Head gasket leak check,,,, how to

[hi pinion]

Ok, as you all may know, i have been having some major overheating problems. I kind of turned my eye at first to the fact that it might be a head gasket leak, because i * really * diddnt want it to be that.

But, i am at the stage now, where, its either the water pump, the sensor or the head gasket blown. Because i keep getting irratic readings.

Whats the easyiest way to check for a head gasket leak? Someone said there was a kit you could buy, for the parts store etc. Its either the impeler on the waterpump is rotten, the sensor is bad, or the thermostat i replaced is not working. Theres only a few things left IMO i changed just about everything on the cooling system alredy.

 

[4X4HIGH]

You can have a smog shop stick their exhaust sniffer near the radiator opening to see if there are hydrocarbons present which would indicate a blown head gasket. This is assuming that you don't have water in the oil or water coming out the tail pipe right now.

 

[Corey 78K5]

Do a compersion test one each cylinder. They should all be within 10-15 lbs. of each other. Do You have water in the oild or oil in the water?

 

[hi pinion]

You can have a smog shop stick their exhaust sniffer near the radiator opening to see if there are hydrocarbons present which would indicate a blown head gasket. This is assuming that you don't have water in the oil or water coming out the tail pipe right now.

ARR ARR ARRR, now see, i dont have that trained experianced eye to tell if there oil in the water like you guys. I have an old plumbing buddy that if i bug him good enough, hell come over real quick to check it, but not withought bitching at me real good first, witch im going to have to deal with.

What if its leaking so slightly it dosent really SHOW us anything? In the iol or water? ,,,

With all the money ive thrown at this thing its gotten better, but, after my second clutch fan ( the first new one from napa STOPPED when it was running , indicating either wrong part, or bad clutch i think) its gotten better, but still acts real weird.

Also, do sensors just "go bad" all at once, or do they have the tendency to freak out first and then go bad? Mabey work sometimes and then freak out before finall failure? Like slowly go out or something?

As you can tell,im getting beat by this thing. Today after i installed the 225 dollar fan clutch i got from the dealer, it ran killer for a long while, way better that before ,than with the first napa clutch fan. When i put it in today it ran on the "O",,, on the temp guage that says "NORMAL",,, and then jumped up on me all the sudden again to the "M" on the guage, and then went back down slowly to the "R" .

I wish i could give you guys some more information , like constant solid info, but the thing is acting different each time i add a new part

I am starting over again tommorow with a DEALER thermostat (yes im changing it AGAIN) because i diddnt test the first one with boiling water , so im not "SURE" if it was even good.BTW i out in a 195, but it calls for a 192, if that makes any difference. Im starting to hate this thing, it only has 87 thou on it, but its a 96. I guesss ill do the sensor tommorow, t-stat (again),and
then, the only thing is head gasket, water pump.

I also checked the BOTTOM hose, it has a spring in it, but it looks like its bulging and theres some play in between the spring and the hose, so ill change that too.

This all sounds retarted, the way i posted it and all , but its leaving me scratching my head and loosing faith. I wished it was easyier to describe . Later guys, Jacob

 

[fatbob]

It is kinda hard to dianose problems with the "NORMAL" gauge. When the cooling system is operating normally, the temperature will rise untill the thermostat opens then it will cool back down a bit. Kinda like you described with the O to M to R. That this point I would put a real temperature gauge in it so we have some real numbers to work with. If the R in NORMAL actualy represents 190 degrees for example, then you could be doing alright. You could just be overly sensitive to the temp because of resent problems.

Good luck

 

[hi pinion]

I think the "R" is for retarted at this point. It will be the third day of me throwing parts at the thing, ill be on my second stat, my second fan clutch, im putting new hoses, new temp sending units, dragging my buddies (the ones you dont want to interrupt their time on the weekends) ,to check for water in the dang oil, oil in the water , tranny fliud in the oil, blinker fluid in the glovebox carberator, and all that good stuff.


Pretty soon there will be nothing left to replace, and it will be a damn head gasket,i already know,,, ill rip the motor out, throw a mild cam and have some headwork done, and mabey then my horse and buggy will go. I hate ford, i beat on some old company fords a long time ago and thought they were good vans,

There not good vans, anyone that has an "R" to mark 180 degrees has to be "RRRetarted" lol. But i know someone here who changed the head gasket out, and it wasnt the problem after all, i felt sorry for him lol. Im checking everything else first. Im still in denial about the head gasket. Ill chack it last

 

[r_pogo]

Air Pockets

I have been told drilling a 1/8 inche hole in the thermostat helps purge air pockets from the cooling system that can cause goofy temp readings.

Maybe someone who knows more can confirm this?

 

[hi pinion]

I have been told drilling a 1/8 inche hole in the thermostat helps purge air pockets from the cooling system that can cause goofy temp readings.

