Disappearing Coolant?

[Kingkong0192]

Well, recently there has been some disappearing coolant in my XJ. It's a 1999 XJ with 118,000 miles, and supposedly the head-gasket was changed out at around 90k miles by the dealer that i bought it from. Was overheating, they towed it, said it was the headgasket, fixed it, and gave it back. Don't know whether they lied or not.

Anyways, i thought i had a hole in the radiator, so i recently replaced the;

-Radiator
-Thermostat Housing
-Thermostat
-Water Pump
-Fan Clutch
-All Hoses
-Rad Cap.

Still loosing coolant out of the reservoir once again. Bought a combustion leak tester, and according to that, i do not have exhaust gases in the coolant. (A bunch of coolant leaked out of the rad cap when the engine was warming up.)

Went out today and saw this under the jeep. (The oil looking stuff.) Most of the coolant was already on the ground from it leaking out of the rad cap when i was testing it.

If there is oil leaking, what does that mean? What should i do next?

I've read about a bad HG causing your engine bearings to wear out. Can someone please explain to me what engine bearings are?

Thanks in advance.

 

[rockfrog]

I am willing to bet you have a cracked head. My 99 would swallow 1/2 gallon of coolant with in 50 miles but mine ended up in the oil pan, not puking oil out of the radiator. My head was cracked between cylinder 3 and 4. Any good machine shop can pressure test the head to see if there is a crack. Drain your oil and see how much coolant is in the pan, the water is heavier than the oil so if you have a lot of water in there it will be noticable, mine sure was. A head gasket itself won't destroy engine bearing its the coolant that is allowed into the oil that kills bearings. Oil and water don't mix, and water does not lubricate very well. Most likely if you caught it early everything will be ok.

Here is a link about engine crankshaft bearings. http://www.aa1car.com/library/ar797.htm
Connecting rods also have bearings as do cam shafts, they all basically work off the same principle .

 

[Kingkong0192]

I am willing to bet you have a cracked head. My 99 would swallow 1/2 gallon of coolant with in 50 miles but mine ended up in the oil pan, not puking oil out of the radiator. My head was cracked between cylinder 3 and 4. Any good machine shop can pressure test the head to see if there is a crack. Drain your oil and see how much coolant is in the pan, the water is heavier than the oil so if you have a lot of water in there it will be noticable, mine sure was. A head gasket itself won't destroy engine bearing its the coolant that is allowed into the oil that kills bearings. Oil and water don't mix, and water does not lubricate very well. Most likely if you caught it early everything will be ok.

Here is a link about engine crankshaft bearings. http://www.aa1car.com/library/ar797.htm
Connecting rods also have bearings as do cam shafts, they all basically work off the same principle .

I don't think the oil came out with the coolant. I think it came out after. I don't even know if it's from the jeep. I'd assume it is, as it's under it, but i personally didn't see it leak out. I'm going to clean the floor and repark the jeep in there and see what happens.

I didn't think the 99 head would crack. Does it crack in the same place as the 0331 head?

So if i bring my jeep to a good garage they can test it for a cracked head? I just want a diagnosis, i DO NOT want them to fix it. I can do it myself. There is no way i can test for a cracked head for free? I honestly don't want to dish out $100+ for them to go "yeeeeuuup it's a cracked head".

So just empty my oil like i'm changing it, and then look in the pan and see if it looks all watery?

Any way to test the bearings to see if they're shot? I've honestly been driving it a lot like this.

 

[centuryhouse]

Just pull the dip stick and see if the oil is normal, or looks 'milky' or 'chocolate milky'. I am dealing with a blown head gasket on my Dodge pickup. Sucks. Basically I was losing coolant and the engine was getting warmer than usual. Turns out the coolant was going into the oil.

 

[Kingkong0192]

Just pull the dip stick and see if the oil is normal, or looks 'milky' or 'chocolate milky'. I am dealing with a blown head gasket on my Dodge pickup. Sucks. Basically I was losing coolant and the engine was getting warmer than usual. Turns out the coolant was going into the oil.

That's the thing. I bought a combustion leak tester and it came up saying that there was no leak in my headgasket. Oil looks fine, although when i pulled the dipstick tonight it did seem a little watery, but the color looked normal.

I'm going to drain all the oil out tomorrow and see what it looks like. The oil fill cap looks chocolate milk though. I'm totally lost.

My engine runs cooler than it did before i did the radiator and everything else. Runs like 20 degrees under 210 now.

 

[rockfrog]

My head was actually cracked in the water jacket on the head and not into the combustion chamber, so all my coolant was draining down the the oil galley directly into the pan. You will most likley have to take the head off to have a machine shop test it, but you have to take it off anyhow to figure out what the problem is.

