will keep an eye on it; the knock is pretty sporadic now and chances are when we bring it in it won't act up for the mechanics.

Thanks again for your time and advice.

Robin M.

Do the later year 2nd gen Rodeos have oil consumption issues like the earlier 2nd gen Rodeos? I mention this because monitoring oil level between oil changes in a early 2nd gen Rodeo is very important as it can in some cases burn a quart every 500 miles or so. I believe they corrected this sometime around the 2002 model, but can't remember which year exactly, AND, if that correction "completely" solved the problem for the newer models. either way, watch your oil level is always a good idea. Many a 6 cyl 3.2 litre have gone to the graveyard due to this a lack of oil (again an earlier 2nd gen issue I believe).

I think the 2002 Trooper had some redesigned PVC (screw in type) and bigger holes in the pistons.

So I would think the 3.2 got the same things.

The 3.2/3.5's tend to have a rythmic sewing machine clickedy-clickedy sound to them at idle. That's normal due to the valvetrain. A knock-knock does not sound normal. Hopefully it's a heatshield or exhaust hitting something?!? Has the engine ever been run low on oil? I've never heard of a rod-knock (bad connecting rod bearing) on these engines UNLESS the engine was run low on oil. Once it all it takes. There is no room for error on them. Our 2002 will sometimes race for a second or two on a cold start. If it idles right down it's okay. A racing or erratic idle could be a bad intake manifold gasket which is a free fix covered under your powertrain warranty (seals and gaskets).
G/luck
Joel

There was a thread on either PlanetIsuzoo or 4x4Wire about 2004 Rodeo engine noise. IIRC one source of the noise (on DI Rodeos) was the fuel injectors.

I think the 2002 Trooper had some redesigned PVC (screw in type) and bigger holes in the pistons.

So I would think the 3.2 got the same things.

Yep. The 2002 rodeo, 2002 trooper and 2003 rodeo's in my family all have a thread-in PCV valve. The word on the streets is this is the 'updated' piston (drain-back hole) engine. Thing is- the only one that doesn't use much, if any oil on high speed hywy runs is the 2002 rodeo. I've pulled the dipstick on my SIL's 2003 to find it nearly 3qts low :uhoh: :disappoin .
G/luck
Joel