I'm posting here to see if anyone has any insight to my problem. I have a 2005 Grand Caravan, 59K miles on the 3.8. I had a 3/36K warranty so I'm well past that. Just last week it reached it's mileage for an oil change and it began to make what sounded like a loud lifter tick (above the "normal" lifter ticking it's been making for years). The tick is louder when the engine warms up and is loudest under acceleration.
After much searching on the internet and finding many others with similar problems, I tore into the top end and pulled off the heads. I found one pushrod with abnormal wear at the rocker seat. So I replaced all the lifters, pushrods and the bad rocker and put back together. The lifter noise is LOUDER now, although the engine purrs like new. I was really disappointed.
I checked the oil pressure at the sending unit and got as-expected pressure for all conditions, looked great. The oil is still nice and clear after a week of driving. The tick seemed to be coming from the front head using a stethescope. I pulled the cover and checked oiling when running. Lots of oil from shaft over rockers but the pushrods look bone dry. I can't put a feeler gauge under any of the rockers/stems. When the cover is off the noise seems deeper than the heads, like the lifters are skipping on the camshaft lobes due to lack of oil in the lifter plungers.
Anyone have any suggestions? Any help is greatly appreciated! I'd like to try and fix this problem before everything seizes up and the engine is shot.
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Welcome to DF
We have had found that a piston would cause the same type of noise when engine gets warm. How is the noise when the engine is cold?
Thank you for your reply! The noise is pretty quiet when cold and gets loud when warm. It is loudest under acceleration and at idle. It quiets down at cruise speeds.
When I pulled the heads off I didn't see any abnormal cylinder wear, except for a few pistons that had more carbon build up than I'd expect. It was enough that chunks were falling off the head chambers and falling onto the piston when I cracked it open. One cylinder seemed to be mis-firing, it was a dark and a little oily on the valves. I attributed that to a bad plug even though I had changed the plugs about 30K ago with Champion Double Platnum the plugs looked worn and gap increased to about .065.
The problem that we found in the shop was a number 4 piston rod bearing was causing the noise, but only after the engine was warm. We also remove the heads and replace the lifters too. And the noise was still there. After removing the rod bearing caps, one at a time then we found the cause of the noise. i ended up replacing the crankshaft all one piston and all rod and main bearing. I not saying that is whats wrong with your noise, but its something other than I don't know.
The worn pushrod was on cylinder #4 exhaust...Hmmm...
Can I replace the rod/main bearings from below with the engine installed? I'm hoping I can at least get to the rod bearings and see if this is the issue.
I found a rebuilt engine available for 1,845 (long block).
If I had to take this engine out I'd just assume rebuilt it myself by taking it down to a local engine shop.
Any reason I couldn't do that? Dealer service tech says they can't replace cam bearings and have to put in a new short block if they've failed. Seems like it should be a standard cam bearing replacement with the special tool at an engine shop?
If I took your route and had to replace a crank, piston and rod, do you think I'd be better off just getting a long block after buying that many piece parts?
I use to replace camshaft bearings all the time. You do need a cam bearing remove/ install tools to do that. Call your local machine shop and ask them if they can to the cam bearing. If they can, have a new camshaft for them too, because they will make sure it doesn't bind. And if you have the know how to heads, youcan rebuild an engine. Because you have the forum to help you when you need them.
I tore into the bottom end yesterday, took off oil pan and found flakes of bearing in the bottom of the pan. Removed rod caps and found 3 of 6 galled up and destroyed, but about 1/2 of bearing surface intact. Crank seems okay. Main bearings okay. I plan to polish crank to remove some stuck-on bearing material and replace bearings with same size.
Anyone know a way to tell if the cam bearings are galled up with the cam installed still?
Okay, I replaced the rod bearings and the van runs very smoothly now. Hopefully the cam bearings are okay. Seems like a bad rod bearing causes what sounds like a lifter tick in the upper end. Go figgure.