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Info for 2.7 owners

136K views 195 replies 64 participants last post by  deerhunter1679 
#1 · (Edited)
Ive had many questions about 2.7's and their lifespan, and hi-jinks, so here is some info about the causes and effects of their failure, and how to keep them alive, at least what Ive found to be successful.

Heres what I have found over the years of working on these things...dont believe everything you read online... the thing about them, is most are people that make assumptions, and really have no true idea of what was going on...im not saying the 2.7 is an innocent engine either..so dont get me wrong...hehe.

99.99999% of all 2.7 failures are caused by the water pump. They are not caused by poor maintenance, although that can be a major contributing factor in speeding the process along.

1. Sludge -- Sludge is caused by coolant leaking internally into the engine, from the water pump. The pump begins seeping, and being an internally mounted pump, it goes right into the oil, via the timing chain housing. Over time the coolant mixing with the oil causes the sludge. This problem is exacerbated by poor maintenance of the PCV system, as it becomes plugged or inoperative due to buildup in the hoses (weak design here), and the hoses collapse, or the PCV valve itself seizes closed, and the engine cant breathe. The result, general moisture/vapor from intake air, condensation, combustion, etc, has no where to go, and more moisture = more sludge. Sludge sort of acts like atherosclerosis, slowly filling in and plugging oil galleys and passages. In frequent oil changes make this even worse. Now....sludge doesnt always happen...it depends on where the water pump decides to leak. They dont always leak into the oil when the bearings start to fail. Sludge can also clog and starve the oil pickup and bearings, and cause a knock, before the water pump ever has a catastrophic failure. In some instances, sludge formation from a bad water pump has caused seizure/knocking before the water pump leak is found. There are a few other causes of sludge, but as far as the 2.7 is concerned, this is the most relevant.

2. Water pumps -- the water pump is a poor design, there is no doubt about that. It has been shown that even 3.2/5 engines have water pump issues, at about the same mileage, but are much less failure prone, due to the use of a timing belt, amongst other factors. In the 2.7, the water pump has a high amount of load on it, from a very long and heavy timing chain, along with the vibration of operating 4 camshafts at once. It is simply not heavy enough to handle the load for an extended period of time (100,000+ miles, years, etc)...so the bearings and seals fail, resulting in leakage into the engine, and outside thru the weep hole. When the bearings fail, the timing chain comes off, can come thru the valve cover or cause damage to the engine block, and with the cams and crank rotating free, pistons hit valves, and they bend. Catastropic in most cases, and the engine is scrap metal. Just a few minutes of inspection for a bad water pump can completely prevent this.

3. Small oil passages -- this is a myth...the oil circulation is actually pretty decent in these engines, it is the sludge that causes problems there. One is the timing chain tensioner, since its operated by oil pressure, and one of the last components to get oil, it is especially sensative to sludge buildup, so if sludge is occuring, then it will not be able to maintain good tension on the timing chain. Usually by this time, the bearings are beginning to fail in the water pump...

4. Rebuilding a 2.7 -- I see many people attempt to repair these engines when its too late. When the bearings or tensioner fail, or begin to fail in the water pump, and the timing chain starts rubbing the front cover, or chewing on metal parts, these parts end up in the oil pump, and into the bearings. All too often I'll see one that has just had a brand new chain put on, and is knocking a week later. Oil pump/pickup, and oil pan must be removed and thoroughly cleaned, (or oil pump replaced) if this has happened. Its also a very good idea to remove the rod and main bearing caps and inspect for metal shaving damage.

4. Detecting it before it gets bad...the first symptoms of water pump problems in a 2.7...unexplained coolant loss (no external leaks), and no heat at idle. Along with that, any abnormal ticking/grating, or metallic noises, that are not consistent. If you are experiencing this, get it checked ASAP, in fact, dont drive it until you do. There is a weep hole that the pumps are supposed to leak from, which is located behind the alternator to the bottom left of the thermostat housing/lower radiator hose, but the problem is, it often does not leak while the car is not running, so the average person will never know it.

5. Keeping the 2.7 alive -- the rest of the 2.7 is actually a very tough design. They are built very well, except for the water pumps...hehe...to keep them alive, full synthetic oil changed every 4,000 miles from day 1, water pump changed every 75,000 miles, or checked for leaks and change as needed. Update to the new style timing chain, tensioner, and water pump (heavier and less problems), if you have an older engine. Change PCV valve and hose once every 2 years, or if the hose becomes mushy. Several 2.7s locally have had this maintenance regiment, and are still alive and well, one pushing 350,000 miles, and another well over 200,000. This is proven.

The 2.7 may be a good little engine, but the problem is, it is sensitive. The average every day car owner doesnt check under the hood, or doesnt know how to check under the hood, or know how to look for problems. Many repair shops/ and even some dealerships know little about the specifics of these engines, nor how to keep them alive. Many just do not know its ins and outs, so they are not able to keep it alive.

