2009 Lexus RX350, it failed the pressure test but we still couldn’t figure out where the leak is. He tested the head gasket it came back inconclusive, we can look into this further but it’s going to be even more expensive. It’s not in the oil, there’s no white smoke, I haven’t noticed external leaks, not in the transmission fluid either.
First started a little over a month ago when I noticed the reservoir was empty when we were traveling. We decided to do a radiator flush and bled the system then continued to check it until we could make it back home to the mechanic. It never leaked again and he told me to just take it home and keep an eye on it. Yesterday I went to check the coolant for the first time in 3 days (I haven’t driven much) and the reservoir was empty and the radiator is super low. I’m going to refill it and take it in but I’m unsure what the issue could be and where this could be going?? Anyone have other ideas to check?
Chech between the sparkplugs , some enginew have water seals that can go bad unoticed.
2010-2015 had issues with the pick up tube in the coolant overflow reservoir bottle.
Have you checked the inside the combustion chamber?
There is a metal coolant pipe that connects to the water pump with an o ring, and the pipe then runs under the intake manifold through the intake valley to the transmission end of the engine, where the pipe connects to coolant hoses. These can leak there. You might, possibly be able to check for dried coolant residue at the transmission end of this pipe, but it’s gonna be really hard to see without removing the intake.
A blown head gasket is also a very real possibility, it should be detectable by pressure testing the system.
Only part of cooling system not checked in a leak down test is the radiator cap.
Take spark plugs out… look in the cylinder and see if it looks like it’s steam cleaned indicator of blown head gasket… also how does your oil level look
Get a new mechanic.
When it’s hot have you noticed any hoses swelling? If s thermostat gets stuck the coolant will super heat while stuck inside the hose causing it to expand like a balloon. This.could lead to a pinhole or tear which will spray coolant everywhere.
Just another idea, happened to me once, would also cause a fail in pressure test.
Thank you everyone for the advice! I have several good starting points now before the dreaded head gasket repair if that’s what we need. After I posted this I realized that there is a white chalky residue all over the engine, that was actually dried coolant. I just didn’t question it before with the snow and salt on the roads. So it definitely is going somewhere externally, just need to find where it’s coming out of.
Couldn’t leave the house today but planning on getting more coolant & test strips before taking it into the mechanic tomorrow. Then a new radiator cap for the hell of it as it’s probably never been changed so might as well try the easiest thing first. Really hoping it’s an easy fix but prepared for the worst lol.
Bad radiator cap won’t hold pressure and overflows the reservoir which dumps it on the ground.
I’m having the same issue. I replaced the radiator cap so we’ll see if that helps.
Old cap . You can see where it ran down the rubber hoses
Get some UV dye with a black light.
If you can’t find a leak then it’s most likely going out the exhaust.
Easiest way to test that you could do now is smelling the exhaust. Coolant will make it smell sweet
Test the radiator cap. A defective cap can actually pump coolant out of the system, and it’s a very easy item to overlook when chasing a coolant leak.