naviathan Posted April 29, 2007 Share Posted April 29, 2007 Ok, check these out they're left to right by cylinder: #1 looks oil burned and the rest seem lean to me, but they're not. When I pressurized the cylinders (connected an air line from my compressor) they all checked out except #5 which blew quite a bit out of the crankcase through the valve cover. I was actually looking for a leak into a water passage but found none. my cars been drinking about 2.5 gallons of coolant a week. I didn't get any blow back into radiator at all. I'm utterly confused on this one. #1 looks oil burnt, but checks out, #5 looks clean, but blows out the crank case. Any thoughts? Quote Link to comment Share on other sites More sharing options...
naviathan Posted April 29, 2007 Author Share Posted April 29, 2007 Ok here's the compression numbers just incase anyone has any ideas. 1 - 170 2 - 168 3 - 171 4 - 161 5 - 170 6 - 164 The numbers just don't seem to match the plugs or the pressure test. Quote Link to comment Share on other sites More sharing options...
JSM Posted April 30, 2007 Share Posted April 30, 2007 Your loosing 2.5 gallons a week with not white smoke out of the exhaust and no water in the oil? You sure it's not leaking on the ground? Quote Link to comment Share on other sites More sharing options...
gjc5500 Posted April 30, 2007 Share Posted April 30, 2007 Yea thats alot of coolant w/o smoke or water in oil. Quote Link to comment Share on other sites More sharing options...
naviathan Posted April 30, 2007 Author Share Posted April 30, 2007 Trust me I know this. I don't get it either, but I have not been able to find a leak anywhere and there's no oil in the coolant or coolant in the oil, no white smoke or steam except on cold startups, but that's normal. No wetness in the floorboards, nothing on the bellypan, the sides of the block are dry. I'm completely and utterly confused on this one. No idea where it's going to. The only thing out of the ordinary (besides the missing coolant) is whenever I pull the radiator cap after it's cooled down it sounds like someone flushed a toilet. Like there's air in the system and the cap is holding the water in the radiator then when the cap is removed the pressure releases the water into the rest of the block. I've replaced the cap and the thermostat in the last two weeks. Still nothing seems to be working. Quote Link to comment Share on other sites More sharing options...
stony Posted April 30, 2007 Share Posted April 30, 2007 how much do you drive it per week? Quote Link to comment Share on other sites More sharing options...
naviathan Posted April 30, 2007 Author Share Posted April 30, 2007 how much do you drive it per week? Mostly just back and forth to work, usually around 500miles a week give or take. Quote Link to comment Share on other sites More sharing options...
ezzzzzzz Posted May 1, 2007 Share Posted May 1, 2007 It has to be going somewhere either out the exhaust or into the oilpan. One alternative is the rad cap (you say it's new though) is failing and allowing coolant to overflow. Maybe the overflow tank is leaking too? I'd do a pressure test of the coolant system. Some of those plugs also look mighty clean which would typically indicate lean burn, excess advance or coolant ingestion to the cylinder(s). Quote Link to comment Share on other sites More sharing options...
naviathan Posted May 1, 2007 Author Share Posted May 1, 2007 Well, I don't think it's a lean burn. The plugs are pretty new, say a month at most. The car was running rich because the O2 went out then I replaced that and the plugs at the same time because of the rich running. They do have a very slight tan coming in on the ceramic portion of the electrode, but it is very light. Maybe it is burning in the cylinders, but all of them at the same time? I pressured tested for that very reason and got nothing back from the cooling. Quote Link to comment Share on other sites More sharing options...
Lewis Maudlin Posted May 1, 2007 Share Posted May 1, 2007 You never said whether you looked on the ground. Sounds like your overflow or radiator cap is allowing it to spill on the ground. Fill it up with coolant then let it idle in the driveway for a while after it has warmed up. Let us know if there is a wet spot. Quote Link to comment Share on other sites More sharing options...
naviathan Posted May 1, 2007 Author Share Posted May 1, 2007 Sorry, thought I'd gone over that. been there done that. Nothing on the ground. A friend at work suggested a freeze plug could be seeping and it dries on the block or under the exhaust manifold before it hits the ground. I'm going to look into that one. Quote Link to comment Share on other sites More sharing options...
jtmny1999 Posted May 1, 2007 Share Posted May 1, 2007 Heater core? Quote Link to comment Share on other sites More sharing options...
naviathan Posted May 1, 2007 Author Share Posted May 1, 2007 Heater core? Already checked. Quote Link to comment Share on other sites More sharing options...
