Mystery of disappearing antifreeze and other funny things. Many Dodge owners complained about this phenomenon at Dodgetalk.com and other blogs. Unfortunately, it happened to me, too. I need your experience and the brain-power to solve this mystery!
My truck: 1999 RAM 1500 SLT, 5.9L Magnum, code “Z”, 96,000 miles, Fastman TBI, ACCEL variable flux super coil, K&N, 8mm wires. Used daily, highway.
Couple weeks ago, (33F outside), my coolant temp gage chime rung after driving only a mile. Gage went up to 260 F. I stopped the truck, checked coolant level in the radiator overflow tank. It seemed OK. With a rubber glove I partially turned the radiator cap. Some air bubbled out. When I started the engine, temp gage went down to 160 F, then raised to 180-190F and started cycling normally. For the rest of the trip (100 miles) the temperature did not go over 200F. Two weeks later, the same s… happened, except I “lost” quart or so of coolant. I replaced it. I replaced the radiator cap. Everything was “fine” for a couple of days. Than, it happened again! This time, I “lost” 2+ qt of coolant. Power and acceleration seemed to be good. No idle change, no sputter. There were no leaks or puddles under the truck and no wetness in the engine compartment. NONE! I drained the engine oil; there was no antifreeze contamination, just “pure” oil.
Next, I run a cooling system pressure test. With engine cold, it dropped from 22psi to 18psi in 10 minutes and… stayed there. Gage showed 18psi after 2 hours. Now, I am totally confused! Why it did not drop any further? I de-pressurized the system and started the engine with the radiator pressure gage attached. After 10 min of idling temp gage on my dash started going over 200F. At the same time radiator pressure did not go past 6 psi. No apparent loss of power, not smoking, no hesitation.
I pulled all plugs. Looking good. (With a high energy coil voltage arch they can not look bad!). I decided to run a compression test.
cylinder 2 4 6 8
pass side dry (psi) 115 125 110 135
wet first puff 115 125 125 130
wet @4rev 130 140 140 145
cylinder 1 3 5 7
driver side dry (psi) 135 105 120 110
wet first puff 120 140 120 120
wet @4rev 150 145 125 130
Cylinder 3 & 5 look suspicious (?). Any thoughts? What might have happened?
I took the water pump off; looking good. Next, I took the intake manifold off.
The whole underside was covered with 1/8 to ¼” black hard baked sludge deposit! It was thicker & bubbled @ the front, by the thermostat.
All injectors, but all, on the Driver side, Cyl 1,3,5,7, exhibit very small bright “wash off” areas, perhaps, narrow spray cone angle, (or low air velocity?).
All injectors on the Pass side, Cyl 2,4,6,8, have large bright “wash off” areas, extending towards the head ports, indicating much wider
spray cone angle or larger air flow. Any ideas why?
Why such a difference? Would it have something to do with different air velocity @ Dr vs Pass cylinder bank. ( Fuel rail pressure was OK.)
Pan gasket was bulging & protruding outward between cyl 4&6 ports, passenger side. There were no gaps; gasket was still sealing both parts!!!
In two places gasket was marginal, but still had solid 1/8” overlap. Judging from impressions on the gasket and a pan surface, there were NO leaks.
(Pic shows gasket broken, I bumped into it). I am replacing it with Hughes Engines aluminum belly pan! http://www.hughesengines.com
Now things are getting very interesting.
Upon the belly pan removal there were puddles of oil inside at the bottom of (now inverted upside down) manifold.
Inside surfaces of cyl 1,2 and 5,7 runners had a continuous oil coating as far as I could see the bottom. Cyl 3 runner had some residual oil film.
Cyl 4, 6&8 runners were SQC (squeaky clean)! Picture below, upper left.
Inside surface of the belly pan shows oil splatter area under the cyl 5 and 1,3 runner inlets. Take look at this picture. All on the passenger side!
(Also: see pic showing 1,3,5,7 injectors minimal wash off pattern. )
What would cause oil splattering under the runner inlets? If the kegger was tight, where did the oil come from?
Pic above: 5,7 runner inlets and a splatter pattern under. (Itried to post some pictures, but it did not work well)
Pan area under cyl 2,4 and 6,8 runner inlets, is clean, showing a bare metal!
Cyl 5 head port shows suspicious dark discoloration area.
pic below: 1, 3 ports look darker than 2,4 or 6.8.
Here is 2, 4 port for comparison, below.
At this point, you may ask what antifreeze has to do with all of this? I dunno- is my answer. I am digging deeper and deeper. Still, no antifreeze. It disappeared!
Below, couple pics of the gasket surface @ heat passages. May be you’ll find a clue.
Did miss anything? I hoped I don’t have to remove heads, but… you tell me what to do next.
Thank you for any opinion or advice.