The Chrysler Minivan Fan Club Forums banner
1 - 12 of 12 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter · #1 ·
1999 3.8l 230k.
About 2 years ago the van developed a significant increase in oil consumption.
It was a very quick increase in oil consumption over a period of months that went from 2000 miles (where it had been for a long time) to 1000, 750, 250 miles per quart.

Since that time, it has got new rocker cover gaskets, head gaskets, valve seals, oil pressure switch.
An oil catch can was added to the PCV valve line and it gets about 4oz of oil per 1000 miles.
None of the above reduced the oil consumption.
Took it to a mechanic today for additional opinion as would like to go on long road trip without having to add oil at every gas stop. Mechanic advised while there is a leak from the rear seal is not enough to justify the 250 miles per quart oil consumption and that it must be burning.

Do not see smoke coming out the van exhaust at idle however there is a dark ring on the end of the tailpipe.
There are no engine codes.
Van runs fine.

What next?
For $700 I can have the rear seal replaced but mechanic does not think it will reduce oil consumption significantly.
Can continue adding the quart every 250 miles.
 

·
Registered
Joined
·
95 Posts
It's probably not worth doing the rear seal if you can keep the oil level in the safe range. Move to heavier weight oil like 20W-50 if you're just on the road.

You will plug your catalytic converter before long and your van is really ready for either the glue factory or a new engine. I drove cars cross country and added a quart of oil every 250 miles back in 1970 when I was 18 years old using straight 40 and 50 weight oil. It's not anything that should be considered normal or sustainable at this level of oil consumption and I would not do long trips in such a sick vehicle. Sorry.
 

·
Registered
Joined
·
6 Posts
Discussion Starter · #3 ·
It's probably not worth doing the rear seal if you can keep the oil level in the safe range. Move to heavier weight oil like 20W-50 if you're just on the road.

You will plug your catalytic converter before long and your van is really ready for either the glue factory or a new engine. I drove cars cross country and added a quart of oil every 250 miles back in 1970 when I was 18 years old using straight 40 and 50 weight oil. It's not anything that should be considered normal or sustainable at this level of oil consumption and I would not do long trips in such a sick vehicle. Sorry.
Thanks for the feedback.
It gives me direction on the next steps.
Just needed someone else to say it.
Wish the used car market was not so over priced at the moment though.
 

·
Registered
Joined
·
115 Posts
If I were you I'd go up to the next weight oil. If you are doing 10/30 now, go up to 10/40 and that should cure or lessen the problem. As the car ages, that's just normal procedure. The catch can is a good lick as it will help extend the life of your converter. If you are worried about the van's longevity do a compression test, that will tell you if she is getting tuckered out. You can also put a vacuum gauge on it. If, at idle warm, it reads between 17-20 inches she's good to go (closer to 20 the better). This is a good reference https://d2culxnxbccemt.cloudfront.net/car/content/uploads/2017/03/10131139/CCRC-Vacuum-image.png
 

·
Loveably weird
Joined
·
397 Posts
If an engine is burning oil, generally getting in from one of two places: the valve seals or the piston rings. Since you say you've already done the valve seals, I would suspect the rings. As Oscarphone suggested, do a compression check. Do it once with engine "dry", after it's sat for a few hours, then add a bit of oil to each cylinder before you check it again. If the compression goes up, the rings aren't sealing properly and it's time for an overhaul or replacement, neither of which is cheap.
 

·
Registered
Joined
·
6 Posts
Discussion Starter · #6 ·
I agree it is most likely the rings are either seized on the piston or the bore is worn. Not sure if I will ever get around to pressure testing before disposing of but if I do, will share the numbers.
Thanks for the heavier weight oil suggestion. Been running with 10w40 now for 6 months but no noticeable change in consumption. Was thinking next of trying an additive just to see if it will reduce the consumption - for now it is still a consistent 250 miles to the quart.
Van has started leaving a black oily exhaust mark - exhaust tip faces downward - whenever it is stationary so that at least's confirms the mechanics point of view that the rear seal was not the major issue.
Current plans are to keep driving until I work out its replacement.
 

·
3rd gen > all others
Joined
·
3,885 Posts
It shouldn't be burning that much at 230K. Even mine at 225,000 would only need a quart between oil changes @3k.

Clean or replace the PCV valve. Run some automatic transmission fluid in the oil for a while, or some other methods to clean the engine internally. The rings may have gotten gummed up and sticking. With that kind of oil consumption burning, you would see a trail of blue smoke behind the van. The spark plugs would look oil-fouled.

Is there an engine oil cooler? It could be leaking oil into the coolant (or vice-versa) but you'd know that with milkshake present on the bottom of the oil cap. The coolant would get oil in it.
 

·
Registered
2006 Dodge Caravan SXE
Joined
·
975 Posts
I agree it is most likely the rings are either seized on the piston or the bore is worn. Not sure if I will ever get around to pressure testing before disposing of but if I do, will share the numbers.
Thanks for the heavier weight oil suggestion. Been running with 10w40 now for 6 months but no noticeable change in consumption. Was thinking next of trying an additive just to see if it will reduce the consumption - for now it is still a consistent 250 miles to the quart.
Van has started leaving a black oily exhaust mark - exhaust tip faces downward - whenever it is stationary so that at least's confirms the mechanics point of view that the rear seal was not the major issue.
Current plans are to keep driving until I work out its replacement.
For piston rings, do a compression test. Low compression will tell you if the rings are getting by-passed. This is a 'common' problem with the 3.8L and minor issue with the 3.3L. The 3.8L has the longer stroke block vs. the 3.3L block. Otherwise, it's basically the same engine.

