Glad to hear someone else takes higher mileage vehicles on road trips too! With any vehicle of that age and mileage a few problems can be expected, especially if it hasn't been maintained very well (I.E. the spark plug situation). But it sounds like you know a thing or two about your vehicle. Now onto the overheating issue. I think a big mistake made from the get go is using bars leak, I have heard nothing but bad things about that stuff. It plugs up radiators, small coolant passages and can mess with sensors. I would imagine that if you didn't have any over heating (but leaking) issues before adding the stop leak, that's what caused the problem. Even though a few coolant lines were replaced, I would imagine that the radiator is plugged up (not completely) but enough to cause the issue. I would replace the radiator and again, thoroughly flush the system. As for the radiator, I recently replaced one in my 2003 with a "Spectra Premium" from Autozone and I haven't had any troubles. Granted it has only been a month or two, but it also has a "lifetime" warranty so if it does cause me troubles, I can somewhat easily get a replacement. Whether you want to get a new aftermarket radiator or one from the junkyard should really be a matter of how much longer you're planning to use the vehicle. Hope this helps! Safe travels home!

 

Not that I'll be of any help, but it's nice to see someone besides myself taking a high mileage van on a devil-may-care trip. I bought my '96 3.8 about five years ago with 205k already logged in. After a going over by a mechanic, & replacing belts, hoses, & whatever else that could eminently fail, I took it on an 8000 mile venture, looping the USA. Not one problem then, & nothing major since. Now, at 240K she's still hummin' along. I hope you'll get everything straightened out, 'cause these old beasts are worth hanging on to.

 

The hardness in the upper radiator hose when it's hot is relatively normal but the popping is an indicator of a high temperature condition. (Think pressure-cooker). It looks like you have played it smart so far and waited for the engine to cool off before doing anything with the radiator cap or hoses. That is hopefully going to continue. Coolant can scald you badly in these situations. I think I'd do the thermostat again just to be sure it was installed properly and hasn't gotten any of the bars leak stuck on it that may have been floating around. Oh, and the ECT as well, (Engine Coolant Temp Sensor)

I've not heard the 6 month life warning on aftermarket radiators but, I don't know what they are selling in CA. I would think you can find a supplier that will warranty the product in your home state as well.

The P0700 is a engine DTC that is generic in nature. It simply alerts the MIL to turn on due to the presence of another DTC in the trans controller. i.e. since you had P0731 and P0715 on the trans side, it signals a P0700 on the engine side. Both sensors usually do not fail at the same time but, shops really hate installing one sensor and then have the customer return for the other sensor in a week or two. Not that it WILL happen, it's just burned more than one tech before.

Here's hoping for a safe return!

 

If you go the junkyard radiator route, I'd suggest taking it to a good radiator repair shop and getting it pressure-tested, then getting any leaks repaired before installing it in your van. I just had tranny problems with my van, something similar to yours. In my case, the problem was the solenoid pack. While they were checking out that problem, they discovered my radiator was leaking, so I had them replace that as well. I was happy to find that they installed a CSF radiator, as it has a copper/brass core instead of the usual aluminum you see today on most radiators. In addition, I had them install an auxiliary transmission cooler under the bumper, as there is no place else to install one if you have the rear a/c condensor. So far it has worked fine, with the exception that I now need to relocate the ambient temperature sensor for the CMC, as it reflects the temperature of the aux cooler instead of the outside temps.

 

In addition, I had them install an auxiliary transmission cooler under the bumper, as there is no place else to install one if you have the rear a/c condensor. So far it has worked fine, with the exception that I now need to relocate the ambient temperature sensor for the CMC, as it reflects the temperature of the aux cooler instead of the outside temps.

aKids2003_DGC installed a transmission cooler to the front of the van even though he has the rear A/C, but he had to cut the metal bumper to accommodate the tranny cooler, not sure if you'd feel comfortable doing that to your bumper.

Here's the video of how he did it: https://www.youtube.com/watch?v=6MGMt82u-FQ

 

Yes, I saw that thread. Nope, not comfortable ruining the integrity of an expensively designed bumper, which is why I didn't go that route. I don't have the skills or equipment to do such a thing anyway. There is another thread where another Arizona member mounted an auxiliary cooler under his bumper in a manner similar to mine. The secret seems to be in measuring the space available and finding a cooler that fits that very limited space. The other AZ member used a tube style cooler, while mine is a plate type. Considering the position of the cooler, I think a plate type would work better for rocks and debris, though the other member never had any problems with his before he sold it.

 

I'm a little late but it probably was your water pump.

 

^^^And how's that? It was rusted out rear heater lines (common problem), which were replaced and the cooling system now holds pressure and doesn't leak, so how could it be a water pump? Heater is working, so water pump is doing it's job.

If the thermostat was upside down, the engine would GROSSLY overheat. I think the Bars' Leaks probably clogged up the radiator. I try to never use any stop leak product, because they don't fix the real problem and have the potential to do even MORE damage (like a clogged up heater core!).

Oh, by the way, the rear heater lines can be bypassed without having to remove the top of the engine. I've done it twice by removing the battery, moving battery tray and removing the air intake ducting.

 

I've had 2 aftermarket radiators fail internally. The stupid baffle that separates the passenger side radiator tank breaks effectively nullifying the cooling capability of the radiator. I'm on my 3rd radiator now and it is doing fine (knock on wood). Might be worth a shot.