Bad head gasket or cracked head?

[Mitchs07explorer]

Since I've gotten the 5.0 running I've filled and drained the coolant a few times as I've repaired different systems. I checked the coolant about a week ago it's now been in the cooling system for several weeks and noticed it had a black hue to it. I wasn't immediately suspicious because when coolants mix it can make a darker colored coolant. There was the old coolant in the system when I did the flush and I have no idea how old or what brand it was but it looked terrible. I put new coolant in after running a cleaner and distilled water through it. I thought all was good with the system, it never leaked and the engine temperature stays where it should. After running the engine several more times I decided to take a look in the radiator just to make sure it had plenty of fluid. I checked the coolant expansion tank and it was still full but when I looked in the radiator the coolant was a few inches from the top. I topped it back off and ran it for a while and checked it the next day. The coolant was fine in the expansion tank was fine but lower in the radiator again. Upon further inspection I noticed a trickle of coolant right around the tube where the hose for the expansion tank hooks to the radiator. I pulled the rubber hose off and took a good look at the hose and the plastic tube it connects to. The hose was in good condition but on the radiator where the hose connects there were imperfections and deep gouges in the plastic that coul allow air or coolant to escape. Now I'm assuming the radiator must be replacement based on the poor QC. I took some high temp in weld and filled in the gouges and filed the raised seams so the rubber expansion tank line would have a smooth surface to connect to. I cut an inch off of the rubber tube and after I let the in weld cure I reconnected it the radiator. I borrowed a radiator pressure checker from oreillys and hooked it up, pumped it to 16lbs and started to hear dripping. I looked under the the car and my waterpump to lower pipe hose was leaking. I wanted to replace it when I replaced the pump but the old one seemed a better fit than the AC delco brand hose I'd picked up to replace it, so I just used the old one. Ironically, when the truck is running whether its up to temp or not it doesn't leak a drop. So I'm going to replace that hose and pressure test again but now I fear the head gasket is blown. I got the truck up to running temperature and I looked in the expansion tank and can see air bubbles coming into it but no visible leaking from anywhere. My oil is very clean with no coolant in it, I need to check my coolant color again but when I drained it last time it was dark but didn't have any oil in it.

Before I start taking the heads off is there anything/anywhere else I should look for? Others tests I should perform? Once I have the heads off do I need to go to a machine shop to have them checked? I understand heads can warp and crack, I just want to make sure I do it right so I don't have to do it again.

This is the gasket kit I'm looking to use as a replacement for the others https://www.rockauto.com/en/catalog...e,cylinder+head+gasket+/+head+gasket+set,5412

 

[08EddieCA]

**run a compression check...

Check for hydrocarbons in your coolant: block test. Mine tested positive before I did any repairs.
I replaced both heads, head gaskets, and bolts. Machine shop charged me $125 for each head swap (had to be rebuildable), about $30 for each head gasket, and about $20 per side for head bolts. Add another $100 in cleaning materials and add a week to your timeline for unknowns. That's my experience.

 

[Mitchs07explorer]

**run a compression check...

Check for hydrocarbons in your coolant: block test. Mine tested positive before I did any repairs.
I replaced both heads, head gaskets, and bolts. Machine shop charged me $125 for each head swap (had to be rebuildable), about $30 for each head gasket, and about $20 per side for head bolts. Add another $100 in cleaning materials and add a week to your timeline for unknowns. That's my experience.

Were your heads cracked or warped beyond repair? Just curious why you opted to change the heads over repairing them. I'm gonna rent a kit to do the compression test next to determine if it's definitely the head gasket which I'm pretty sure it is. I guess I need to be a 100% certain but considering I'm losing coolant and I don't see any puddles it only makes sense. I just hope it's not a cracked head but the coolant loss is minimal enough I assume it's just the gasket.

 

[RandomNerd2000]

Just a hunch but have you checked to make sure that the level when it goes down it doesn't continue going down?

 

[08EddieCA]

Were your heads cracked or warped beyond repair? Just curious why you opted to change the heads over repairing them. I'm gonna rent a kit to do the compression test next to determine if it's definitely the head gasket which I'm pretty sure it is. I guess I need to be a 100% certain but considering I'm losing coolant and I don't see any puddles it only makes sense. I just hope it's not a cracked head but the coolant loss is minimal enough I assume it's just the gasket.

I needed new valve seals. A valve job plus the seals, for some reason, cost more than a swap. The swap included complete rebuilds, pressure tested, new hydro lifters, seals, ground valves and seats,etc. Price savings was close to $40 a head. I also needed three spark plug holes "fixed" at $20 each. So a swap made sense to me.

How did I know the LH was cracked? I could see the cracks visually. Compression in that cylinder was 30% lower than the other cylinders too. It was cracked on the top of the head - I could see it.

Since I was going to work on one head, I decided to go with a rebuilt swapped RH while I was at it. Who ever put the original heads together on the reman engine I bought less than a year ago did not do the best of work. Having both heads worked on/swapped was more of piece of mind. Coolant did test positive for hydrocarbons in my coolant so I know there was a problem. Most likely it was the crack. I have the old head gaskets but I don't know what I'm looking for in terms of a failure point.

The compression test will be informative. Perform a dry test and a wet test. See if the numbers jump or remain the same.

 

[Mitchs07explorer]

Just a hunch but have you checked to make sure that the level when it goes down it doesn't continue going down?

I'm not sure what you're asking... do you mean does the level of coolant continue to go down? It seems like I can run the engine for about 30 min or so and the level of coolant in the expansion tank will go down and I estimate it's about a 1/2 of a cup worth. I can also see air bubbles coming into the the expansion tank while the engine is idling. I had a leak on the top of the radiator where the neck connects to the expansion tank hose via that smaller tube. Before I fixed that part the radiator wouldn't draw any coolant from the expansion tank. Once it was fixed I performed a pressure test on the radiator and found that my lower waterpump to pipe hose dripped at 16lbs and overall lost pressure fairly quickly. Ironically it doesn't drip while the engine is running regardless of temperature. I don't get any white smoke out of the exhaust but perhaps that's because the leak is mostly minimal at this point.

 

[RandomNerd2000]

What I was trying to ask is that, if you were adding let's say 1 cup of coolant every 100 miles, at 150 miles, or 200 miles in theory, does the amount you have to add change, or was it leaking out a set amount. I overlooked the tidbit about the expansion tank hose nipple being messed up so just ignore that bit.

I can't help but wonder, have you done a hydrocarbon test on your coolant? I think you can rent the tool to do that. Another way one can check for coolant getting out the system would be the oil, and an abnormally clean spark plug I think is a sign of water in the chamber. Compression test is another way to check, a leak from the chamber into the cooling system will show in a compression test.