The 1st shop i took my head milled it down beacause it had a slight warp, I put it back on same problem, took it back and the guy said well it looked like it was cracked but wasn't sure. I said can get a partial refund, he said Nope! NEVER use Laniers Speed Shop in Colorado Springs!!!!. The second shop didn't charge to pressure test it but the used head I got needed a full valve job. Total cost for the junkyard head, valve job, and milling down .020 cost $400.00

If the oil is milky you definitely have water in the oil, check the bottom side of the oil filler cap for milky or anything that looks like condensation. Wipe you finger along the bottom of the filler cap and taste it, if it has a slightly sweet taste you have coolant in the oil.

Mine ran cooler than normal too.

Not too sure where the 0331 heads crack, but mine was between cylinder 3 and 4, mine had 200k miles on it.

 

[Ecomike]

Hard to say at this point, you could of had aire trapped in the block that blew coolant out after all the new parts were installed. If keeps blowing coolant out the over flow, replace the rad cap with a new one and make the store pressure test the new one first!!! They be bad off the store shelf. Did you over fill the coolant bottle?

Look for water underneath the oil (oil floats on water) when you drain the oil.

Coolant leak in the head may evaporate before it reaches the oil pan. Coolant can leak into the combustion area, so pull the spark plugs inspect them for signs of coolant, use a flash light to inspect the piston. Pull the valve cover and look for any coolant puddles on the top of the head.

The block testers are not conclusive for all types of head gasket leaks, only for exhaust leaks into the coolant.

 

[Kingkong0192]

My head was actually cracked in the water jacket on the head and not into the combustion chamber, so all my coolant was draining down the the oil galley directly into the pan. You will most likley have to take the head off to have a machine shop test it, but you have to take it off anyhow to figure out what the problem is.

The 1st shop i took my head milled it down beacause it had a slight warp, I put it back on same problem, took it back and the guy said well it looked like it was cracked but wasn't sure. I said can get a partial refund, he said Nope! NEVER use Laniers Speed Shop in Colorado Springs!!!!. The second shop didn't charge to pressure test it but the used head I got needed a full valve job. Total cost for the junkyard head, valve job, and milling down .020 cost $400.00

If the oil is milky you definitely have water in the oil, check the bottom side of the oil filler cap for milky or anything that looks like condensation. Wipe you finger along the bottom of the filler cap and taste it, if it has a slightly sweet taste you have coolant in the oil.

Mine ran cooler than normal too.

Not too sure where the 0331 heads crack, but mine was between cylinder 3 and 4, mine had 200k miles on it.

Thanks for that. I know that the 0331 head is prone to cracking, and that Clearwater Cylinder Head makes a replacement 0331 head. Would that head fit onto a 99 XJ or no? I think if my problem lies within the head, instead of trying to "patch it up" i'd be better off just buying a new head and dropping it in.

I just realized i made a thread on this last week, (more along the lines of me thinking i had a head crack) and i should of posted all of this in THAT thread, but i forgot about it. I apologize for double threading.

Anyways, my oil cap does have that milky stuff on it, but my dip stick does not. I will drain the oil today and see how it looks.

Hard to say at this point, you could of had aire trapped in the block that blew coolant out after all the new parts were installed. If keeps blowing coolant out the over flow, replace the rad cap with a new one and make the store pressure test the new one first!!! They be bad off the store shelf. Did you over fill the coolant bottle?

Look for water underneath the oil (oil floats on water) when you drain the oil.

Coolant leak in the head may evaporate before it reaches the oil pan. Coolant can leak into the combustion area, so pull the spark plugs inspect them for signs of coolant, use a flash light to inspect the piston. Pull the valve cover and look for any coolant puddles on the top of the head.

The block testers are not conclusive for all types of head gasket leaks, only for exhaust leaks into the coolant.

Alright. I think you missed what i was saying. The coolant isn't coming out of the overflow on the bottle. When i took the radiator cap off to use the combustion leak tester, coolant just kept coming up and going over onto the ground.

I'm going to go perform a leak down test on the jeep now and see what it's looking like.

Here's a picture of my oil fill cap and my spark plugs.

 

[AZ Jeff]

That oil cap indicates a LOT of moisture in the crankcase. I would have the oil tested for the presence of coolant, and/or the coolant tested for the presence of hydrocarbons (oil).

I am betting your head is cracked. The 0331 head usually cracks after an overheating episode......

 

[Ecomike]

I would pull the valve cover next, after seeing that cap, to see what the top side of the valve trane looks like. You might even see where the coolant leak is if there is one. The cap sure looks like a top side coolant leak.

