burning antifreeze like crazy and missing when hot!! Help??

[94 splash]

Ok well hers my problem I'm burning thru antifreeze like crazy.. so i figured that i had an intake problem.. but after it gets hot it starts missing so ive had a few people tell me that it sounds like a bad head gasket or a cracked head... And the system will not stop pushing air thru the cooling system so its pushing air in thru somewhere.. Im gonna check the compression in a few after it cools off but was looking for some expert opinion... Thanks Derek

 

[Sunk]

Check your oil also, as that very well could be where all the coolant is going. If it looks milky then you have a bad head gasket.

 

[94 splash]

Nope oil looks just the way it should and the antifreez is still bright lime green

 

[ff2024]

I had a similar problem...I was losing antifreeze but couldn't find the leak, and my oil was fine. But come to find out it was the head gasket. I would leak to the outside of the head and burn off before I could notice it. So I replaced the head gasket and all is well.....for now.

 

[MAKG]

It's possible -- and not all that unlikely -- to breach a head gasket from the water jacket directly into a cylinder. It's easily detectable with a leakdown test. If it's severe, it will make clouds of persistent, sweet smelling white smoke even when completely warm.

It's also rather easy to have a small or moderate leak to the outside without making puddles. Look around the ENTIRE cooling system for corrosion tracks and white deposits. Do NOT skip the water pump. A failing water pump will leak out a weep hole in the bottom of the snout.

If an external leak is bad enough to cause rough running, internal engine damage becomes likely. This includes scuffing cylinders (leads to oil use through piston rings, especially at high throttle) and "flattening" pistions (leads to engine knocks). It may or may not show up as overheating on the temperature gauge. Usually, though not always, the gauge reads abnormally COLD when this is going on. That's because the gauge sender is measuring air.

 

[Bob Ayers]

Your vintage 4.0L is known for the lower intake bolts to loosen up. I suspect you now need to replace the lower intake gaskets. To verify this theory, spray some carb cleaner on the lower intake to head interface, while the engine is idling. If you have a leak, you will see a change in RPM.

 

[94 splash]

It's possible -- and not all that unlikely -- to breach a head gasket from the water jacket directly into a cylinder. It's easily detectable with a leakdown test. If it's severe, it will make clouds of persistent, sweet smelling white smoke even when completely warm..

Thats exactly what my dad said... so last night i checked the compression ,, cylinder 5 had decent compression about 179 ish and the 4 cylinder only had 150 and the plug was really oily so it looks like i need a head gasket.. the 1,2,3 cylinders all have 190-180 for compression.. just hoping it not a cracked head

 

[MAKG]

That is definitely out of spec, but before you pull this thing apart, run a leakdown test.

Pressurize the suspect cylinder to 100 PSI at TDC/compression, remove the rad cap and look for bubbles. Also listen at the exhaust pipe and throttle body (with the intake hose removed) for hissing. This tells you if your low compression is because you need a valve job.

Also, try a "wet" compression test on #4 and see if it improves. Just a few squirts of clean engine oil in the cylinder. This tests the piston rings.

The lower intake being loose will oil foul plugs very easily, and can cause coolant burning (though it's hard to imagine it not getting coolant in the oil). It will NOT affect compression or cylinder leakdown. Bob's test is correct, but kinda difficult on a V6 because the relevant joints are inside the valve covers.

Note that low compression by itself will explain some degree of rough idling.

 

[94 splash]

Ok well pulled the head off and i have problems.... First off my had gasket was blown big time in the # cylinder:mad and it also has some pretty good scoring.. so anyone have any ideas except dropping the piston and honing it out ???

 

[94 splash]

Had a little typo it is my #6 cylinder that is bad not the #4 sori its kinda been a long night

 

[MAKG]

If it's scored, you really have no option but boring it out. Unless these are extremely shallow scores. Then you might get away with honing, but your ring gaps and piston clearance are going to be big.

But there is no way you can get scores out without some machine work. And you probably need pistons too (certainly if boring is needed), since there is probably some damage to it that you can't see.

It may be cost effective just to get a replacement (junkyard) engine. 4.0Ls are not at all rare. I suppose a rebuilt short block, but that's probably much more expensive.

 

[94 splash]

Well me and my dad just said screw it and decided to get a re ring kit from northern.... i got the engine on the stand now and im gonna pull the pistons tomorrow and do all my measuring and gonna try honing it but if not im gonna bore it so ill have pics soon

 

[woodyedmiston]

You are about to do a lot of hard work and you won't be happy with the result

 

[94 splash]

You are about to do a lot of hard work and you won't be happy with the result

y is that????