Maybe someone who knows more can confirm this?

Thats exactly what the guy at the shop said to do too, but i dont like idea of something like that in there. I want a stat that works by not drilling holes into it lol. I may work, it may throw lots of codes too, i dont know. Might work. The guy at the shop says it worked on his, but i would think the check engine light would come on with that.

 

[diesel4me]

Hot stuff....

Most thermostats already have a hole or a "wiggle pin" in a hole to let air bleed out ,but maybe not all of them do(especially the 2$ ones)...

I hate to say it but it sounds like classic symptoms of head gasket leaks--many times they only leak slightly,and only allow combustion gasses into the coolant,but no coolant leaks into the oil(at least not enough to detect visually,it goes out the exhaust )--thats why most shops use the emission test "sniffer" to read hydrocarbons by holding it over the open radiator cap spout with the motor running to diagnose a bad head gasket-

-many times we could only confirm the head gasket was to blame when we had it in our hands,and found the "bad spot"--usually the steel "O" ring rotted away just enough to let compression sneak into the water jackets..

-many times the leak is not big enough to show up on a compression test..they also have a kit with dye that glows under a black light to aid in diagnosis too..Most of the cars and trucks we had erratic readings on the temp gauge had rotted head gaskets--many of them didnt act up for days at a time,then they would overheat and boil over once in a while..a few customers tried cracked block sealer from Moroso,like the racers use,and had no further problems--I know a used car guy that swears by that stuff--hasnt changed a head gasket in years!!.--he calls it "Head gasket in a bottle!".( personally I dont trust sealers to do much more than stop a radiator leak,but it seems to work for him..--.

It could be a rotted impeller on the water pump--I've seen a 3.8 T-bird that had that problem--but its owner complained of poor heat,and running hotter than usual on the gauge at idle or low speed-We could run it a half hour and the heater hoses were stone cold,but if you revved it up to a fast idle they would get hot and the heat was fine!-we changed the thermostat,flushed out the heater core,did everything but the head gaskets because the car had a new long block installed under warranty 6 months before--it turned out the dealer put the old water pump with a rotted out impeller back on the new engine! --new water pump--problem solved...

Does it spew coolant out the overflow??--is it really overheating,or is a faulty gauge or sending unit giving you false readings,and making you THINK there is a problem,but there really isn't??..Been that route more than once too....

 

[hi pinion]

Im afraid to answer that . ...


What about the stat? The guy at the shop looked at it, looked all around, bled the air out and said, "Ill bet a different stat would fix it". Mabey its getting stuck shutt too? Its weird, when i put on the new correct clutch fan, it acted alot different. Like night and day from before the old. I dont want to jump right to the gasket before i do the rest of the motions, even though it keeps tipping towards the damn head gasket. Alot of guys at my other site swear up and down its the water pump, its the water pump,,, some say air in the lines, getting stuck up into the engine, remember this is a furd im talking about. I just find it irronicly weird the difference in the fan clutch from the dealer compared to the 2 day old defective napa clutch was night and day.
Has it ever NOT been the head gasket? Boobby on here is and was having the same problem with the truck overheating too, on his blazer, nothing would work, so he changed the head gasket, still , it diddnt work. Its something easy ill bet poor guy, ITS WAS COOL BEFORE THOUGH!!! Even with the head gasket replaced its the same, so it has to be something else besides that. And it may be the case here too.

Also, i guess some of the newer vehicles(like 1995 lol new to me ) reqiure a special machine to evac the old fluid and install the new fluid to prevent any air getting trapped up inside the engine. No one has posted anything about that . Dosent your heater core have to be open with the thermostat open as well to have a complete "loop" opening up ALL the water passeges to allow the fluid to get in all the way?Isnt the core a second radiator in a sense?? Its not a self priming deal on mine , we had to remove what air we could by slowly removing the cap on the radiator when it was hot, we had the heater going, and the stat appeared to be open as well.......

If the stat wasnt open, that means the passeges were not open all the way right? So if the stat dosent open all the way,or is no good from out of the box,, theres a chance air could be in there still, from the first time i put it in, right? If this is true the system was partially blocked , and it could be trapping or may have trapped some air up in there mabey. Mabey its trapped in there throwing things wacky. Because it never had a chance to fully open up,,, boy im tired, its something , but we are getting warmer.

 

[Stoopalini]

Not sure if anyone suggested this yet, but one way you can check for a blown head gasket is to remove the radiator cap, make sure the radiator is full, and start the engine. See if water spurts out of the radiator fill hole. If it does, this means the head gasket is blown allowing cylinder pressures into the coolant system.

If the water does not sputter out, it doesn't mean the head gasket is fine though; it could still be bad, but not between a cylinder and coolant passages.

Good luck!
Thomas.