 

[Kingkong0192]

That oil cap indicates a LOT of moisture in the crankcase. I would have the oil tested for the presence of coolant, and/or the coolant tested for the presence of hydrocarbons (oil).

I am betting your head is cracked. The 0331 head usually cracks after an overheating episode......

How would i go upon doing this? Take out some oil and send it off to a company for testing? Any companies that ring a bell in your head?

Jeep is a 1999 with the distributor. No coil pack. It shouldn't be a 0331 head.

I would pull the valve cover next, after seeing that cap, to see what the top side of the valve trane looks like. You might even see where the coolant leak is if there is one. The cap sure looks like a top side coolant leak.

If i pull the valve cover, i need a new valve gasket, correct? I should go buy one of those if i need it before i pull the valve cover.

If it is a top side coolant leak, what would that consist of fixing it? I know just about nothing about engines. The top end is the head, camshaft, lifters, etc etc, and the bottom is where the crankshaft and the engine bearings are, correct?

Currently trying to get the first cylinder up to TDC so i can do a leak-down test. Any easy ways to get it to TDC?

 

[Kingkong0192]

Found TDC on cylinder #1.

According to my gauge there is 100% leakage in cylinder one. I can hear air rushing out of the intake. I guess my intake valve is shot? Going to continue the process and see what the rest of the cylinders are saying.

Maybe i didn't find TDC?

How do i tell the difference between the intake stroke and the compression stroke? I stuck a screwdriver down into the spark plug hole, spun the crankshaft until the screwdriver moved up, and when it hit it's max and started to slightly recede, i pulled out the screwdriver, screwed in my tester, and pumped air into the cylinder.

Here's a video of my process.

http://www.youtube.com/watch?v=k2zK3SMcK6E

 

[Ecomike]

I think the newer XJs had valve cover gaskets that are reusable, but not sure what the dealership used on the head job on yours. Can you see a blue rubber gasket at the edge, if yes, it is a reusable rubber/silicone gasket.

Sounds like you have found TDC #1, but maybe went too far, or have the intake stroke? Did the piston and crank move due to the air pressure pushing on the piston??? IIRC you need somehow make sure the air does not push the piston and rotate the crankshaft. But it needs to be done safely!!!!!!

You may be using too much air pressure???

It is intake versus combustion (not compression) stroke. The difference is one complete 360 degree turn of the crank shaft!! You need to find the other TDC #1, compression stroke, to do the test!!!!

Compression is going up, intake is going down.

Compression stroke up (cycle 1), expansion (power) stroke down (Valves are sealed, cycle 2), then exhaust stroke up (cycle 3), and intake stroke down (cycle 4).

Takes two complete 360 degree rotations of the crank shaft.

Sounds like you were on "exhaust stroke up (cycle 3), and intake stroke down (cycle 4)." as the valves overlap open near TDC on the 4.0 I think.

 

[Ecomike]

"If it is a top side coolant leak, what would that consist of fixing it? I know just about nothing about engines. The top end is the head, camshaft, lifters, etc etc, and the bottom is where the crankshaft and the engine bearings are, correct?"

Top side coolant leak I am thinking of would be a cracked head on the valve side, top side. If it is cracked you need at buy a good used junk yard pulled and rebuilt from a local machine shop head. Let the machine shop get the head for you.

The 4.0 is over head valve, not over head Cam. The cam is in the block on a 4.0, and the lifters are below the head in the block riding on top of the Cam Shaft lobes, and you got the rest right. What you described is a common overhead CAM engine. The Jeep 4.0 is overhead valve (commonly what they are called OHV or OHC or DOHC for a V engine, Dual over head Cam).

 

[Kingkong0192]

Thank you. I think it's a rubber gasket.

One last question;

Can i remove the A/C compressor, the battery, and some other components to make removing the valve cover easier?

I spun my crankshaft 360 degrees and tried it again. There is still air coming out of the intake. I'm going to cut my air down to 50 PSI and try again. Can i perform a leak down test with the valve cover off?

ie; Can i spin the crankshaft without the serp belt on it, or will it throw everything out of line and mess up my timing?

Thanks for all the help. I can almost see the dollar signs i'm saving if i have to do a head job.

 

[Ecomike]

You should not need to remove anything to remove the valve cover, the cover is on top of the head, top of the engine, are you thinking of the timing gear cover on the front of the engine?

Can i perform a leak down test with the valve cover off?

YES!!! And you can see if the valves are open or closed too!!! And visually inspect the top of the head for cracks and coolant puddles stuck on top of the head.

