For Chrysler/Dodge Caravan/Plymouth Minivan Owners

[MaximumMini]

Please feel free to discuss anything related to Chrysler/Dodge/Plymouth minivans.

I've been tinkering around with cooling system tweaks lately and one of those is trying different thermostats...just for the knowledge.
The car has a relatively new radiator, new water pump, new radiator hoses, new radiator cap, new temp sensor, new fan relay and recent coolant flush. Keep in mind I live in a Tropical zone where we rarely ever see temps below 50F and summers are quite hot and muggy for a long time. If you live in a colder more Northern zone your cooling requirements are probably much different.

I'm doing this in a 1999 Gen 3 with a 3.3L

Recently I tried a Motorad 2340-195 "High Flow" thermostat.
After several hundred miles of driving I can't really see any significant difference over the Standard Motorad 195F thermostat for this same vehicle.
One thing I did notice was a consistent 5F increase in coolant temp at highway speeds, which is a bit odd.
It seems this thermostat is slow to open and just barely begins to open at 195F but doesn't allow a significant flow until over 200F, resulting in a warmer temp. I tested this thermostat and another of the exact same in a pot of boiling water with a laser thermometer and both opened at the same temperature (so consistency), but both are slow to open and not fully open until near 206F.
The standard Motorad 195F opens earlier, at around 192F even though it claerly has 195F marked on it. That results in a running temp of about 194F while on the highway.

I went into this knowing that changing just a thermostat is not going to do much, but curiosity got the best of me.
I wanted to try a high flow 192F thermostat but Motorad doesn't make this for a Gen 3 Caravan and I couldn't find one.
I'm also going to run the vehicle with no thermostat so I can get a baseline as to how cool it will run without one.
This should give me a better idea of how increased flow rate alters the coolant temps.

Basically, if you really want to lower the overall operating temp of your 3rd (or 2nd or 4th Gen) Chrysler minivan, you'll probably need to change the radiator to one that offer more heat rejection. I'm doing just that. Today my new 3 row all aluminum radiator for this vehicle arrives.
Will let you know how that goes here.

Note: Motorad 2040 series thermostats will not fit in 3rd or 4th Gen Chrysler minivans. The base support posts are too wide. They fit Gen 1 and maybe Gen 2.

 

[D60]

One of the coolest hacks on some of the transverse motors is to fish the p/s pump out by the high pressure line and drop it back into place the same way.

I did this either on a '94 or an '03 -- can't remember now!!

 

[MaximumMini]

One of the coolest hacks on some of the transverse motors is to fish the p/s pump out by the high pressure line and drop it back into place the same way.

I did this either on a '94 or an '03 -- can't remember now!!

Yes indeed. I did the power steering pump on one of my minivans (can't remember which one right now) and I don't recall it being particularly "fun". will remember this trick

 

[MaximumMini]

My radiator just got here woot!
It's the Spawon, all aluminum 3 row radiator and it's going in my favorite Caravan, the 1999 SE, 3.3L
What am I hoping for? I would really like to see it stay at a slightly lower coolant temp on hot days sitting at lights whee it often climbs to 224F before the fans come on and then struggles to keep it under 220F. If this radiator helps it sit around 215F while sitting at lights on hot summer days I'd buy another for my other caravans. Will know soon.

There it is! Oh boy!

Nice sturdy box. Well packed.

Nice looking. Looks and feels pretty good.

The welding looks pretty good to me.

This is all the hardware it came with.

I'm going to use Rislone Hyper Cool in it and a reduced ratio of antifreeze...maybe 70water/30antifreeze since it never gets cold here.
Heading out to the shop now to git er done.

 

[AZjeff]

Lotta love for a 26 YO minivan.

 

[MaximumMini]

Lotta love for a 26 YO minivan.

I drive her a LOT. she has over 300k miles on the clock and still going strong.
So I treat her like an aircraft. Maintenance OCD.
Yes, I do love this minivan.

I honestly wouldn't take a new vehicle if it was offered for free (except maybe to immediately sell it).

