Oh and, where are the coolant hose Y things that should be changed from the old plastic to something new and better?

 

Y connectors only apply if you have rear heat. They are near the back, closer to the firewall. Horizontal one is very visible, and it hides the vertical one behind it. (on my 2016 DGC)

If your reservoir empties on cool down, coolant is being sucked back to the engine. A leak in the system, unless very small, would not normally allow that to happen. Air would be sucked in through the leak instead. That's why one can't trust only the reservoir to determine coolant level in the system.

What work has been done on the coolant system recently? What engine and normal operating range? 234 is within the operating range, I believe. 180F to 235F/240F possibly.

A previous Thread that relates:

2011 town & country

What can be done to make cooling run when temp is over 200?

www.chryslerminivan.net

Plan your analysis, fill it up and see what happens. Hose clamps in good shape? Sometimes they lose all strength.

 

I changed the thermostat in late August, the bleed was good afterwards and the temps have been pretty good since. It runs between ~205-221 most of the time, will drop to 190s on long descents and go to about 123 on ascents with the AC on. This time it just kept climbing, even with the fan operating, until I got moving again and jumped as soon as I stopped.

What would it mean if it gets sucked back into the engine on cool down? Bad head gasket?

 

A pressure test will tell you two things about the leak:

• its location, maybe
• how the leak is responding to the pressure (watch the pressure drop)

 

Hitting 234, you probably blew the heads. Need to find where the leak is coming from and fix that. If it continues to overheat, then the head gaskets went.

 

That's encouraging 🥴

 

What engine are we talking about? On my 2007 GC 3.8L, the lights and alarm went off when a lower radiator hose clamp (OE spring type) let go. Got some water in there eventually and nursed it home (about 7 minutes from where I stopped). Replaced the clamp after that.

No leaks for years after. Eventually 3 or 4 years later, the radiator sprang a leak and we replaced that.

For the Pentastar engine, I believe the normal range is up to around 230 although Jeep JK Owners are mentioning 240, even 245. The engine tends to like higher temperatures. Well, maybe not so much when it comes to the needle bearings in the rockers.

3.6 pentastar overheating

Hi, i am newbie in this forum. i have done my homework regarding 3.6l engine running hot. the problem i live in harsh environment which is 125f+ in the summer time and 45f to 60f in winter time. so let me tell you what i have done to fight the overheating on my 2014 JKU robicon Auto trans...

www.jkowners.com

230 is definitely not overheating for the 3.6L, even seeing 240 is pretty typical. A lot of us (including myself) don't really like seeing the numbers so high, but there's no choice but to accept that the engineers designed the engine to operate at this temperature range. When it's hot weather I try to monitor it and back off the throttle to keep it below 230 because I feel it might stand a chance of increasing engine longevity, but that's far from actually overheating for this engine.

Air in the system will present some weird temperature fluctuations though. Back in the days of the Bricklin.

TECH TIP: Overheating

.

A bricklin with a 15 pound radiator cap will not boil the water in the radiator until the coolant reaches approximately 250 degrees temperature. With anti-freeze, the boiling point is 250 to 260 degrees. You can run your car at 240 or 250 degrees without hurting anything, as long as the water in the radiator doesn't boil. Once the water boils, it will immediately push water out the overflow, lower the coolant level in the radiator, and give you air bubbles circulating through the cooling system. Air bubbles do not cool an engine, so the engine temperature will immediately skyrocket. Your main concern should be to keep your engine below the boiling point of your coolant. If your radiator cap is no good, it will lower the boiling point of your coolant to 212 dgrees. A leak of any type anywhere in your cooling system will have the same effect. That is why you must have a good radiator cap on your car
Many people get worried if their car gets up to 220 degrees. On a hot day, going up a hill with your air conditioner on, that is a normal temperature, and is nothing to worry about, as long as you aren't losing coolant. You can safely operate to 240. Above 240 you are nearing the boiling point of your coolant, so start being concerned.

So, 234 was ........not so bad??

 

...
For the Pentastar engine, I believe the normal range is up to around 230 although Jeep JK Owners are mentioning 240, even 245. The engine tends to like higher temperatures. Well, maybe not so much when it comes to the needle bearings in the rockers.
...
So, 234 was ........not so bad??

230 is the peak of the normal range. Beyond that is an issue.

You're missing one of the posts in that Jeep thread. Those guys hitting the 240s must have their radio up too loud to hear the boiling.

My 2012 had an issue getting 236+. My alarm I have set at 235*. I flushed the cooling system, replaced the water pump, and installed a 180* t-stat. After ever wheeling trip I hose out the radiator from both sides till the water runs clear. And she was still getting hot... 3.6, auto, 33s and 3.21 at the time, 115* ambient air temperature, running down the road and in 4low.

Attached is a pic of what my radiator liked like when I pulled it out. You have to remove the radiator to truly get it clean. After I got that clean no issues... 117* air temp, 4low, 37s with 4.88s, 45 min at 1200 rpm high idle pulling winch operations, and temps never went over 226*.

Not saying that your issue is the same but it's only going to cost you some time and a jug of coolant to find out. Which is cheaper than a new radiator.

 

That's useful info. Thanx. Sorry, 2015 with the 3.6.

I replaced the thermostat about 2 months ago and it seems to have gone bad. I got everything dried off, refilled and bled sufficiently and as it warmed up over ~190° it started dripping from under the radiator cap so I let it go for a minute that way. When I shut it off the radiator level dropped immediately but the reservoir is now about an inch above the max level. I let it sit and cool down below 100° while I wiped it down again and restarted. Immediately it was dripping out of the thermostat, it looks like it has a small crack so it's getting replaced and we'll see where it goes after that.