I think some people use a socket and breaker bar and cheater pipe attached the front crank shaft, harmonic balance bolt, and lodge it against the driveway concrete to keep the crank from turning, but you need to know what you are doing to make sure it does not rotate the other direction and send the tool flying like a missile!!!

I would start with about 10 PSI myself!!! If you had a manual transmission, just set the parking brake, wheel chucks and put it in gear first. Autos are not as easy.

 

[Kingkong0192]

You should not need to remove anything to remove the valve cover, the cover is on top of the head, top of the engine, are you thinking of the timing gear cover on the front of the engine?

YES!!! And you can see if the valves are open or closed too!!! And visually inspect the top of the head for cracks and coolant puddles stuck on top of the head.

I think some people use a socket and breaker bar and cheater pipe attached the front crank shaft, harmonic balance bolt, and lodge it against the driveway concrete to keep the crank from turning, but you need to know what you are doing to make sure it does not rotate the other direction and send the tool flying like a missile!!!

I would start with about 10 PSI myself!!! If you had a manual transmission, just set the parking brake, wheel chucks and put it in gear first. Autos are not as easy.

No, i was thinking about the valve cover. Just thought that would make it easier. Anyways, i didn't have to. Just pulled the valve cover off. Looks bad inside. I think i see a tint of green, but i might be seeing things.

I think (unless you have a better way) my best way to figure out where the problem is is to keep doing a leakdown test so i can see/hear air coming out of somewhere.

I do think this is a serious problem now. I don't think i just have coolant dripping out of a hose or something. I'm positive it's something internal now.

It's an automatic. I'll drop it down to 10 PSI and see what happens.

 

[Ecomike]

That is definitely green coolant on the bolt head. That confirms the white goo emulsion inside the valve cover. Looks like a small crack in the head leaking coolant up top. Might not be any noticeable coolant in the oil sump yet, if you are lucky, and got to it early???

Time to pull the head and send it to a machine shop, or start shopping for a head. If you run the engine any more you risk wiping out the crank shaft and bearings!!

Time to drain the oil, see if it is white, or normal, or has any coolant in the oil yet down below in the pan.

So far it looks and sounds like it was a slow small leak top side on the head, and you may have avoided needing to replace the engine!!! But let's see how the leak down test goes.

BTW, I usually do a compression test first, to see if I need to bother with a leak down test.

 

[Kingkong0192]

That is definitely green coolant on the bolt head. That confirms the white goo emulsion inside the valve cover. Looks like a small crack in the head leaking coolant up top. Might not be any noticeable coolant in the oil sump yet, if you are lucky, and got to it early???

Time to pull the head and send it to a machine shop, or start shopping for a head. If you run the engine any more you risk wiping out the crank shaft and bearings!!

Time to drain the oil, see if it is white, or normal, or has any coolant in the oil yet down below in the pan.

So far it looks and sounds like it was a slow small leak top side on the head, and you may have avoided needing to replace the engine!!! But let's see how the leak down test goes.

BTW, I usually do a compression test first, to see if I need to bother with a leak down test.

Sadly, i don't think i got to it early. It's been like a month or a little more. I haven't really driven much, but i have driven it. I went through about a gallon or so of coolant from it just disappearing.

I think i'm just going to buy a whole new head instead of shopping for a used one. I don't plan on running it anymore.

Going to go drain all the oil out right now, and i will return with pictures.

Lets say i did need to replace the engine. That means i have to pull the entire thing and swap in an engine from another XJ, correct? Or can you literally rebuild the internals of my engine, or is that not worth it?

I can still do a compression test at this stage, correct? I'll do one of those as well. Might as well see the compression in the cylinders, then i'll leak down each one because i have nothing better to do tonight.

Is there a way to tell if my engine bearings are shot, or a way to tell if i toasted my engine?

 

[Ecomike]

If the leak was slow enough, it may have boiled out before doing any real damage. I would do the compression test now, yes you cab still do the compression test, just disconnect the CPS sensor so the computer kills the spark and fuel feeds, and skip the leak down test as it is a waste of time if you are replacing the head anyway, and if the compression test was good. If the compression is good, it confirms good pistons and rings and cylinder walls. If compression is bad, it does not confirm where the leak is!!! But wasn't this engine still running smoothly??

If the compression test is bad, a leak down test might help collect data on the leak source, ie rings, head gasket or valves, or might not.

You can drop the oil pan and pull the crank bearings, inspect them and the crank bearing surfaces and install new bearings, with out pulling the engine.

How was the oil pressure???????????? If it was still good, that is a great sign!!!

Most of us get a JY core ( I let the machine shop get mine), and have a machine shop test (full inspection) it and rebuild it. New head, if they even make them won't be cheap!