Almost Overheated my Engine...

[SnowSurfLax]

So, I was waiting at the Mexico border. It was ~93F yesterday. For those that don't know, the border is a huge CF of people cutting other people off to get a few car lengths ahead in line to cross the border. It can take hours (took us 2.5 hours yesterday) and is not fun.

So for about 30 minutes, I was just a few inches from the guy in front of me, trying to prevent people from cutting in line. It was hot and I was running the AC the entire time (mind you I have a black QX4). So I felt a slight shudder in my engine and looked down and saw my temp gauge right at the top of the operating temp range.

I paniced and shut the car off then turned it on w/o starting and ran the temp up to blow as much hot air through the vents as possible. The car started back up fine and stayed hot for a while, but always in operating temp range. It came back down to around normal, but whenever I'd run the AC it would climb to about 3/4 of the operting temp range and never higher. I cycled the AC for the next 1.5 hours (to not overheat my wife and I or the car) and the temp would climb a little when I ran it but would fall back to slightly warmer than normal operating temp.

When I got across the border, it was fine from then on, even running the AC constantly again. Even today, which is hotter, running around with the AC on and it's not even budging from the usual temp spot.

So it got HOT, but didn't overheat. No fluids lost and still have the same amount of coolant in the reserve as I've had since it got flushed.

Is there anything else I should check? I'm assuming it's fine and just want some reassurance that I'm right. It probably just didn't get enough air through the radiator from being so close to the car in front of me. I do know that I need to get the radiator fins washed out as there are a bunch of bugs and dust in it.

Fueler: Ever had any experience with it running hot at the border?

[fueler]

HHAHAH YES i deal with that at least once every year, always in November coming back from San Felipe. I wait ~3 hours at the calexico/mexicali crossing too, (Sunday after thanksgiving is always a killer) and its warm there too. Havent had so many problems at the Tijuana crossing but its usually cooler temps there (not lately!) When you use Air conditioning, the AC condensor (in front of your radiator) gets warm/hot which directly affects engine temps. We have mechanical fan to cool the engine (instead of electric) The speed at which the fan spins is directly related to engine RPM. What I do, when the needle is starting to get noticeably high, is throw transmission in Neutral, and rev it lightly (maybe 2k rpm) for 10-20 seconds. You will hear the fan spinning a lot harder. It cools it down quickly. Now remember that the thermostat opens and closes so half the time you wont see a difference immediately but as soon as the thermostat opens up, the needle will drop. So just rev it up like 2k rpm for 10-20 seconds and within a minute your temp will be normal again, at least for a few mins I hate the border wait on hot days for this reason. You cant turn the engine off cause you gotta move forwards like every 30 seconds and if you dont, cars will cut you off, then you got kids asking you if you want to buy a porcelain statue of garfield and other assorted crap and u start to go crazy Damn hot isnt it?? i bet your wife was hating you for turning AC off. LOL Where did you go by the way?

[fueler]

PS whats cool about the calexico border crossing is youre along the border fence the whole 3 hours, and once in a while youll see a Mexican come out of nowhere, look both ways, then quickly climb the fence, drop down the other side, and run into good ol' USA!!! Meanwhile i still got 2 hours of overheating to go!!

[SnowSurfLax]

We just went down to the dentist. Dirt cheap and best dentist I've ever had. Doesn't hurt that they're all nice to look at too.

Isn't there also an auxillary fan? I hear one kick on when I turn the AC on when I'm at idle.

Yeah, I've sat at the border numerous times for many hours with the AC running the whole time. Never seen the temp needle even tick. But its been hot as hades lately. I'll remember the revving bit. I didn't realize it was attached to the crank. I gotta open my hood more and take a look in there once in a while.

Oh yeah, forgot a nice little detail. When I was freaking out about the overheating, I lowered all the windows to vent the hot air and had some poor india fea begging my wife for money and she wouldn't take NO for an answer!

[fueler]

Nope no extra fans! What you might be hearing is the AC compressor engaged, it makes some extra noise when AC is on.... My parents used to take me to a Tijuana dentist when I was a young kid!

