I just few moments ago came from the garage, my meaning was to remove oil pump and correct the shaft BUT then i noticed something clear dripping down from the pump. My heart stopped. COOLANT.

I instantly put oil can under the car and opened oil screw... 4 liters of coolant plus 5 liters of oil squirt out. HOW?

Head has been machined a little over year ago, and it has run strong since. I recently took it out because i painted engine bay + engine and accessories. I DID change one thing to engine: TIMING COVER. Could it be that the coolant have leaked from there? I have not run engine since last fall (and it run perfectly then)

I just cant figure out anything else. Did compression check, 1st time: 1-5 steady 150psi, number six was about 130+. Then i started from rear to front: 6 was now 150 and for some reason nr 2 was only 100+. Then i started from front again and nr2 rise up to 140+. I guess my battery started to be little low on current or something? I didnt have throttle open on first test, only on second and third.

I was supposed to go to car show this wednesday, well it aint happening.. :mad:

You're not having a very good month are you? Sometimes the Z gods test us more than seems fair. Chin up!

The coolant certainly passed through the front cover, so it appears likely that the gasket between the cover and the block is leaking or the front cover is cracked. You did put new front cover gaskets on after the change, didn't you ?

The quantity (all) of coolant in the oil pan sure points to it coming from the front cover straight down and into the oilpan. Head gasket leaks tend to be more subtle. Coolant gets burned off or mixes with the oil.

To test this, remove the thermostat, put the housing back on, with the oil pan empty, plug out, I'de just fill the rad, and wait and see how long it takes coolant to leak out into the oil pan. If you don't get much of anything in 10 minutes, take the fan belt off and spin the water pump by hand (same direction as engine rotation of course) and see if that speeds up the coolant leak. Take the valve cover off and look down the chain way with a strong light and try to see where coolant is coming from as you spin the water pump.

Hint: Use an electric drill with the fan belt just on the water pump pulley and over the drill chuck to spin it faster.

In any event, I think you're pulling that front cover to have a look at what is going on. Water doesn't make a very good lubricant either, hope you didn't run it much.....

Jim

Edited April 29, 201311 yr by zKars

There are some interesting bolt passages and coolant passages in the front cover. If I recall correctly there are areas where an accidental fracture can cause this problem near the lower corner bolts.

Yea, coolant was not yet mixed with oil. When i removed the bolt, first came coolant, then oil. Nicely separated. Thank god i did not run the engine, as the distributor/oilpump shaft was aligned incorrectly. SO only tried to start it a few dozen times but no go.

*sigh* i guess this is a test of a true Z believer. Oh ye of little faith.

Maybe one of your water pump bolts cracked the front cover? I hope you get that figured out.

No bolts were cracked or damaged. I did found ONE difference between old and "new" valve cover. The lower part of the cover (one that mates with oil sump) was way thinner in "new". Still it does seem to fit engine same way as does the old, there must be few millimeters of difference somewhere, where it has leaked all the coolant. Im a bit confused right now but hopefully putting old one back solves this.

CRAP! Im getting weird compression readings from cyl nro 2. It is now way less than 100 when others are 150. Have i destroyed piston rings? Im starting to lose hope here :'(

Adjusted valves, they were quite tight. Compression still extremely low on cyl 2. Bypass test led me to believe that its a valve failure.. I have no idea can you change valves with head on plus is there any sense to change valves to just one cylinder?

Did you check the front cover to make sure that there were no cracks, holes, etc. on the side that faces the engine? I once had a problem like that caused by the coiled wire stiffiner inside of the radiator hose getting caught on the water pump impeller and it scraped a hole in the back of the cover.

My guess would be that you inserted a too-long bolt somewhere into the front cover area and cracked into an internal passageway.

What about that bolt in the thermostat housing everybody talks about going too far in?

EDIT: that bolt hits the timing chain guide. SORRY

Edited May 4, 201311 yr by siteunseen
My mistake

I used only standard sized bolts. Im taking the head off tomorrow to see if there is any damage in head gasket. Have to rule that out too.. *sigh*

How about dropping the oil pan, refilling the cooling system with water, then use a pressure tester to pressurize the cooling system. You may be able to see where the coolant/water is coming from.