My thinking is the stat can't do it's job because it's leaking there and letting it get hotter than usual and it's spewing out at the cap. Sound right? I will get a new cap too and maybe the 2 hoses also if the store that has the new thermostat has them. Is there anything else that would cause enough pressure to blow out at the cap that I should be concerned about?

 

Sounds like you are on the right track to me.

Air bubbles do not cool an engine, so the engine temperature will immediately skyrocket.

!6 psi isn't much. It's about equivalent to a 7 kg turkey perched on top of your radiator neck.

 

I think I got this one solved. I spotted that small leak at the thermostat so I went and got a Dorman and replaced it. All seems well now, the temp is running right where it should and revved up with the AC on it still drops almost immediately after it tops at 221° and the fan is doing it's thing. That thermostat was only 2 months old. Now I need to drain the distilled water out and fill it with the right stuff.

Unfortunately this led to a bigger problem. I've had "the tick" for a while now and was all ready to order some rockers and lifters today but figured I'd run it back up to temp to make sure it was still ok. It did it's regular knock-tick thing but didn't throw an 0300 misfire code so I got sort of excited and revved it to 2k to bring the temp up and 💥 there's a P0020 code 😕 This is starting to get beyond my rookie ability to fix.

 

That's the code for the cam actuators. You may have bumped one of the connectors loose while doing the thermostat.

 

I definitely did 🫣 I should go check the wires and plugs I guess. Should I also spray some contact cleaner around them because it sprayed and got a bunch of stuff wet when it overheated?

 

Contact cleaner wouldn't hurt, but probably not necessary unless coolant got inside the connectors.

 

That was it 👍 I like having smart friends like you 😎 I had to disconnect the battery for a minute to clear it but it's not knocking and it's not coming back so it looks like I owe you a beer (or 3).

 

First follow up. That plug must have been questionable for a while. I've been getting more concerned that 'the tick' has been getting worse and had turned into a cold start knock that was going to be catastrophic 💥 Now that I made sure the plugs that got wet are good the tick is back to what it was so, for the moment, status quo is going to be the approach 🤷 Oil flow must have been messed up since that's the wire to the oil control valve doh🫣 I have a plan formulating...

Second thought, I'm having a hard time finding the right OAT coolant in a concentrate rather than premix so I'm running just distilled water and whatever was left in the system. All of the stores here have universal or HOAT and I figure if I'm gonna make the effort I should use the right stuff so I ordered it. It's running cooler than ever, granted it's not 90° air temps now but, 185> ~205 with the occasional run up to 220 or so is better than 203>222 with the occasional boil over. I kind of wish it wasn't going into winter and I could leave it mostly water for a while...

 

HOAT is fine, just avoid the Dexcool branded junk. It turns to mud faster than the rest. Prestone universal yellow is a good one.

The connector left off the actuator wouldn't have caused an oiling issue. All it was doing was preventing the cam from coming off of its base position.

Tick is usually rockers... a few people have done them lately and I can't keep them straight. Are you the one that did one head and not the other?

 

^^
Good.

So, could that base position miss affect oiling in some way? There's a noticeable difference.

Oh, for sure it's a rocker thing. I can't tell by sound if there's more to it but the more time I spend under the hood the more stuff I see that should be done. I spotted a significant crack in the intake plenum and a little bit of oil near the base of the filter housing so that's an obvious issue. Is the rough idle associated with that, have the plugs ever been changed, etc.

I wish you were closer 😎

 

If the cooler is leaking, that's your first priority. Get the all metal Dorman one. What kind of a crack in the intake? If it's drawing air you would have high idle and probably codes for throttle control and MAP.

While you have the intake off to do the oil cooler, pull the valve covers and look for the bad rocker(s) and see if it damaged the cam yet. (Or since you already know it's an issue, just order all 24 and do them and the cooler at once if you can afford it.) If it hasn't eaten the cam, you should order parts and drive it as little as possible until you put them on. If it has, you're going to be replacing the cam anyway. Cams aren't too hard aside from holding them while putting on the torque for the OCV.

 

Yeah so, I've mentally committed to taking it off the road for a few days (or more) and I'm working my way up to doing all of these things. Is it pulling air? Tough call. I should do a smoke test but again, I figure if it's going to come apart just deal with it all at once so I'll either seal it or get a new plenum. I'm working on the total cost and figuring out how to make it happen, and how quickly I can make it happen, but the other side of that is a good (?) used engine is likely around the same price (but how much tlc does it need).

Thanx for working with my stream of consciousness. I am, strangely, really enjoying this thing and want to make it as good as it wants to be. For a guy that has long standing FWD issues and minivan stigma that's a heckuva place to be 🤷

 

Doesn't make sense to change it for a cooler and a tick. Fix those, and if it has issues you can transfer the parts to a new one.

 

If you do any repairs to your engine and take the intakes off then I highly suggest using the Haynes torque specs instead. 106in-lbs lower and 89in-lbs upper intake bolts might be too tight. I used those specs and my lower intake cracked in two places from the seemingly weakest points - the two corners near the oil filter cap.
Haynes says to use 71in-lbs on both intakes plus on the upper intake there’s actually 7-9Nm (62in-lbs - 80in-lbs) written on it.
I’m just hoping that those cracked corners on mine won’t spread and that I don’t have to replace the whole intake. It’s pretty expensive for a piece of plastic.

 

That's what I think happened to my upper where I spotted a crack at a corner. After a few decades of turning wrenches on bicycles I'm pretty sensitive to this problem and I'll often use a very small dab of blue loctite and back off 2Nm from spec.