Over heating issues

[nrs]

I enjoy this forum very much and I'm hoping someone here might be able to help me out - not too much of a car guy, but I try to use a bit of common sense and my noggin' and it usually works out ok.

2002 Ford Explorer, v6 - with somewhere around 150K on it. No huge issues - I noticed theres not much difference on the blower settings for the ac /head. It drove fine through the winter but when it got warmer outside the AC wasn't cool so I recharged it. I did notice that the passenger was cooler than the drivers side and I was just about borderline for needing another can of 134a (which I haven't put in yet)

Went to see the in-laws this weekend (600 miles round trip) to Michigan and all highway driving, not much stop and go, average speed around 75 MPH. Way up was fine, trip back home was when I started having issue. It was real hot outside and after 2 hours the AC started acting up - not blowing cool air - it came back only to go out and cycled like that a few times until I found if I backed off on the cruise control (down to around 70 from 77) the AC came back on. Around that time I noticed the temperature gauge was at about 3/4. I noticed that accelerating made it get hotter and we pulled off the interstate. We parked and I let the car cool off and then got going again, this time on side streets. Again the temp was around 3/4 but started to peg higher than that. I again found a parking spot, turned off the car and popped the hood. I checked the coolant and saw that it was even with the bottom line of the cold fill zone. After 30 minutes we left again and while on side streets to get to interstate had some jerky up shifting and temp gauge bouncing from 3/4 to 1/2 to just shy of the red mark. Back on the highway as long as I kept the car around 60 MPH we were fine but the A/C was in and out. Had to accelerate to avoid an accidentt and the temp gauge pegged in the red and check gauge came on for around 5 seconds.

Normal driving on Monday - Spotty AC and temp gauge reading about 3/4 (even after the car sitting all night and just 3 miles of in town stop and go driving.) Brought car home and let sit for 4 or 5 hours. Checked coolant level on cold engine and found it to be be a bit below the cold fill zone. Added peak 50/50 premix and brought it up to the top of the cold fillzone.

This morning the A/C worked fine but temp gauge was still around 3/4 - even after a few miles of in town driving. Parked car for around 3 hours and checked coolant - same level as last night. After a few hours of driving the car is still hitting around 3/4 on temp gaugue but A/C is not working properly. Shutting veh off and then starting fixes ac for a while.

I'm honestly not sure if my issues are related or not - is the veh just going to run at around 3/4 on the temp gauge and I need another can of A/C recharge? Should I be looking for issues with my water pump (how do I check that) or a leaky radiator (I have not noticed any thing under the vehicle.... how do I tell leaky radiator from A/C condensation?) I visually checked the outside (front) of the radiator and couldn't see any blockages

 

[DLinkOZ]

Look at the K-member, directly behind the radiator. Mine has a very slight leak, and at first would puddle (you can tell the difference between it and water from the AC, much thicker and pools higher). Now there's no puddling, when I shut off the engine it seals itself back up quickly (seal between plastic end-tank and aluminum core). But after driving for more than an hour or so it will slowly dribble coolant and the incoming wind splashes it onto that k-member.

Also check the t-stat, might be stuck closed - mine did that, and it would go up to the top end of the gauge and then come back down to middle. Rinse repeat, not a safe thing to do, as it can lead to much more expensive repairs (head gasket, etc).

*EDIT*
I should also add - when my t-stat stuck closed, in addition to the movement in the temp gauge I experienced an unaccountable loss of coolant. Nothing milky behind the t-stat, oil looked fine, I suspect it pushed out the end-tank seal as a weak link. I thought to mention since you also experience what I read to be a one-time coolant loss that you can't account for.

 

[nrs]

Thanks for the help - my wife picked me up from work this evening, and she had failed to mention that for most of the afternoon she had been driving the vehicle around with the temp near or in the red and the check gauge light on and off - with no AC.

We made it home and I decided to stop at the auto parts store to grab some antifreeze and a flush kit. On a whim I asked the parts guy for the price on a tstat - my jaw about hit the floor when he said $12 (I had no idea how much.. I was expecting $40) so I went ahead and bought the tstat too. I hit up the neighbor who's a bit more handy in these areas than I - and he agreed it might be the tstat stuck. With a bit of his assistance I was able to yank off the old one, discover that it was stuck - and replace it, all in about 10 minutes.

We tried as hard as we could- and without fully driving around for an hour couldn't get the temp to budge from nominal and the AC was nice and cold. We shall see the full results tomorrow - if the fix holds up. I should say that at least the tstat makes sense - I can't imagine that from a cold engine in the morning to 2 miles / 5 miles down the road the engine would make it to *near* red - and then my wife could drive around in the red with check gauge on and besides no AC have no issues.

Thanks again for the help ...

PS: as far as the coolant loss goes - I'm not sure if I've got the full story. I have never checked the coolant in the past before I found it to be a bit shy of the cold fill zone. Apparently coolant will pool and not evaporate - there no evidence of that anywhere in the garage or driveway. It could have just been slowly evaporating or what not for a while.

 

[zoso1030]

Thanks for the help - my wife picked me up from work this evening, and she had failed to mention that for most of the afternoon she had been driving the vehicle around with the temp near or in the red and the check gauge light on and off - with no AC.

We made it home and I decided to stop at the auto parts store to grab some antifreeze and a flush kit. On a whim I asked the parts guy for the price on a tstat - my jaw about hit the floor when he said $12 (I had no idea how much.. I was expecting $40) so I went ahead and bought the tstat too. I hit up the neighbor who's a bit more handy in these areas than I - and he agreed it might be the tstat stuck. With a bit of his assistance I was able to yank off the old one, discover that it was stuck - and replace it, all in about 10 minutes.

We tried as hard as we could- and without fully driving around for an hour couldn't get the temp to budge from nominal and the AC was nice and cold. We shall see the full results tomorrow - if the fix holds up. I should say that at least the tstat makes sense - I can't imagine that from a cold engine in the morning to 2 miles / 5 miles down the road the engine would make it to *near* red - and then my wife could drive around in the red with check gauge on and besides no AC have no issues.

Thanks again for the help ...

PS: as far as the coolant loss goes - I'm not sure if I've got the full story. I have never checked the coolant in the past before I found it to be a bit shy of the cold fill zone. Apparently coolant will pool and not evaporate - there no evidence of that anywhere in the garage or driveway. It could have just been slowly evaporating or what not for a while.

coolant could be going into the engine so check on that. It happened to me.

 

[DLinkOZ]

Yeah, if she drove around like that then it's definitely a good idea to change the oil and take a peak. See if it's got any light-colored milky constency to it.

 

[nrs]

Sorry I never followed up on this - ended up being a bad thermostat. Easy fix and we're back rolling.