Dragonfly Posted May 1, 2007 Share Posted May 1, 2007 naviathan is this in your 280ZX? The reason I am asking is because my buddies 280ZX is doing exactly what you are describing. Him and I are both gear heads and we can not find any indication of where the coolant is going. There is no white smoke, no sweet smell, no water marks or puddles under the car and he tells me that he did not find any wetness inside the car. I examined the bottom of the radiator and the underside of the coolant hoses, checked the oil and any place on the car I could think of that the coolant may have left a mark. We have found nothing, if you find it on yours let me know and if we find the problem first we will let you know. Dragonfly Quote Link to comment Share on other sites More sharing options...
naviathan Posted May 1, 2007 Author Share Posted May 1, 2007 naviathan is this in your 280ZX? The reason I am asking is because my buddies 280ZX is doing exactly what you are describing. Him and I are both gear heads and we can not find any indication of where the coolant is going. There is no white smoke, no sweet smell, no water marks or puddles under the car and he tells me that he did not find any wetness inside the car. I examined the bottom of the radiator and the underside of the coolant hoses, checked the oil and any place on the car I could think of that the coolant may have left a mark. We have found nothing, if you find it on yours let me know and if we find the problem first we will let you know. Dragonfly Dragonfly, Yes this is on my 280ZX. Sounds like your buddy has run into the same walls I have so far. Baffling isn't it? Quote Link to comment Share on other sites More sharing options...
eec564 Posted May 1, 2007 Share Posted May 1, 2007 I think I know what it is, my ZX used to do the exact same thing. It used to go through cooloant FAST, around a half gallon at a time, ever time or two I parked it. What was happening is I'd park the car hot, and there was enough heat soak to cause some of the coolant to boil and overflow the overflow tank. It would then cool off and suck air into the system. I fixed it by letting my car idle down using the turbo timer feature in my remote start/alarm system. If the car is really hot, I'll leave the heat on with the 2min turbo timer. Because of the way the expansion tank sits, the overflow from it dosen't always drain to the ground, but sometimes just seems to dissapear. I first figured out the problem when I was checking my oil with a really hot engine, and coolant started shooting up from the little hole in the overflow cap. Normaly it would take 2-5 mins to start to overflow, but with a HOT engine it will take around 30 seconds. naviathan - if you open your radiator cap cold and it's seriously sucking, you may have too high pressure of a double valve in. The caps have two springs and valves in them, one that opens at the specified pressure to let coolant out, and another that's supposed to open very easily in the other direction to allow coolant to flow back in. Some new caps will allow a large vaccume to develop before sucking coolant, but the OEM ones open easily. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted May 1, 2007 Share Posted May 1, 2007 I chased a coolant leak on my 240 for years. Finally someone told me the head gaskets tend to "weep". So I dumped a tube of green food coloring into the radiator, surrounded the head gasket with clean white paper towels and started the engine. I then put some cardboard in front of the radiator to get the idling car to heat up and pressurize. sure enough the paper towels at the back of the head turned green. Since it was just venting steam I didn't have any water trails cause it would vaporize and condense in the air. just dump a tube of stop leak in the radiator. That is what fixed mine. The sucking sound is air going back into the radiator after the coolant has cooled down and condensed. Quote Link to comment Share on other sites More sharing options...
Daeron Posted May 2, 2007 Share Posted May 2, 2007 a laser pointer can be of great assistance trying to track down a pinhole leak.. Quote Link to comment Share on other sites More sharing options...
naviathan Posted May 2, 2007 Author Share Posted May 2, 2007 A laser pointer? This is a new one on me, how does that work? Quote Link to comment Share on other sites More sharing options...
gjc5500 Posted May 2, 2007 Share Posted May 2, 2007 You point the lazer pointer around the areas you think are leaking. since you cant see the lazer until it hits an object, it will show up on small amounts of steam. so if its shooting a stream of steam out that you cant see, the lazer will show up on it. correct? Quote Link to comment Share on other sites More sharing options...
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