overheating problems

[chris82]

did a search and found a ton of info on this but wanted to get some one on one info if possible about my problem. my exploder has never had overheating issues whatsoever. the other day on the way to work in the cold rain my truck just shot up to H, 98 explorer, so i let off the gas and then it went back down to normal running temp fast enough to where i could watch it go back down. it did this every 30 seconds or so. so i went home and parked the truck thinking t-stat. so i drove it to autozone and the conditions never came back, the temp stayed right where it should have. So i decided to change the t-stat, which is a ongoing process due to the location on the 302, what a pain to clean the old gasket off. when i pulled over when it was "overheating" the engine didn't feel any hotter than normal. I replaced the t-stat but had a small leak at the housing but i could get the truck to overheat still, according to the gauge. while it was overheating, i put an infared thermo in the motor and couldn't get it to register over 192 or so. But the radiator hose feels like it doesn't have alot of pressure, so i went to get a cap, of course they gave me the wrong one. stant 11229 is not the right cap for a 302 explorer. So i have to get that back today to get the right one and then fix the t-stat housing leak. any other ideas?

 

[chris82]

just thought of a few more things. i opened my radiator cap when the truck cooled down a bit and it didnt release any pressure at all and i could not see any coolant. My overflow is full though. I also noticed that my radiator hose didn't tighten up at all and was very squeezable when the t-stat opens up. could that be my pressure cap?

 

[BrooklynBay]

Replace the cap, and the temperature sending unit. What temperature was the thermostat you put in? How many pounds is the cap on there now?

 

[chris82]

i haven't had the truck on the road with the new t-stat due to having a small leak that i want to fix first from the housing. that should be done tonight. The t-stat is a 195*, stock replacement, although the stock was 192 i think. The pressure cap is 13lb. which is considered stock replacement but they gave me the completely wrong size for that. have to take that back today and get the correct one.

 

[manaen]

X2 on the cap and sending unit

 

[bluesman2333]

FWIW, I've had problems with those lever vent caps leaking. After a few weeks they have a ring of crud around the shaft seal and I had one engine running hot due to pressure loss in the cooling system. Replacing them with regular ones cured the problems.

 

[CDW6212R]

Ditto, change the cap, also add an additive like Water Weter, it helps a good bit in transferring heat. You don't have too much antifereeze do you, 50% should be maximum. I use 20% and the Water Weter, for best heat transfer for my climate. Good luck,

 

[chris82]

well i ran the truck tonight after replacing the cap and that seemed to pressurize the radiator hose which made me happy. my temp gauge in the truck seems to be going towards the hot, not sure how high, about 3/4's before i turned around and came home. as soon as i come down to idle the truck levels out or cools back off. i used a infared thermo while the truck was running and still at 3/4 on the gauge and it was reading anywhere between 195 and 198 so that seems about right. i think the gauge or sending unit might be bad. i reinstalled the thermo and still have a small leak coming from the bottom of the housing, could that be from the stat moving while i'm putting the housing on and falling a little out of its perch??also i notice that when i turned off the truck and then opened up the radiator cap there was no depressurization and i still can't see coolant in there. any ideas?

 

[CDW6212R]

Get the system full of coolant first, it takes some time to remove all of the air.

 

[wpurple]

Install one of those Prestone flush kits, by keeping the cap open on the "T" fitting while you add antifreeze, it allows the air to escape. I never have to add any afterwards once I let the air out that way.

 

[CDW6212R]

It should only take a couple of engine uses to get the air out. Fill it as much as possible while running with no cap, then cap it, add coolant to the overflow bottle to a couple of inches over full. Check it and top off the bottle later.

 

[chris82]

my neighbor is a mechanic so i took it to his shop up the street to look into the radiator. i should be able to see fluid there, so there is something blocking the flow through the radiator.

 

[zims666]

would synthetic oil have anything to do with overheating?
i started having the same problem the very day i had my oil changed to full synthetic...

 

[BrooklynBay]

Oil reduces friction so it can't be the cause of the problem.

 

[gijoecam]

Why are you not fully filling the radiator? With a cold motor, pop the cap off, start the motor, and fill the radiator. Put the cap on. The most air you will have left will be in the upper radiator hose, and that will slowly but surely work its way to the radiator when the thermostat opens.

When the temp gauge says it's overheating, is there any coolant bubbling out the reservoir?

