Greetings!
Trying to get some help here with the 3.7 engine. Paint it ugly. This is first foray into land of new-ish Jeeps.... I've tons of experience in old and some 90's SOHC Fords, but not the SOHC 3.7 Dodge/Chrysler mill.
Truck is stuck in Colorado Springs near where she lives and this is a reeeeemote diagnosis by a fairly known shop...to someone else. I'm stuck further west.......no idea how good these guys are but they seem to have the correct gear...!
Daughter just bought the truck about a year ago at the most....ran great....and never really put that many miles on it due to her location and working from home.
She started truck one morning about 6-8weeks back during the BIG cold spell many days under zero.....and it started having problems. Noisy engine clatter......(as it was told to me...)
Fast forward to finally getting the truck to a shop with actual competent mechanic(s). Compression test (dry???) shows even across the board 90's one 100 (#4) and one 45 on #5.
ECM code shows a fault of P0304....???
They also sent back a running video of #4 on a compression tester gauge and it is very rough......not holding up.....but I would think any cylinder would show that if you took the valve out of the gauge!!!??? See my NOTE: at bottom of post.....needed to rethink this!
1) I don't know, I've never tried to rely on a running compression test......is that even real? Yes bubba, it IS real! (See below note!)
2) Would like to see the compression test results on a "wet" test. (Spec for 2008 3.7 shows 170-225??? Sea level?)
3) This is high altitude..... can one expect to see results in the 90-100 instead of higher? (140-160 SOHC Static- Seal Level?)
4) What sort of wear can one expect on the Dodge 3.7 engines for cylinders and rings if not running synthetic oils?
4.5) Are valve springs a common issue with these engines?
5) Based on results of #4, two rebuilt heads in order......or get pulled into long block?????
Uugh!
After re-reading the tech comments below, and watching a couple of good u-tube videos, it would sound like potentially two bad cylinder heads.....but that all depends on how Dodge 3.7's react to mileage, ie see my question #4 above. Rings will likely wear fairly uniform in my experience....outer cylinders more than inners.... (outers are cooled more....metal wears less at elevated temps on the inner cylinders!)
The last 5L Ford I tore down several years back, from a 95-sh T-Bird, had over 250K on it and the cylinder walls still had cross hatch markings! My bore wear tool hardly registered .002-,003" of wear!
I was thinking this looked a lot like a bad valve spring.....and the bouncy running test is suspect.......never done that. Would have been nice to see a running test on say....#1, or 2, or 3........
Here is the tech's write up:
For noise concern and compression test on Cyl #4, I started by removing all ignition coils and spark plugs on all 6 cylinders. See photo #3 for compression test results. Cylinder #4 actually tested okay for static compression at about 100 psi. 100 psi is lower than we want, but I was surprised to see it as high as it was. The weak cylinder ended up being Cyl #5 at 45psi. Specification for static engine compression is 170-225psi, but that will not happen with our conditions in Colorado. I would expect to see about 120-160 psi with a good running engine. 45psi on Cyl #5 indicates cylinder damage or leakage in the cylinder. I then installed 5 of the 6 spark plugs and ignition coils, leaving out Cyl #4, then running the engine to check a running compression test. See video #2 for running compression test results. You can see that while running that cylinder does not hold pressure well and also is only producing about 45 psi. This tells me that two cylinders are damaged, not just the one. At this time, due to excessive engine wear and lack of compression on multiple cylinders, we recommend engine replacement. I do not believe that it is worth the cost to repair cylinder heads or head gaskets due to lack of compression on Cyl #5.
Note: After looking up "how to conduct a running compression test" I found it can be done both ways, with Schroeder valve in and out...... It is possible that a loose valve seat could be at fault, or perhaps a valve spring...... Most interesting!
THANKS FOR LOOKING!!! Intelligent and informed comments are most welcome here in this ugly situation!
Cheers!
Steve
Trying to get some help here with the 3.7 engine. Paint it ugly. This is first foray into land of new-ish Jeeps.... I've tons of experience in old and some 90's SOHC Fords, but not the SOHC 3.7 Dodge/Chrysler mill.
Truck is stuck in Colorado Springs near where she lives and this is a reeeeemote diagnosis by a fairly known shop...to someone else. I'm stuck further west.......no idea how good these guys are but they seem to have the correct gear...!
Daughter just bought the truck about a year ago at the most....ran great....and never really put that many miles on it due to her location and working from home.
She started truck one morning about 6-8weeks back during the BIG cold spell many days under zero.....and it started having problems. Noisy engine clatter......(as it was told to me...)
Fast forward to finally getting the truck to a shop with actual competent mechanic(s). Compression test (dry???) shows even across the board 90's one 100 (#4) and one 45 on #5.
ECM code shows a fault of P0304....???
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They also sent back a running video of #4 on a compression tester gauge and it is very rough......not holding up.....but I would think any cylinder would show that if you took the valve out of the gauge!!!??? See my NOTE: at bottom of post.....needed to rethink this!
1) I don't know, I've never tried to rely on a running compression test......is that even real? Yes bubba, it IS real! (See below note!)
2) Would like to see the compression test results on a "wet" test. (Spec for 2008 3.7 shows 170-225??? Sea level?)
3) This is high altitude..... can one expect to see results in the 90-100 instead of higher? (140-160 SOHC Static- Seal Level?)
4) What sort of wear can one expect on the Dodge 3.7 engines for cylinders and rings if not running synthetic oils?
4.5) Are valve springs a common issue with these engines?
5) Based on results of #4, two rebuilt heads in order......or get pulled into long block?????
Uugh!
After re-reading the tech comments below, and watching a couple of good u-tube videos, it would sound like potentially two bad cylinder heads.....but that all depends on how Dodge 3.7's react to mileage, ie see my question #4 above. Rings will likely wear fairly uniform in my experience....outer cylinders more than inners.... (outers are cooled more....metal wears less at elevated temps on the inner cylinders!)
The last 5L Ford I tore down several years back, from a 95-sh T-Bird, had over 250K on it and the cylinder walls still had cross hatch markings! My bore wear tool hardly registered .002-,003" of wear!
I was thinking this looked a lot like a bad valve spring.....and the bouncy running test is suspect.......never done that. Would have been nice to see a running test on say....#1, or 2, or 3........
Here is the tech's write up:
For noise concern and compression test on Cyl #4, I started by removing all ignition coils and spark plugs on all 6 cylinders. See photo #3 for compression test results. Cylinder #4 actually tested okay for static compression at about 100 psi. 100 psi is lower than we want, but I was surprised to see it as high as it was. The weak cylinder ended up being Cyl #5 at 45psi. Specification for static engine compression is 170-225psi, but that will not happen with our conditions in Colorado. I would expect to see about 120-160 psi with a good running engine. 45psi on Cyl #5 indicates cylinder damage or leakage in the cylinder. I then installed 5 of the 6 spark plugs and ignition coils, leaving out Cyl #4, then running the engine to check a running compression test. See video #2 for running compression test results. You can see that while running that cylinder does not hold pressure well and also is only producing about 45 psi. This tells me that two cylinders are damaged, not just the one. At this time, due to excessive engine wear and lack of compression on multiple cylinders, we recommend engine replacement. I do not believe that it is worth the cost to repair cylinder heads or head gaskets due to lack of compression on Cyl #5.
Note: After looking up "how to conduct a running compression test" I found it can be done both ways, with Schroeder valve in and out...... It is possible that a loose valve seat could be at fault, or perhaps a valve spring...... Most interesting!
THANKS FOR LOOKING!!! Intelligent and informed comments are most welcome here in this ugly situation!
Cheers!
Steve
