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99explorer losing coolant


November 25, 2010
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Year, Model & Trim Level
99 XLT
Hi all, Im suspecting I might have a blown head gasket,but i'm in denial as I don't want to tear this engine down.Was hoping it was only a bad intake gasket but all I read here points to the heads.Engine is the 4.0sohc with 145,000.Found radiator to be leaking and low on coolant. Gauge never showed hot.replaced radiator,but ended up with a single coil instead of the double coil that was on it.Was told the double coil was for the towing package and wasn't needed for regular driving.Anyway, thats all I could find at the time so I tried it.Thought all was fine for a few minutes, but then coolant started leaking from the fill cap.I had the old one ,so I put it on with the same results. Once warmed up it quit leaking but the temp gauge wasn't riseing and had no heat at the vents.Reving the engine some the heat gauge shot up to near hot then droped back to center point on gauge where it droped and rose some in the mid point.Heat would only blow warm when engine was reved some.Air pressure seems present in the radiator as it bubbles and tends to want to flow out with cap off. Short test drives (7 miles round trip) show temps no heigher than mid way on gauge. But i'm loosing some coolant when I drive it.I seems to run great and no coolant is in crankcase so far.Saw some white smoke but it was cold and i figured it was just that the air temp. was so cold...Can't smell coolant in exhaust and dont see steam when the day is warm..Can a compresson tester help me figure out if it;s the head gasket or the intake gasket.Would hate to go that far into the engine if I didn't have to. Sorry for the long post, and thanks in advance...

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x2 - head gasket maybe, but you would have coolant in oil or oil in coolant. Don't throw in the towel yet..just keep coolant close.

Thanks for the quick response guys! Can that tool be bought at local parts place? It would be great if thats all thats going on with our engine! I'll look into that tomorrow for sure...thanks again

I have always used this method to remove air from the cooling system...

When I drained the coolant and refilled it after replacing my radiator, I filled the radiator with coolant and I filled the overflow bottle and then started the engine...

I did verify the thermostat was new and the radiator cap was sealing and would hold pressure and run the engine until it got to operating temperature...Then I let the engine cool off and saw the coolant level drop in the overflow bottle as the air bubbles were displaced from inside the engine...After the overflow level dropped, I refilled it and monitored the overflow over the next week...

I haven't needed to add any more coolant since May...

If the coolant blows out of the radiator, using a pressure tester SHOULD point out a leaking head gasket, leaking coolant connection, or cracked or leaking head...And a leaking head gasket or cracked head does not always leak oil into the coolant or coolant into the oil...And the sohc heads tend to leak from porosity in the casting ranther than crack like the cast iron ohv heads do...

Thanks for the quick response guys! Can that tool be bought at local parts place? It would be great if thats all thats going on with our engine! I'll look into that tomorrow for sure...thanks again

yes most stores, nappa, autozone, pepboys sell it, i was searching for images, and that was from google image search.

that kit is the best way to bleed the coolant.

to me you have alot of air the cooling system. which is why your a popping the psi cap. working as intended due to air.

Found radiator to be leaking and low on coolant. Gauge never showed hot....But i'm loosing some coolant when I drive it.

Might be a good idea to get a UV dye and light kit to see if there is another leak besides the radiator. Along with a compression test, but the UV check will be easier and shouldn't cost much.

ended up with a single coil instead of the double coil that was on it.

Do you mean single row instead of double row? I'm not familiar with the term coil on a radiator.

Heat would only blow warm when engine was reved some.

If this continues after you purge the coolant of air I'd start looking at your thermostat.

Thanks for the info Ranger..Testing coolant system now. Cap is good. Put 20lb. into radiator an hour ago and sprayed soapy water at all hose fittings involved, but found no leaks.So far the gauge has droped to 18 lbs. That should tell my the leak is in the intake gaskets or heads and a compression test is needed. You all know what a pain it is to get to and remove the plugs on the passanger's side.Getting each plug to TDC will be fun.Is there an easy way to do this once #1 is tested?I have a remote starter switch...And can I leave the plugs out as i test each cylinder for basic compression or do they need to be replaced before testing the next cylinder?Thought it would be easier if they were left out for the next test of applying regulated air to each cylinder while on TDC. Oh, Idid replace the thermostat along with the radiator, but wasn't aware that these engines were picky about useing Ford only brand. This one is a Stant.Should I replace it again with a Ford brand? Thanks again from under my shade tree. P.S. Three hours and pressure is still at 18lb.

Ok, Testing is done and i'm getting water in #5 cylinder...Compression at #5 was first at 132lbs. #4 was 162 ND #6 was162lbs.Checked drivers side but engine had cooled some by the time I got to all three on that side(still warm)as they were hard to get to. #1 was150...#2 was143...And #3 was138lbs. Thinking that side had cooled too much for a good reading. Re-checked #5 and got 150lbs.(weird)Decided to torn engine over with remote starter and watch for water...Had coolent system presserised to 30lb.This time I saw coolant sprayingout of #5 cylinder...In the past few days code concerning #5 mis-fire had come up several times,so I should have figured something was going on.With the compression also low on #3 (other head) maybe i should check it for water also.Guess it doesn't matter as both heads need to come off,and I'll know when there checked.Thanks for everyones help.

you sure it was coolant not fuel.

no offense, but coolant testers will lose air pressure over time. you lost 2psi in 4 hrs i would say the system is fine.

my guess is you saw the fuel shooting out of the cylinders.

try this.

put the plugs back in
put the coolant tester on the car at zero psi.

run the car for 30 min. whats the pressure reading?

Hi Waskly, It was coolant .I cuped my hand and caught antifreeze in my hand as i turned engine over with a remote starter.Had been getting #5 cylinder mis-fire code on that cylinder also so that explained the code keeping poping up also.Was fouling plug...I understand what you are saying, but i'm sure it's coolant so it;s got to be a bad head/gasket in this case...Wish it wasn't....LOL Thanks for you'r input.Got intake off and almost all under intake wireing loose.Next day off i'll try to figure out how to get those exhaust manifolds loose and that main fuel line loose.None of my plastic fuel line tools seem to be working. Thanks again!

i would leave the exhaust manifold on the head, and unbolt the 2 bolts at the cat under the vehicle.

the 2 flange bolts.

pb blaster works wonder soak them in it a while...

silly question is the oil muddy? i would drop the oil, antifreeze floats on top, that would make it oil first then antifreeze.

Thanks for the tip Waskly. Saw that that needed doing when I got all the driver's side manifold bolts out and it didn't give enough to let head studs clear .Will dump oil again and check for antifreeze again like you mentioned. Oil didn't look muddy,but this will tell better.Hoping that head is not warped or cracked, and only need gaskets replaced.Not my luck though...lol...Dont think the dealership really replaced the old style cam tensioner's during the recall, because when we got it back the bolts were still dusty and didn't appear to have been touched. No sign of any repair's being done under the hood.This will be a good time to check for up-dated tensioner's.If not new one's,i'm telling!...lol