So, 2.7s are a pain in the ass, but if you know how to keep them happy, they will last a very long time, and it will save you tons of money on repairs, or an engine swap. Of course upgrading to a 3.2/5 is a huge improvement, but not everyone can afford it, or is willing to have it done, when a little more attention to their 2.7 will keep the car running just fine.

Just for grins, here is a 2.7 with 160,000 miles on it, maintained with Royal Purple synthetic oil, (excellent maintenance by LittleRedTrep), you can see it looks very normal inside. Also note how close the timing chain runs to the front cover/engine block. That will give you an idea of how little play/lack of tension it takes to get it rubbing something it shouldnt be. This engine still runs like a top, although transplanted into another trep...and is driven daily.....

 
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#3 ·
Average is about 80,000 miles, when they start leaking. Some of it depends on how they are driven, engines with more highway miles tend to last a bit longer.
 
#8 ·
Good info., Dan!

My sample of one went 207k miles before I replaced chain or water pump. Phil (Va3ux) didn't change his until either 212k or 217k, I forget which. So there's two samples. But apparently ours are exceptions. Phil's water pump actually started coming apart, but he stopped the engine in time to avoid damage. Mine didn't have any problem when I replaced it - Phil's experience scared me, so I did it. Strangely, my old pump turned silky smooth by hand after I removed it, had zero play in the bearings, and had *no* signs of leaks - not even residue anywhere. Weird (in a good way).

Mine does get driven daily (5 days a week) 80 miles a day, which goes along with what Dan was saying about highway miles being good for them.

They had come out with the re-designed chain, pump, and sprockets just before I did mine, so I feel fortunate with that. I'm at 226+k now - still running like a top (I did replace the valve stem seals and oil pump at the same time).

Oh yeah - oil pump - that reminds me. I remember reading that they increased the capacity of the oil pump (maybe in 2000?) due to some supposed failures of one of the crank or rod bearings in particular? Anyway - yeah - I could tell that the replacement oil pump I put in was bigger (rotor was thicker, maybe some diameter increase too.

Comments on the oil pump capacity increase Dan? Was there some bearing failure problem with the original pump that you've seen?
 
#5 ·
I had 83,000 on an excellently maintained 2.7 and the water pump started to leak. Sometimes it would leave a puddle on the garage floor, next day it would not. I quit driving it immediatly and had it towed to Dan's place. There were no warning signs. And from what I heard from some, the water does not always leak onto the floor. Rather into the oil. Regular checks of water and oil levels are critical.
 
#6 ·
Finally. Thank you Dan. A thread that DOESN'T bash the 2.7. Very good info for those who are ignorant of the 2.7's TRUE design flaws and not this bull that you see on these websites that average Joes ***** on whenever they don't even know the difference between a lugnut and gascap. This thread should be stickied!
 
#10 ·
Good write up Dan, sound advice on maintaining the engine - in fact, all engines-, too.
One thing I was told by a Chrysler tech, was that the oil pick up tube sits too low to the bottom of the pan, and this can cause a problem in colder areas, especially on start-up, as the pump can cavitate briefly, sending air bubbles into the oil galleries.
Not good it is in fact does this.
He told me the shop he is foreman of raised the pickup by 1/4" to cure cold morning engine knock.
What's your take?
 
#15 ·
Thanks for sticky-ing this. i get frustrated every time someone goes on about tiny oil galleries and whatnot.

I check my oil and coolant levels once a week religiously as well as my PCV system. Though I am fairly sure the chain has been replaced before I got it, and I'm 98% sure this isn't even the original engine, I will most likely put a new updated pump and chain set in it when the temps warm up. Or I will at least pop a valve cover off and see if it has the new style chain which would be nice. There is orange high temp RTV under the valve covers and front cover, so I can imagine an engine was acquired, and the chain/pump replaced before install, but who knows. I have only put about 13,000 miles on it since I got it in 07. I have also never heard a single weird tick or knock, even in 9 degrees below zero startup, except for the loose torque converter bolts fiasco. I change the oil every 6 months, I never reach 3000 miles on each interval, and the oil is always pretty clean at change time.

Speaking of PCV system, I never see it mentioned here but once a winter I remove the curved box section of intake just prior to the elbow that connects to the throttle body and empty a ton of water out of it. I also clean out both PCV hoses and make sure the valve is 100% awesome. This isn't needed in the summer because I don't idle the engine long in the summer. In the winter though, if it is 3 degrees out, it runs about ten minutes before I drive it. That is because I leave my driveway, go 400 feet, then get onto a 65 mph highway. Don't want to do that on a bone cold engine.

I doubt I am the only one who has water collect in that intake section, though maybe it evaporates so I don't actually have to worry about it, but still. I have never seen anything like this in any other vehicle. It's like they designed this section specifically to collect water.
 
#17 ·
daytrepper.. i have a 03 SE, in your post you said to"update to newer timing chain, tensioner, and water pump if you have an older engine". Is the 2.7 in my car an older model? If so, what are the part numbers i should get for the timing chain, tensioner, and water pump? if it matters, i have about 60k on the clock.
 
