Cracked flex plates generally change in tone and volume when in drive (loaded) compared to park.
First, remove the drive belt and start the engine to see if the noise changes before going after the flex plate.
1 Like
Thank you Nevada_545ā¦I did remove the serpentine belt several months ago and had no change in the noise.
An update to this storyā¦
I checked the plugs and reinstalled themā¦they were all tight.
I used an auto stethoscope and was unable to locate the noise.
I took the van to a mechanic and he ended up taking the flex plate to converter bolts out, pushed the converter back, and started the van and the tick remained. He also pulled the wires on each spark plug one at a time to determine if any of these caused a change in the sound and it did not. He talked about issues with the piston skirt, but indicated that these usually produced noises that go away when the engine is warm. Also added the same comment about lifters. He said at this point, the only thing he knew to do was to start taking it apartā¦but added that it may be hard to find a problem since it only exhibits itself when it is hot. He also added that we could just continue to drive it until it quits.
1 Like
OKā¦an update to this story. Around mid-April, the check engine light appears. I visit an auto parts store and use their code scanner to read the code. It comes back as low exhaust gas flowā¦an issue Iāve dealt with and corrected multiple times in the past on this vehicleā¦I even replaced the EGR valve at one point when I was troubleshooting this problem. I normally just remove the throttle body and the EGR valve and then snake a narrow, plastic, flexible rod-shaped tool through the exhaust gas port and with some throttle-body cleaner, remove the built up carbon. I put the car back together and the next time I have it by the auto parts store, stop in to clear the codes. My son gets home from college and we begin using his car and leave the van sit. This past weekend, I drove it and lo and behold, the tick was gone. I started doing some research on what a clogged exhaust gas recirc path could cause and found a ticking engine as one of the issues. It explained that the engine tick was due to elevated temperatures in the intake manifold causing pre-detonation since the exhaust gas non-combustibles were not present and able to drop the temperature.
Nonetheless, it appears the problem is now solved and Iāve become a little wiser. Thank you to all who contributed with your suggestions and offersā¦I was getting ready to replace the lifters and then if that didnāt work pull the transmission to examine the flexplate. Would that have ever been frustrating.
Good to know youāve got the problem resolved. EGR is indeed used to cool the cylinder temperatures. The main reason is to minimize formation of nitrogen compounds which are air pollutants. The nitrogen doesnāt come from the gasoline, it comes from the air which is 70% nitrogen. But if the cylinder is hot enough the nitrogen in the air will combine with the gasoline to form air polluting nitrogen compounds. The way the engine designers lower the temperature of combustion is to allow some of the exhaust gas back into the cylinder. Similar to how youād lower the temperature of your camp fire by pouring a cup of water on it. The lower temperature you get inside the cylinder when the egr system is working properly also can prevent pinging, which I presume was the ticking noise you were hearing.
The way Iāve always checked the egr, I apply a vacuum to the egr valve vacuum input, and if the egr recirculates the exhaust gas like it should, it causes the engine to stall at warm idle.
The EGR valve does not control engine knock during idle, it is a factor under load. The only connection between the EGR circuit and idle noise would be an exhaust leak between the exhaust port and the EGR valve.
If your idle racket has gone away without a good reason the noise will probably return.
OKā¦thanks again for the replies. So maybe either the EGR valve or the exhaust pipe to it was not tight and when I removed it and reinstalled it to clean the exhaust gas path, I reinstalled it correctly. Odd though that this started out of thin air. The last time I had the EGR valve off was when I did the head gasket job in November of 2015. I drove it for almost a year and then the tick shows up.
hmmm ā¦ I wouldnāt have guessed that. If the EGR system wasnāt doing its thing, the cylinder would heat up enough when under load to form hot spots that would cause pinging, and then when coming to a stop and idling, the pinging would continue at idle. It takes a while for an overheated cylinder to cool off all the hot spots at idle? And couldnāt a non-functional EGR cause deposits to form inside the cylinder and act as permanent problematic hot spots?