05 ram intermittent overheating...

[Texan4Life]

Truck in my sig. And by intermittent overheat i mean 30 seconds after i noticed it on the heat gauge it is back to normal. and it will only do it like once a week. sometime when i'm driving, sometimes after coming to a stop.

Not technically not an overheat, 3/4 on the gauge instead of the normal half.

I have noticed that sometimes my engine fan is engaged at startup on a cold engine. which is confusing since it is a viscous clutch. When this fan gets fully engaged you now by the semi truck like roar.

Today (96F) i noticed the heat at 3/4 at a stop sign and when I pulled out i didn't hear it roar up with the RPM like normal. but it was back to half buy the time i got up to speed.

For what it is worth that much swing in temp isnt the normal experence in the truck. there is only a little, even when i was towing 6k in 107F heat.

So whats yall take on it? viscous fan clutch, t-stat, wonky heat gauge?

 

[SteveSRT8]

Likely a fan clutch if equipped. I know on my fleet trucks with viscous clutch fans we can only tell at idle as they simply do not overheat if you're moving. Sometimes you can feel the AC die off at a stop too due to low/no airflow.

Gauges are always suspect, I check with a real thermometer.

The other thing that comes to mind is a steam bubble if you've been messing with the coolant.

 

[97f150]

The clutch fan engages on cold start up to circulate the silicone and aid in warming the engine up as it creates a load.
I have a 4.7 liter in the 2002 Ram flavor. One thing that is common on these trucks is the radiator clogging. When was the last time the coolant was flushed? While driving the air passing over the fins of the radiator is supposed to keep it cool while the fan cools it when stopped. I would try flushing the radiator if it has been a while. In my case, a week after my truck started doing the same thing you describe, it built pressure from the clog in the radiator and blew the seal between the plastic end cap and aluminum.

 

[Texan4Life]

about a week ago i flushed and refilled with coolant. The old looked clean as well as what I can see in the rad.

it has 57k on it so I assumed I was draining the factory fill.

Basically just something odd i noticed and if possible wanted to fix it before it goes from "odd" to "problem". it did it a few times with the old coolant. and today it did it again. so I was just trying to think out loud as to what might be causing this.

 

[97f150]

When you flushed the coolant, did you "burp" the air out of the system? An air bubble could cause that scenario? Prior to when you noticed the temp rising like that had the system been opened, maybe allowing air inside?
If you hadnt bled the air out, park the front of the truck higher then the back, when it cools down remove the radiator cap then start it and let it run to operating temp with radiator cap removed.

If that doesnt fix it, I would replace the clutch fan and thermostat (thermostat should have been replaced with coolant flush IMO), then radiator in that order as the fan and thermostat is cheapest.

 

[Texan4Life]

Originally Posted By: 97f150
When you flushed the coolant, did you "burp" the air out of the system? An air bubble could cause that scenario? Prior to when you noticed the temp rising like that had the system been opened, maybe allowing air inside?
If you hadnt bled the air out, park the front of the truck higher then the back, when it cools down remove the radiator cap then start it and let it run to operating temp with radiator cap removed.

If that doesnt fix it, I would replace the clutch fan and thermostat (thermostat should have been replaced with coolant flush IMO), then radiator in that order as the fan and thermostat is cheapest.


good idea to double check for air, i'll do that tomorrow.

 

[SteveSRT8]

repeat: The other thing that comes to mind is a steam bubble if you've been messing with the coolant.

And no offense intended, but parking it at an angle is not going to replace the burp procedure from the maker.

On my Mopar the burp fitting is just under the Tstat housing.

Good luck with the diagnosis.

 

[97f150]

Originally Posted By: SteveSRT8
repeat: The other thing that comes to mind is a steam bubble if you've been messing with the coolant.

And no offense intended, but parking it at an angle is not going to replace the burp procedure from the maker.

On my Mopar the burp fitting is just under the Tstat housing.

Good luck with the diagnosis.


You are correct. And I know that every vehicle is different, but on my particular truck running with the radiator cap off burps it better then that goofy plug and doesnt waste coolant all over the driveway.

 

[SteveSRT8]

But many of us have no radiator cap! It's on the coolant tank if it's pressurized.

NP. Hopefully the OP can get his truck running right. I'm a big believer that steam bubbles can damage head gaskets.

 

[97f150]

Having a 4.7 liter, I believe the same, as well as looking at the heads too hard can blow the head gaskets. My cap is on the degas bottle as well. Its just that trying to use that screw never worked and one day I decided to go unconventional and do it the old way and voila, air pocket gone. OP can try both ways if the screw doesn't work, just an idea. Having an 05 he *should* have a cap on the radiator itself as well.

 

[Texan4Life]

The last thread about how long do tstats last reminded me to update this thread!

I put in a new tstat and that fix it, rock solid now.