#18 ·
There was a new chain design (different pitch) with new cam sprockets and water pump for compatibility that was just starting to be supplied as the replacements for our cars about a year ago when I did my chain and pumps (water and oil). I don't know if that's the new design that Dan was talking about. I suspect that they are the design used in the LX platform 2.7, and were not sold before a year ago to go into our cars, though they are backward compatible as my engine (a '99) proves.

If Dan was referring to something different as far as a newer design, he can explain. But if it's the new design that I'm talking about, then I believe your engine would have come with the older design - I could be wrong. Perhaps the newer design did in fact come on later year LH's, and only recently were starting to be sold for use in the earlier engines. Oh Dan . . .
 
#19 ·
I have a 02 Interpid with a 2.7 its at 74K and I had to change the thermostat 2 years ago. My problem is everytime it rains or it gets cooler outside my check engine light comes on and stays on. and dont understand why its just during the rainy or cooler seasons I live in Florida so during the summer it never comes on?
 
#23 ·
another question daytrepper,

i've noticed that my car squeals whens its cold or raining when its idleing and as soon as i press the gas pedal it goes away. what can be the cause of that? i thought about taking it to a shop but it only happens when its cold or raining so my luck it will be a perfect day out and no problem when i decide to take it.
 
#27 ·
IMO, it is not for the faint of heart, nor for the backyard mechanic. $5-$800 in parts by the time your done with timing chain/water pump, tensioners, gaskets, etc, price can vary whether or not you go OEM. If you have little or no automotive experience, especially with internal engine repair, I dont recommend doing it.
 
#28 · (Edited)
I must be tempting fate. Just rolled over to 170k miles last week. '03 SE, bought it with 7k, has all original engine parts and still runs like a top. My main issue is the front end bushings are starting to get loose.

Thanks for the info on that PCV hose; it is starting to get a little mushy/oil rot.
 
#30 ·
My 2.7 made it to 196,000 before I yanked it. It's currently sitting in the garage. Still ran good the day I pulled it but the oil was abit milky and it burned oil....I'd like to get it back into shape and drop it in another car some day.

2.7's seem to have oil burning issues, is there a particular reason for that? Is it the valve stem seals?
 
#31 ·
Its not tecnically burning oil. The exhaust valve seals leak, causing oil to leak into the exhaust port. As more and more oil leaks out, it gets into the cat, which is where it actually burns. After this happens for awhile, the oil ends up choking the cat (lol) and you get the Catalytic Converter Inefficient code.
 
#36 ·
I assume you mean the light is on when sitting idling with it in gear, but it goes out if you take it out of gear or start moving. If this is the case you need to simply replace the oil pressure switch (on lower passenger side of engine). That part you want to get only from the dealer - people have more trouble with the ones from aftermarket sources.
 
#37 ·
Aside from the obvious difference of size- 3.2 liter versus 3.5 liters, are there any other differences between these two engines? either internally or externally? I realize pistons and bore are different, but are cams, heads, timing gear, intake, etc all the same between the two? What is the horsepower rating for a 99 3.2? Do they perform as good as a 3.5? Can the same performance mods done to a 3.5 be done to a 3.2? Sorry if I kinda hijacked this thread but I want to be ready when the 2.7 gives up.
 
#38 ·
3.2 is identical to 3.5, right down to the part numbers. Only difference is cylinder bores, and pistons. They can be modded just the same, ive got mine up in 3.5 territory HP wise... :riptires:

3.2 was around 226, and 3.5 252HP, slight variances in different applications.
 
#42 ·
I agree with Daytrepper observations 100 percent and why I preach about using synthetic motor oil every 3000miles/5000k

-The coolant temperatures are pretty high (the high speed fan comes on at 230º)
That means making sure the entire coolant system is up to snuff (Radiators, Fans, Air dams Trans/Engine oil coolers a/c condensors etc)

-The engine only holds four and a half quarts of oil, so the oil gets too hot and it begins to break down. Multi-viscosity oils revert back to their base viscosity if they're subjected to too much heat and pressure, so a 5W-20 may well revert back to a 10W or even a 5W viscosity if it's abused, and that's just not good enough for these engines.

Running the oil too hot explains why we see the brown stains on the inside of the heads and block and may even help explain the heavy, thick, greasy sludge that we see on some of the heads

Adding an oil cooler to these engines is an asset in getting longevity to these engines
 
#43 ·
How do you know when your 2.7 has flat lined?
Im hearing the knocking in my new 99 trep and was wondering if its worth trying to fix just so i can get around in it temporarily between engine swaps?

I remember the nut it took to remove my water pump/timing chain in the 3.2 i figure the 2.7 is cake compared? besides that and oil pump being changed is there anything else i can do to possibly rectify the knocking?
 
#44 ·
If its a bottom end knock, its toast. nothing you can do short of rebuilding it, which will cost roughly 8-900 bucks. your best bet is to find a 3.2 or 3.5 out of a 98-01 LH and do a transplant. And the TC and WP is much worse on a 2.7 than the TB/WP on a 3.X.
 
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