 

[70~K5]

Not sure if anyone suggested this yet, but one way you can check for a blown head gasket is to remove the radiator cap, make sure the radiator is full, and start the engine. See if water spurts out of the radiator fill hole. If it does, this means the head gasket is blown allowing cylinder pressures into the coolant system.

If the water does not sputter out, it doesn't mean the head gasket is fine though; it could still be bad, but not between a cylinder and coolant passages.

Good luck!
Thomas.

But this could happen with air in the cooling system too. If you have a air bubble trapped it will cause surging.

You could take it to a shop that has a pressure pump/ gauge that replaces the radiator cap to see if the system will hold pressure.

If you have water in your oil it will look whitish and foamy.

 

[sweetk30]

if you have a napa near bye thay sell a block tester kit for about 55-60 buck and you can reuse it over and over again . the fluid is blue and when incontact with exaust gases it turns yellow. and if so then you have a leak some where in the cooling system and thats all ths tells you. works great for small leaks and or major leaks. i have my own kit at work in my box , but its there or i could tell you the part # for it. i love it . and when the bottle runs out just buy a nother bottle for about 15 bucks. if this is to much for you just call some shops and ask if thay have one or ask the napa guy who he sells them to and ask them if thay will test it for you. i had a car that lost coolent in 2-3 weeks and i tested it and it took about 20-25 min to show up. that how good it works.

 

[beater_k20]

you say its a 96? i'm assuming its a GM, with a V8 in it, if so, its got the Vortec engine in it, which are notorious for intake leaks, which leak coolant right into the lifter valley. pull you engine oil dipstick, if it looks like a milkshake, i'd almost be that's where your problem is.

 

[sweetk30]

you say its a 96? i'm assuming its a GM, with a V8 in it, if so, its got the Vortec engine in it, which are notorious for intake leaks, which leak coolant right into the lifter valley. pull you engine oil dipstick, if it looks like a milkshake, i'd almost be that's where your problem is.

yes now that i reread the thread . those vortecs are bad intake gasket eaters. you can get i was told regular gaskets to replace the plasic ones if the pitting is bad and wont seal with the new o.e. style. from felpro i was told.

 

[3 on the tree]

Your oil will look like choc milk if any appreciable amount of anti-freeze gets in it. I knew an old mech who would rig up a compression tester fitting to air pressure and check each individual cylinder with both valves closed. If the head gasket was leaking on that cylinder, air bubbles would show up in the radiator. It sounds to me like you have a very sensitive temp gauge. On my 81 460, I can monitor the stat opening and closing by watching the temp gauge, very definite rise and fall of the needle. All else fails, put a T fitting on the port for the temp sending unit and run a mech gauge also, that will tell you if it is really overheating. Luck

 

[r_pogo]

Air in Cooling System

You might be a bit too worried about air in the cooling system. Air tends to work its way out all by itself. Here is how I get most of the air out when doing a flush -- others probably have a better way but this works for me.

After draining the system and flushing with clean water a couple times (and saving the old coolent in milk jugs to deliver to the city recycle center), I add 1/2 gal of antifreeze (in desert Arizona we don't need much), then a bottle of RedLine Water Wetter, then fill the radiator with distilled water. I fill to above the top of the upper hose, but just slightly below the cap neck. The cap then goes on loose just to keep the water from splashing out.

The engine is started and kept at idle. After all the sloshing is reduced I remove the cap and slowly add more water to the radiator keeping it just below the filler neck to keep frommaking a mess. After the thermostat starts to open (the radiator starts to get hot) the engine idles for another few minutes, the cap goes back on loose, the engine is raced a couple times, water added again to fill the neck to the top, idled a bit more and then engine turned off. After a few minutes I then fill the radiator to the very top of the neck again this time making sure the overflow hose gets filled, and then jam the cap into the water at the top. Then add enough water/antifreeze to the overflow tank to bring it up to the top mark.

As the radiator starts to cool the water tends to contract a bit and pull water from the overflow tank through the "backward" valve in the radiator cap so I top up the overflow tank the next day.

When the engine is started and run again the remaining air will tend to work its way up to the filler neck. As the water expands most of this trapped air will be forced out to the overflow tank and will escape. When the radiator cools off again water from the overflow tank will be drawn back in to the system essentially replacing the air with water from the tank. I check the overflow tank a couple times after this and add when necessary. Each time the engine goes through this hot-cold cycle any residual air is forced out to the overflow tank.

If there are no leaks in the system the water in the overflow will stabilize at a more or less constant level depending on water temperature. Over time however it willl lose a little to evaporation. Obviously if water continues to disappear out of the overflow tank look for leaks.

I would guess in your case that after a couple days of driving all the air would work itself out and if your removed the cap when the engine is cold you will find the water will be all the way to the top with no room for any air at all.