Engine Mechanical problem
2002 Dodge Caravan 6 cyl Two Wheel Drive Automatic 77000 miles
I have an '02 Dodge Grand Caravan 3.3L V6 with 77k miles on it. Bought it with 58k. Have only used synthetic oil since then & it has always run smoothly. Recently I went a bit long between changes (maybe 2k mi. Overdue) & it started to tick slightly. Now that I have changed the oil, it is ticking worse. Sounds like it's coming from the back of the engine (right bank?) And I can hear it better from underneath. I used a stethoscope (long piece of flexible tubing) to try locating the sound and can hear it loudest when the tube is over a freeze plug (but the water pump sounds fine). I put in oil additive (the thick stuff used to reduce smoking), but it's made no difference. It has never smoked and doesn't now, but I thought it might help with the tick. Oil level is correct on the dipstick. I have a P0420 code. Could it be a bad rocker or lifter and be misfiring and causing the sensor to pick it up in the exhaust? The tick is easy to hear at idle but can't be heard at high RPMs. It's practically impossible to hear from inside the vehicle. Power & mileage still seem OK.
Hi: Good question. I would have a Chrysler mechanic listen to it. The 3.3L had a problem with cracked rocker towers. (I had one myself) Where the rocker bolts to the head is where the problem exists. It cracks and the only way to repair it is to replace the head.
Let me know what you find out. I would like to know if I'm correct on this one.
October, 27, 2008 AT 10:45 PM
Hey, thanks for the reply. I spent more time under the hood poking around with the stethescope, and I think I've located it in the a/c compressor. When I place the tube over the engine case or valve covers the sound is very faint. However, when I move the tube over the compressor, the sound intensifies. It has a rhythm like helicopter blades chopping the air (very fast) but the tone sounds most like the knock caused by low octane gas (only it doesn't have to be under load to hear it). The sound intensity varies depending on where on the compressor case I place the tube.
I assume there is no way to service the compressor, but does anyone know of a way to isolate it to confirm if it is indeed the problem? Can I run the engine for a short time with the belt off or not? It doesn't make a difference whether the a/c is on or off. I guess there are probably bearings that could be going bad?
I'm sure that wouldn't affect the cat converter or cause the P0240 code. So, I may have an entirely different problem where that's concerned. I replaced both O2 sensors last year.
October, 28, 2008 AT 6:27 AM
Hi: If you try it without the belt make if a very limited time. The waterpump will not be cooling the engine, thus it will heat up very fast.
Let me know what you find.
December, 15, 2008 AT 3:00 PM
Well. I have been driving my Caravan continuously since first noticing the ticking sound. I just made sure to keep a close eye on fluid levels. About two week ago, the ticking stopped completely, and that made me think it must have been a lifter. I must have been wrong about the A/C.
Last week, I made a long, cross-country trip to the Smokie Mountains. We drove about 500 miles or so to get there and the engine still sounded fine when we arrived. We drove all throgh the mountain region for about 4 days with no ticking at all.
Then about half way home, I noticed the tick starting again when I pulled in for gas. It was not loud enough to hear while on the interstate though. I know the engine was under more stress than usual. I ran an average speed of about 75mph most of the way. When I finally pulled into my driveway, the ticking noise was loud and clear again.
Probably a lifter, huh? Is there any way to manually pump them up or check them without any major disassembly?
December, 15, 2008 AT 4:20 PM
Hi: There really isn't a way to pump it up. Regardless if you did, it would end up doing the same thing. If it continues to get worse, you may need to replace it. Also, if you ever get back into the engine, check the rocker towers and make sure nothing is cracked.
January, 6, 2009 AT 2:35 PM
Thanks for all the input. Turns out it was the water pump. I took it to my local Dodge dealership and paid them $35 to diagnose it. The mechanic put it on the rack, removed the belt and cranked it up. No ticking noise. He isolated it to the water pump and then quoted me $380 to replace it.
I bought a brand new pump from the local parts store for $38 and had it installed in just a little more than two hours.
On removal of the old pump, I found the plastic impeller was broken into two pieces almost right down the middle. There was just enough of the center left to hold one half of the impeller on the shaft. The other half had lodged in a recess in the wall of the pump housing. The noise was coming from the connected half hitting the disconnected piece.
Apparently, it had enough of the impeller left to keep pumping and would stop making the clicking noise when the broken off half would move just enough to not get hit as the other half rotated.
Funy thing was, I had to use a large crow bar to pry the engine away from a main body support about 1/4 inch to gain enough clearance for the new pump to slide into place. Evidently, there is a bit of flexibility in the mounts. Thought others might like to know that in case they run into the same dilemma.