Overheating... just the thermostat?

[WoodenBirdOfPrey]

Headed down the road tonight after letting Virginia warm up for a couple minutes.  About 34 degrees out.

I made it a mile or 2 down the road and noticed my temp gauge was at the very top edge of the green zone.  I watch the temp gauge pretty closely and it never goes more than a couple mm from the bottom of the green zone, even in August with the A/C on.  I pulled off onto a side road, put it in park, and gave it a little throttle to help the fan cool it down, no help, the temperature kept on climbing so I shut it off.

The engine didn't seem any hotter under the hood than usual, but after it cooled down for about 5 minutes I verified that the fan was spinning, the radiator and overflow tank both had coolant in them, and the radiator was hot so some coolant is getting through the system.  I started it back up after it sat a bit, and the temp gauge dropped back down.  I turned around to head home and swap the Eagle for my truck, and on the way back it did the same thing, the needle hit the red as I coasted into the driveway.

My first instinct is to replace the thermostat and go from there.  There are a couple things that don't seem right to me.  Minor, and maybe just coincidental.  First, I noticed when I started it up before the overheating, that even though the car had sat outside in the cold for at least 3 hours since I drove it last, when I got in the temp gauge was sitting at the bottom of the green zone, when I think it should have had plenty of time to cool down.  Same thing again a few minutes ago when I got home.  The car sat from 9:30 to 1:30 and it's under 30 degrees tonight, yet the temp gauge was sitting in the green or just below it.  So now I'm wondering if it was actually overheating, or if my temp sender is getting funny with me.

The other goofy thing it did tonight, is when I was driving it back home to get my truck, I had the heat and fan on full blast, and the battery/alternator dummy light on the dash was ghost lit.  Not lit brightly, but just enough for me to notice it and be bothered by it.  I never noticed this before.  I don't think it's related to the issue at hand, but who knows.  Not me.

So the big question is what do I try first?  Temp sensor or thermostat?  I'm pretty sure this isn't a head gasket issue, none of the signs are there.  No gassy odor in the coolant, no coolant loss, nothing burning.

[ammachine390]

Sounds like the sending unit could be faulty. They are easy to replace and only around $15.

As for the alternator light, mine did the same thing for probably at least a year. I ended up having to replace the alternator. It was able to provide enough amps for just the basic stuff, but couldn't provide enough amps to power all the headlights and accessories on at the same time.

[68AMXGOPAC]

Hmmm, how about the water pump belt or the pump itself not moveing enough flow.........My yard wagon did that , and I pooped the hood and the belt was bad...just a thought. Even if the stat is open it might overheat without enough flow....

[WoodenBirdOfPrey]

That's another thing on the agenda.  The belt seems to be a little on the loose side, when the engine accelerates when it's cold the belt will squeal for a second before everything catches up, but after that initial squeal it's quiet.  Is it actually possible for the belt to slip without making noise?  Because it seems like it's turning the fan fine, it's throwing out a good amount of air.

So how do I tighten the fan / water pump / power steering belt?  I know it has something to do with the power steering pump but I was expecting to find a slotted bolt hole somewhere and I can't see anything like that.

[WoodenBirdOfPrey]

Replaced the thermostat.  The one in it was from 2005, along with the coolant, so the coolant needed changed anyways.  I'm letting the RTV on the gasket set up, and I'll pick up a couple gallons of antifreeze on the way home from work tomorrow and see what happens.  I'll tighten up the belts at the same time if I can figure out how to do that.

[mudkicker715]

Power stewing has a hidden bolt on the back. 2 on front iirc.

Water pump is tightened on the tensiometer hoch is just off center ds.

[WoodenBirdOfPrey]

Power stewing has a hidden bolt on the back. 2 on front iirc.

Water pump is tightened on the tensiometer hoch is just off center ds.

I think you're describing it on a different engine or accessory config.  I have 3 belts: 



Crank to water pump to power steering (this one is the loose one)
Crank to A/C to tensioner
A/C to alternator

There's no tensioner on the driver side.  The power steering pump has a 1/2" drive on the back for a breaker bar/ratchet to aid in adjusting the tension, I just don't understand what bolts I have to loosen first.  There's about 8 bolts down there related to the ps pump and bracket, and I don't see how any of them will let the thing pivot to adjust the belt tension, and of course none of them are easy to get to so I want to avoid the trial and error tactic with this one.

[mudkicker715]

As I said outcry. Haha whoopsy. As I said there is 3 bolts that I recall 2 front 1 back for power steering. Also a half inch box for tightening

[68AMXGOPAC]

I believe my idler swung to provide the tension on the belt.

[WoodenBirdOfPrey]

Alright, it's definitely the temp sender.  Hand on block, engine is about 70 degrees during warmup, and gauge is already in the red.  Ordered a new one.  Really wishing I tried that first but the coolant definitely needed replaced anyways.

So now i'm in the process of trying to flush the cooling system.  What I don't understand, is if the system capacity is 14 quarts/ 3.5 gallons, how come when I drain it I only get about 2 gallons out of it?  I know there isn't 1.5 gallons sitting in the heater core, so where is it all hiding?  And how am I supposed to get the right ratio of coolant to water if I can't get all the water out after flushing it?

Thanks for the help guys.

[ammachine390]

There will still be some in the heater core, recovery bottle, and intake manifold.

[WoodenBirdOfPrey]

So recovery bottle is included in the capacities as well?  I didn't even think of that but it makes sense.  I bet that alone is about half a gallon to the fill line.  Thanks.

[mudkicker715]

Engine block holds most of it even after draining it.

[ammachine390]

So recovery bottle is included in the capacities as well?

I just assumed so, after all, its still part of the cooling system technically. The intake manifold does hold quite a bit though.

[68AMXGOPAC]

I would mix it 50/50 at least and put in that way, premixed.flush and fill your overflow with straight antifreeze.