So I think I blew the head gasket or cracked the head on my XJ6, do you guys think this sounds about right?

Months ago I had an overheating problem which has been solved, but since then I have been losing coolant to an internal leak, which has been getting progressively worse.

Possibly unrelated, I've also been burning oil since I had the oil changed last week and it the levels were pretty low (though the mechanic didn't say anything about the color).

I've noticed more often recently white smoke coming out of the tail pipes, but mainly on startup if at all. On two occasions I've seen smoke coming from under the hood that smelled like the coolant (and after talking about it my girlfriend said she had noticed it too). The last time it occurred (over the weekend) I checked and it looked like it coolant was coming from the exhaust manifold gasket, as well as bubbling out of where the o2 sensor plugs into the exhaust manifold. Oddly enough it all burned off and and car was driven as normal for the rest of the day.

My girlfriend was driving the car two days later and it died on her and sputtered to a stop and we haven't been able to get it started since. I ran a compression test last night on it and the results came as follows:
1:120
2:140
3:150
4:150
5:120
6:120

Does this sound like a head problem to you guys? Thanks everyone.

 

Could be. Sounds like it.

The best way to confirm a head gasket leak is to use an exhaust gas sniffer to test for hydrocarbons in the coolant. Many shops have exhaust analyzers. Or, a DIY "block test kit" (from the local parts store like NAPA) that uses a color-changing chemical that detects hydrocarbons.

Or....


Leave the over night and pull the plugs before starting the engine the next morning. Sometimes you can actually see coolant on the spark plugs in, if you have a small flashlight, see droplets of coolant in the cylinders


Or....

Remove the cap to the header tank and run the engine. If the coolant is bubbling you have compression being pumped into the cooling system.

Or.....

In extreme cases the oil will turn light brown due to large amounts of coolant and water being mixed.

Cheers
DD

 

Well anything that involves the car running isn't an option but well doing a compression check I swore I saw some green in the spark plug holes but it was dark out when I checked after the test it wasn't there. I left the plugs out so I'll check that out later today.

Then if I see the coolant (like I suspect )I know I have a serious problem.

Assuming this is the problem, I don't think I'll be fixing it, so if anyone needs anything off of a 86 shot me a message, because there is a good chance I'm going to start striping parts of this thing as early as today or tomorrow.

Thanks again Doug, you've been a huge help with this car the past few months.

 

Droti, you are only really going to know if you pull the head off. As an '86, you should have the slotted block which was much better for HG failures, but even so, they do eventually go, (sorry !).

Your symptoms do sound like HGF to me. There is another potential path for coolant to enter the oil and that is by corrosion of the wall in the timing chest cover where the coolant passes into the block. If the car has been neglected apropos coolant, (antifreeze), changes, corrosion can cause a hole here, so the coolant leaks into the timing chain chest, but it is rare, unlike HGF which is common.

Yet another path, very rare, is diaphram failure in the heater water valve, letting the coolant into the vacuum circuit, and hence into the inlet manifold.