2000 Caravan 3.0 V6 leaking coolant, overheating

Maintenance/Repairs
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Seeking WOTL for this 2000 Dodge Caravan Base 3.0 V6 coolant leak. :face_with_monocle:

Last night, overheating returned. :grimacing: Ding - alarm sounded once, then again, temp gauge almost at H. Moments later, Ding-Ding-Ding & on & on, gauge on H and the temp red dash light came on. Immediately pulled over. Was able to add 3/4 gal coolant to the dry reservoir tank and drive home. To help cool, I set the heater on full and heat very much came thru the vents. The temp gauge dropped one notch. And as the drive continued, the gauge would drop to the midpoint, then up almost at H, then back to midpoint. Made it home.

Am guessing that the coolant in the reservoir did not make it back into the engine. Today I added almost a gallon directly into the radiator. Ran a 10 mile r/t errand, then, over cardboard, ran the engine at idle. Coolant was fast-drip (1/sec) leaking and I could see it dripping off the rear side of the oil pan. I need more room to get under safely to see whatā€™s what. The reservoir level didnā€™t seem to change at all. After 45 minutes letting it cool, the reservoir dropped 2/3 between max toward min.

:upside_down_face: In April this year 2019, there was a ā€˜mysteriousā€™ leak - I think it was the same issue, very similar gauge activity - and I saw coolant leak where the fluid dripping near the rear of the engine. My shop said after some time running under pressure test that the problem was the cap and they replaced it. That was almost 1K miles ago, about my usual mileage.

In the 1 1/2 months between, I have had no noticeable problems. Iā€™ve read that there is a rear coolant (inner?) metal tube that others have patched with a rubber tube, I wonder how difficult it is to replace if thatā€™s the leak.

FYI: I reported a non-overheating condition a couple of years ago, here: 2000 Caravan NOT Overheating?

Also - I donā€™t want to throw my mechanic under the bus - but am wondering why I saw coolant leaking in April and his pressure test did not show a leak, now Iā€™m seeing a similar coolant leak - both times without pressurizing - am thinking about going somewhere else.

Apologies to length but I do have some history and detail that might make sense to you. :cowboy_hat_face: Help!

Bardi

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I had a 1995 Caravan with this engine, so I am very familiar with working on it. There is a steel ā€œcrossover pipeā€ which goes across the center of the engine block in the ā€œVā€. This pipe connects to the inlet of the water pump, and is made up of two pieces. A rubber O-ring is used at the water pump, and where the two pieces of the ā€œcrossover pipeā€ connect.

Over time, the coolant causes this pipe to rust, and it will corrode away in the area where the O-ring(s) seat. This will result in an external coolant leak, and possibly drawing air into the cooling system.

There is a Dorman version of this part, which I bought online. A quick Google search found this, but there is also a second piece, which may also be bad.

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bcohen, I am pretty sure itā€™s either the pipe or o-ring - either way, Iā€™d replace the pipe. Soā€¦

Do you have a procedure for that?

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BTW, I see the part thatā€™s compatible with my 2000 Caravan is the Dorman 626-302. As well, Amazon states that the one you mentioned does not fit my vehicle.

From Dorman: https://www.dormanproducts.com/p-12049-626-302.aspx

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Avoid driving your Caravan until the coolant leak is repaired. Even a single overheating incident could cause a major repair expense, not worth the risk. .

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Looks like a-lot of work to get to this $25-40 part. Hereā€™s someone whom had a leak on the other side of the engine, but went to this tube first: https://www.youtube.com/watch?v=mx3pv8fBNEI&list=WL&index=58&t=0s

And George_San_Jose1, I AGREE. I would be happy to use other transportation but Iā€™m stuck as far as 4-wheels go. I have coolant in it now and will continue to monitor as I use it.

So, I ask the Car Talk MultiVerse again, is there a procedure for replacing this tube that doesnā€™t require pulling the plenum and all its attachments off?

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Thereā€™s a minivan forum at allpar.com, a site that specializes in Chrysler products. You may find info at that site, or an answer to your questions at that minivan forum. Good luck and please keep us informed.

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another place you can try

https://forum.chryslerminivan.net/forumdisplay.php/30-3rd-Generation-Chrysler-Minivans-1996-2000

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Iā€™ve no experience w/that engine. But you shouldnā€™t have to invent the procedure yourself. Donā€™t you have the applicable Haynes or Chiltonā€™s repair manual for you car? If not head over to the local public library, they many have a copy. I have both a Haynes repair manual and the factory service manual for my Corolla, and while the factory manual might be a little better, the Haynes manual would have a workable diyā€™er procedure for something like that.

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our opel v6 has a similar pipe feeding the thermostat. the thermostat replacement job is a few hours. the pipe is under the lower intake. the pipe snakes between the head and timing cover and has a nice little aluminum arm that holds it and is real easy to pry on and it snaps off, so, remove the upper plenum and than remove the lower intake. as much fun as it sounds

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I appreciate the additional suggestions about finding how-to instructions in print or video.

I did decide to temporarily deal with this issue with Bars Leaks, and Iā€™ve been reporting on that here: Bars Leaks for radiators - how well does it work & perhaps last?

I have not had time to investigate replacement further but I hope the patch effort lasts long enough for me to get around to replacing this tube assembly.

Thanks for reading & responding. I will jump back in after replacement with a post-mortem on the effort.

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No. When I had to replace this pipe on my Caravan, I had to remove the upper intake, as well as the timing belt and water pump. Also, the service manual specifically said not to get any oil or grease on the O-ring mating surfaces, but I couldnā€™t get them to slide together if my life depended on it. I used some lithium grease on both ends (where the one half of the crossover pipe slides into the other, and where the water pump slides over the crossover pipe). The grease made it slide on easily.

This is not an easy job, but get it done. This engine does not tolerate overheating. Even overheating this engine once can result in head gasket leakage between adjacent cylinders, and although the resulting misfire is only noticeable at idle, it will turn on the Check Engine light and prevent you from passing an emissions test.