More troubles with the Dakota

[destrekor]

Okay, so yesterday when I was driving around town, I hear a beep and look down to see the 'Check Gauges' light is on, and then I look around... oil's fine, but engine temp... hmm it's red-lined (260 in the Dakota.. a range somewhere around 200 is optimal, maybe somewhere between 180 and 220?, with 130 the lowest).

No issues otherwise evident... no smoke from tailpipe or from engine. First thing I did was turn the vents on heat, and pumped out hot air. But it varied between pumping out hot and just normal air.

Today I take a closer look once I find out what to do (i know jack shit about cars for the most part), take the radiator cap off and coolant is pretty much up to the top.
Now, here's the part I'm not too sure about... the coolant reservoir/overflow bottle seems to be pretty low, but I'm not sure how much is supposed to be in there. My dad talked with our mechanic and they said the bottle would have a marking for cold and hot. Well the dipstick had two markings, but one for ADD and one for FULL. I was under the impression it was just for overflow and there shouldn't be much in there, but like I said, I know nothing... never had to deal with coolant before. But basically it's right about at the ADD line.
But after I checked that, I figured I should turn the car on again to see how it behaves.
Yesterday it was doing that right before I got to Kroger. There were no leaks, and hasn't been anything so I wasn't sure what it could be, figured just an electronics fluke. Turn the car on after my shopping and it basically nearly instantaneously hit red.
But back to today. I start it up and rev it a little bit and let it run for awhile, and it stays at the minimum for temperature. Kind of makes sense, it's barely doing anything.
So I figured I should take it for a 5 minute drive, with the assumption that maybe it's just the thermostat.
Well, turn heat on, and get no heat, just air. Go driving for awhile, accelerate a little more than normal to stress test, and slowly the temp starts to climb. This makes sense, as it started at minimum and wasn't even into the middle 'normal' range. Vents still pumping out plain air like it was just a fan... and not on heat.
Engine temp keeps rising a little bit, and hits the max of the optimal range, like I said early, probably about 220. After keeping to that temp for awhile, all of a sudden it just jumps to red. After a few moments, I get some heat pumping out of the vents, and then it drops back to around 220 and the vented air returns to air that is not warm. And after a few moments, back up to red, and then maybe 20 seconds later the warm air comes back and the cycle repeats until I get it back to my place.
No smell of coolant, no visible evidence of any problems.

Is it just the thermostat and there is no worries about engine damage? Do I drastically need coolant and shouldn't drive till I add some to the overflow reservoir?

Just a month or so ago we had a new water pump and serpentine belt and belt tensioner installed.
This thing I swear is telling me its ready to be put down, with all these peripheral things going bad on me. The engine is still kicking, and at only about 110k thousand, it better keep kicking. I need this truck to last me a few more years, a couple years after graduation and I'm active would be great, so then I'd more readily be able to afford something newer.

 

[Elstupido]

Wow, that's a lot to read!

Basically you need to make sure you have enough antifreeze in your expansion tank. Two things can fuck with you, your thermostat, number one, and an airlock, number two.

#1 is a no brainer, if #1 is ok, then, you need to remove your radiator cap when cold, and let it run till you can see the coolant flowing freely for a while to get rid of airlock.. BTW, the coolant flowing freely indicates that your tsat is open, and working properly.

 

[LTC8K6]

It actually sounds like the water pump is not working very well to me.

"#1 is a no brainer, if #1 is ok, then, you need to remove your radiator cap when cold, and let it run till you can see the coolant flowing freely for a while to get rid of airlock."

I'd look for that coolant flow.

 

[destrekor]

Originally posted by: LTC8K6
It actually sounds like the water pump is not working very well to me.

"#1 is a no brainer, if #1 is ok, then, you need to remove your radiator cap when cold, and let it run till you can see the coolant flowing freely for a while to get rid of airlock."

I'd look for that coolant flow.

Well if that's the case, it's be good if it was the water pump because it was just replaced, meaning no expense... then again, I'm down here in Columbus, while it was replaced by our mechanic in Toledo. Hmm.

Can I run the car with the radiator cap off? It says not to remove while engine is hot, which makes sense due to pressure. But if its already off, then it'll be fine and not go spurting all over the place?
And with flow... since it's a somewhat narrow opening, looking down about a 2-3" pipe and then I see the coolant... will it be easily noticeable?

 

[Elstupido]

Run it cold, with the cap off. When the tstat opens after a few minutes, then you should easily see the flow of coolant through the cap opening, like a river running through it.. If not then you have problems with the stat , or pump. More likely the stat, if you replaced the pump lately. This should also purge any air in the system.

 

[radioouman]

It is a sticking thermostat. Just replace it.

This is a Dakota, and these don't have much of a problem with air getting trapped. To prove that, open the radiator cap and push down on the upper radiator hose. If there are any air bubbles, they will come out.

The thermostat is a pain to change. You'll need to pull the alternator to get to it. Also, if you've never replaced the coolant bypass hose, you need to do it. It is the little hose that goes from the top of the waterpump to the head. You can only get to it by pulling the A/C compressor and the bracket that holds it.

This holds true for both the 3.9 liter and the 318 (5.2 liter).