Testing for failed head gaskets on my 96 2.5

Is there a way to test head gaskets with the engine out of the car? Recently put a refreshed 2.5 (but has 250,000 miles on its clock) in but didn't have the heads milled or even checked for flatness by a machine shop. I did it myself with a flat bar and feeler gauges. Mistake number 7,497.

Anyway, long story short, got it back in and it starts eating coolant right away. Also blows coolant out of the open radiator cap. Brokeindark brought over a Hydrocarbon test kit but we were unable to get the fluid to change from blue to yellow.

I've got the engine out and on a stand, and have rigged up a compression tester hose with the screw in type of end, to take air from my compressor. BTW, 3 of the 4 new spark plugs came out looking brand new, the driver's side rear came out with a little brown on the ceramic.

How much air should I inject when the piston is at TDC to check for a gasket leak?

Tom

You can take off the valve cover gaskets & check the condition of the oil & see if you smell coolant. If coolant were going into the engine, it would definitely be circulated through the heads.

with some work, you could pressure test the cooling system. you would have to plug 3-4 openings and pump in some air. not impossible but still some work.

and and turning the engine over by hand with the cooling system plugged / with a pressure gauge may , MAY show cylinder pressure getting in to the cooling system. i think this is a long shot unless the gasket is really bad. the pressure when running is going to be WAY WAY higher than the pressure when turning it over by hand.

just a thought,
you might consider taking your ''flat bar'' to a machine shop to see how ''flat'' it is. if it is close then maybe things are flat enough. but if it is way out well then you will know. i'm not sure if this is practical or not.

i assume there is no evidence of leaking coolant on the engine. not the cross over pipe?

i like pressurizing the cooling system the best. if it does not hold pressure .......

you may even hear the leak.

Another sure sign is oil mixed with the coolant in coolant expansion tank, just 1 smell is all it took

I have neither oil in coolant or vice versa. When we first put it back together I used just water with no coolant. I couldn't get more than a mile from home and it would show high temps on the gauge, the upper hose would be hot and hard as hell. Pull over, let it cool down enough to open radiator and a half gallon of water would be gone.

Pressure tested the coolant system/engine and found a really really small pinhole leak in one of the heater hoses near a hose clamp. Shortened it up and thought I had found my problem, since it now held 15 psi for hours and hours. Nope.

Pulled the spark plugs and all but the driver's side rear look like new still, with that one having a little discoloration on the ceramic, so I assume that is where my problem lies.

I just bought a leak down tester from Horror Fraught and will do a leak down test on all cylinders so I can see what the general health of the cylinders are before I apply 160 psi to each cylinder to emulate combustion pressure.

My flat bar is a 2' by 2" by 16" stainless steel bar, but aside from the initial machine finish on it, I have never had it checked.

Tom

Well, I did a leak down test and all the cylinders passed; in fact the driver's side rear has the best results and it had the only spark plug with any residue on the ceramic.

About ready to put 150 psi to each cylinder.

Stay tuned to this station for further updates.

Tom

EDIT! Don't put 150 psi to engine that can rotate, especially if you have a 2' breaker bar attached to the front crank sprocket. Just sayin...

Almost as if it is evaporating lol

Any heater core leaks?

Well, I anchored the flex plate at each of the four TDC positions and tried to get the cylinder pressures up to 150 but as soon as any got near 85-100 psi, the nitrogen would start coming out of the exhaust port on the head. So can I assume that at the least the exhaust valves are burnt, worn out? Wish I could have gotten the pressure up to 150 to see if the nitrogen escaped out the coolant tube.

I guess I'll pull these heads off and take them to a machine shop for cleaning, inspection and re-building. Drat.

Tom

Originally Posted by subieadam

Any heater core leaks?

No, once I fixed the pinhole leak in the heater hose, it held 15 psi for hours.

Tom

Gotchya, dang this is a mystery sofar..