Has anyone found a good all metal radiator for the 1st gen 3.9?
I'm losing coolant as detected by the overflow losing fluid level, I find no sign of it going out the exhaust or into the oil. I figure the replacement rad I put in years ago must have a crack in the plastic top or bottom that opens up when it gets up to pressure.

 

Pressure test the system. See if you can find the leak. Make sure that it is indeed the radiator, before you go out and spend money.

 

You got any idea what test kit will fit the Dakota? I don't. I got that one they have at autozone which has at least 3 dozen different pieces and not one of them would fit on the top and seal. The rubber thing you pump up like a pig plug in a pipe blew off 3 times before I stopped trying it.

 

Is there a radiator shop in your area? If so, and your old one is all metal, they may be able to rebuild it.

There's also a possible run to a boneyard.

Side note - Too bad you're not close to Longview TX; they have two Dakotas with the Extreme Cooling radiator and shroud (although missing a few of the doors on the shroud), all metal, original Mopar, at Andy's U-Pull-It.

They can be rebuilt; neither one shows signs of leaking, TBH (no rust trails that I could see.)

Aside - same place has gas tanks in all four Dakotas (a 1987, 1988, 1989, and a 1990 !!!) although the 1990 is a 2.5L truck. They all have the fuel pumps still too ...

(I may try to buy the fuel pump assemblies; they sell tank AND pump for $65 they pull and drain for you.)

RwP

 

I agree with pressure test first. You could also just get it up to temp and check the upper rad hose is solid and look at it. Also if your rad cap is weak it will push the coolant out the overflow bottle when hot.

 

Thank You Ralph, Glenn, Hey. There is a shop in town. I suppose I'll have top pay them to test it.
When I changed out the old radiator I did not pay attention. It was probably OE and this one is plastic tanks from RA.
I've seen some all aluminum on Summit. They even have one claiming to be OE brass/copper. and a nice one for only $584 and change with two electric fans attached :-)

 

I got a tester from O'Reilly's. The cap and radiator held pressure. It ejected some coolant when I released pressure. So I removed the overflow and cleaned it out and refilled it with 50/50 to the full line. It is easier to see now. I changed my oil over the weekend and it was low so maybe that was making it hotter? I did not notice the interior gauge showing it was hot.

Edit- I just looked up the FSM and I did not test it at full temp. Shazbot!

 

If you don't have a UV test kit, it's a good thing to have. Put some water based dye in the system and see where it's leaking. Why replace a radiator when it's the weep hole on your water pump that is the loss site? I'm not a fan of throwing parts at a problem.

 

Well you don't want to touch the cap on a hot system as theres excessive pressure in the system. 15-20psi pressure test will find most if not all leaks one way or another. The pressure will open up any cracks in the system regardless of being hot or cold

Check your passenger floor mat and/or ac drain make sure its not the heater core leaking

 

I'm referencing putting the tester on the rad when cold and running it until at full temp. I actually made this same mistake with another rig years ago. I guess I forgot. The number on the cap said 16v so I pumped it up to15/16psi. If I remember correctly that is to see if the system is running at pressures higher than normal.

Edit 5-27-21 Doing some thinking and research I don't think it necessary to test this truck at running temp. I don't have the kinds of problems I was having with the other one I did it on. All the mechanic made vids I can find indicate the cold pressure test is adequate for normal circumstance. I'll keep an eye on the overflow if it starts dropping again I'll reconsider.