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Heating/Cooling Issues

3399 Views 18 Replies 5 Participants Last post by  bigbris1
I have a 1996 4.0SE and after going thru the car wash yesterday I got out to wipe the truck down. Lo and behold she was overheating and coolant was coming out of the expansion tank overflow! To top it all off I was locked out. I quickly broke in via the moonroof & pulled her to the side of the road and shut it off. Let it cool & limped home. Flushed the cooling system with the Prestone coolant flush stuff & refilled with Dexcool & tap water (last time I flushed the system I used tap).

It was still overheating. I did some searches here and found tap to be a no-no. So I looked into the hoses and expansion tank & there was a lot of gunk in there. Cleaned it out as best as I could & put in another jug of cooling system flush, drove around last night and then again today until it overheated again. Let it cool, flushed with water twice then added pre-mixed coolant & drove a short distance. It stayed at operating temp (a hair past 12 o'clock) & I believe I bled the system of air properly. Now the coolant leaks thru the expansion tank overflow pipe when idling at operating temp. Going to let it cool off then top up with coolant.

Prior to this and now I only get heat in the cabin when driving or revving the engine in park. Otherwise it would go cool. Any ideas?

Thanks in advance.
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You are leaking coolant somewhere and it got too low. Only having heat while driving is a sign of very low coolant or a failing waterpump. Now that you are blowing coolant out the expansion tank you have most liklely cooked the engine and have a blown headgasket or dropped liner. Is your top hose hard at temp?
Top hose is firm but not rock hard. I just drove it and it overheated again. I checked the hoses and the top hose to the rad was hot but the bottom ones were cool. I'm thinking a blocked radiator. Could this be it?

Hopefully it's not the water pump.
New Radiator, new thermostat....no question about it and dont drive the Rangie till its done
Check water pump too but they wear out before they fail....
Took it to my mechanic yesterday and after cleaning the outside (fins) of the radiator, removing the upper and lower hoses and spraying inside the rad with a hose, finally he told me it's the water pump. Especially since I'm only getting interior heat when the engine it at high rpms. Ordered a new one ($55 Deutsche Parts USA) and will have him do the thermostat also. Hope that works.

One tip of importance I have been seeing is radiators blocking up on the lower part exterior due to oil seepage from other coolers

On a 1999 recently I replaced radiator, l'd say half the radiator fins were completly blocked up from oil seepage which then collects dirt etc and hold it there, interior was fine apart from the broken top air bleed off pipe being broken now the customer is very happy cos the Rangie goes better than it ever did before as the raditor is now passing on correct cooled cooolant through engine, very often over looked item
So we replaced the water pump (there was a lot of play in the impeller) and she's still overheating. There is steam coming from the overflow cap so that will be replaced tomorrow along with a low temp thermostat. Water was flowing freely (at least I thought so) thru the rad so I'm hoping it's not a clogged radiator.

This is very frustrating.
There would be no need to change the temp of your thermostat. Unless your thermo is not operating properly leave it alone and trouble shoot other possible issues. If you are boiling out of your fill tank you have bigger issues.

Was the system properly purged? If not an air bubble will cause all sorts of headaches. Is it overheating on the road or from cold at idle? Is the coolant level still dropping? Have you checked your spark plugs for signs of "steam cleaning"? Any steam from the tail pipe?
From cold it goes to normal operating temp & stays there until it's under load (driving) then climbs to the red zone. I haven't noticed any steam from the tailpipe (I don't have a tailpipe, the exhaust ends abruptly after the middle box). The water level seems to remain constant save the loss out of the vent tube on the expansion tank when it starts to boil.
So I just added another gallon of water which is what I suppose was lost on the trip home from the garage. Left the expansion tank cap off, turned the heat on high and let her idle to operating temp. Warm air coming from interior vents and bubbles coming from the exp tank. I figured maybe there was still air in the system but the air is coming from the skinny hose that runs from the top of the rad to the exp tank. I disconnected it from the exp tank side and sure enough all that was coming out was steam. Is this normal?
:doh: Poor Rangie. My condolences.

Should we send flowers or make a donation to your local mechanic.?
Thanks, I'm not giving up on her yet. My 4.6 Kensington gave me way more worries than this one.

I just went out and made sure she was full of water (removed bleed hose from rad, kept pouring water into exp tank while at idle until a steady stream of water was coming out of the rad nipple) and went for a quick drive. I'm losing water from the expansion tank vent. So once the level gets low enough, she starts to overheat.

Hopefully the new expansion cap I ordered will sort things out. Thanks to rrtoadhall for bumping this thread at the very least :thumb:
I have my fingers crossed. However, a properly burped system that is operating correctly won't overheat... I know.. DAH. :lol: If she has been fully burped, radiator is clear, only overheats under load and is loosing coolant it sure sounds like a head gasket. Easy fix, only a couple days work, and not that expensive. I jsut hope that with all the overheating you haven't toasted your engine to a higher level of rebuild or burial. :?
Just changed out the expansion tank cap. While she's no longer spewing hot water from the exp tank, she's still over heating :crybaby2:

I thought I bled the system correctly but did so in a rush so tonite I shall try it again. The upper hose was significantly firmer this time around, tho.
I'm happy to report she is now working OK!

Changed the coolant expansion tank cap ($18) after the water pump ($60 + $150 labor) and I'm now getting interior heat at idle and she is no longer overheating.

Came home from work today and bled her properly with water inside. Drove around for a while and noticed that at speed the temp needle actually dropped a bit while under load. Success!

Went to Autozone and filled her with 2 gallons of 50/50 DexCool and almost half a gallon of full strength DexCool. Drove like a madman for a while with the interior temp on LO and she didn't overheat. Took her and got an oil change and wash. Left her running the whole time it was getting washed and while I towel dried her and did the rims/tires. Drove home and no overheating!

Tomorrow I will top up the coolant and keep running. It should be noted that I ran her into the red at least 5 times over the past few days yet she's still running smoothly with no tapping noise.
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did you do the expansion cap and pump at the same time? I'm having similar problems and bought a new thermo...where did you get a cap for 18?
I got the cap from a local auto parts store. I did the water pump a day before the cap.
Well, apparently the problem has returned. She runs fine for a couple of days and then bam! temp starts climbing again. I'm hoping it's just an intermittent thermostat as I can drive it hard on the highway for a long while. Then when I get to the local streets the temp starts to climb after a couple of light. Super frustration here.
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