I too had a 2005 SXT 3.8L. Before the engine went, it was going thru 1-QT every 1,500 miles, then weeks prior to failure 1-QT every 500 miles, Then it was 1-QT every 50 miles. Then it died leaving us all stranded. I had a case of oil in the van too. I kept popping the hood every 25 miles checking too.

So, it sounds like your right at the cusp of blowing the engine ! o_O

I now drive a 2006 SEX 3.3L (took all the SXT loaded options to a SE model.) :ROFLMAO:
 

·
Registered
Joined
·
6 Posts
Discussion Starter · #9 ·
For piston rings, do a compression test. Low compression will tell you if the rings are getting by-passed. This is a 'common' problem with the 3.8L and minor issue with the 3.3L. The 3.8L has the longer stroke block vs. the 3.3L block. Otherwise, it's basically the same engine.

I too had a 2005 SXT 3.8L. Before the engine went, it was going thru 1-QT every 1,500 miles, then weeks prior to failure 1-QT every 500 miles, Then it was 1-QT every 50 miles. Then it died leaving us all stranded. I had a case of oil in the van too. I kept popping the hood every 25 miles checking too.

So, it sounds like your right at the cusp of blowing the engine ! o_O

I now drive a 2006 SEX 3.3L (took all the SXT loaded options to a SE model.) :ROFLMAO:
That 50 mpq information :eek: helps me know when to call a taxi to meet me at the nearest junkyard and avoid the stranding :).
Like how you were able to migrate the options to the replacement van.

Van has done about 2500 miles at the current oil consumption level. It would seem for this 1999 van the ending is going a bit slower than the 2005 mentioned - the consumption with the 1999 increased rapidly and then levelled off at where it is now. Though I do not expect or plan to have it in my stable come 2023.

Starting to notice occasional smoke from the rear which the mechanic had said would occur as the CAT gets saturated.
However the amount of smoke is not even close to a newer and lower miles Saturn I had (with the known oil ring problem) which pumped out a smoke screen at stop lights - that Saturn was 750mpq.
 

·
Registered
2006 Dodge Caravan SXE
Joined
·
975 Posts
Like how you were able to migrate the options to the replacement van.
Once the 2005 3.8L SXT was to the point of nearly no return of loud rod knock and couldn't keep enough oil in the engine for a a single direction driving into town, I parked it in the driveway. I looked for a week on CL and found an identical body Caravan in color inside and out, lower miles 2006 3.3L SE. It took two weekends to transfer all of the loaded option I could out of the SXT to the SE. Radio, extra power outlets, center dash console, handle grab assist on the A-pillars (need to add 4 Rivnuts with mallet), radio speakers, power seats, upgraded dome light assemblies, etc.

I wish the 2005 rims were not so badly pitted, else I would of changed the rims. I was debating on swapping the entire front fascia, but ran out of time. Someone wanted the the van badly because their 2005 was badly rear-ended. They too had a good working 3.8L to drop into it. Bet they swapped thing into my old van that I traded with as well. LOL
Being on the forum here, I've not heard of anyone - - - yet stepping up saying they swapped in a 3.8L from a damaged van out of Nashville. ;)

The 3.3L with the shorter stroke doesn't suffer as bad with the worn rings and oil blow-by issues. And having the 3.8L TB on the 3.3L engine is a big welcome making it feel as near to a 3.8L as I can get it.
 

·
Registered
Joined
·
1,201 Posts
Wonder how he knows how much the rear seal leak is. If just slightly wet around there, I would agree with him. The rear seal has a Teflon lip and seems to last a very long time, compared to old graphite rope seals and such, which have a slit. It goes over the crankshaft end, which is why the transmission and flex-plate must be off. I changed it while "in there", but the OE seal appeared pristine and was totally dry there at ~200K miles. If excessive blow-by past the rings, you can see that if you remove the oil fill port and cap off the PCV hose. That is a common diagnostic for old diesel engines, like my 1985 M-B, and you can find many youtubes to judge. If puffing out a lot of smoke at idle, that is a sign of bad rings.
 

·
Registered
2006 Dodge Caravan SXE
Joined
·
975 Posts
Wonder how he knows how much the rear seal leak is. If just slightly wet around there, I would agree with him. The rear seal has a Teflon lip and seems to last a very long time, compared to old graphite rope seals and such, which have a slit. It goes over the crankshaft end, which is why the transmission and flex-plate must be off. I changed it while "in there", but the OE seal appeared pristine and was totally dry there at ~200K miles. If excessive blow-by past the rings, you can see that if you remove the oil fill port and cap off the PCV hose. That is a common diagnostic for old diesel engines, like my 1985 M-B, and you can find many youtubes to judge. If puffing out a lot of smoke at idle, that is a sign of bad rings.
Bad rings are so easy to fix on a diesel compact tractor, 4 easy hours taking your time from the bottom end. Not so on a passenger minivan gasser V6. LOL
 
1 - 12 of 12 Posts
Top