[SnowSurfLax]

Damn. Like I said, I need to pop my hood more often and take a look in there. Wouldn't be so hard if I had a garage or a drive way to work in.

Wonder if one could be added on for such occasions....

[fueler]

Good idea. Maybe add a small FAL electric fan up front, set up to push air through the AC condensor like this kind: on a 12v switch to turn on when idling for long periods of time http://www.flex-a-lite.com/aut....html They also have one that replaces the fan clutch assembly totally. I bet it would free up some horses and save gas mileage, but i wonder if it would provide enough CFM as the stock one? Stock one blows pretty damn hard.... http://www.flex-a-lite.com/aut....html

[Issac]

You might check the face of the radiator for bugs and weeds and grease/dust clogs. Back flush gently with hose. got to pull a little plastic to get there, but you might find it dirty. This junk insulates, which is not what we want.

[fueler]

You might check the face of the radiator for bugs and weeds and grease/dust clogs. Back flush gently with hose. got to pull a little plastic to get there, but you might find it dirty. This junk insulates, which is not what we want.

GREAT POINT my man issac!! I completely forgot about this

I read on a 4x4 forum that its a good idea to take a garden hose, and with low water pressure (just enough to not bend the fins), push water through the back of the radiator, towards the front. Now I had always washed the radiator from the front and it looked clean to me. (Little did I know) I tried this back to front method and the water that came out was DARK BROWN and there was all sorts of dirt chunks and sticks, etc that was hidden in the fins of the radiator. It helped my overheating problem about 98%. (But i have done a lot of muddy offroading) Now I only see the needle go up on extremely hot days, when moving very slowly or idle, just like a Mexican border wait

I dont know how much mudding youve done snowsurflax but it wouldnt hurt to do it anyways next time you wash your car, for good measure.... You can get some of it from the top, and the other half from underneath the car up above the fan shroud.

I dont have a bottom splash guard either which might add to the overheating problem, I've read that the splashguard helps with airflow

[Issac]

Thanks Fueler. I found a lot of junk down low on the front side, plus a layer of deep dust and leaves etc. on the bottom. You have to do a little playing with it to get down in there. Shoot maybe I am thinking of my other car now. Well anyway.

My truck has the opposite problem. I sit on the cool side. Some mild soap/degreaser (probably not simple green by the way) , might help break up residue. Grime and stuff gets dirt and can plug some even in certain sections.

Man TJ-couldn't pay me to go there. Everyone has a TJ story.

[SnowSurfLax]

Hehe. You guys have ADD like me! I already said I needed to probably clean the radiator as there are a number of bugs and whatnot in there.

But, I didn't know about the reverse flow part! Thanks for the HU.

As for TJ, it's kind of like Vegas. Most people never, ever see beyond the main tourist drag which never resembles the rest of the city. If you bother to venture beyond the tourist trap, there are some great places to check out. But, just remember, it is a foreign country and like the rest of the world, they may not appreciate you for being american.

[Issac]

Well it has been my experience that some appreciate American very much. Especially the US dollar. Enough to demand them in fact.But TJ is not Mexico. Mexico is great for the most part. Grew up in SD

[Transtek]

Hehe. You guys have ADD like me! I already said I needed to probably clean the radiator as there are a number of bugs and whatnot in there.

But, I didn't know about the reverse flow part! Thanks for the HU.

As for TJ, it's kind of like Vegas. Most people never, ever see beyond the main tourist drag which never resembles the rest of the city. If you bother to venture beyond the tourist trap, there are some great places to check out. But, just remember, it is a foreign country and like the rest of the world, they may not appreciate you for being american.

Depends where and what you're doing. Obviously, walking round in shorts and a Hawaiian-print shirt shouting "gee, honey, look at all those cute little indians!" ain't gonna get you too many friends and there are always some who are anti-US (whilst working in US-owned companies), and I've had to put a few of 'em down for looking American, but on the most part, if you act nomal and are polite, shouldn't have too many problems.

BTW Fueler, I haven't received your PayPal details yet for the rear cargo cover in black!! (send them to [email protected]).

[fueler]

Sorry man been busy! I still have the cover ill email you now