Coolant leaking fast, not sure where it is going

Roy,

Is there anything else I can check before going straight to testing?

Hey,

I squeezed in a last minute appointment (somehow) with my mechanic and he took a look at it. He looked over the engine, found nothing but a small puddle of oil underneath the oil cap (told him the owner did an oil change last Thursday before he gave me the car, so he may have split some?). I told him about me losing about a full tank and a half of coolant. He opened the radiator cap and it was full, opened up my coolant cap and stuck in an exhaust meter thing which reads the levels for exhausts (he thought it was a bad head gasket) but it read -01 which was great. He lifted the car and looked at my thermostat housing, nothing there. Looked everywhere under the car, it was completely dry. He said if it was a heater core I would have smelt the coolant by now. The only issue he found was my transmission coolant line was leaking a little bit, but nothing about me losing coolant. Told me to keep an eye on my coolant levels to see if they change, but other than that he has no clue.

Note: when he did the exhaust test for my coolant cap area, he didn’t have the car running. Could that have been a false negative for the emissions test?

I’m at a loss. He saw nothing. Not from my water pump, coolant, radiator, thermostat. I’m still worried about it leaking coolant into my oil, mainly because I feel like the emissions test didn’t work properly.

Does any of this sound right?

Roy,

My oil looks fine, from what I can tell at least. Is there anything I can do to show you things? I can take pictures of my oil cap, anything you need. I’m not sure if there’s anything else you can help with. I told him go ahead and buy those parts for the transmission cooler lines, but I don’t want to spend $200 fixing that if there is a leak that needs to be fixed. My car runs fine, coolant levels are a steady 185-190, shifts perfectly, etc.

I’m completely lost. Do you have any links from Walmart/AutoZone/O'Reillys where I can get a cheap test kit to test my coolant, if that works?

Roy,

Yes, but if I’m losing that much coolant then wouldn’t it be bad? I’ll keep monitoring my levels and see if they drop again. I’ll go out and check soon as I just drove 27 miles.

He said if I bought it and it had no coolant, it would go through that much to fill whatever it fills. Is this correct?

Also, are you saying that if I bought dye, put it in the coolant and checked my dipstick, I wouldn’t see any under UV light?

Thank you so much Roy.

Edit: I’m not sure what he used. It didn’t look like a leak down tester from the google pictures. It was a long metal rod with a big spring around it, he shoved it as far as he could down there. Then it linked up to a small handheld computer that read (I believe) 2 levels, one read -01.

Edit #2: realized you weren’t talking about him using a leak down tester.

Roy,

Thank you. I need to drive to Walmart tonight, so I will drive and check my levels. Was he right about the “if you bought the car and the coolant was empty, it could have gone through a tank and a half to fill what it needed to”?

I’ll keep you updated!

Roy,

Got to work this morning from a 27 mile drive and checked my coolant when it got cold. I’m down about 3/4 an inch, called the mechanic. Asked him about the false negative and he said he’s never seen that before with his test. If it’s not a bad head gasket, what the heck else could it be?

Will this work?

Roy,
What is this part on my vehicle? Right in the middle of the engine, in the front.

Roy,
Sorry about that. The big black thing shaped like an L that looks like it has a small leak.

Roy,

I have an appointment tomorrow at 9:00 AM with the mechanic to do more tests, but I have a quick question. My coolant hasn’t gone down in 2 days, but it seems like my oil dipstick is awfully high. Would it “stop” leaking into the engine when it reaches a certain capacity, or would it keep leaking until the point of overfill? Spilling out of my dipstick tube? I’m just having my hopes up that it’s a bad reading, maybe oil from the tube is making the stick wet?