This is the 6th Dakota my family has owned and I've always done all my own maintenance and repairs on them -- but this one's got me stumped:
I recently purchased a 2000 Dodge Dakota, with 2WD, 3.9L V6, AT. Really low miles, at 72K. After I drive it and the vehicle comes up to temp, I find that I smell antifreeze afterward. I don't smell antifreeze inside the vehicle, but outside after I exit. Over time I can slowly watch the reservoir get lower and lower as it slowly drains down -- maybe a half inch a week. There are no obvious problems or leaks like from the heater core. I tried using UV leak detector and also couldn't see any leaks. I tested for the coolant for combustion byproducts, and again nothing.
I desperation, I changed out the radiator cap and thermostat. I have it in my head that maybe it's a little better, but maybe that's just my imagination. One odd thing about the thermostat I removed: It was only 160 degree. That's weird, really weird -- as I'm in Minnesota, where people change out thermostats with higher temp stats, not lower temp ones. Because of the 160 degree stat, I have it in my head that the previous owner might have had some sort of problem and tried the radically colder stat.
My thinking is to just keep driving and keep and eagle eye on the temp gauge. Hopefully the issue will progress until it's obvious what's going on. However, it would be best if I can figure it out before it leaves me on the side of the road.
Thanks in advance,
Larry
You might want to try pressure-testing the cooling system.
Thanks for the reply. However, I'm not quite sure what pressure testing gets me, since I'm already pretty sure there's a leak. Unfortunately, as I mentioned previously, I didn't see any leaks when I put the dye in the coolant. Even a couple weeks on, I'm not seeing anything.
Larry
It's possible that with the cooling system under pressure and engine not running you might spot something you didn't see before. May be worth a shot, the antifreeze has to be going somewhere, either leaking or burning. (I hope it's not going into your transmission via a leak in the radiator trans cooler!)
I had the transmission serviced when I first got the truck. There didn't seem to be any coolant in the transmission.
But your other point got me thinking: I wonder what would happen if I did the pressure test on a cool engine? It might be that there is a pinhole leak and the coolant is vaporizing when it hits hot metal. However, since I'm not seeing any UV leak detector, it would have to hit something hot enough (exhaust?) to burn it off. I wonder if that's even possible?
Possibly. I've certainly found pinhole leaks and loose clamps with pressure testing but haven't used UV dye.
Hmm When I run into a issue similar to this it’s usually my intake manifold but you’d still see a leak even if it’s small, give a look at your intake just in case because you won’t see much coolant on the ground if it’s your intake and you say you only lose a very small amount a week. This is just from my experience of this situation
Dakota intake manifolds are a two part affair. They are known to suck oil out of the engine. Typically the intake gaskets themselves don't give many problems. However, it's worth checking out. Is there some way to test for coolant in the exhaust?
Larry
It's either leaking somewhere or burning it. Only two choices. By the way, what is the correct temperature thermostat you put back in the truck? It sounds like the previous owner used a lower temp thermostat to cover up an over heating issue.
I'm not averse to the idea that I'm burning it. However, my suspicion is that because I'm smelling it, that it's leaking and I'm just not seeing it. It seems like I might just have to wait until the source of the leak becomes apparent.
I replaced the stat with the standard 190 degree unit. I'm likewise thinking the previous owner was trying to cover up something.
Larry
Bummer! {pear}:surprised:
Thanks for the reply. However, I'm not quite sure what pressure testing gets me, since I'm already pretty sure there's a leak. Unfortunately, as I mentioned previously, I didn't see any leaks when I put the dye in the coolant. Even a couple weeks on, I'm not seeing anything.
Larry
I had a similar issue with a jeep. It ended up being a blown head gasket. Check you coolant and make sure no oil sludge is collecting on the cap. Chrystlers are bad at blowing head gaskets.
Also check the thermostat and the thermostat housing that is a common place for it to leak on chryslers as well.