 

[MaximumMini]

Ran into a problem installing the new Spawon radiator.
The issue is that the brackets that secure the radiator to the condenser are spaced 10mm too far to the center of the radiator.
This results in the radiator not being able to clear the condenser so it wont go all the way in to give the correct clearance between the radiator and condenser. The gap is about 15mm more than it should be. Contacted the seller. waiting for a response.

I could cut that bracket at an angle and make it work but I want the seller to approve the modification to keep the warranty intact.
IIRC, I read where someone else had this same problem but they zipped the bracket off and aluminum welded it back on.
I don't have any aluminum welding expertise so I can't do that.

This especially zuks because I'm in the middle of renovating a house and I use this vehicle exclusively for getting there 150 miles away and carrying all my stuff. (all seats removed except for driver seat). Now I'm in limbo waiting on a response. I may even have to reinstall the other radiator I just removed today

 

[Speedy3861]

Just a lookback, but I remember when you actually mixed antifreeze, I was cautioned to use only distilled water.

 

[MaximumMini]

The seller replied.....
"Take it to a shop and have it professionally installed" was their reply. Completely ignoring the clear photo I sent them of the bracket not being able to clear the condenser. Any shop would face the same issue.

I did get the radiator installed and checked the inlet and outlet temperatures with a laser thermometer. There is negligible temperature drop across this radiator. I highly suspect there is no cross flow whatsoever. From the temperatures I observed, the passenger side of this radiator is nothing more than an empty tank that allows water to enter then exit the side tank directly back into the engine. The water enters the radiator at the inlet and the vast majority of the water simply exits directly below at the outlet. "Some" coolant might make it into the cooling rows by trickling into the rows, but there seems to be no internal baffling to direct such flow.

If you know of any other tests I could run to verify please let me know.

At this point, I would rate this radiator from Spawon as a gimmick and not an actual efficient radiator.
It's going back. The $100 radiators on Amazon do just as good a job. Very disappointed. I had high hopes for this radiator.

 

[D60]

Just a lookback, but I remember when you actually mixed antifreeze, I was cautioned to use only distilled water

Supposedly pre-mix comes with deionized which is even better. Less chance of that electrical/water science-y stuff happening

 

[clinebarger]

The seller replied.....
"Take it to a shop and have it professionally installed" was their reply. Completely ignoring the clear photo I sent them of the bracket not being able to clear the condenser. Any shop would face the same issue.

I did get the radiator installed and checked the inlet and outlet temperatures with a laser thermometer. There is negligible temperature drop across this radiator. I highly suspect there is no cross flow whatsoever. From the temperatures I observed, the passenger side of this radiator is nothing more than an empty tank that allows water to enter then exit the side tank directly back into the engine. The water enters the radiator at the inlet and the vast majority of the water simply exits directly below at the outlet. "Some" coolant might make it into the cooling rows by trickling into the rows, but there seems to be no internal baffling to direct such flow.

If you know of any other tests I could run to verify please let me know.

At this point, I would rate this radiator from Spawon as a gimmick and not an actual efficient radiator.
It's going back. The $100 radiators on Amazon do just as good a job. Very disappointed. I had high hopes for this radiator.

The tank with the inlet & outlet needs a dividing wall....Like this.

 

[MaximumMini]

Just had my car run the hottest I have ever seen it run in 20 years.
Made sure there was no air in the system, fans working properly....

The Spawon radiator is simply not well made. I do not recommend it. At least this one for the Dodge Minivans.
Undoing all I did today and putting the Spectra Premium radiator that was in it previously back in the vehicle.

 

[MaximumMini]

The tank with the inlet & outlet needs a dividing wall....Like this.

Agreed. I can all but assure that this Spawon radiator has no divider based on the heating patterns I measured on it.
It apparently enters in the inlet, and then passes out the outlet directly below with nothing to force the water across the radiator.
Terrible design. Made my vehicle run hotter than I have ever seen it run.

A basic Spectra Premium for this vehicle for $50 - $60 less does a much better job.
A lot of work for nothing. I have to remove this new radiator and reinstall the old one. It worked MUCH better.

 

[clinebarger]

Wuhan Institute of Cooling Technologies