-Joe

 

[Double0X]

Redhot overheated

Ok... this is the story. My battery was dying in my Ex. So i left my Ex at the house and drove my sisters car to walmart for some groceries. When i came back home i noticed my dad was outside with my hood popped. I pull up next to him and see he has changed out my battery(he pulled a semi used one out of his boat). The motor was on now, and he was just letting it run to "fully charge the battery"(his words). So i get out of my sisters car and am standing next to the passenger fendor looking down at the motor. I hear an unusual sound and ask him to turn off the car. He does and the sound i was hearing was something boiling. In a frantic rage i run around to the dash and see the temp gauge above The Red H! This temp gauge was reading as hot as it could go. . . . . . . .. .. ... .. . ... ... . GRRRRRRRRRRRRR. Ok. WTF. Anyway, . . . i was pretty upset about that and i start yelling "What did you do?" (Felt like an ass after this) All my dad had done, according to him was change out the battery. .. . . . I have no clue why my car got that hot, it has never gotten so hot before. I have an elec fan, and he said the whole time the motor was running he didnt see/hear the fan come on. . . . . So here i am with the car off and a loud boiling noise coming from under the hood. It sounded like it was coming from the motor and the radiator. i JUST got a new radiator. And i JUST changed the oil(100 miles ago). ...... After looking closer at the heads on the motor i notice a "liquid" coming from what looked to be the back PCV hose. It just kind of dripped out onto the head. And on the passenger side, where the oil is poured into the motor, i noticed the same color liquid coming from the connecter peice that connects the oil funnel thing to the head. ...... After waiting about 10 mins the motor quit boiling and the temp dropped down almost to normal. I took it for a 1-2 min drive up and down the street to see if the elec fan would come on. It did! While driving i noticed the car seemed to kind of surge forward a bit and let off then repeat. I then pulled back into my drive, and my car is almost to normal temp by now. . . I turned it off. Its there now.
My questions are... What was boiling? Do i need to flush the radiator now? Do i need to change my oil again now? Is my engine seized? Are the pistons melted? What will that temp effect? (parts/performance, etc).

 

[Double0X]

Bump

 

[Double0X]

Bump

 

[gijoecam]

Bump

First, relax. You may only bump a post once in 24 hours. You posted at 7:00 on Super Bowl Sunday... Things are going to be kinda slow on a weekend to start with, let alone on a huge TV night...

Second, this probably should have been a new thread.

Third, you need to start with the basics. It overheated, plain and simple. Check the cooling system for oil and the oil pan for coolant. Check the thermostat for proper operation (I'd just go ahead and replace it) and check to see if there are any loose connections on the cooling fan's electrical controls that could have caused it to not come on.

I *suspect* everything's fine and you simply need a new thermostat. Odds are your electric fan uses a temp sensor that either presses into the cooling fins of the radiator, or otherwise reads the coolant temp at the radiator near the inlet from the upper radiator hose. If the thermostat stuck closed, it never let any warm coolant through to trigger the sensor while it was overheating in the mean time. A stuck thermostat explains both problems (overheating and non-functioning fans).

Good luck!

 

[Double0X]

First, relax. You may only bump a post once in 24 hours. You posted at 7:00 on Super Bowl Sunday... Things are going to be kinda slow on a weekend to start with, let alone on a huge TV night...

Second, this probably should have been a new thread.

Third, you need to start with the basics. It overheated, plain and simple. Check the cooling system for oil and the oil pan for coolant. Check the thermostat for proper operation (I'd just go ahead and replace it) and check to see if there are any loose connections on the cooling fan's electrical controls that could have caused it to not come on.

I *suspect* everything's fine and you simply need a new thermostat. Odds are your electric fan uses a temp sensor that either presses into the cooling fins of the radiator, or otherwise reads the coolant temp at the radiator near the inlet from the upper radiator hose. If the thermostat stuck closed, it never let any warm coolant through to trigger the sensor while it was overheating in the mean time. A stuck thermostat explains both problems (overheating and non-functioning fans).

Good luck!

Well First, i was upset when i first posted that... not really anymore now. Second, no one told me i could only bump every 24 hours, it doesn't say that anywhere. Now i know. Third, I posted last night and when i got on this morning i noticed the thread had dropped about 13 positions so i just posted bump again to put it at the top.
I'm not trying to be an ass, im actually a great guy but one of my greatest downfalls is patience. I have none. Anyway, thank you for the input!
I came to the conclusion last night while trying to sleep that it was probably only my T-stat. However, do you think i will need to change my oil? Or drain the radiator fluid and refill it?
Also, i feel dumb asking this but ...You said to "Check the cooling system for oil and the oil pan for coolant. " So coolant has leaked into my oil? It that what you are saying? Its a little confusing is all.
Thanks again!