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2005 Chrysler Town & Country, Limited, 3.8L
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Discussion Starter · #1 · (Edited)
But no water in the crankcase.

I have been told by my local garage mechanic that it's one or both heads cracked. The thing has never overheated. And of course I check all fluid levels religiously.

My question is: is it a bad gasket, and is there some additive available to get it down the road a few thousand miles more? The van only has 160K on it and is otherwise in good shape. This is my 5th Dodge van, it drives nice and I'd like to keep it.
 

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Hmmm... from your description, it would seem to mean that oil at a higher pressure must be making its' way to a coolant passage at lower pressure. Indeed, the cylinder heads are one such location where oil is flowing under pressure (probably greater than 40 psi) in close proximity to coolant (normally no more than 16psi or so); however, I'm not sure how you make the leap to blaming the cylinder heads right off the bat without further investigation as this same pressurized oil and coolant is also passing through the cylinder head to engine block interface where a gasket failure might allow the same thing.

Not saying cracked cylinder heads are impossible; however, I can't recall ever hearing anyone else here on this forum complaining of cracked heads...

As for additives that might somehow block such a leak, I'm not in the know and must leave that to others to chime in. Would generally be concerned for any such additive clogging up other important oil passages; however, "to each his own."

Did these shops give you any justification of how they arrived at the cracked head diagnosis? Have the cylinder head gaskets already been replaced? I'm beyond 280,000 miles on my original cylinder heads, only just recently having replaced the cylinder head gaskets which were definitely leaking fluids. If cylinder head gaskets have not been replaced, I'd be suspicious of them more than the probability of the cylinder heads cracking.

All that said, perhaps some other folks here might chime in with additional thoughts.
 

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Discussion Starter · #3 ·
Hmmm... from your description, it would seem to mean that oil at a higher pressure must be making its' way to a coolant passage at lower pressure. Indeed, the cylinder heads are one such location where oil is flowing under pressure (probably greater than 40 psi) in close proximity to coolant (normally no more than 16psi or so); however, I'm not sure how you make the leap to blaming the cylinder heads right off the bat without further investigation as this same pressurized oil and coolant is also passing through the cylinder head to engine block interface where a gasket failure might allow the same thing.

Not saying cracked cylinder heads are impossible; however, I can't recall ever hearing anyone else here on this forum complaining of cracked heads...

As for additives that might somehow block such a leak, I'm not in the know and must leave that to others to chime in. Would generally be concerned for any such additive clogging up other important oil passages; however, "to each his own."

Did these shops give you any justification of how they arrived at the cracked head diagnosis? Have the cylinder head gaskets already been replaced? I'm beyond 280,000 miles on my original cylinder heads, only just recently having replaced the cylinder head gaskets which were definitely leaking fluids. If cylinder head gaskets have not been replaced, I'd be suspicious of them more than the probability of the cylinder heads cracking.

All that said, perhaps some other folks here might chime in with additional thoughts.
Thank you. It just needs the heads pulled and inspected. And like you said, any additive to seal a leak is likely to cause more problems than it solves.

I did buy a radiator flush kit. But I'm hesitant to use it as it may have the exact opposite effect and allow more oil into the coolant system. Lol I dunno
¯\(ツ)
 

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How much oil are you talking about being in the radiator?

Cylinder head itself seems like a pretty unlikely culprit. IIRC, I believe there is only one oil port (hole) carrying pressurized oil up to each cylinder head and I believe it pretty much goes directly up to the elevated oil supply "bar" that the rocker arms ride on. Being a push-rod engine, there are no lash adjusters in these heads to require distibuting oil around within the head itself. Lash adjusters in our engine are supplied by oil runs within the block itself.

Replaced the head gaskets in my '05 3.8L this summer. It's a bit time consuming but can be done without removing the engine from the vehicle.
 

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Pretty sure the '05 3.8L does not have an engine oil cooler from the factory, but worth looking into.
Why wouldn't it? It's part of the factory tow package. Even 5th gens have them. It IS optional however.
 

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2006 Dodge Caravan SXE
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Hmmm... from your description, it would seem to mean that oil at a higher pressure must be making its' way to a coolant passage at lower pressure. Indeed, the cylinder heads are one such location where oil is flowing under pressure (probably greater than 40 psi) in close proximity to coolant (normally no more than 16psi or so); however, I'm not sure how you make the leap to blaming the cylinder heads right off the bat without further investigation as this same pressurized oil and coolant is also passing through the cylinder head to engine block interface where a gasket failure might allow the same thing.

Not saying cracked cylinder heads are impossible; however, I can't recall ever hearing anyone else here on this forum complaining of cracked heads...

As for additives that might somehow block such a leak, I'm not in the know and must leave that to others to chime in. Would generally be concerned for any such additive clogging up other important oil passages; however, "to each his own."

Did these shops give you any justification of how they arrived at the cracked head diagnosis? Have the cylinder head gaskets already been replaced? I'm beyond 280,000 miles on my original cylinder heads, only just recently having replaced the cylinder head gaskets which were definitely leaking fluids. If cylinder head gaskets have not been replaced, I'd be suspicious of them more than the probability of the cylinder heads cracking.

