Hey thezentree - odd thing, I noticed a situation similar to yours a couple of weeks ago. This morning, I went out and did my fluid checks before going out and about. The reservoir was empty, and I couldn't see coolant in the radiator under the cap. It took about 2 cups of coolant mix to top off the radiator, and the other two cups I had mixed up went into the reservoir, going a little above the full line. So, I'd lost a little less than a quart of coolant.
Where did it go? ATF looks happy, oil looks happy, no white steam coming out of the tailpipe, no obvious leaks dripping off the undercarriage, no puddles or stains on the pavement, no coolant leaking out of the lines to the rear seat heater. Weird.
A little later in the day, after driving around a bit, I popped the hood in a parking lot and my chica and I gave it a good look. nothing. A fellow T4R owner drove by, stopped, asked if we were ok. We 'splained. He leapt out, pointed his flashlight straight down behind the alternator toward the forward shield/pan thingy, and sure enough, it was wet with what looked like coolant from that distance. "Probably the water pump," he said. We chatted for a bit, and off he went. We're imagining that the leak is slow enough and happens when the truck is running, so it blows off while driving.
We have a receipt for water pump, timing belt, spark plugs, and some other stuff from a hefty 90K service bill. We're at 141K now. When we bought the truck at 114K miles, I checked the spark plugs and discovered that they were single electrode, wrong spec, and nearly gone. I replaced them with proper stuff. This got me thinking that the shop that did the work probably didn't use good parts in general, and may not have done good work putting it all back together. The truck has consistently run hot at 204-207 (ScanGauge II), suggesting a possible improper thermostat or proper thermostat with jiggle valve in the wrong position. There has been a slightly unpleasant sound coming from what I think may be a bearing in the vicinity of the timing belt idler pulleys and water pump. So, who knows what the shop didn't do right during the big service if they couldn't get the sparkplugs right?
Our awesome tool guy - Tim - on this forum posted this vid:
https://www.youtube.com/watch?v=vHC46ypHxWc&frags=pl,wn. Check it out at 56:50 and you'll see him pulling the water pump off and discovering that the previous replacement did not include the proper gasket. Could be your situation and mine.
So, now I'm looking at cost-risk-benefit for doing the job myself or finding someone I think I can trust to do it. Also, gonna refresh every wear item on the way in to the water pump with OEM since the bulk of the money is in time spent - radiator, timing belt, tensioners, idler pulleys, crankshaft oil seal, thermostat, water pump, drive belts, and whatever else looks tasty. Chica's lost interest and said something like, "fix the Snoop." Marching orders... First, I have to confirm the ooze in the pan is coolant, and that it's coming from the water pump area.
tim
ps, I was on the verge of ordering Bridgestone Dueler A/T Revo 3s when this popped up. Arrgh! Snoop's new shoes are delayed.
