The blue dye tester is the best way to check for combustion gasses. The pressure tester is also a good test for the integrity of the cooling system. Both methodolgies combined gove the most accurate results. In some cases, when a smmall crack is present, the pressure alone may be inconclusicvce unless you allow it to heat up sufficiently for the crack to open up.

To be sure, use both tests. Pressure first to make sure it isn't a hose, cap, or hole in radiator or other sealing surfcae such as tstat housing or pump.

A leak down test may prove sucessful, but if the cyl leaks down more from valves or rings, it may not go to cooling.

Bottom line, several test methods in combination may be required to determine source of problem.

Test whatever methods you have available, then if nothing shows, use cooling system flush, plain water, flush, plain water, etc. Repeat as necessary to clean it all out before adding coolant back to system. Watch carefully for several days for more signs of crud.

 

Not to compound the issue but I looked back through my post and forgot one more important thing. I have been burning through about a QT of oil every 1000 miles or less. This suprised me after putting on new heads. This is another reason I was leaning towards the head gasket. Here's a pic of plug #7 a couple months ago. Something going on in that cylinder. Maybe the valve guide seal? Would that cause the oil consumption? The rest of the plugs looked great.

 

Plenum been fixed?

 

Plenum has been fixed. along with new radiator, heater core, timing chain and gears, waterpump, lifters, heads and all new gaskets and plugs while I was in there. Radiator and heater core were leaking and a head was cracked. Thought I would just freshen up everything else that might fail in the near future by replacing the rest on the list.

 

Anyone have thoughts as to why only plug # 7 looks like this and the rest are fine. Was told by someone that could be a leaking valve guide seal. These were new heads so that suprises me a little. But you never know I guess until you get in there.

What would I look for on a bad valve guide seal? I have extras to put on either way, but I was just wondering for my own knowledge.

 

Check compression as well. Valve seals are easy enough. Just change 'em.

 

When you say plenum is fixed did you replace the plate with a aluminum one? Was this before or during headjob? O2 sensor and cat changed? And were the heads remanned or new.castings?

 

Plenum was changed with Hughes aluminum plate before the heads were replaced. Cat and O2 never replaced. Had the cats checked and they were fine. The heads were a set of Clearwater heads with the new thicker castings. Maybe they were bad from the factory. Always had a little rattle in the valve train front passenger, but ran well.

If i pulled the heads I know how to check for warpage, but how would I check for bad valve grind or leaking guide seal?

 

was your engine using oil?. the second thing was it over heating if not i don't thing the head gaskets or bad castings would be at fault. i would do a leak down test make sure #7 is up there with the rest of the cyl, then comp test. if all good throw some valve seals in flush the rad and if you can pull the block drains out and flush the block out as well.

 

Op did you install new lifters when you did the rest of the work or they the old ones? Could be a simple as a failing lifter.