LOTS of great ideas here. I know because I've tried most of them lately. I've been fighting a major problem with coolant loss and over heating in a (don't hurt me) 3.0 V6 Toyota in my 93 Camry. I did a leak-down test, did a sniffer test for exhaust g***es in the coolant while running (thanks to fellow HAMBer 'Dammit' and his diagnostic equipment), changed the water pump, flushed the system, changed the thermostat, changed rad caps (darn thing runs 17psi and has two rad caps) and changed radiator. Oh yes, I also checked the cooling fan. Get this: some 92-93 Camrys have a hydraulic cooling fan that runs off of the power steering system. Seriously. The problem was an air pocket not bled out properly after I changed a piston (which was damaged by overheating with the previous owner) and re-***embled. The poor thing was getting a steam pocket. It was boiling up the coolant there. Jacked the ****** up in the front so the air could rise out and kept filling until it stopped. Took hours a little at a time. Then I found out that the new-fangled way to fill the cooling system is to use a vaccuum (no, not a shop-vac). They build a vaccuum in the system to 28 millibars or something and then flip a valve to let the coolant rush in with no air left in the system. Now this may not be your problem becuase mine was severe but guys, if you are like me and remember the OLD ways... those old ways don't always cut it on the new cars. New ways are needed. Unreal how complicated filling the cooling system has become. The smell of coolant can be coming from under the hood or in the cab from the heater core. Not easy to find unless you can (like was suggested) block off the heater for a while to eliminate that. Once the engine is warm enough to open the thermostat, turn the vent on recirculate instead of fresh air and crank up the fan. If the smell is gone then it probably isn't in the heater core. Turn it on fresh air and it gets air from the front of the vehicle which means under the hood air. If you smell it then... you have issues under the hood (the car, not you). Good luck.
My father's new Buick was doing the same thing. His had a pin hole in the very bottom of the recovery tank. But neither of us could see anywhere where it was leaking. The Dealer fixed it as is was only a year and a half old. They said sometimes they leak in the seams where they are molded And it's fairly common. I'd dump a jug of stop leak in it, and watch it for a while, and see if it gets better, as it looks as if you have covered the bases already.
I talked to the shop today that did the machine work on the engine.He told me in his 30 years of experience if an engine is leaking antifreeze into the oil at the rate of a 3 cups to a quart between oil changes the oil would be the typical brown mess.The oil in my my engine stays really clean even after 2000-3000 miles.So I doubting any internal cracks or intake manifold water p***ages leaking into the engine. One guy here mentioned in a PM he had a similar problem with a SBC.Turned out to be a slight casting defect in the head that was seeping a little coolant in the exhaust port after the valve. I'm gonna pump up the radiator testor again and let it sit for awhile to see if I can spot any external leaks.Thanks for all your suggestions........
I bought a brandy new pressure tester instead of the leaky one I was using.Pumped it up 20 psi on a cold engine,let it sit for an hour.Went back and checked,the pressure had only dropped 1/2 psi...but....a close inspection with a bright light and there's a slight seepage. Both heads,between the first and second headbolt from the front.Not seeping past the head bolts but between the headgasket and head on one side and the headgasket and block on the other side.Just a drop or two but it's there.Like some of you said,the coolant was evaporating before I could see it and that must be the faint coolant odor I smell inside the car occasionally. So....I'm figuring it's a very small leak,not going inside the engine or into the oil..........I've had the heads off once allready,don't wanna pull them right now........so.....you think use a coolant sealer? And worry about it during the winter when the car isn't driven.
Obviously doesn't sound internal in nature. I would check for weeping out of the weep hole on the water pump. If you have the green, just change the pump anyway since the engine had a problem before it was worked on and the pump was re-used. Everything I have read in this thread so far point to the water pump, very small leak around the seal, mostly evaporating but occ***ionally enough for a little stream to vaporize and you to get a whiff of the coolant. I'd change the pump out of spite, but that's me...
The pump shows no sign of leakage.I've been told by good mechanics that a drop or two on occasion from a good water pump is not a good enough reason to change it,whatever. I didn't mention it in this post that this 1990 305 roller cam block was decked .040 to get the pistons at .005 below deck.I got the dis***embled short block from a local machine shop that has done quality work for me in the past.A customer didn't pay the bill,so he sold me the block and parts for cost.The original build was for some low buck circle track cl*** where you must use stock parts as in pistons and lifters.But shaving the blocks and heads for compression is ok.The heads I had and they are only milled .010. So maybe milling .040 off the deck on one of these thin casting 305's is enough to create minute coolant seeps that don't matter on a water only cooled 25 lap engine.The shop says he's done quite a few 305's decked .040 with no problems.Leave it to me to have the one in thousand that will have a problem.At any rate this lowly 305 runs a lot better than a 305 should run....so..........treat it like a sore **** and don't **** with it for now.
I'm glad it wasn't a problem. My 1990 350 in my truck had a problem with the heater hose fitting in the intake p*** side rear. It was a popular problem back then for the SBC. If it hasn't been replaced keep an eye on it. We found my leak with the good old pressure tester. A can of Bars leak might be in order to stop the small oozing. There are other brands but Bars leak was the cats meow in the 60s so I stick with what works for me. It's not for larger leaks but it will stop the tiny ones.
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