All that said, perhaps some other folks here might chime in with additional thoughts.
When you state oil, it's engine oil? OR - - - - trans fluid behaving like oil in the coolant?

If trans fluid, then just replace the radiator with the trans cooler built into the side tank.

This is a 'generic' image of where that cooler sits in the side tank of the radiator. When these leak trans fluid to the coolant, it has that oily look in the coolant.

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When you state oil, it's engine oil? OR - - - - trans fluid behaving like oil in the coolant?

If trans fluid, then just replace the radiator with the trans cooler built into the side tank.

This is a 'generic' image of where that cooler sits in the side tank of the radiator. When these leak trans fluid to the coolant, it has that oily look in the coolant. View attachment 64234
Not possible in 4th gens, as the transmission fluid cooler is totally separate from the radiator. It is it's own unit from 2001-04, and part of the A/C condenser in 2005-2007.
 

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Discussion Starter · #11 ·
How much oil are you talking about being in the radiator?

Cylinder head itself seems like a pretty unlikely culprit. IIRC, I believe there is only one oil port (hole) carrying pressurized oil up to each cylinder head and I believe it pretty much goes directly up to the elevated oil supply "bar" that the rocker arms ride on. Being a push-rod engine, there are no lash adjusters in these heads to require distibuting oil around within the head itself. Lash adjusters in our engine are supplied by oil runs within the block itself.

Replaced the head gaskets in my '05 3.8L this summer. It's a bit time consuming but can be done without removing the engine from the vehicle.
I would call it a moderate buildup on the radiator cap. Every few months I pull about a tablespoon sized glob out with my finger. It's also using water and oil. No leaks I can see. I believe it's blowing out the tail pipe somehow.

The transmission does seem to shift funny. Once, on a hot day a while driving cross country it slipped but only for a few moments. Hasn't done it again, but I'm driving more than about 20 miles at a time these days.
 

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Discussion Starter · #12 ·
When you state oil, it's engine oil? OR - - - - trans fluid behaving like oil in the coolant?

If trans fluid, then just replace the radiator with the trans cooler built into the side tank.

This is a 'generic' image of where that cooler sits in the side tank of the radiator. When these leak trans fluid to the coolant, it has that oily look in the coolant.

View attachment 64234
It smells like motor oil to me but I suppose it could be trans fluid. That gets low too, not as often as the oil level though.

Several possibilities mentioned here I had no idea about. I will look in to this stuff and get back to you guys.

Thank you for the feedback!
 

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Being you have a 2005, it's going to burn some oil as that year there was a part change in the engine and oil consumption went way up.

Any coolant in the crankcase? If left to settle for a few days, it'll be the first thing to come out when you pull the drain plug on the oil pan. It could be a small enough leak that most of the coolant vaporizes. Might see milkshake forming on the bottom side of the oil fill cap.

Transmission doesn't figure into the problem at all. The shifting issue though, can come from worn accumulator pistons at higher mileage. Joel_B posted about this and using Sonnax valves and springs to restore the shift feel. This is the thread: Anyone used Sonnax accumulators in the transmission...

If you do have an oil cooler, it may be possible to bypass it with a piece of pipe the proper size and a couple of hose clamps. Then if you start to see oil dripping from the water port on the cooler, you have your culprit.
 
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Discussion Starter · #15 ·
And what does the trans oil look like?

And what does the engine oil look like on the dipstick?
I just changed the motor oil and filter last month. It got dark pretty fast as the dust out here is bad. But otherwise it's normal. I have had cracked blocks in the past and know very well water in the oil looks like.

The trans fluid also looks and smells okay. When low it makes a noise that sounds exactly like low power steering fluid level. The pan has no drain plug, has to be removed to change fluid.

I looked at the crankcase oil filter from the top and can't really see well enough to determine if there's an oil cooler. Need to borrow a floor jack to get under it safely.

I'm also building a house on a small lot at a Texas Hill Country lake while living in a tent camper. I have my hands full with various projects.
 

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Discussion Starter · #16 ·
Being you have a 2005, it's going to burn some oil as that year there was a part change in the engine and oil consumption went way up.

Any coolant in the crankcase? If left to settle for a few days, it'll be the first thing to come out when you pull the drain plug on the oil pan. It could be a small enough leak that most of the coolant vaporizes. Might see milkshake forming on the bottom side of the oil fill cap.

Transmission doesn't figure into the problem at all. The shifting issue though, can come from worn accumulator pistons at higher mileage. Joel_B posted about this and using Sonnax valves and springs to restore the shift feel. This is the thread: Anyone used Sonnax accumulators in the transmission...

If you do have an oil cooler, it may be possible to bypass it with a piece of pipe the proper size and a couple of hose clamps. Then if you start to see oil dripping from the water port on the cooler, you have your culprit.
Great insight. Thank you. I am just about positive there is no oil in the crankcase. No milkshake on the dipstick on oil fill cap. However, when I changed the oil recently I did not inspect the old oil. Will definitely do so next oil change.

My catalytic converter clogged up about 1500 miles after buying the van, wouldn't run at all. I feel like coolant vaporization contributed to that but not sure. I beat a 5/8" pipe through to open it up and it runs good. I do have a new cat con but don't want to install just yet if it will ruin it. Need to resolve this problem with trans fluid in the radiator first.
 
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